The Enigma of Yersinia enterocolitica biovar 1A

Introduction

Yersinia enterocolitica, an important food- and water-borne enteric pathogen is known to cause a variety of gastrointes-tinal problems. Most commonly it causes acute diarrhea, terminal ileitis, and mesenteric lymphadenitis (Bottone, 1999). Blood transfusion associated septicemia due to Y. enterocolitica has been reported to have high mortality (Leclercq et al., 2005). The organism is extremely hetero-geneous biochemically, serologically, and pathogenically. Currently, it is represented by six biovars namely 1A, 1B, 2, 3, 4, and 5. The biovar 1B strains are highly pathogenic whereas biovars 2–5 have moderate to low pathogenicity. Their pathogenicity is attributed to a virulence plasmid termed pYV (plasmid for Yersinia virulence) (Cornelis et al., 1998) and several chromosomal determinants (Revell and Miller, 2001). Contrary to this, biovar 1A strains lack pYV plasmid and the major chromosomal determi-nants of virulence. Consequently, biovar 1A strains have generally been regarded as avirulent. Nevertheless clinical, epidemiological and experimental studies have implicated them in disease (Tennant et al., 2003). The present review critically analyses data to assess these contradictions and discusses future directions, which need further exploration to unravel the enigma of Y. enterocolitica biovar 1A.

Ecology and host range

The biovar 1A strains of Y. enterocolitica are distributed globally. These have been isolated from asymptomatic and symptomatic humans. Biovar 1A strains have also been isolated from birds, fish, insects and a wide range of mammals such as cattle, sheep, rodents, and pigs. Y. ente-rocolitica biovar 1A was the predominant biovar isolated from both livestock and humans during a national survey in Great Britain in 1999–2000 (McNally et al., 2004) and diarrheic patients in Finland in 2006 (Huovinen et al., 2010). These have also been isolated from a wide vari-ety of environmental niches such as soil, water sources (including fresh water such as rivers, lakes, well water, and waste water), and various foods viz. raw and pasteur-ized milk, pork, packaged meat, seafood, and vegetables (Tennant et al., 2003).

Serological and molecular heterogeneity

Y. enterocolitica biovar 1A is quite heterogeneous sero-logically though molecular typing revealed only limited genetic heterogeneity.

Critical Reviews in Microbiology, 2010, 1–15, Early Online

Address for Correspondence: Jugsharan S. Virdi, Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi–110021, India. E-mail: [email protected]. Ph: + 91-11-24110950. Fax: + 91-11-24115270

R E V I E W A R T I C L E

The Enigma of Yersinia enterocolitica biovar 1A

Neeru Bhagat and Jugsharan S. Virdi

Microbial Pathogenicity Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Jaurez Road, New Delhi-110021, India

AbstractYersinia enterocolitica, an important food- and water-borne enteropathogen causes acute diarrhea, terminal ileitis, and mesenteric lymphadenitis. It is represented by six biovars (1A, 1B, 2-5). The biovar 1A strains are generally regarded as avirulent as they lack pYV plasmid and major chromosomal virulence genes. Despite this, some biovar 1A strains produce disease symptoms indistinguishable from that produced by known pathogenic biovars (1B, 2-5). Suggested prospective studies to understand pathogenic potential of biovar 1A should focus on role of insecticidal toxins, urease, protease, superoxide dismutase, and host responses. These studies should also take into account the clonal groups of biovar 1A.

Keywords: Biovar 1A; virulence-associated genes; heterogeneity; pathogenicity; clonal groups

(Received 19 May 2010; revised 23 June 2010; accepted 02 July 2010)

ISSN 1040-841X print/ISSN 1549-7828 online © 2010 Informa Healthcare USA, Inc.DOI: 10.3109/1040841X.2010.506429 http://www.informahealthcare.com/mcb

Critical Reviews in Microbiology

2010

00

00

000

000

19 May 2010

23 June 2010

02 July 2010

1040-841X

1549-7828

© 2010 Informa Healthcare USA, Inc.

10.3109/1040841X.2010.506429

MCB

506429

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

http://informahealthcare.com/doi/abs/10.3109/1040841X.2010.506429

2 Bhagat, and Virdi

Somatic (O) and Flagellar (H) Antigens

More than 75 O-antigens have been described in Y. ente-rocolitica and “Y. enterocolitica-like” species (Wauters et al., 1991). Thirty distinct O-antigens have been identi-fied in Y. enterocolitica. The biovar 1A strains alone are represented by more than 17 distinct O-antigen types (Table 1). Among these, O:5, O:6,30, O:6,31, O:7,8, O:10, and non-agglutinable (NAG) strains are most common. Some O-antigens like O:3, O:5,27, O:8, and O:9 occur both in biovar 1A and the known pathogenic biovars (1B, 2-5). In such cases, flagellar (H) antigen typing may be used to distinguish the strains. Some biovar 1A strains possess a number of H-antigens, for example, strains of serotype O:6,31 have up to 13 H-antigens and O:5, O:6,30, and O:7,8 serotypes have up to 15. The H-antigens of biovar 1A strains are more diverse compared to that of biovars 1B and 2-5.

Among biovar 1A strains, O-antigen structure of O:6,31, O:7,8, O:10, O:11,23, O:11,24, O:19,8, and O:28 has been determined (Skurnik, 2004). Interestingly, the O-antigen structure of O:7,8 and O:19,8 is similar to that of serotype O:8 which belongs to the highly pathogenic biovar 1B. The genetic organization of these antigens, except the serotype O:5, has not been determined as yet.

Genetic heterogeneity

Y. enterocolitica strains are classified into Y. enterocolitica subsp. enterocolitica and Y. enterocolitica subsp. palearc-tica based on 16S rRNA gene sequence (Neubauer et al., 2000). The majority of the Y. enterocolitica biovar 1A isolated from different countries has been identified as Y. enterocolitica subsp. palearctica (Floccari et al., 2003; Kotetishivli et al., 2005; Neubauer et al., 2000; Sachdeva and Virdi, 2004; Sihvonen et al., 2009).

Molecular typing using pulsed-field gel electrophore-sis (PFGE) (Najdenski et al., 1994), randomly amplified polymorphic DNA (Rasmussen et al., 1994), entero-bacterial repetitive intergenic consensus (ERIC)/PFGE (Falcao et al., 2006), and comparative phylogenomics (Howard et al., 2006) showed Y. enterocolitica biovar 1A to be quite heterogeneous. However, in majority of these studies, genotyping data was not analyzed by cluster

analysis. More recent studies in which cluster analysis was carried out revealed that Y. enterocolitica biovar 1A has only limited genetic heterogeneity (Gulati et al., 2009; Sachdeva and Virdi, 2004). Repetitive extragenic palindromic (REP)-/ERIC-PCR genotyping of biovar 1A strains belonging to diverse serotypes isolated from different sources and geographical regions clustered these into two clonal groups (Sachdeva and Virdi, 2004). This was reiterated by 16S–23S intergenic spacer- and gyrB-RFLP (Gulati and Virdi, 2007). Multilocus enzyme electrophoresis clustered biovar 1A strains into three to four groups (Dolina and Peduzzi, 1993; Mallik and Virdi, 2010). Fluorescent amplified fragment length polymor-phism (FAFLP) (Fearnley et al., 2005), amplified fragment length polymorphism (AFLP) (Kuehni-Boghenbor et al., 2006) and multilocus variable-number tandem repeat analysis (MLVA) (Gulati et al., 2009) grouped biovar 1A strains into two to four groups.

Other important insights obtained from genotyping studies revealed that clinical serotype O:6,30–6,31 strains constituted a discrete cluster separate from the aquatic serotype O:6,30-6,31 strains (Gulati and Virdi, 2007; Sachdeva and Virdi, 2004) indicating that aquatic biovar 1A strains might constitute an independent reservoir. It was also hypothesized that aquatic serotype O:6,30–6,31 strains constituted the ancestral strains from which clinical serotype O:6,30-6,31 strains originated by host adaptation and genetic change (Gulati and Virdi, 2009; Mallik and Virdi, 2010). Furthermore, it was also shown that distribution of virulence-associated genes in biovar 1A strains correlated with the clonal groups (Bhagat and Virdi, 2007). The identification of clonal groups may provide a convenient handle to circumvent the problem posed by the diversity of the strains isolated from humans, animals and food. It would be worthwhile to assess the pathogenicity of biovar 1A strains from the point of clonal groups rather than the source of isolation.

Pathogenicity

Association with clinical disease

The clinical disease with which Y. enterocolitica biovar 1A has been reported to be associated most commonly is gastroenteritis, and rarely septicemia and reactive arthritis.

Studies from several countries across the globe have reported isolation of Y. enterocolitica biovar 1A from stools of diarrheic humans (Table 2). In some of these studies, bio-var 1A strains were isolated in significant proportion from patients with no other etiologic agent of diarrhea (Bissett et al., 1990; Greenwood et al., 1975; Onyemelukwe, 1993; Sulakvelidze et al., 1996). These observations are further supported by case-control studies, which are summarized

Table 1. Different O-antigenic types and H-antigens detected in Y. enterocolitica biovar 1A.

Biovar O-antigen type (H-antigen)*

1A O:5 (b, c, d, e, i); O:6,30 (a, b, d, g, i); O:6,31 (b, c, d, e, i); O:7,8 (d, e, f, g, h); O:7,13 (b, c, e, f, k); O:10 (n); O:14 (m); O:16 (b, c, d, e, i); O:16 (z); O:19,8 (b, d, e, i, k); O:36 (n); O:41,42 (b, d, e, g, i); O:41,43 (n); O:63 (z

2); O:65 (z

4);

O:66 (z 5); O:72 (NT)

O:4, O:21, O:22, O:25, O:37, O:46, O:47, O:57, NAG* Wauters et al. (1991).NT: Not tested; NAG: non-agglutinable.

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

Yersinia enterocolitica biovar 1A 3

Table 2. Isolation of Y. enterocolitica biovar 1A from diarrheic patients.

Period/ Year Country Biovar 1A strains# Serotypes (n) Reference

1963-1975 Belgium 23 of 1781 O:6 (14); O:7,8 (2); O:10 (3); O:14; O:16 (2); NAG Vandepitte and Wauters 1979

1966-1972 Canada 13 of 256 O:5; O:6,30 (6); O:12,25; O:34; NAG (4) Toma and Lafleur 1974

1966-1977 Canada 106 of 977 O:4,33 (2); O:5 (7); O:6,30 (25); O:6,31 (4); O:7,8 (2); O:7,13 (5); O:8,19; O:11; O:12,25; O:16 (3); O:16,29 (3); O:34 (3); NAG (49)

Toma et al. 1979

1967-1977 France 21 of 169 O:6 (11); O:7,8 (3); O:10K1 (3); O:11; O:12; O:13,7; O:16 Alonso et al. 1979

1968-1975 USA 16 of 24 O:5 (5); O:6 (2); O:8; O:10 (2); O:11 (2); O:13 (3); O:16 Bissett 1976

1968-1977 USA 4 of 33 O:6 (2); O:11; O:13,7 Bissett 1979

1970-1980 USA 44 of 100 O:5 (2); O:5,27; O:6 (6); O:6,O:28; O:6,30; O:6,31 (2); O:7,8 (2); O:7,8,13 (3); O:7,13; O:11,13; O:11,23 (2); O:13,18 (2); O:14; O:19; O:19,O:16; O:34; NAG (16)

Kay et al. 1983

1972-1977 USA 25 of 68 O:5 (4); O:6 (5); O:7; O:19 (2); NAG (13) Quan 1979

1975-1977 Canada 36 of 157 O:5 (3); O:6,30 (6); O:6,31(3); O:7,8; O:8,19; O:10; O:13,7 (3); O:16; NAG (17)

Caprioli et al. 1978

1976-1977 New York 14 of 52 O:5 (2); O:6,31 (3); NAG (9) Shayegani et al. 1979

1976-1980 USA 46 of 120 O:3; O:4,33 (3); O:5 (4); O:6,31 (9); O:7,8 (4); O:12; O:12,25 (2); O:14; O:18; O:25 (3); O:31; NAG (16)

Shayegani et al. 1981

1978 S. Africa 2 O:5; O:6 Robins-Browne et al. 1979

1978-1983 Japan 43 of 161* O:5; O:6; NAG‡ Fukushima et al. 1985

1978-1985 Italy 131 of 403 O:4 (7); O:4,10,16 (10); O:4,16 (4); O:4,32 (4); O:4,33 (6); O:5 (6); O:6 (23); O:7,8 (18); O:10,16 (4); O:10K

134 (9);

O:16 (4); NAG (6); others (30)

Chiesa et al. 1987

1978-1989 USA 125 of 277 O:5 (22); O:6,30 (26); O:6,31; O:7,8 (15); O:12,25 (5); O:12,26; O:7,13 (9); O:34 (2); O:36 (5); O:41,42 (13); O:41,43; O:46 (2); O:50,51; O:52; NAG (21)

Bissett et al. 1990

1978-1989 Italy 3 of 10 O:7,8,13,19; O:39,41,42,43; O:49,51 Nanni et al. 1991

1979 Czechoslovakia 16 of 57 O:5 (9); NK (7) Aldova and Laznickova 1979

1979-1989 Belgium 1428 of16 226 NT Verhaegen et al. 1991

1980/1978 USA 5 of 238* O:5 (2); O:6,30; O:7,8 (2); NAG Weissfeld and Sonnenwirth 1980

1980-1981 USA 2 of 5 O:6,30 (2) Marymont et al. 1982

1981-1990 Republic of Georgia

53 of 84 O:1,2,3 (3); O:5 (13); O:6 (2); O:6,30 (8); O:6,31 (2); O:7,13 (2); O:10 (2); O:10,46 (8); O:14; O:16; O:38 (3); O:41,42 (2); O:41,43 (2); O:42,43 (2); O:65; O:78

Sulakvelidze et al. 1996

1981-1985 Italy 1 of 35 O:6‡ Mingrone et al. 1987

1982-1985 Canada 120 of 127 O:5 (16); O:6,30 (16); O:6,31 (2); O:7,8 (17); O:7,13 (13); O:16 (2); O:16,29; O:34 (4); O:41 (2); O:41,42 (8); O:41,43 (8); O:46 (9); O:52; NAG (21)

Noble et al. 1987

1982-1991 The Netherlands 28 of 206* O:6,3 (4); O:7,8 (12); NAG (12) Stolk-Engelaar and Hoogkamp-Korstanje 1996

1983 Finland 2 of 46 O:6; O:7 Skurnik et al. 1983

1984 Bangladesh 1 O:7,8 Butler et al. 1984

1984-1993 UK 1246 of 1390 NT Greenwood 1995

1986 UK 26 of 52 O:5,27 (10); O:6,30 (5); O:7 (2); O:34; NAG (8) Lewis and Chattopadhyay 1986

1986-1992 Canada 23 of 79* O:5; O:6,30; O:7,8; NT‡ Cimolai et al. 1994

1987 UK 72 of 77* O:6,30; O:7; NT‡ Greenwood and Hooper 1987

1988-1991 Eastern Nigeria 3 of 9 O:6 (3) Onyemelukwe 1993

1988-1991 Georgia 2 of 76* NAG (2) Metchock et al. 1991

1988-1993 New Zealand 21 of 918 NAG (21) Fenwick and McCarthy 1995

1991 Australia 24 of 100 O:5 Pham et al. 1991

1991-1996 The Netherlands - O:5 (7.5%); O:6 (5%); O:6,30 (1.5%); O:7,8 (4%); O:7,13 (1%)

van Pelt et al. 2003

1995-2000 US 74 of 126 NK Scheftel (2002)

Table 2. continued on next page

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

4 Bhagat, and Virdi

in Table 3. The most noteworthy among these is the pro-spective case-control study of infants with diarrhea, in which significant association of Y. enterocolitica biovar 1A with diarrhea was discerned (Morris et al., 1991). A sig-nificant association between gastrointestinal disease and biovar 1A strains has been shown in other case-control studies also (Ebringer et al., 1982; Marks et al., 1980; Snyder et al., 1982; Verhaegen et al., 1998). In a recent case-control study, majority (65%) of Y. enterocolitica isolated from diarrheic patients belonged to biovar 1A (Huovinen et al., 2010). One study however reported no association between infection with Y. enterocolitica biovar 1A and the gastroin-testinal symptoms (deWit et al., 2001). Such contradictory findings bring out the enigmatic nature of Y. enterocolitica biovar 1A. Another evidence of potential pathogenicity of Y. enterocolitica biovar 1A strains is their association with clinical disease indistinguishable from that caused by the known pathogenic biovars as reported by Swiss National Reference Laboratory for Foodborne Diseases (Burnens et al., 1996), and more recently by Scheftel et al., (2002). A single fatal case of diarrheal illness in an 8-month-old child from whom Y. enterocolitica serotype O:7,8 and Shigella boydii were isolated post-mortem was reported by Butler et al. (1984).

Seto and Lau (1984) described four patients from whom Y. enterocolitica biovar 1A was isolated from blood. This is the only report in which biovar 1A strains have been implicated in septicemia. All four patients had underlying illnesses such as metastatic neoplasms or burns. The isolates were of serotype O:17 in three patients and a non-typeable strain in one. Unlike sep-ticemia due to pathogenic biovars in which mortal-ity is quite high, all four patients recovered fully after antibiotic therapy.

In a case-control study, Y. enterocolitica biovar 1A was isolated from 4% of the 86 patients with rheumatoid arthritis, and 4.5% of the 140 patients with ankylosing spondylitis (Ebringer et al., 1982). These isolates were either non-typeable or belonged to serotype O:6,30. Some patients with ankylosing spondylitis from whom biovar 1A strains were recovered in fecal culture had exacer-bations of ocular and spinal joint symptoms (arthritic disease), suggesting that Y. enterocolitica biovar 1A may play role in initiating or exacerbating existing disease. A biovar 1A strain belonging to serotype O:6 isolated from the stools of a patient was also implicated in arthritis (Skurnik et al., 1983).

Outbreaks

Four well-known outbreaks, two each of food-borne and nosocomial infections have been reported to be caused by Y. enterocolitica biovar 1A.

The first food-borne outbreak involving two epi-sodes was reported from a district hospital in England (Greenwood and Hooper, 1990). In the first episode, Y. enterocolitica biovar 1A serotype O:10K was recovered over a period of two months from 19 pediatric inpa-tients. The index patient was a one-year-old female who did not carry any other causative agent of diarrhea namely Salmonella, Shigella, Campylobacter, rotavi-rus, and enteropathogenic Escherichia coli. However, one-fourth of the patients also excreted non-typeable Y. frederiksenii. Subsequently, within one month, Y. enterocolitica bioserovar 1A/O:6,30 was isolated from another 17 hospitalized children. The source of this infection was traced to pasteurized milk (Greenwood et al., 1990).

Period/ Year Country Biovar 1A strains# Serotypes (n) Reference

1992-1994 Switzerland 26 of 71 NK Burnens et al. 1996

1996-2003 California 4 of 22 NK Shin et al. 2005

1999-2000 Great Britain 87 of 164 O:3; O:4,32 (3); O:5 (13); O:5,27; O:6,30 (11); O:6,31 (4); O:7; O:8 (5); O:10K1 (2); O:13,7; O:19,8 (6); O:41,43 (6); O:36 (2); O:46; O:48; O Rough; NAG (28)

McNally et al. 2004

2000-2003 India 36 O:6,30 (19); O:6,30-6,31 (8); NAG (9) Singh et al. 2003

2000 Canada 54 of 655 O:5 (9); O:5,27; O:6,30 (3); O:6,31 (2); O:7,8 (3); O:7,13 (6); O;41,42 (6); O:41,43 (7); NT (5); NK (12)

Demczuk et al. 2001

2001 Canada 69 of 804 O:5 (5); O:5,27 (2); O:6,30 (4); O:6,31 (2); O:7,8 (11); O:7,13 (3); O:34; O:36; O:41,42 (5); O:41,43 (3); NT (9); Rough (3); NK (20)

Demczuk et al. 2004

2004 Australia 24 of 96 O:5 Ashbolt et al. 2005

2006 Finland 302 of 386 O:5 (42); O:8 (56); NK (204) Sihvonen et al. 2009

Modified from Tennant et al. 2003.#: Strains from total number of isolates recovered.* Number of patients positive for biovar 1A strains out of the total patients tested/positive.Number in parentheses indicate the number of isolates recovered; if only one isolate of a serotype was recovered, it is not indicated in parentheses.NAG: non-agglutinable; NK: not known; NT: not tested.The serotypes which were recovered in maximum numbers are indicated in bold.

Table 2. Continued.

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.


Tabl

e 3.

Cas

e co

ntr

ol s

tud

ies

rep

orti

ng

asso

ciat

ion

of Y

. en

tero

coli

tica

bio

var

1A w

ith

dia

rrh

ea/g

astr

oin

test

inal

sym

pto

ms.

Stu

dy

Per

iod

Cou

ntr

yIm

por

tan

t ch

arac

teri

stic

s of

the

stu

dy

Sero

typ

e (n

)#Te

sted

for

oth

er e

nte

ric

agen

t(s)

Ref

eren

ce

1967

-199

6B

elgi

um

9.5%

of t

he

stra

ins

bel

onge

d to

bio

var

1AN

TN

oV

erh

aege

n e

t al.

1998

1977

-197

8C

anad

a12

of 1

81 Y

. ent

eroc

olit

ica

stra

ins

belo

nge

d to

bio

var

1A is

olat

ed fr

om 6

364

child

ren

(ag

e ≤

18

yrs)

bu

t n

ot fr

om a

ny

of 5

45 a

sym

pto

mat

ic c

hild

ren

in a

p

rosp

ecti

ve s

tud

y

O:5

; O:6

,30

(4);

O:6

,31

(2);

O:7

,8

(3);

NA

G (

2)N

oM

arks

et a

l. 19

80

1977

-197

9U

SA74

str

ain

s of

Y. e

nte

roco

liti

ca w

ere

isol

ated

, b

iova

r 1

stra

ins

from

70

per

son

sO

:7,8

(4)

; NT

(4)

Cu

ltu

red

for

Salm

onel

la a

nd

Shi

gella

Snyd

er e

t al.

1982

1979

-198

0

Clin

ical

an

alys

is o

f 41

pat

ien

ts in

fect

ed w

ith

Y.

en

tero

coli

tica

, in

clu

din

g 33

per

son

s in

fect

ed

wit

h b

iova

r 1

stra

ins

that

wer

e as

soci

ated

wit

h

acu

te g

astr

oen

teri

tis

O:5

(4)

; O:7

,8 (

2); O

:10

K1;

NA

G

(3);

NT

(23

)N

o

1978

-198

0U

KC

ase-

con

trol

stu

dy

show

ing

sign

ifica

nt d

iffer

ence

in

isol

atio

n r

ate

of b

iova

r 1A

str

ain

s fr

om p

atie

nts

w

ith

dia

rrh

ea/g

astr

oin

test

inal

sym

pto

ms

and

h

ealt

hy

con

trol

s

O:6

,30

(5);

NA

G (

3), N

TSa

lmon

ella

on

3 o

ccas

ion

s; S

hige

lla

and

Cam

pyl

obac

ter

spp.

on

ce e

ach

Eb

rin

ger

et a

l. 19

82

1987

-198

9C

hile

Pro

spec

tive

cas

e-co

ntr

ol s

tud

y of

infa

nts

wit

h

dia

rrh

ea in

Ch

ile, s

how

ing

sign

ifica

nt a

ssoc

iati

on

of Y

. en

tero

coli

tica

bio

var

1A w

ith

dis

ease

O:6

; O:7

; O:7

,8 (

3); O

:10

(2)

Cam

pyl

obac

ter

jeju

ni i

sola

ted

from

on

e p

atie

nt

Mor

ris

et a

l. 19

91

1996

-199

9Th

e N

eth

erla

nd

sIs

olat

ed b

iova

r 1A

str

ain

s fr

om b

oth

pat

ien

ts a

nd

ag

e m

atch

ed c

ontr

ols

O:6

,31;

O:6

,30

(2);

NA

G; N

TSa

lmon

ella

, Shi

gella

, Cam

pyl

obac

ter,

E

. col

i, ro

tavi

rus,

ad

enov

iru

s,

Nor

wal

k-lik

e vi

rus,

inte

stin

al

par

asit

es a

nd

oth

ers

de

Wit

et a

l. 20

01

2006

Fin

lan

dB

iova

r 1A

str

ain

s ac

cou

nte

d fo

r 65

% o

f th

e to

tal

Y. e

nte

roco

liti

ca is

olat

esN

TC

amp

ylob

acte

r, S

alm

onel

la, S

hige

lla,

Cry

ptos

por

idiu

m, v

iru

ses

Hu

ovin

en e

t al.

2010

# Nu

mb

er in

par

enth

eses

ind

icat

es th

e n

um

ber

of i

sola

tes

reco

vere

d; i

f on

ly o

ne

isol

ate

of a

ser

otyp

e w

as r

ecov

ered

, it i

s n

ot in

dic

ated

in p

aren

thes

es.

NA

G: n

on-a

gglu

tin

able

; NT

: Not

typ

ed.

The

sero

typ

es w

hic

h w

ere

reco

vere

d in

max

imu

m n

um

ber

s ar

e in

dic

ated

in b

old

.

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

6 Bhagat, and Virdi

An outbreak of Y. enterocolitica gastroenteritis due to serotypes O:3 and O:6,30 (biovar 1A) was reported in the summer of 1987–88 from Australia (Butt et al., 1991). In order to investigate the source of Y. enterocolitica, authors examined 39 randomly selected pasteurized milk samples and isolated 11 Yersinia strains, including nine Y. enterocolitica and one each of Y. frederiksenii and Y. intermedia. Majority of the isolates was of sero-type O:6,30 and one each of serotypes O:5 and O:41,43. The outer membrane protein profiles of serotype O:6,30 isolates from humans and milk were similar, suggesting milk as the possible source of the outbreak. An outbreak due to Y. enterocolitica biovar 1A serotype O:6,30 was also reported by Barrett (1986).

Ratnam et al., (1982) reported first nosocomial out-break due to Y. enterocolitica biovar 1A belonging to serotype O:5, which involved nine patients admitted to a hospital in Canada. Although, on admission the index patient was asymptomatic, rectal swab culture from this patient following temporary colostomy showed presence of Y. enterocolitica serotype O:5. All except the index patient showed abdominal cramps and diarrhea of 2–3 days duration. The stool cultures of control population (hospital staff) were negative for both Y. enterocolitica and other commonly recognized enteric pathogens.

A biovar 1A associated nosocomial transmission between two adults was reported from U.K. (McIntyre and Nnochiri 1986). The index patient, an 81-year-old diabetic female with a 3-day history of diarrhea, inter-mittent abdominal pain, nausea and low-grade fever was admitted to the hospital. Within a short interval of 72 h, the patient on the bed opposite to the index patient who was admitted five weeks previously with hypother-mia showed similar clinical symptoms. Analysis of stool samples from both patients recovered Y. enterocolitica biovar 1A serotype O:6,30. Analysis of stool samples from several individuals in the hospital that included four other patients in the same unit, three patients in the same ward, and 41 staff members that were in contact with the case patients did not yield Y. enterocolitica.

Experimental evidence on biovar 1A virulence

Several experimental studies have reported detection of known or putative virulence-associated genes or deter-minants in strains of Y. enterocolitica biovar 1A. These are summarized in Table 4.

EnterotoxinY. enterocolitica is known to produce three types of heat-stable enterotoxins— YstA, YstB and YstC—and accordingly three genes (ystA, ystB, and ystC) have been identified (Ramamurthy et al., 1997). The known patho-genic biovars (1B, 2-5) produce YstA (Delor et al., 1990). YstC is rare and has been reported to be produced by

only a few strains of Y. enterocolitica (Huang et al., 1997; Ramamurthy et al., 1997).

Most biovar 1A strains produce YstB (Table 4) which has been inferred either from production of enterotoxin per se or detection of ystB gene (Bhagat and Virdi, 2007; Grant et al., 1998; Kot et al., 2007; Platt-Samoraj et al., 2006; Ramamurthy et al., 1997; Singh and Virdi, 2004). The proportion of enterotoxigenic biovar 1A strains has varied in different reports (Pai et al., 1978; Robins-Browne et al., 1993; Singh and Virdi, 2004; Takeda et al., 1992). The biovar 1A strains isolated from diarrheic humans and swine produced enterotoxin whereas those isolated from aquatic sources were not enterotoxigenic (Singh and Virdi, 2004). Evidence indicate that YstB plays a major role in the pathogenesis caused by Y. enterocolitica biovar 1A. These include (1) freshly isolated strains harboring ystB gene produce enterotoxin as shown by suckling mouse assay (2) minimum effective dose of purified YstB is 19.5-fold lower than YstA (0.4 pmol versus 7.8 pmol) (Okamoto et al., 1982) with potency identical to that of E. coli STh enterotoxin (3) enterotoxin is produced in vitro at 37°C under osmolarity and pH similar to that present in the human intestine (Paz et al., 2004; Singh and Virdi, 2004), and (4) no obvious ulcerative or inflammatory changes were evident on endoscopy in patients infected with Y. enterocolitica biovar 1A (Simmonds et al., 1987). However, not all strains that carried ystB gene produced enterotoxin (Grant et al., 1998; Singh and Virdi, 2004).

The genes encoding YstA and YstC have been detected only rarely in Y. enterocolitica biovar 1A (Falcao et al., 2006; Grant et al., 1998; Kwaga et al., 1992; Lee et al., 2004; Ramamurthy et al., 1997). In one study, the gene for YstC (rarest subtype) was detected in 2.2% of biovar 1A strains (Ramamurthy et al., 1997), while all other studies have reported it to be absent (Bhagat and Virdi, 2007; Grant et al., 1998; Singh and Virdi, 2004).

Adhesion, invasion, and escapeIn the pathogenic biovars, the chromosomal genes namely inv (invasin) and ail (attachment invasion locus) enable Y. enterocolitica to adhere and invade epithelial cells. Although inv gene is present in all biovar 1A strains (Table 4), it is non-functional (Pierson and Falkow 1990). However, in the study by Pierson and Falkow (1990), only four biovar 1A strains were investigated. In view of the diversity of biovar 1A strains isolated from human, animal and food this conclusion appears untenable and needs to be investigated with a larger number of strains. The ail gene has however been reported to be present only rarely in biovar 1A strains (Table 4).

The ability of Y. enterocolitica biovar 1A strains to adhere, invade and survive in cultured epithelial cells has been well documented (Grant et al., 1998; McNally et al., 2006; Singh and Virdi 2005). The isolation of some biovar 1A strains from extraintestinal sites of diarrheic humans

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.


(Bissett et al., 1990) further support their invasive abil-ity. Most biovar 1A isolates exhibited adherence to HEp-2 and CHO cells. The degree of adherence was dependent on cell type, and was independent of the source (clinical vs. non-clinical) of isolation of strains (Grant et al., 1998; McNally et al., 2006).

Following adhesion, biovar 1A strains invade cultured cells, albeit to a degree lower than that reported for patho-genic biovars (Lee et al., 1977; Schiemann and Devenish, 1982). Unlike adhesion, clinical and non-clinical biovar 1A strains differed significantly in their ability to invade. Clinical strains invaded HEp-2, CHO, and T84 cells

significantly more than the non-clinical strains (Grant et al., 1998; Singh and Virdi, 2005). Among non-clinical, strains of swine origin exhibited significantly more inva-sion than the aquatic isolates (Singh and Virdi 2005). Thus, a gradation in their ability to invade cultured cells has been discerned. In contrast, McNally et al. (2006) showed that 39 biovar 1A isolates from clinical and animal (cat-tle, sheep, and pig) sources showed no significant differ-ence in invasion. This contradiction might be attributed to genetic differences in the strains isolated in different parts of the world and needs to be investigated further. Both clinical and non-clinical biovar 1A strains invaded

Table 4. Detection of virulence-associated genes or factors in Y. enterocolitica biovar 1A.

Gene(s) orProtein#

Technique(s) used# Important observations Reference(s)

ystA DBH, P, SH Gene absent Delor et al. (1990); Durisin et al. (1998); Ibrahim et al. (1992); Robins-Browne et al. (1993)

Enterotoxin SMA ca. 50% of strains produced enterotoxin Pai et al. (1978)

ystA, ystB, ystC; enterotoxin CH, DBH, MP, P, SMA

ystB (78-100%); ystA (0-26%); ystC (0-2%). ca. 50% of clinical and swine isolates produced enterotoxin. No aquatic isolates produced enterotoxin

Falcao et al. (2006); Kot et al. (2007); Lee et al. (2004); Platt-Samoraj et al. (2006); Ramamurthy et al. (1997); Singh and Virdi (2004)

ystA, ail, inv, ML, enterotoxin, HEp-2 invasion

CH, SMA ystA, ail, ML (0%); inv (100%); invasion (1 isolate); enterotoxin (28.6%)

Morris et al. (1991)

ystA, ailC, inv, pYV, ML SH ystA and pYV (0%); ailC (30%); inv (98%); ML (0%)

Sulakvelidze et al. (1996)

ystA, ail, inv CH, DBH, SH, P ystA (3-14%); ail (3%); inv (100%) Falcao et al. (2006); Kwaga et al. (1992); Lee et al. (2004)

ystA, ystB, ail, yadA, virF P, SH ystA and ail (0%); ystB (80%); yadA (2%); virF (2%)

Thoerner et al. (2003)

ystA, ail, virF MP, DBH All strains were negative Harnett et al. (1996)

ystA, ail, virF, rfbC MP Genes absent Thisted Lambertz and Danielsson-Tham (2005)

ystA, ail, virF, yadA, myfA, irp1, ureC, ymoA

P Four strains carried only ureC and ymoA Gierczynski et al. (2002)

ystA, ystB, ystC, ail, myfA, ymoA, pYV P, SH ystA (0.9%), ystB (85%). ystC (0%), ail (7.2%), myfA (11.7%), ymoA (100%), pYV (0%)

Grant et al. (1998)

ystA, ail, inv, virF, yadA, V-Antigen P ystA, ail, virF, yadA, V-antigen (0%); inv (60%) Floccari et al. (2003)

ystA, ystB, ystC, ail, virF, hreP, sat, myfA, inv, tccC, fepA, fepD, fes, ymoA

P ystA, ystC, ail, virF (0%); ystB, hreP and sat (79%); myfA and fepA (44%); inv, fepD, fes and ymoA (100%); tccC (9%)

Bhagat and Virdi (2007)

ail, inv, pYV, virF, yadA CH, MP, P, SH ail (0-3.9%); inv (100%); pYV (0%); virF (0%); yadA (0%)

Burnens et al. (1996); Kot et al. (2007); Nakajima et al. (1992); Nilsson et al. (1998); Pierson and Falkow (1990); Platt-Samoraj et al. (2006); Robins-Browne et al. (1989); Thisted Lambertz et al. (1996)

hreP SH All positive under moderate stringency conditions

Heusipp et al. (2001)

myfA SH Gene absent Iriarte et al. (1993)

tcbA, tcaC, tccC SSH tcbA (21.7%); tcaC and tccC (23.6%) Tennant et al. (2005)

tcaA, tcaB1, tcaB2, tcaC P, SH Genes absent Bresolin et al. (2006)

Superoxide dismutase M Cu-Zn SOD present Howard et al. (2006)

fepA, fepD, fes P, SH Strain positive for the three genes Schubert et al. (1999)

The presence of genes in a group of strains is indicated as percentage in parentheses.# CH: Colony hybridization; DBH: dot-blot hybridization; M: microarray; ML: mouse lethality; MP: multiplex PCR; P: PCR; SH: southern hybridization; SMA: suckling mouse assay; SSH: suppression subtractive hybridization.C

ritic

al R

evie

ws

in M

icro

biol

ogy

Dow

nloa

ded

from

info

rmah

ealth

care

.com

by

122.

162.

152.

19 o

n 09

/30/

10Fo

r pe

rson

al u

se o

nly.

8 Bhagat, and Virdi

some CHO cells and spared others. Contrary to this, the pYV-cured Y. enterocolitica biovars 1B and 2 invaded the cells uniformly. In epithelial cells, the clinical biovar 1A isolates were localized within vacuoles suggesting that these strains probably employed novel mechanism to invade cells. Interestingly, within CHO cells, biovar 1A strains were shown to replicate more efficiently than biovar 2 strains (Grant et al., 1998).

In another study, prior incubation of a biovar 1A strain (serotype O:6,30) with cultured epithelial cells (HEp-2) lead to significant reduction in the attachment of Y. ente-rocolitica biovar 4 (serotype O:3) but failed to do so in vivo (Hussein et al., 2003). Recently, flagella have been shown to play role in the invasion of epithelial cells by biovar 1A strains (McNally et al., 2007).

Interestingly, both pYV-cured biovars 1B and 2 strains, and the biovar 1A strains were able to escape from the cultured epithelial cells (Grant et al., 1999). The clinical biovar 1A strains however exhibited a better ability to escape than the non-clinical biovar 1A strains.

Interaction with macrophages and polymorphonuclear leukocytes (PMNs)The ability of Y. enterocolitica biovar 1A to resist innate immune system has been investigated by its interaction with macrophages in vitro (Grant et al., 1999; McNally et al., 2006). It is well known that virulence plasmid (pYV) encoded Yops (Yersinia outermembrane proteins) by the pathogenic biovars provide protection against phagocy-tosis. Despite lacking pYV plasmid, the biovar 1A strains persist within macrophages suggesting presence of novel defense mechanism which needs to be investigated.

Interaction with IFN-γ activated murine macro-phages (J774), revealed that though the clinical and the non-clinical biovar 1A strains, and the pYV-cured Y. enterocolitica biovar 2 strain were phagocytosed to varying extent, the difference was not significant statisti-cally (Grant et al., 1999). However, strains obtained from symptomatic humans were significantly more resistant to killing by macrophages than strains isolated from non-clinical sources (Grant et al., 1999; Singh and Virdi, 2005). Besides murine macrophages, biovar 1A strains also persisted within cultured human macrophages (McNally et al., 2006). These authors also reported that biovar 1A strains isolated from pig and sheep persisted within mac-rophages to higher degree than biovar 1A strains isolated from human and cattle (McNally et al., 2006). The prob-able reasons that underlie such contradictory findings might be attributed to strain or host response differences. As with the epithelial cells, the clinical strains were local-ized within large vacuoles, and escape from macrophages did not involve cytolysis. The strains, which remained intracellular in HEp-2 cells, also remained so within macrophages and those, which escaped from HEp-2 cells, likewise escaped from the macrophages. Although, the

mechanism by which Y. enterocolitica biovar 1A strains resist killing by macrophages is not known, flagella have been shown to play a role (McNally et al., 2007).

As most biovar 1A strains were killed rapidly by PMN, sequestering and survival within macrophages seemed to protect them against destruction by PMNs and comple-ment (Grant et al., 1999).

Colonization of gut and infectionThe ability of Y. enterocolitica biovar 1A to colonize ileum and colon has been demonstrated in mice inoculated perorally with 109 cfu (Grant et al., 1998). The duration of colonization by clinical strains was significantly longer than that by non-clinical strains (up to 4 days vs. 0 day in ileum, and up to 10 days vs. 4 days in colon). Biovar 1A strains also colonized pig intestinal tissue in in vitro organ culture (IVOC) (McNally et al., 2006). However, peroral inoculation of rabbits or gnotobiotic piglets with biovar 1A strains of non-clinical origin (serotype O:5, O:6,30) did not produce any pathology (Pai et al., 1980; Robins-Browne et al., 1985; Une, 1977). Earlier, biovar 1A strains were shown to be avirulent, even when administered orally to adult mice pretreated with iron dextran or desferrioxam-ine (Robins-Browne and Prpic, 1985). However, yersiniae were cultured from liver and intestinal tissue homoge-nates when mice infected with Y. enterocolitica were sacrificed 40 days after inoculation (Schiemann, 1989). A biovar 1A strain of serotype O:6,30 isolated from the liver of an aborted lamb was reported to cause placentitis and abortion in pregnant ewes (Corbel et al., 1992).

Suggested prospective studies

Several virulence-associated determinants, which play role in the pathogenicity of other biovars of Y. enteroco-litica, have not been investigated in biovar 1A strains. These include insecticidal toxins, urease, host respon-sive elements, superoxide dismutase, and a host of other determinants. Besides the routine assays, namely detec-tion of virulence genes, use of experimental models and in vivo expression technology (IVET), it might be impor-tant to study the host responses to assess the pathogenic potential of Y. enterocolitica biovar 1A. These include expression of a variety of cytokines, and signaling mol-ecules following host-pathogen interaction. Furthermore, whole genome sequencing and comparisons of biovar 1A strains isolated from humans, animals, and environmen-tal sources would help provide a unifying hypothesis on the pathogenicity of biovar 1A strains.

Insecticidal toxin

Homologues of insecticidal toxin complex (tc) ele-ments namely tcbA, tcaC, and tccC were identified in

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.


Y. enterocolitica biovar 1A while elucidating genomic differences between clinical and food strains, and shown to play role in virulence (Tennant et al., 2005). The tc complex genes were more common in clinical than non-clinical (27% vs. 7–14%) biovar 1A strains. However, other genes of this family namely tcaA, tcaB1, tcaB2, and tcaC were not detected in biovar 1A strains (Bresolin et al., 2006). The tc gene complex of biovar 1A strain (Tennant et al., 2005) differs from that of biovar 2 strain W22703 (Bresolin et al., 2006).

An isogenic mutant for tc complex genes exhibited decreased ability to colonize ilea, ceca, and colon of perorally inoculated mice. This suggested the possible role of insecticidal toxin in persistence of bacterium in the gastrointestinal tract (Tennant et al., 2005). In Y. pes-tis and Y. pseudotuberculosis, this toxin is also active against cultured mammalian cells (Hares et al., 2008). The exact role of tc complex genes in the colonization of gut by Y. enterocolitica biovar 1A and the underlying mechanisms need further investigation.

Urease

In Y. enterocolitica, urease has been reported to enable biovar 1B and biovar 4 strains to survive the acidic pH of the stomach (de Koning-Ward and Robins-Browne, 1995; Gripenberg-Lerche et al., 2000; Young et al., 1996). Y. enterocolitica biovar 1A also produce urease and it is conceivable that it might contribute to their survival in gut. Recent work showed that Y. enterocolitica biovar 1A survived up to 2 h in pH 2.5 in vitro in the presence of urea (Bhagat and Virdi, 2009). However, no viable cells were recovered in the absence of urea. Further work using an isogenic urease mutant would elucidate the role of urease in the survival of Y. enterocolitica biovar 1A in acidic pH.

Another acidic environment encountered by Y. ente-rocolitica biovar 1A strains is within the macrophages, where these are known to survive (Grant et al., 1999). It would also be worthwhile to explore the role of urease in intraphagocytic survival of Y. enterocolitica biovar 1A.

Host Responsive Element P (HreP)

HreP of a family of subtilisin-kexin like proteases, is one of the host responsive elements (hre) which is expressed in vivo early during Y. enterocolitica O:8 infection but not in vitro, and was identified using IVET (Heusipp et al., 2001). The transcription of hreP gene is positively regu-lated by three genes viz. pypA, pypB, and pypC (Wagner et al., 2009). The hreP gene is required for virulence of Y. enterocolitica bioserovar 1B/O:8 but the exact role in pathogenesis is not understood. This gene has also been identified in biovar 1A strains. The distribution of this gene in biovar 1A strains correlates with the presence of

ystB (enterotoxin) gene (Bhagat and Virdi, 2007). The role of hreP in virulence of biovar 1A strains however needs to be investigated.

Fimbrial adhesins

Myf (Mucoid Yersinia factor) are narrow flexible fimbriae which confer mucoid appearance to Y. enterocolitica (Iriarte et al., 1993). Evidence suggests that Myf may play role in adhesion to specific sites in the intestinal epithelium. Some of these are (1) the narrow fibrillar structure of Myf resembles intestinal colonization fac-tors of enterotoxigenic E. coli (Knutton et al., 1989; Nataro and Kaper, 1998) or adhesin of Helicobacter pylori (Doig et al., 1992) (2) the major structural subunit i.e. MyfA shows homology with PapG protein of pyelonephritis associated pili, and (3) similarity of MyfA to the pH 6 antigen (Psa) of Y. pseudotuberculosis which mediates thermoinducible binding to cultured cells (Yang et al., 1996). Although earlier studies reported absence of Myf in biovar 1A strains (Diaz et al., 1985; Toyos et al., 1986), recent studies have identified myfA gene in these strains. Its distribution correlated with ystB gene. All the strains that carried myfA also carried the ystB gene but not the vice versa (Bhagat and Virdi, 2007). Biovar 1A strains with or without myfA however did not differ in colonization of epithelial cells (Grant et al., 1998). Thus, the role of Myf might be similar to Psa of Y. pestis, which serves as an antiphagocytic factor (Huang and Lindler, 2004). It would therefore be interesting to unravel the significance of Myf in Y. enterocolitica biovar 1A.

Superoxide dismutase

The ability of Y. enterocolitica biovar 1A to survive within IFN-γ activated macrophages suggests their resistance to bactericidal action of reactive oxygen intermediates (ROI). This characteristic is known to be mediated by pYV plasmid-encoded proteins in biovars 1B, and 2-4. For biovar 1A strains however, some analogous fac-tors must come into play as these lack pYV plasmid. Superoxide dismutase (Sod), which dismutates highly reactive superoxide radical to hydrogen peroxide and molecular oxygen, might contribute to survival and pathogenesis of biovar 1A. Although speculative as yet, it needs to be investigated thoroughly. The speculation is based on the observation that biovar 1A strains of Y. enterocolitica possess SodC, a Cu-Zn SOD (Howard et al., 2006). SodC is reported to be located in the peri-plasm, and serves to protect bacteria against oxidative stress encountered inside the phagocytic cells (Battistoni et al., 2000). The role of Mn-SOD (SodA) in removal of endogenous and exogenous ROI encountered during infection has been suggested for bioserovar 1B/O:8 (Roggenkamp et al., 1997). Besides this, SodC might

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

10 Bhagat, and Virdi

modulate bacterial survival within epithelial cells as suggested for Salmonella choleraesuis (Battistoni 2003). The role of none of these enzymes has been studied in Y. enterocolitica biovar 1A.

Lipopolysaccharide (LPS)

The role of LPS in virulence of Y. enterocolitica biovar 1B has been shown by signature-tagged transposon mutagenesis (Darwin and Miller, 1999; Gort and Miller, 2000), IVET (Young and Miller, 1997) and suppression subtractive hybridization (Golubov et al., 2003). Various components of LPS, namely O-antigen and outer core are required for pathogenicity. The detection of recep-tors for phage ØR1-37 in biovar 1A strains of serotypes O:6, O:6,31, O:25,26,44, O:41,43, O:41(27)43 and O:50 suggested presence of an outer core in these strains also (Skurnik et al., 1999). Outer core has been suggested to be required for prolonged survival of bacteria in Peyer’s patches and invasion of deeper tissues like liver and spleen (Skurnik and Bengoechea, 2003). The role of O-antigen and outer core in virulence of biovar 1A strains needs to be investigated.

Iron utilization

Y. enterocolitica biovar 1A produce water-soluble siderophores, which have not been characterized biochemically or molecularly (Chambers and Sokol, 1994). The biovar 1A strains are also endowed with genes such as fepA (receptor), fepD (transporter), and fes (esterase), which encode proteins for the utilization of enterochelin, a catecholate siderophore (Bhagat and Virdi, 2007; Howard et al., 2006). Unlike the known pathogenic biovars, the fepA gene in Y. enterocolitica biovar 1A seems to be functional due to the presence of a 41-bp sequence (Bhagat and Virdi, 2007; Schubert et al., 1999). However, the fepA gene for enterochelin receptor was not present in all biovar 1A strains. Biovar 1A strains may also utilize iron by making use of the exogenous hydroxamate siderophores like desfer-rioxamine (Chambers and Sokol, 1994). The ability to utilize desferrioxamine makes low pathogenicity biovars of Y. enterocolitica virulent in patients with iron overload who are regularly administered des-ferrioxamine (Desferal) (Robins-Browne and Prpic, 1985). Interestingly, the extent and the duration of excretion of a biovar 1A strain in the faeces of mice increased following pre-treatment of mice with iron and desferrioxamine (Tennant et al., 2003). The whole gamut of iron acquisition by Y. enterocolitica biovar 1A needs to be understood. The TonB-independent and non- siderophore yersiniae ferric uptake (yfu) system present in biovar 1A strains of Y. enterocolitica (Saken et al., 2000) also remains unexplored.

Flagella/Flagellin

Y. enterocolitica biovar 1A require flagella to invade HEp-2 cells and for persistence within human macrophages in vitro (McNally et al., 2007). This was shown using an iso-genic mutant for fliA gene, which encodes a sigma factor for flagellar operon and is essential for expression of flag-ella. Within the infected macrophages, the appearance and the distribution of the vacuoles in which the wild-type and the mutant strains were located also varied. The wild-type strain was present in tight vacuoles with no surrounding space whilst the mutant was present within a large phagosomal vacuole. Also, the aflagellate mutant was attenuated in its ability to colonize porcine intestinal tissue in vitro signifying the role of flagellin in binding to intestinal tissue.

It was suggested that differences in the persistence of aflagellate and flagellate strains inside macrophages might be due to variations in the response of macro-phages. The secretion of TNF-α (pro-inflammatory cytokine) increased and that of IL-10 (anti-inflammatory cytokine) decreased following infection of macrophages by an aflagellate Y. enterocolitica biovar 1A (McNally et al., 2007). Thus, a low inflammatory response to flagellate Y. enterocolitica biovar 1A indicates possible role of flagellin in pathogenicity. Furthermore, as flagella are known to be repressed at 37°C in Y. enterocolitica, their role seems to be confined to early phases of infection in the host.

Modulation of host cell cytokines

The pathogenicity of an organism depends inter alia on its ability to modulate the host responses in its favor. The differences in the virulence characteristics of various bio-var 1A strains (Grant et al., 1998; Grant et al., 1999) have not been attributed to any particular gene or factor per se. Thus, an alternative could be a difference in the response of the host to the invading organisms. How might a host respond to different biovar 1A strains has been addressed by McNally and coworkers (2006) by measuring expres-sion of different cytokines. The interaction of biovar 1A strains with cultured human macrophages exhibited modulation of cytokines. In general, secretion of low amounts of pro-inflammatory and high amounts of anti-inflammatory cytokines by host cells favors the pathogen. In this respect, the potential of clinical biovar 1A strains to evade host immune response seemed better than bio-var 1A strains of animal origin as macrophages infected with clinical strains secreted less of pro-inflammatory cytokines (IL-6 and IL-8).

Macrophages infected with biovar 1A strains pro-duced ca. 4-8 fold higher TNF-α (pro-inflammatory cytokine) compared to those infected with pathogenic biovars (McNally et al., 2006). Among biovar 1A strains, the macrophages infected with clinical strains produced

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.


ca. two-fold higher levels of TNF-α compared to those infected with strains of animal origin. These observa-tions indicate better survival of pathogenic biovars and biovar 1A strains of animal origin. However, it is known that secretion of TNF-α leads to migration of increased number of macrophages to the site of infection. This fact coupled with the observation that macrophages are the preferred site for survival of biovar 1A strains, suggests that some strains evaded the host immune response by secreting higher levels of TNF-α. These observations suggest that differences in virulence characteristics of clinical and non-clinical biovar 1A strains reported ear-lier (Grant et al., 1998; Grant et al., 1999; Singh and Virdi, 2004) might be attributed to host response per se.

From the foregoing discussion, it is apparent that the key to understanding the pathogenicity of Y. enterocol-itica biovar 1A may lie in an in-depth analysis of the host responses.

Type II Secretion System

Two types of type II secretion systems (T2SS) have been identified in Y. enterocolitica: yts1 and yts2 (Iwobi et al., 2003). Among these, yts1 is unique to highly pathogenic biovar 1B and plays role in virulence while yts2 is com-mon to all biovars. It would be interesting to explore the role of yts2 in pathogenicity of Y. enterocolitica biovar 1A. The transcription of yts2D gene was higher at 27°C and only basal activity was detected at 37°C. Although, this observation is contradictory to the role of yts2 in patho-genicity, several virulence factors like enterotoxin and invasin, which were earlier shown to be expressed maxi-mally at 28°C were later shown to be expressed at 37°C under specific conditions (Straley and Perry, 1995).

Concluding remarks

The biovar 1A strains of Y. enterocolitica are considered avirulent as these lack pYV plasmid – a major hallmark of Y. enterocolitica pathogenicity. These strains also lack major chromosomal virulence genes. Nevertheless, attributes like enterotoxin production, invasion of epithe-lial cells in vitro and survival inside macrophages indi-cate their pathogenic potential. Some biovar 1A strains have also been implicated in food-borne and nosocomial outbreaks and were reported to produce disease symp-toms indistinguishable from that produced by the known pathogenic biovars. These contradictions galore bring out the enigmatic nature of Y. enterocolitica biovar 1A. In future, detailed studies on insecticidal toxins, urease, host responsive elements, flagella and intricacies in the host immune response need to be undertaken. It would also be worthwhile to analyze these data vis-à-vis the clonal groups identified in Y. enterocolitica biovar 1A. This would

help in fully understanding the pathogenic potential and true public health significance of Y. enterocolitica biovar 1A.

Declaration of interest

The financial assistance from Indian Council of Medical Research (ICMR), Defence Research and Development Organization (DRDO), Department of Biotechnology (DBT), Ministry of Environment and Forest (MoEF), Department of Science and Technology (DST), and University of Delhi to strengthen R & D doctoral research program is acknowledged gratefully.

References

Aldova E, Laznickova K. (1979). Comments on the ecology and epi-demiology of Yersinia enterocolitica in Czechoslovakia. Contrib Microbiol Immunol 5, 122–131.

Alonso JM, Bercovier H, Servan J, Mollaret HH. (1979). Contribution to the study of the ecology of Yersinia enterocolitica in France. Contrib Microbiol Immunol 5, 132–143.

Ashbolt R, Barralet J, Bell R, Bittisnich D, Black A, Combs B, Carson C, Crerar S, Dalton C, Gregory J, Harlock M, Hall G, Hogg G, Kirk M, Lalor K, Merritt T, Munnoch S, Musto J, Mwanri L, Neville L, Oxenford C, Owen R, Raupach J, Sault C, Stafford R, Telfer B, Vally H, Yohannes K (2005). OzFoodNet: enhancing foodborne disease surveillance across Australia: quarterly report, October to December 2004. Commun Dis Intell 29, 85–88.

Barrett NJ. (1986). Communicable disease associated with milk and dairy products in England and Wales, 1983-1984. J Infect 12, 265–272.

Battistoni A, Pacello F, Folcarelli S, Ajello M, Donnarumma G, Greco R, Ammendolia MG, Touati D, Rotilio G, Valenti P. (2000). Increased expression of periplasmic Cu, Zn superoxide dismutase enhances survival of Escherichia coli invasive strains within nonphagocytic cells. Infect Immun 68, 30–37.

Battistoni A. (2003). Role of prokaryotic Cu, Zn superoxide dismutase in pathogenesis. Biochem Soc Trans 31, 1326–1329.

Bhagat N, Virdi JS. (2009). Molecular and biochemical characteriza-tion of urease and survival of Yersinia enterocolitica biovar 1A in acidic pH in vitro. BMC Microbiol 9, 262.

Bhagat N, Virdi JS. (2007). Distribution of virulence-associated genes in Yersinia enterocolitica biovar 1A correlates with clonal groups and not the source of isolation. FEMS Microbiol Lett 266, 177–183.

Bissett ML, Powers C, Abbott SL, Janda JM. (1990). Epidemiologic investigations of Yersinia enterocolitica and related species: sources, frequency, and serogroup distribution. J Clin Microbiol 28, 910–912.

Bissett ML. (1976). Yersinia enterocolitica isolates from humans in California, 1968-1975. J Clin Microbiol 4, 137–144.

Bissett ML. (1979). Yersiniosis in California. Contrib Microbiol Immunol 5, 159–168.

Bottone EJ. (1999). Yersinia enterocolitica: overview and epidemiologic correlates. Microbes Infect 1, 323–333.

Bresolin G, Morgan JA, Ilgen D, Scherer S, Fuchs TM. (2006). Low tem-perature-induced insecticidal activity of Yersinia enterocolitica. Mol Microbiol 59, 503–512.

Burnens AP, Frey A, Nicolet J. (1996). Association between clinical presentation, biogroups and virulence attributes of Yersinia ente-rocolitica strains in human diarrhoeal disease. Epidemiol Infect 116, 27–34.

Butler T, Islam M, Islam MR, Azad AK, Huq MI, Speelman P, Roy SK. (1984). Isolation of Yersinia enterocolitica and Y. intermedia from

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.


fatal cases of diarrhoeal illness in Bangladesh. Trans R Soc Trop Med Hyg 78, 449–450.

Butt HL, Gordon DL, Lee-Archer T, Moritz A, Merrell WH. (1991). Relationship between clinical and milk isolates of Yersinia ente-rocolitica. Pathology 23, 153–157.

Caprioli T, Drapeau AJ, Kasatiya S. (1978). Yersinia enterocolitica: sero-types and biotypes isolated from humans and the environment in Quebec, Canada. J Clin Microbiol 8, 7–11.

Carter PB. (1975). Pathogenicity of Yersinia enterocolitica for mice. Infect Immun 11, 164–170.

Chambers CE, Sokol PA. (1994). Comparison of siderophore produc-tion and utilization in pathogenic and environmental isolates of Yersinia enterocolitica. J Clin Microbiol 32, 32–39.

Chiesa C, Pacifico L, Cianfrano V, Midulla M. (1987). Italian experi-ence with yersiniosis (1978-1985). Contrib Microbiol Immunol 9, 76–88.

Cimolai N, Trombley C, Blair GK. (1994). Implications of Yersinia ente-rocolitica biotyping. Arch Dis Child 70, 19–21.

Corbel MJ, Ellis B, Richardson C, Bradley R. (1992). Experimental Yersinia enterocolitica placentitis in sheep. Br Vet J 148, 339–349.

Cornelis GR, Boland A, Boyd AP, Geuijen C, Iriarte M, Neyt C, Sory MP, Stainier I. (1998). The virulence plasmid of Yersinia, an antihost genome. Microbiol Mol Biol Rev 62, 1315–1352.

Darwin A, Miller V. (1999). Identification of Yersinia enterocolitica genes affecting survival in an animal host using signature-tagged transposon mutagenesis. Mol Microbiol 32, 51–62.

de Koning-Ward TF, Robins-Browne RM. (1995). Contribution of ure-ase to acid tolerance in Yersinia enterocolitica. Infect Immun 63, 3790–3795.

de Wit MA, Koopmans MP, Kortbeek LM, van Leeuwen NJ, Bartelds AI, van Duynhoven YT. (2001). Gastroenteritis in sentinel general practices, The Netherlands. Emerg Infect Dis 7, 82–91.

Delor I, Kaeckenbeeck A, Wauters G, Cornelis GR. (1990). Nucleotide sequence of yst, the Yersinia enterocolitica gene encoding the heat-stable enterotoxin, prevalence of the gene among pathogenic and nonpathogenic yersiniae. Infect Immun 58, 2983–2988.

Demczuk W, Ahmed R, Woodward D, Clark C, Ng LK, Dore K, Ciampa N, Muckle A. (2004). Laboratory surveillance data for enteric pathogens in Canada Annual Summary 2001. (http://www.nml-lnm.gc.ca/NESP-PNSME/assets/pdf/2001AnnualSummary.pdf ).

Demczuk W, Ahmed R, Woodward D, Clark C, Rodgers F. (2001). Laboratory surveillance data for enteric pathogens in Canada Annual Summary 2000 (www.nml-lnm.gc.ca/NESP-PNSME/assets/pdf/2000AnnualSummary.pdf ).

Diaz R, Urra E, Toyos J, Moriyon I. (1985). Characterization of a Yersinia enterocolitica antigen common to enterocolitis-associated sero-types. J Clin Microbiol 22, 1035–1039.

Doig P, Austin JW, Kostrzynska M, Trust TJ. (1992). Production of a conserved adhesin by the human gastroduodenal pathogen Helicobacter pylori. J Bacteriol 174, 2539–2547.

Dolina M, Peduzzi R. (1993). Population genetics of human, ani-mal, environmental Yersinia strains. Appl Environ Microbiol 59, 442–450.

Durisin MD, Ibrahim A, Griffiths MW. (1998). Detection of pathogenic Yersinia enterocolitica using a digoxigenin labelled probe target-ing the yst gene. J Appl Microbiol 84, 285–292.

Ebringer R, Colthorpe D, Burden G, Hindley C, Ebringer A. (1982). Yersinia enterocolitica biotype I. Diarrhoea and episodes of HLA B27 related ocular and rheumatic inflammatory disease in South-East England. Scand J Rheumatol 11, 171–176.

Falcao JP, Falcao DP, Pitondo-Silva A, Malaspina AC, Brocchi M. (2006). Molecular typing and virulence markers of Yersinia enterocolitica strains from human, animal and food origins isolated between 1968 and 2000 in Brazil. J Med Microbiol 55, 1539–1548.

Fearnley C, On SL, Kokotovic B, Manning G, Cheasty T, Newell DG. (2005). Application of fluorescent amplified fragment length polymorphism for comparison of human and animal isolates of Yersinia enterocolitica. Appl Environ Microbiol 71, 4960–4965.

Fenwick SG, McCarthy MD. (1995). Yersinia enterocolitica is a common cause of gastroenteritis in Auckland. N Z Med J 108, 269–271.

Floccari ME, Neubauer HK, Gomez SM, Lodri C, Parada JL. (2003). Molecular characterization of Yersinia enterocolitica 1A strains

isolated from Buenos Aires sewage water. Adv Exp Med Biol 529, 345–348.

Fukushima H, Tsubokura M, Otsuki K, Kawaoka Y, Nishio R, Moriki S, Nishino Y, Mototsune H, Karino K. (1985). Epidemiological study of Yersinia enterocolitica and Yersinia pseudotuberculosis infec-tions in Shimane Prefecture, Japan. Zentralbl Bakteriol Mikrobiol Hyg B 180, 515–527.

Gierczynski R, Jagielski M, Rastawicki W. (2002). Molecular virulence attributes and occurrence of pYV-bearing strains among human clinical isolates of Yersinia enterocolitica in Poland. Eur J Clin Microbiol Infect Dis 21, 158–159.

Golubov A, Heesemann J, Rakin A. (2003). Uncovering genomic dif-ferences in human pathogenic Yersinia enterocolitica. FEMS Immunol Med Microbiol 38, 107–111.

Gort AS, Miller VL. (2000). Identification and characterization of Yersinia enterocolitica genes induced during systemic infection. Infect Immun 68, 6633–6642.

Grant T, Bennett-Wood V, Robins-Browne RM. (1998). Identification of virulence-associated characteristics in clinical isolates of Yersinia enterocolitica lacking classical virulence markers. Infect Immun 66, 1113–1120.

Grant T, Bennett-Wood V, Robins-Browne RM. (1999). Characterization of the interaction between Yersinia enterocolitica biotype 1A and phagocytes and epithelial cells in vitro. Infect Immun 67, 4367–4375.

Greenwood JR, Flanigan SM, Pickett MJ, Martin WJ. (1975). Clinical isolation of Yersinia enterocolitica: cold temperature enrichment. J Clin Microbiol 2, 559–560.

Greenwood M, Hooper WL. (1987). Human carriage of Yersinia spp. J Med Microbiol 23, 345–348.

Greenwood MH, Hooper WL, Rodhouse JC. (1990). The source of Yersinia spp. in pasteurized milk: an investigation at a dairy. Epidemiol Infect 104, 351–360.

Greenwood MH, Hooper WL. (1990). Excretion of Yersinia spp. asso-ciated with consumption of pasteurized milk. Epidemiol Infect 104, 345–350.

Greenwood MH. (1995). Human carriage of Yersinia species and inci-dence in foods. Contrib Microbiol Immunol 13, 74–76.

Gripenberg-Lerche C, Zhang L, Ahtonen P, Toivanen P, Skurnik M. (2000). Construction of urease-negative mutants of Yersinia ente-rocolitica serotypes O:3 and O:8: role of urease in virulence and arthritogenicity. Infect Immun 68, 942–947.

Gulati P, Varshney RK, Virdi JS. (2009). Multilocus variable number tandem repeat analysis as a tool to discern genetic relation-ships among strains of Yersinia enterocolitica biovar 1A. J Appl Microbiol 107, 875–884.

Gulati PS, Virdi JS. (2007). The rrn locus and gyrB genotyping confirm the existence of two clonal groups in strains of Yersinia entero-colitica subspecies palearctica biovar 1A. Res Microbiol 158, 236–243.

Hares MC, Hinchliffe SJ, Strong PC, Eleftherianos I, Dowling AJ, ffrench-Constant RH, Waterfield N. (2008). The Yersinia pseu-dotuberculosis and Yersinia pestis toxin complex is active against cultured mammalian cells. Microbiology 154, 3503–3517.

Harnett N, Lin YP, Krishnan C. (1996). Detection of pathogenic Yersinia enterocolitica using the multiplex polymerase chain reaction. Epidemiol Infect 117, 59–67.

Heusipp G, Young GM, Miller VL. (2001). HreP, an in vivo-ex-pressed protease of Yersinia enterocolitica, is a new member of the family of subtilisin/kexin-like proteases. J Bacteriol 183, 3556–3563.

Howard SL, Gaunt MW, Hinds J, Witney AA, Stabler R, Wren BW. (2006). Application of comparative phylogenomics to study the evolution of Yersinia enterocolitica and to identify genetic differ-ences relating to pathogenicity. J Bacteriol 188, 3645–3653.

Huang X, Yoshino K, Nakao H, Takeda T. (1997). Nucleotide sequence of a gene encoding the novel Yersinia enterocolitica heat-stable enterotoxin that includes a pro-region-like sequence in its mature toxin molecule. Microb Pathog 22, 89–97.

Huang XZ, Lindler LE. (2004). The pH 6 antigen is an antiphago-cytic factor produced by Yersinia pestis independent of Yersinia outer proteins and capsule antigen. Infect Immun 72, 7212–7219.

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

http://www.nml-lnm.gc.ca/NESP-PNSME/assets/pdf/2001AnnualSummary.pdf)



(www.nml-lnm.gc.ca/NESP-PNSME/assets/pdf/2000AnnualSummary.pdf

(www.nml-lnm.gc.ca/NESP-PNSME/assets/pdf/2000AnnualSummary.pdf


Huovinen E, Sihvonen LM, Virtanen MJ, Haukka K, Siitonen A, Kuusi M. (2010). Symptoms and sources of Yersinia enterocolitica-infection: a case-control study. BMC Infect Dis 10, 122.

Hussein HM, Fenwick SG, Lumsden JS. (2003). Competitive exclusion of Yersinia enterocolitica biotype 4, serotype O:3 by Yersinia ente-rocolitica biotype 1A, serotype O:6,30 in tissue culture and in pigs. N Z Vet J 51, 227–231.

Ibrahim A, Liesack W, Stackebrandt E. (1992). Polymerase chain reaction-gene probe detection system specific for patho-genic strains of Yersinia enterocolitica. J Clin Microbiol 30, 1942–1947.

Iriarte M, Vanooteghem JC, Delor I, Diaz R, Knutton S, Cornelis GR. (1993). The Myf fibrillae of Yersinia enterocolitica. Mol Microbiol 9, 507–520.

Iwobi A, Heesemann J, Garcia E, Igwe E, Noelting C, Rakin A. (2003). Novel virulence-associated type II secretion system unique to high-pathogenicity Yersinia enterocolitica. Infect Immun 71, 1872–1879.

Kay BA, Wachsmuth K, Gemski P, Feeley JC, Quan TJ, Brenner DJ. (1983). Virulence and phenotypic characterization of Yersinia enterocolitica isolated from humans in the United States. J Clin Microbiol 17, 128–138.

Knutton S, McConnell MM, Rowe B, McNeish AS. (1989). Adhesion and ultrastructural properties of human enterotoxigenic Escherichia coli producing colonization factor antigens III and IV. Infect Immun 57, 3364–3371.

Kot B, Trafny EA, Jakubczak A. (2007). Application of multiplex PCR for monitoring colonization of pig tonsils by Yersinia enterocolitica, including biotype 1A, and Yersinia pseudotuberculosis. J Food Prot 70, 1110–1115.

Kotetishvili M, Kreger A, Wauters G, Morris JG Jr, Sulakvelidze A, Stine OC. (2005). Multilocus sequence typing for studying genetic relationships among Yersinia species. J Clin Microbiol 43, 2674–2684.

Kuehni-Boghenbor K, On SL, Kokotovic B, Baumgartner A, Wassenaar TM, Wittwer M, Bissig-Choisat B, Frey J. (2006). Genotyping of human and porcine Yersinia enterocolitica, Yersinia intermedia, Yersinia bercovieri strains from Switzerland by ampli-fied fragment length polymorphism analysis. Appl Environ Microbiol 72, 4061–4066.

Kwaga J, Iversen JO, Misra V. (1992). Detection of pathogenic Yersinia enterocolitica by polymerase chain reaction and dig-oxigenin-labeled polynucleotide probes. J Clin Microbiol 30, 2668–2673.

Leclercq A, Martin L, Vergnes ML, Ounnoughene N, Laran JF, Giraud P, Carniel E. (2005). Fatal Yersinia enterocolitica biotype 4 serovar O:3 sepsis after red blood cell transfusion. Transfusion 45, 814–818.

Lee TS, Lee SW, Seok WS, Yoo MY, Yoon JW, Park BK, Moon KD, Oh DH. (2004). Prevalence, antibiotic susceptibility, and viru-lence factors of Yersinia enterocolitica and related species from ready-to-eat vegetables available in Korea. J Food Prot 67, 1123–1127.

Lee WH, McGrath PP, Carter PH, Eide EL. (1977). The ability of some Yersinia enterocolitica strains to invade HeLa cells. Can J Microbiol 23, 1714–1722.

Lewis AM, Chattopadhyay B. (1986). Faecal carriage rate of Yersinia species. J Hyg (Lond) 97, 281–287.

Mallik S, Virdi JS. (2010). Genetic relationships between clinical and non-clinical strains of Yersinia enterocolitica biovar 1A as revealed by multilocus enzyme electrophoresis and multilocus restriction typing. BMC Microbiol.

Marks MI, Pai CH, Lafleur L, Lackman L, Hammerberg O. (1980). Yersinia enterocolitica gastroenteritis: a prospective study of clin-ical, bacteriologic, epidemiologic features. J Pediatr 96, 26–31.

Marymont JH Jr, Durfee KK, Alexander H, Smith JP. (1982). Yersinia enterocolitica in Kansas. Attempted recovery from 1,212 patients. Am J Clin Pathol 77, 753–754.

McIntyre M, Nnochiri E. (1986). A case of hospital-acquired Yersinia enterocolitica gastroenteritis. J Hosp Infect 7, 299–301.

McNally A, Cheasty T, Fearnley C, Dalziel RW, Paiba GA, Manning G, Newell DG. (2004). Comparison of the biotypes of Yersinia entero-colitica isolated from pigs, cattle and sheep at slaughter and from

humans with yersiniosis in Great Britain during 1999-2000. Lett Appl Microbiol 39, 103–108.

McNally A, Dalton T, La Ragione RM, Stapleton K, Manning G, Newell DG. (2006). Yersinia enterocolitica isolates of differing biotypes from humans and animals are adherent, invasive and persist in macrophages, but differ in cytokine secretion profiles in vitro. J Med Microbiol 55, 1725–1734.

McNally A, La Ragione RM, Best A, Manning G, Newell DG. (2007). An aflagellate mutant Yersinia enterocolitica biotype 1A strain displays altered invasion of epithelial cells, persistence in mac-rophages, cytokine secretion profiles in vitro. Microbiology 153, 1339–1349.

Metchock B, Lonsway DR, Carter GP, Lee LA, McGowan JE Jr. (1991). Yersinia enterocolitica: a frequent seasonal stool isolate from chil-dren at an urban hospital in the southeast United States. J Clin Microbiol 29, 2868–2869.

Mingrone MG, Fantasia M, Figura N, Guglielmetti P. (1987). Characteristics of Yersinia enterocolitica isolated from children with diarrhea in Italy. J Clin Microbiol 25, 1301–1304.

Morris JG Jr, Prado V, Ferreccio C, Robins-Browne RM, Bordun AM, Cayazzo M, Kay BA, Levine MM. (1991). Yersinia enterocolitica isolated from two cohorts of young children in Santiago, Chile: incidence of and lack of correlation between illness and proposed virulence factors. J Clin Microbiol 29, 2784–2788.

Najdenski H, Iteman I, Carniel E. (1994). Efficient subtyping of patho-genic Yersinia enterocolitica strains by pulsed-field gel electro-phoresis. J Clin Microbiol 32, 2913–2920.

Nakajima H, Inoue M, Mori T, Itoh K, Arakawa E, Watanabe H. (1992). Detection and identification of Yersinia pseudotuber-culosis and pathogenic Yersinia enterocolitica by an improved polymerase chain reaction method. J Clin Microbiol 30, 2484–2486.

Nanni F, Pacifico L, Renzi AM, Volterra L, Chiesa C. (1991). Urease-negative strains of Yersinia enterocolitica and related species iso-lated from human and nonhuman sources. Contrib Microbiol Immunol 12, 44–49.

Nataro JP, Kaper JB. (1998). Diarrheagenic Escherichia coli. Clin Microbiol Rev 11, 142–201.

Neubauer H, Hensel A, Aleksic S, Meyer H. (2000). Identification of Yersinia enterocolitica within the genus Yersinia. Syst. Appl Microbiol 23, 58–62.

Nilsson A, Lambertz ST, Stalhandske P, Norberg P, Danielsson-Tham ML. (1998). Detection of Yersinia enterocolitica in food by PCR amplification. Lett Appl Microbiol 26, 140–144.

Noble MA, Barteluk RL, Freeman HJ, Subramaniam R, Hudson JB. (1987). Clinical significance of virulence-related assay of Yersinia species. J Clin Microbiol 25, 802–807.

Okamoto K, Inoue T, Shimizu K, Hara S, Miyama A. (1982). Further purification and characterization of heat-stable entero-toxin produced by Yersinia enterocolitica. Infect Immun 35, 958–964.

Onyemelukwe NF. (1993). Yersinia enterocolitica as an aetiological agent of childhood diarrhoea in Enugu, Nigeria. Cent Afr J Med 39, 192–195.

Pai CH, Mors V, Seemayer TA. (1980). Experimental Yersinia enteroco-litica enteritis in rabbits. Infect Immun 28, 238–244.

Pai CH, Mors V, Toma S. (1978). Prevalence of enterotoxigenicity in human and nonhuman isolates of Yersinia enterocolitica. Infect Immun 22, 334–338.

Paz M, Muzio H, Teves S, Santini P. (2004). Analysis of a Yersinia ente-rocolitica isolated from human diarrheic feces in Argentina. Rev Argent Microbiol 36, 164–169.

Pham JN, Bell SM, Lanzarone JYM. (1991). Biotype and antibiotic sensitivity of 100 clinical isolates of Yersinia enterocolitica. J Antimicrob Chemother 28, 13–18.

Pierson DE, Falkow S. (1990). Nonpathogenic isolates of Yersinia ente-rocolitica do not contain functional inv-homologous sequences. Infect Immun 58, 1059–1064.

Platt-Samoraj A, Ugorski M, Szweda W, Szczerba-Turek A, Wojciech K, Procajlo Z. (2006). Analysis of the presence of ail, ystA and ystB genes in Yersinia enterocolitica strains isolated from aborting sows and aborted fetuses. J Vet Med B Infect Dis Vet Public Health 53, 341–346.

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.


Quan TJ. (1979). Biotypic and serotypic profiles of 367 Yersinia ente-rocolitica cultures of human and environmental origin in the United States. Contrib Microbiol Immunol 5, 83–87.

Ramamurthy T, Yoshino K, Huang X, Nair GB, Carniel E, Maruyama T, Fukushima H, Takeda T. (1997). The novel heat-stable entero-toxin subtype gene (ystB) of Yersinia enterocolitica: nucleotide sequence and distribution of the yst genes. Microb Pathog 23, 189–200.

Rasmussen HN, Olsen JE, Rasmussen OF. (1994). RAPD analysis of Yersinia enterocolitica. Lett Appl Microbiol 19, 359–362.

Ratnam S, Mercer E, Picco B, Parsons S, Butler R. (1982). A nosoco-mial outbreak of diarrheal disease due to Yersinia enterocolitica serotype O:5, biotype 1. J Infect Dis 145, 242–247.

Revell PA, Miller VL. (2001). Yersinia virulence: more than a plasmid. FEMS Microbiol Lett 205, 159–164.

Robins-Browne RM, Jacobs MR, Koornhof HJ, Mauff AC. (1979). Yersinia enterocolitica biotype 1 in South Africa. S Afr Med J 55, 1057–1059.

Robins-Browne RM, Miliotis MD, Cianciosi S, Miller VL, Falkow S, Morris Jr JG. (1989). Evaluation of DNA colony hybridization and other techniques for detection of virulence in Yersinia species. J Clin Microbiol 27, 644–650.

Robins-Browne RM, Takeda T, Fasano A, Bordun A-M, Dohi S, Kasuga H, Fang G, Prado V, Guerrant RL, Morris Jr JG. (1993). Assessment of enterotoxin production by Yersinia enterocolitica and identification of a novel heat-stable enterotoxin produced by a noninvasive Y. enterocolitica strain isolated from clinical mate-rial. Infect Immun 61, 764–767.

Robins-Browne RM, Tzipori S, Gonis G, Hayes J, Withers M, Prpic JK. (1985). The pathogenesis of Yersinia enterocolitica infection in gnotobiotic piglets. J Med Microbiol 19, 297–308.

Robins-Browne RM, Prpic JK. (1985). Effects of iron and desferriox-amine on infections with Yersinia enterocolitica. Infect Immun 47, 774–779.

Roggenkamp A, Bittner T, Leitritz L, Sing A, Heesemann J. (1997). Contribution of the Mn-cofactored superoxide dismutase (SodA) to the virulence of Yersinia enterocolitica serotype O8. Infect Immun 65, 4705–4710.

Sachdeva P, Virdi JS. (2004). Repetitive elements sequence (REP/ERIC)-PCR based genotyping of clinical and environmental strains of Yersinia enterocolitica biotype 1A reveal existence of limited number of clonal groups. FEMS Microbiol Lett 240, 193–201.

Saken E, Rakin A, Heesemann J. (2000). Molecular characterization of a novel siderophore-independent iron transport system in Yersinia. Int J Med Microbiol 290, 51–60.

Scheftel J. (2002). Yersinia enterocolitica surveillance in Minnesota In International Conference on Emerging Infectious Diseases (http://www.cdc.gov/iceid/webcast/slide.htm).

Schiemann DA. (1989). Yersinia enterocolitica and Yersinia pseudotu-berculosis. In: M P Doyle (Ed), Foodborne bacterial pathogens Marcel Dekker, Inc, New York, 601–672.

Schiemann DA, Devenish JA. (1982). Relationship of HeLa cell infec-tivity to biochemical, serological, and virulence characteristics of Yersinia enterocolitica. Infect Immun 35, 497–506.

Schubert S, Fischer D, Heesemann J. (1999). Ferric enterochelin transport in Yersinia enterocolitica: molecular and evolutionary aspects. J Bacteriol 181, 6387–6395.

Seto WH, Lau JT. (1984). Septicaemia due to Yersinia enterocolitica biotype I in Hong Kong. J Infect 8, 28–33.

Shayegani M, DeForge I, McGlynn DM, Root T. (1981). Characteristics of Yersinia enterocolitica and related species isolated from human, animal, and environmental sources. J Clin Microbiol 14, 304–312.

Shayegani M, Menegio EJ, McGlynnm DM, Gaafar HA. (1979). Yersinia enterocolitica in Oneida County, New York. Contrib Microbiol Immunol 5, 196–205.

Shin SS, Abbott S, Samuel MC, Vugia DJ. (2005). Epidemiology of Yersinia enterocolitica in the San Francisco Bay Area, 1996-2003. Infectious Diseases Society of America, San Francisco, CA (www.ceip.us/pdf/Winter2006Newsletter.pdf ).

Sihvonen LM, Haukka K, Kuusi M, Virtanen MJ, Siitonen A. (2009). Yersinia enterocolitica and Y. enterocolitica-like species in clinical

stool specimens of humans: identification and prevalence of bio/serotypes in Finland. Eur J Clin Microbiol Infect Dis 28, 757–765.

Simmonds SD, Noble MA, Freeman HJ. (1987). Gastrointestinal features of culture-positive Yersinia enterocolitica infection. Gastroenterology 92, 112–117.

Singh I, Bhatnagar S, Virdi JS. (2003). Isolation and characterization of Yersinia enterocolitica from diarrheic human subjects and other sources. Curr Sci 84, 1353–1355.

Singh I, Virdi JS. (2004). Production of Yersinia stable toxin (YST) and distribution of yst genes in biotype 1A strains of Yersinia entero-colitica. J Med Microbiol 53, 1065–1068.

Singh I, Virdi JS. (2005). Interaction of Yersinia enterocolitica biotype 1A strains of diverse origin with cultured cells in vitro. Jpn J Infect Dis 58, 31–33.

Skurnik M. (2004) Lipopolysaccharides of Yersinia. In: Carniel E, Hinnebusch BJ (eds), Yersinia: Molecular and Cellular Biology. Norwich, UK: Horizon Bioscience.

Skurnik M, Bengoechea JA. (2003). The biosynthesis and biological role of lipopolysaccharide O-antigens of pathogenic Yersiniae. Carbohydr Res 338, 2521–2529.

Skurnik M, Nurmi T, Granfors K, Koskela M, Tiilikainen AS. (1983). Plasmid associated antibody production against Yersinia entero-colitica in man. Scand J Infect Dis 15, 173–177.

Skurnik M, Venho R, Bengoechea JA, Moriyón I. (1999). The lipopoly-saccharide outer core of Yersinia enterocolitica serotype O:3 is required for virulence and plays a role in outer membrane integ-rity. Mol Microbiol 31, 1443–1462.

Snyder JD, Christenson E, Feldman RA. (1982). Human Yersinia ente-rocolitica infections in Wisconsin. Clinical, laboratory and epi-demiologic features. Am J Med 72, 768–774.

Straley SC, Perry RD. (1995). Environmental modulation of gene expression and pathogenesis in Yersinia. Trends Microbiol 3, 310–317.

Stolk-Engelaar VM, Hoogkamp-Korstanje JA. (1996). Clinical pres-entation and diagnosis of gastrointestinal infections by Yersinia enterocolitica in 261 Dutch patients. Scand J Infect Dis 28, 571–575.

Sulakvelidze A, Dalakishvili K, Barry E, Wauters G, Robins-Browne R, Imnadze P, Morris Jr JG. (1996). Analysis of clinical and envi-ronmental Yersinia isolates in the Republic of Georgia. J Clin Microbiol 34, 2325–2327.

Takeda T, Kasuga H, Huang X, Yuan P, Nakao H, Ogawa A. (1992). New subtypes of the heat-stable enterotoxin (Y-ST) produced by Yersinia enterocolitica In Proceedings of the 28th Joint Conference of US-Japan Cooperative Medical Science Program Cholera and Related Diarrhoeal Diseases Panel.

Tennant SM, Grant TH, Robins-Browne RM. (2003). Pathogenicity of Yersinia enterocolitica biotype 1A. FEMS Immunol Med Microbiol 38, 127–137.

Tennant SM, Skinner NA, Joe A, Robins-Browne RM. (2005). Homologues of insecticidal toxin complex genes in Yersinia ente-rocolitica biotype 1A and their contribution to virulence. Infect Immun 73, 6860–6867.

Thisted Lambertz S, Ballagi-Pordany A, Nilsson A, Norberg P, Danielsson-Tham ML. (1996). A comparison between a PCR method and a conventional culture method for detecting pathogenic Yersinia enterocolitica in food. J Appl Bacteriol 81, 303–308.

Thisted Lambertz S, Danielsson-Tham ML. (2005). Identification and characterization of pathogenic Yersinia enterocolitica isolates by PCR and pulsed-field gel electrophoresis. Appl Environ Microbiol 71, 3674–3681.

Thoerner P, Bin Kingombe CI, Bogli-Stuber K, Bissig-Choisat B, Wassenaar TM, Frey J, Jemmi T. (2003). PCR detection of viru-lence genes in Yersinia enterocolitica and Yersinia pseudotuber-culosis and investigation of virulence gene distribution. Appl Environ Microbiol 69, 1810–1816.

Toma S, Lafleur L. (1974). Survey on the incidence of Yersinia entero-colitica infection in Canada. Appl Microbiol 28, 469–473.

Toma S, Lafleur L, Deidrick VR. (1979). Canadian experience with Yersinia enterocolitica (1966-1977). Contrib Microbiol Immunol 5, 144–149.

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

http://www.cdc.gov/iceid/webcast/slide.htm

(www.ceip.us/pdf/Winter2006Newsletter.pdf

(www.ceip.us/pdf/Winter2006Newsletter.pdf


Toyos J, Díaz R, Urra E, Moriyón I. (1986). Analysis by coagglutination of the distribution of a 24,000-dalton surface protein in Yersinia isolates. J Clin Microbiol 23, 804–805.

Une T. (1977). Studies on the pathogenicity of Yersinia enterocolitica I Experimental infection in rabbits. Microbiol Immunol 21, 349–363.

van Pelt W, de Wit MA, Wannet WJ, Ligtvoet EJ, Widdowson MA, van Duynhoven YT. (2003). Laboratory surveillance of bacterial gas-troenteric pathogens in The Netherlands, 1991-2001. Epidemiol Infect 130, 431–441.

Vandepitte J, Wauters G. (1979). Epidemiological and clinical aspects of human Yersinia enterocolitica infections in Belgium. Contrib Microbiol Immunol 5, 150–158.

Verhaegen J, Charlier J, Lemmens P, Delmee M, Van Noyen R, Verbist L, Wauters G. (1998). Surveillance of human Yersinia enterocolitica infections in Belgium: 1967-1996. Clin Infect Dis 27, 59–64.

Verhaegen J, Dancsa L, Lemmens P, Janssens M, Verbist L, Vandepitte J, Wauters G. (1991). Yersinia enterocolitica surveillance in Belgium (1979-1989). Contrib Microbiol Immunol 12, 11–16.

Wagner K, Schilling J, Fälker S, Schmidt MA, Heusipp G. (2009). A regulatory network controls expression of the in vivo-ex-pressed HreP protease of Yersinia enterocolitica. J Bacteriol 191, 1666–1676.

Wauters G, Aleksic S, Charlier J, Schulze G. (1991). Somatic and flagel-lar antigens of Yersinia enterocolitica and related species. Contrib Microbiol Immunol 12, 239–243.

Weissfeld AS, Sonnenwirth AC. (1980). Yersinia enterocolitica in adults with gastrointestinal disturbances: need for cold enrichment. J Clin Microbiol 11, 196–197.

Yang Y, Merriam JJ, Mueller JP, Isberg RR. (1996). The psa locus is responsible for thermoinducible binding of Yersinia pseudotu-berculosis to cultured cells. Infect Immun 64, 2483–2489.

Young GM, Amid D, Miller VL. (1996). A bifunctional urease enhances survival of pathogenic Yersinia enterocolitica and Morganella morganii at low pH. J Bacteriol 178, 6487–6495.

Young GM, Miller VL. (1997). Identification of novel chromosomal loci affecting Yersinia enterocolitica pathogenesis. Mol Microbiol 25, 319–328.

Cri

tical

Rev

iew

s in

Mic

robi

olog

y D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y 12

2.16

2.15

2.19

on

09/3

0/10

For

pers

onal

use

onl

y.

The Enigma of Yersinia enterocolitica biovar 1A

Documents

Transcript of The Enigma of Yersinia enterocolitica biovar 1A