Microbial safety assessment of municipal water and incidence of multi-drug resistant Proteus...

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Current Research in Microbiology and Biotechnology Vol. 1, No. 4 (2013): 189-195 Research Article Open Access

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Microbial safety assessment of municipal water and incidence of multi-drug resistant Proteus isolates in Rajshahi, Bangladesh Abdul Wadud, Aktar Uzzaman Chouduri* Department of Pharmacy, University of Rajshahi, Rajshahi-6205, Bangladesh * Corresponding author: Aktar Uzzaman Chouduri, email: [email protected]

ABSTRACT Municipal water is extensively used for drinking, cleaning and household purposes. In Rajshahi city, water sampling was done on total 100 points uniformly covering the city. Total heterotrophic bacterial counts performed were substantially too high (1×103 to 296×103 cfu/ml) and much beyond the permissible limit of ISI and WHO. Eleven proteus isolates comprising four species were identified that all were susceptible to only amoxycillin and highly resistant against third generation cephalosporins: ceftriaxone, ceftazedime, cefixime. Streptomycin was also effective despite of its intermediate susceptibility to one isolate. Other tested drugs were variably susceptible with no correlation to species. MAR index values ranged 0.25 to 0.58 indicating the exposure of isolates to antimicrobials in natural sources. However, the tested water was unhygienic and hence direct consumption of untreated water poses a great health risk to the users.

Keywords: Municipal water; proteus isolate; multi-drug resistant

INTRODUCTION Drinking water must be free from components which may adversely affect the human health. Such components include minerals, organic substances and disease causing microorganisms. A large portion of the population in developing countries suffers from health problems associated with either lack of drinking water or due to the presence of microbiological contaminants in water [1]. Poor water quality is responsible for the death of an estimated 5 million children in the developing countries [2]. The problem is rapidly aggravated by increasing population resulting in poor water-quality management [3]. Safety and quality of drinking water is always an important public health concern [4-5] as contamination of potable water has been frequently found associated with transmission of diseases causing serious illness and mortality throughout the world [6-8]. Although poor sanitation and food sources are integral to enteric pathogen exposure, drinking water is a major source of microbial pathogens especially in developing countries [9]. Among waterborne diseases of bacterial origin typhoid fever, bacillary dysentery and diarrhea are common in Bangladesh [10-11]. Despite of the

availability and promotion of the use of safe water sources, water-related diseases remain an important cause of mortality and morbidity in Bangladesh [12]. Waterborne disease is reported as the leading cause of death in infants and children in Bangladesh [13] while there are very few reports regarding the microbiological analysis of drinking water in the country [14]. Unfortunately, little attention is being paid to drinking-water quality issues and it remains the priority focus of water supply agencies. There is a lack of drinking-water quality monitoring and surveillance program in the country. Intermittent water supply is common in urban areas and outbreaks of gastroenteritis and other waterborne diseases has become a normal feature. Thus there is a need to find out where the actual problem lies; whether the water sources are contaminated or lapses occur in the distribution system. The present study has, therefore, been undertaken with the objectives of - (i) To assess the bacteriological quality of water supplies in different communities in the city, (ii) To find out the extent of microbial contaminants in municipality

Received: 13 June 2013 Accepted: 02 July 2013 Online: 25 July 2013


supplied water to the residents, (iii) To demonstrate the emergence of multi-drug resistant pathogens associated with virulent waterborne diseases. MATERIALS AND METHODS Sample collection Total of 100 tap water samples were collected at different points of localities over the city during February (late spring) to May (summer) 2013 since high temperature allows the disease-causing pathogens in water to their seasonal outbreak. For most samples experimental processes were carried out within 1-8 hours after its collection. All the samples were kept at 4°C until further analysis. As a negative control water for injection and distilled water was used in this investigation. Culture media and antimicrobial disks The culture media used in this study are Nutrient agar (Difco), Kligner Iron agar (Thermo Scientific), MacConkey agar (Oxoid Cambridge, UK). In some cases media were prepared in laboratory excluding a critical indicator or component. For antimicrobial susceptibility tests all antibiotic disks were purchased from Oxiod, England. The doses of antibiotics and disc diameters were in accordance with the standards of World Health Organization. Heterotrophic plate count (HPC) For enumeration of total heterotrophic plate count of bacteria in each sample the collected water was serially diluted with distilled water following the ten-fold sequential dilution procedure. Five hundred microliter of the original sample and different dilutions (10-1, 10-2, 10-3) were spread onto the culture plate containing nutrient agar and were incubated 24-72 h at 37ºC. The colony forming units (CFU) on each plate were counted and CFU.ml-1 was calculated to get heterotrophic plate count. Identification of Proteus species The samples collected were aseptically inoculated on culture plates of KIA media and incubated at 37ºC for 24 h. The morphological characteristics of the suspected Proteus colonies including size, shape, color, pigmentation, microscopic observation were recorded. Suspected Proteus colonies were then isolated and identified by biochemical tests according to the methods described elsewhere [15-17], based on whether they were positive for nitrate reduction, H2S gas production, methyl-red and urease reactions, glucose fermentation; negative for lactose, mannitol fermentation. Sucrose, maltose and D-xylose fermentation, indole production, acid production from glycerol differentiated isolates into species (Detail in Table 1). Carbohydrate fermentation The carbohydrate fermentation test was performed by inoculating a loopful culture of the isolated organisms into the culture tubes containing different sugars (six basic sugars glucose, sucrose, lactose, maltose, D-xylose

and mannitol) and incubated for 24 h at 37°C (Data not shown). Acid production was indicated by the color change from yellow to red and H2S gas production was noted by the appearance of black colored butt and gas bubbles in KIA culture tube (Fig. 5). Antimicrobial susceptibility tests The antimicrobial susceptibility tests were determined using the standard disc diffusion method [18]. Standardized inoculums of the overnight grown LB broth cultures were spread on Mueller-Hinton agar plates using sterile swabs. The plates were dried at room temperature for 2 hrs before placing the antibiotic disks at equidistance. The plates were incubated at 37ºC and the diameters of zone of inhibition were measured after 18 hr. The interpretation of zone diameter was followed as recommended in the CLSI [19]. A total of 12 antibiotics belonging 6 groups were used in this study. These are Penicillins: Ampicillin (AMP, 10μg), Amoxycillin (AMX, 30μg); Aminoglycosides: Streptomycin (S, 10μg), Kanamycin (K, 30μg); Tetracycline: Tetracycline (TE, 30μg), Doxycycline (DOX, 30μg); Cephalosporins: Cephradine (CE, 30μg), Ceftazidime (CAZ, 30μg), Ceftriaxone (CRO, 30μg), Cefixime (CFM, 5μg); Fluroquinolones: Ciprofloxacin (CIP, 5μg); Folate pathway inhibitors: Cotrimoxazole (Trimethoprim-Sulfamethoxazole, 25μg). RESULTS Microbiological quality and safety analysis Samples were subjected to the heterotrophic plate count (HPC) for microbiological quality assessment. The HPC ranged from 1×103 to 296×103 cfu/ml that were above the maximum permissible limit of 500 cfu/ml set by Drinking Water Standards and Advisories [20]. The highest HPC was found at a point of T.B. hospital quarter (S6) followed by Bornali more (S2), Sopura (S20), Vadra (S57), Munshipara (S78), Panchoboti (S60) and Kathalbaria (S79) (Fig. 3). However, the HPC of samples of these points were too high (>100×103 CFU/ml) and we assumed these areas vulnerable for waterborne diseases. The lowest HPC value was found at a point of Laxmipur bazar (S96) followed by Binodpur bazar (S51), Raypara (S76), Wheat research center (S50) and Meherchandi school more (S40). All the samples tested, therefore, were unsafe to drink based on the WHO and USEPA guideline. The five areas bearing the highest and lowest HPC values were highlighted in the city map (Fig. 1) to be concerned to people and authority. Identification of Proteus species Seasons have influences on the distribution of bacterial pathogens in water [21]. In this study, we aimed to identify either Salmonella or Proteus species since these pathogen-associated infections are very common during the sample collection period in the city. To do so the black centered bacterial colony on KIA culture plate was searched by a routine analysis with each water sample. The obtained black centered colony (Fig. 4A) was spread on separate plate to make a pure culture

A Wadud and Aktar Chouduri / Curr Res Microbiol Biotechnol. 2013, 1(4): 189-195


(Fig. 4B, C) for all positive cases. With pure culture the isolate was identified as genus of Proteus based on their morphological characteristics i.e. swarming and biochemical reactions i.e. acidic reaction, carbohydrate fermentation, H2S production, agar splitting (Fig. 5). The genus Proteus was further confirmed by various carbohydrate fermentation tests, colorless colony on MacConkey agar (data not shown), urease test and other conventional tests (Table 1). To date, five species of genus proteus named Proteus hauseri (Ph), Proteus mirabilis (Pm), Proteus myxofaciens (Pmx), Proteus

penneri (Pp) and Proteus vulgaris (Pv) are known as reported in Wikipedia (updated 7 April 2013) [22]. Next, the proteus isolates were differentiated into their species following the guideline of O'Hara et al. [16]. One isolate (11) was identified as Pv, two isolates (911, 912) as Pm, one isolate (662) as Ph and seven isolates (661, 663, 664, 665, 666, 667, and 668) as Pp. At least one of each isolated species was then subjected to antimicrobial susceptibility tests.

Figure 1. Water sampling points on the study area. Bold circles represent the places from where sampling was done during February to May 2013. The highest, medium, and lowest HPC are indicated by red, blue, and yellow circles respectively. A BAA BB

Figure 2. A representative nutrient agar plate with bacterial colonies. HPC was obtained from serially diluted water samples (A, 10×; B, 102×) inoculated for 24 h at 37ºC Emergence of multi-drug resistant Proteus species The proteus isolates were then subjected to antimicrobial susceptibility tests against twelve antibiotics as described in materials and methods to assess the current status of drug-resistance pattern in proteus species of municipal supplied water (Table 2). Among the tested drugs amoxycillin, a drug of penicillin group, showed the excellent susceptibility against all

isolates and species but ampicillin, a drug of same group, was not so effective. The second-most effective drug was streptomycin although it showed a trend of resistance towards P. mirabilis in isolate 911 (Table 2). The zone of inhibition of ciprofloxacin and doxycycline was in susceptible range for three species, Ph (662), Pp (665) and Pm (912). Other drugs were variably susceptible or resistant with no correlation to proteus species. Among third generation cephalosporins, ceftriaxone, cefixime and ceftazidime, were highly resistant to all isolates except cefixime which was susceptible to one Pm (912). All isolates were categorized as multi-drug resistant proteus since they showed resistance against 4-6 tested antibiotics. MAR index analysis of highly resistant isolates For multi-drug resistant isolates, the MAR (Multiple Antibiotic Resistance) index values (a/b, where 'a' represents the number of antibiotics the isolate was resistant to and 'b' represents the total number of antibiotics the isolate was tested against) were calculated. The values ranged from 0.25 to 0.58 where



species wise index values were 0.25 for Pp (665), 0.33 for Ph (662), 0.42 for Pm (912), 0.58 for Pm (911) and 0.58 for Pv (11). MAR index values ≥0.2 are observed when isolates are exposed to high risk sources of human or animal contamination, where antibiotic use is common. In contrast MAR index values ≤0.2 are observed where antibiotic is seldom or never used [23]. No isolates were found to have the MAR index ≤0.2 in this study indicating that these isolates were

extensively exposed to the sources of human contaminants and we speculated the extensive use of prescribed or self-prescribed cephalosporins against various infectious diseases might make the isolates resistant against cephalosporins since all tested drugs of this group were highly resistant against all species. Very recently by analyzing the MAR index values the increased antimicrobial resistance has been found for Proteus spp in Northwest Atlantic [24].

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B CA B CAAA

Figure 4. Screening of genus Salmonella-Proteus. A: Black centered bacterial colony formed on culture plate marked by white

circles. B and C: Subculture of isolated colony incubated for 24 h and 48 h, respectively

Figure 5. Identification of Proteus species. (I) A suspected colony streaked on KIA slant was tested whether any change of color after 24 h incubation at 37ºC. In+ is inoculated and In- uninoculated slant. (II) The same experiment was carried out excluding glucose in KIA (A, B). B indicated the isolate lactose nonfermenter and D indicated glucose fermenter, H2S producer, and agar splitter. A, C used as negative control



Table 1. Biochemical screening for the differentiation of Proteus speciesa.

Biochemical Test 11 661 662 663 664 665 666 667 668 911 912 Remarks H2S production + + + + + + + + + + + Salmonella / Proteus D-Glucose -Acid production + + + + + + + + + + + ,, -Gas production + + + + + + + + + + + ,, Urea hydrolysis + + + + + + + + + + + Klebsiella/Morganella/Yersinia/Proteus Carbohydrate fermentation -Lactose - - - - - - - - - - - Morganella / Proteus -Mannitol - - - - - - - - - - - Morganella / Proteus -Sucrose + + + + + + + + + + + Proteusb -Maltose + + + + + + + + + - - Maltose -ve : Pm -D-Xylose - + - + + + + + + D-Xylose +ve : Pp Indole production + + Indole +ve : Pv or Ph Acid production from glycerol

+ - Glycerol -ve : Ph

Pm- Proteus mirabilis, Pp- Proteus penneri, Pv- Proteus vulgaris, Ph- Proteus hauseri a Biochemical interpretation is followed as noted elsewhere [15-16, 27]. b Morganella is sucrose nonfermenter. Table 2. Multi-drug resistant Proteus isolates1.

Recommended zone of inhibition (mm) for susceptibility test of Proteusb

Isolate No.

(Spp.)

Tested drugs Disc potency

Mean zone of inhibitiona

(mm) Resistant Intermediate Susceptible

Incidence of resistance

11 (Pv) Tetracycline 30 μg 20 ≤ 11 12-14 ≥ 15 Doxycycline 30 g 10 ≤ 10 11-13 ≥ 14 R Ceftriaxone 30 g 8 ≤ 19 20-22 ≥ 23 R Cotrimoxazole 25 g 9 ≤ 10 11-15 ≥ 16 R Ciprofloxacin 5 g 10 ≤ 15 16-20 ≥ 21 R Cefixime 5 g 12 ≤ 15 16-18 ≥ 19 R Cephradine 30 g 10 ≤ 14 15-17 ≥ 18 R Ampicillin 10 g 24 ≤ 13 14-16 ≥ 17 Amoxycillin 30 g 24 ≤ 13 14-17 ≥ 17 Kanamycin 30 g 18 ≤ 13 14-17 ≥ 18 Streptomycin 10 g 24 ≤ 11 12-14 ≥ 15 Ceftazidime 30 g 14 ≤ 17 18-20 ≥ 21 R

662(Ph) Tetracycline 30 μg 20 ≤ 11 12-14 ≥ 15 Doxycycline 30 g 18 ≤ 10 11-13 ≥ 14 Ceftriaxone 30 g 0 ≤ 19 20-22 ≥ 23 R Cotrimoxazole 25 g 12 ≤ 10 11-15 ≥ 16 I Ciprofloxacin 5 g 30 ≤ 15 16-20 ≥ 21 Cefixime 5 g 0 ≤ 15 16-18 ≥ 19 R Cephradine 30 g 14 ≤ 14 15-17 ≥ 18 R Ampicillin 10 g 11 ≤ 13 14-16 ≥ 17 R Amoxycillin 30 g 20 ≤ 13 14-17 ≥ 17 Kanamycin 30 g 18 ≤ 13 14-17 ≥ 18 Streptomycin 10 g 17 ≤ 11 12-14 ≥ 15 Ceftazidime 30 g 0 ≤ 17 18-20 ≥ 21 R

665(Pp) Tetracycline 30 μg 12 ≤ 11 12-14 ≥ 15 I Doxycycline 30 g 30 ≤ 10 11-13 ≥ 14 Ceftriaxone 30 g 0 ≤ 19 20-22 ≥ 23 R Cotrimoxazole 25 g 15 ≤ 10 11-15 ≥ 16 I Ciprofloxacin 5 g 30 ≤ 15 16-20 ≥ 21 Cefixime 5 g 0 ≤ 15 16-18 ≥ 19 R Cephradine 30 g 18 ≤ 14 15-17 ≥ 18 Ampicillin 10 g 16 ≤ 13 14-16 ≥ 17 I Amoxycillin 30 g 25 ≤ 13 14-17 ≥ 17 Kanamycin 30 g 17 ≤ 13 14-17 ≥ 18 I Streptomycin 10 g 17 ≤ 11 12-14 ≥ 15 Ceftazidime 30 g 0 ≤ 17 18-20 ≥ 21 R

911(Pm) Tetracycline 30 μg 13 ≤ 11 12-14 ≥ 15 I Doxycycline 30 g 12 ≤ 10 11-13 ≥ 14 I Ceftriaxone 30 g 10 ≤ 19 20-22 ≥ 23 R Cotrimoxazole 25 g 0 ≤ 10 11-15 ≥ 16 R Ciprofloxacin 5 g 18 ≤ 15 16-20 ≥ 21 I Cefixime 5 g 14 ≤ 15 16-18 ≥ 19 R Cephradine 30 g 0 ≤ 14 15-17 ≥ 18 R Ampicillin 10 g 11 ≤ 13 14-16 ≥ 17 R



Amoxycillin 30 g 25 ≤ 13 14-17 ≥ 17 Kanamycin 30 g 17 ≤ 13 14-17 ≥ 18 R Streptomycin 10 g 14 ≤ 11 12-14 ≥ 15 I Ceftazidime 30 g 12 ≤ 17 18-20 ≥ 21 R

912(Pm) Tetracycline 30 μg 10 ≤ 11 12-14 ≥ 15 R Doxycycline 30 g 12 ≤ 10 11-13 ≥ 14 Ceftriaxone 30 g 14 ≤ 19 20-22 ≥ 23 R Cotrimoxazole 25 g 0 ≤ 10 11-15 ≥ 16 R Ciprofloxacin 5 g 34 ≤ 15 16-20 ≥ 21 Cefixime 5 g 28 ≤ 15 16-18 ≥ 19 Cephradine 30 g 0 ≤ 14 15-17 ≥ 18 R Ampicillin 10 g 14 ≤ 13 14-16 ≥ 17 I Amoxycillin 30 g 24 ≤ 13 14-17 ≥ 17 Kanamycin 30 g 15 ≤ 13 14-17 ≥ 18 I Streptomycin 10 g 17 ≤ 11 12-14 ≥ 15 Ceftazidime 30 g 14 ≤ 17 18-20 ≥ 21 R

1Isolates, resistant against at least three drugs, are categorized as multi-drug resistant. aEach test was done in triplicate, and mean value was considered for analysis. bRecommended zone of inhibition for susceptibility test of Enterobacteriaceae is followed as mentioned in the guideline of CLSI 2012. DISCUSSION HPC are commonly used to assess the general microbiological quality of drinking water. For HPC analysis the maximum level of microbial contaminants that is allowed in drinking water is not more than 500 CFU.ml-1 which is enforceable standard by Drinking Water Standards and Advisories [20]. In our study HPC measurements were too high that indicated the presence of favorable conditions of bacteria to remain alive and their growth in water pipelines. Most enteric pathogens transmitted by water infect the gastrointestinal tract and are excreted in the faeces of infected humans/animals [25]. They do not survive indefinitely in the environment. Substantial die-off will occur over a period of weeks. Thus, the high HPC is nothing but the entry of human/animal waste into the pipeline through leakage or breakage (Fig. 6) that provides essential nutrition to the pathogens. It is very much possible that even if the water at its source satisfies the specification, it might no longer potable at the user’s end.

A BA B

Figure 6. Leakage and breakage in water distribution network. A: Breakage on a distribution pipe at consumer's end crossed over a drain is rapped with a polyethylene bag. B: Leakage on distribution pipe at a road construction area near new market. However, the present study revealed that municipal tap water in Rajshahi city was contaminated with a number of bacterial species. A number of factors might be involved for such contamination. Rajshahi Water and Sewerage Authority (RWASA) supplies water to

residents' end through a network of underground pipelines. There are leakage and breakage in pipeline through which contaminants from outside the pipe might get mixed with the supplied water. There is also an illegal self-guided practice in the residents' to repair leakage of pipe and/or pipe junction to timely get the supplied water (Fig. 6A). As a result, these phenomena might cause easier entrance of contaminants into pipelines. Moreover, due to improper layout of water supply lines and sewer lines there might be crossing between them. This might cause fecal contamination. Multi-drug resistance profile of isolated proteus species revealed a high risk of public health in the city. Such high incidence of multi-drug resistant might be due to indiscriminate use of antibiotics, which may eventually replace the drug resistant microorganisms from antibiotic saturated environment. Based on our updated data Cephalosporins should not be used for gastroenteritis caused by proteus. Despite of the emergence of highly resistant proteus in water, amoxycillin showed a nice effectiveness for all species. In Bangladesh, for many years self-prescribed antibiotics have been using randomly by the people for treatment purposes. People are not aware about the schedule use of antibiotics. Thus, resistant strains might be emerged by genetic recombination against one or more antimicrobial agent(s) [26]. Moreover, our study of water quality monitoring provides an understanding of: (i) microbiological conditions in local streams of water, (ii) how these conditions may vary locally, (iii) how natural features and human/animal activities affect these conditions, and (v) where these effects are most pronounced in the city. CONCLUSION The municipal water quality in Rajshahi City is unhygienic to use. The estimated bacterial count in water per milliliter ranged 1×103 to 296×103 over the city which is not only below the WHO standard but also a great risk to health. We found leakage and breakage of pipeline and/or pipe junction in many areas during



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sample collection. However, it is being hereby recommended that the authority must pay attention about the regular monitoring and maintenance of water supply through pipeline. Authority also must be strict in their power exercise to dropout the human/animal or household waste material at the marked waste bin since the control of human and animal waste management to prevent sewage from entering into water pipeline is the keys to avoid microbial contamination of drinking water. The isolated proteus species were only susceptible to amoxycillin and third generation cephalosporins were highly resistant and hence the resistant antibiotics must not be used for the treatment of gastroenteritis caused by Proteus in Rajshahi. This study is therefore a step towards the generation of updated national data on the prevalence of antimicrobial resistant pathogens in Bangladesh. ACKNOWLEDGEMENTS The authors wish to thank the Department of Pharmacy, University of Rajshahi, Bangladesh for providing laboratory facilities to carry out the entire experiments. Authors' contribution: AW worked out the experimental part; AC designed, guided the project and drafted the manuscript. Funding: No external funding was received for this research. Competing interests: None declared REFERENCES

1. Van Leeuwen FXR (2000). Safe drinking water: the toxicologist's approach. Food and Chemical Toxicology. 38 (S-1): 51-58

2. Holgate G. In: Environmental and Waste Management. 2000, 3:105-112

3. Huang GH and Xia J (2001). Barriers to sustainable water-quality management. J Environ Management. 61:1-23

4. Hrudey SE and Hrudey EJ (2007). Published case studies of waterborne disease outbreaks-evidence of a recurrent threat. Water Environ Res. 79(3):233-245

5. Reynolds KA, Mena KD and Gerba CP (2008). Risk of waterborne illness via drinking water in the United States. Rev Environ Contam Toxicol. 192:117-158

6. Marshall JK, Thabane M, Garg AX et al. (2006). Walkerton health study investigators. Incidence and epidemiology of irritable bowel syndrome after a large waterborne outbreak of bacterial dysentery. Gastroenterology. 131(2):445-450

7. Jones AQ, Majowicz SE, Edge VL et al. (2007). Drinking water consumption patterns in British Columbia: an investigation of associations with demographic factors and acute gastrointestinal illness. Sci Total Environ. 388(1-3):54-65

8. O’Reilly CE, Bowen AB, Perez NE et al. (2007). A waterborne outbreak of gastroenteritis with multiple etiologies among resort island visitors and residents: Ohio, 2004. Clin Infec Dis. 44:506-512

9. Ashbolt NJ (2004). Microbial contamination of drinking water and disease outcomes in developing regions. Toxicology. 198:229-238

10. Parveen S, Ahmed MSU and Tania N (2008). Microbial contamination of water in around Dhaka City. Bangladesh. J. Sci. industr. Res. 43(2):273-276

11. Begum F, Shahana P, Begum HA et al. (1999). Microbiological quality of different companies mineral and drinking water available in Dhaka city. Bangladesh J Sci and Technol. 1(2):209-212

12. Mitra (1992). The 1991 national survey on status of rural water supply and sanitation for DPHE/UNICEF, Dhaka. Final report, Bangladesh

13. Butler T, Islam M, Azad AK et al. (1987). Causes of death in diarrhoeal diseases after rehydration therapy: an autopsy study of 140 patients in Bangladesh. Bull World Health Organ. 65(3):317-323

14. Moniruzzaman M, Akter S, Islam MA et al. (2011). Microbiological quality of drinking water from dispensers in roadside restaurants of Bangladesh. Pak J Biol Sci. 14(2):142-145

15. Cheesbrough M. In: District laboratory practice in tropical countries, 2000, Part-II. pp180

16. O'Hara CM, Brenner FW and Miller JM (2000). Classification, identification, and clinical significance of proteus, providencia, and morganella. Clin. Microbiol. Rev. 13(4):534-546

17. Barrow GI and Felthan RKA. In: Cowan and Steel’s Manual for the Identification of Medical Bacteria. 3rd Ed. Cambridge University Press. 2003: Cambridge UK. 351-353

18. Bauer AW, Kirby WMM, Sherris JC et al. (1966). Antibiotic susceptibility testing by a standardized single disk method. Amer J Clin Pathol. 45:493-496

19. Clinical and Laboratory Standard Institute. Performance Standards for Antimicrobial Susceptibility Testing, Twenty-Second Informational Supplement. 2012: Vol. 32, No. 3, pp 44-36

20. Drinking Water Standards and Advisories. Spring April 2012, pp 11

21. Ihejirika CE, Ogbulie JN, Nwabueze RN et al. (2011). Seasonal influences on the distribution of bacterial pathogens and waterborne diseases transmission potentials of Imo river, Nigeria. J Res Biol. 3:163-172

22. Wikipedia, the free encyclopedia. Web: http://en.wikipedia.org/wiki/Proteus_(bacterium)

23. Krumperman PH (1985). Multiple antibiotic resistance indexing of Escherichia coli to identify high-risk sources of fecal contamination of foods. Appl. Env. Microbiol. 46:165-170

24. Wallace CC, Yund PO, Ford TE et al. (2013). Increase in antimicrobial resistance in bacteria isolated from stranded marine mammals of the Northwest Atlantic. Ecohealth, May 2013

25. Cabral JPS (2010). Water microbiology. Bacterial pathogens and water. Int J Environ Res Public Health. 7: 3657-3703

26. Buxton A and Fraser G. In: Animal Microbiology. Blackwell Scientist Publication. Oxford, London, Edinburg, Melbourne. 1977: 85-86

27. Choudhury MR. In: Modern Medical Microbiology. 1999, 5th Ed, pp 310-311

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