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Journal of Electrostatics 67 (2009) 640–645

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Journal of Electrostatics

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Inactivation of Escherichia coli by alternative electric current in rivers dischargedinto sea

Meral Birbir a,*, Husniye Hacıoglu b, Yasar Birbir c, Gulsen Altug d

a Marmara University, Science and Arts Faculty, Department of Biology, 34722 Goztepe, Istanbul, Turkiyeb Marmara University, Institute for Graduate Studies in Pure and Applied Sciences, 34722 Goztepe, Istanbul, Turkiyec Marmara University, Technical Education Faculty, Department of Electrical Education, 34722 Goztepe, Istanbul, Turkiyed Istanbul University, Faculty of Fisheries, Department of Marine Biology, 34470 Laleli, Istanbul, Turkiye

a r t i c l e i n f o

Article history:Received 17 September 2008Received in revised form4 December 2008Accepted 19 January 2009Available online 14 February 2009

Keywords:Alternative electric currentEscherichia coliInactivation effectRiverSeawater

* Corresponding author. Tel.: þ90 216 346 45 53/13E-mail address: mbirbir@marmara.edu.tr (M. Birb

0304-3886/$ – see front matter � 2009 Elsevier B.V.doi:10.1016/j.elstat.2009.01.049

a b s t r a c t

Inactivation effect of alternative electric current on Escherichia coli ATCC 25922 and fecal E. coli MAAG1405 found resistant to antibiotics was examined in water samples collected from Ayamama River, SarısuRiver, and their discharge points into sea and from Black Sea and Marmara Sea. In addition to watersamples, lauryl sulfate broth was used as an organic rich medium. Both test strains were inactivatedwithin 1–3 min in media containing marine waters (1 A), 5–10 min in Ayamama River water (1 A), 5 minin Sarısu River water (0.5 A), 20–35 min in lauryl sulfate broth (1 A) by applying alternative electriccurrent.

� 2009 Elsevier B.V. All rights reserved.

1. Introduction

Infectious diseases related to pathogenic microorganisms fromland-based wastewater pollution of coastal areas may affect peoplein high numbers and cause important economic losses [1]. Theconcentration of pathogenic microorganisms in coastal areas islargely affected by fecal pollution from point discharges such assewage effluents, combined sewer overflows, industrial effluents,concentrated animal feeding operations and non-point sourcessuch as agricultural activity and poorly functioning sanitationsystems within the watershed [2]. Furthermore, surface infiltrationmay also cause pollution by carrying surface pathogens intodomestic and storm sewers. Fecal material is transferred directlyfrom sewage discharge and the watershed surface into rivers, lakesand streams, and subsequently to the coastal environment [1–3].

It was emphasized that microorganisms such as Campylobacterspp., Shiga toxin-producing Escherichia coli, Helicobacter pylori,Legionella spp., Leptospira spp., Mycobacterium avium, Salmonellatyphi, Shigella spp., Vibrio vulnificus, Cryptosporidium parvum,Giardia duodenalis, Naegleria fowleri, Schistosoma, Hepatitis A virus,

30; fax: þ90 216 347 87 83.ir).

All rights reserved.

Echovirus, Coxsackievirus and Adenovirus may be transmitted tohumans through recreational water and cause illnesses with severeoutcomes even in average populations [2]. Immunocompromisedindividuals such as AIDS or cancer patients, infants, young children,pregnant women and elderly are especially susceptible to water-borne infections and more severe outcomes such as debilitatingillness and death following infections may occur [4–7].

Researchers have reported 4 outbreaks of E. coli O157:H7 asso-ciated with bathing at a public beach in the Montreal-Centreregion. It has been also mentioned that E. coli O157:H7 can surviveseveral weeks in marine water as the infectious dose for E. coliO157:H7 is low, making transmission easy [8].

A total of 295 E. coli strains were isolated from 108 seawatersamples collected from three main beaches in Fortaleza, Brazil.Seventy-seven (77%) of the samples contained E. coli. Researchersemphasized that E. coli species had a very low tolerance toseawater. However, their number was very high in the testedsamples because of constant discharge of sewage into the sea. Itwas also mentioned that this was an indication of contamination byother fecal-origin pathogenic bacteria such as Salmonella, Shigellaand Vibrio cholerae, among others [9].

Another important problem is the presence of antibiotic-resistant bacteria in domestic sewage and agricultural wastes.Antibiotics are used in medicine for treatment of infectious

M. Birbir et al. / Journal of Electrostatics 67 (2009) 640–645 641

diseases, in agriculture as growth promoting substances and asprophylactic additives. Worldwide, about 50% of all antibioticsmanufactured are used in animal agriculture applications. Antibi-otics are also extensively used in aquaculture (fish farming) and evenin fruit production [10–12]. Increased, inappropriate, indiscriminantand nonmedical use of antibiotics may cause rapid development ofdrug-specific resistance in microorganisms causing disease [10–12].Resistant strains could transfer resistance to sensitive strains by cell-to-cell contact, transformation and transduction [13,14]. The infec-tious nature of the conjugative R plasmid has permitted the rapidspread of resistance through cell populations. Resistant plasmids arenow a major problem when dealing with many antimicrobial drugresistances. Numerous studies indicated that resistance to clinicallyrelevant antibiotics is widespread in aquatic bacteria, includingpotential human pathogens [10–12,15–20].

This important problem was also emphasized in Ref. [21]. Intotal 308 E. coli strains were isolated from Hamilton Harbor (LakeOntario) which supports an active recreational environment withits beaches and offshore areas for windsurfing and boating. It wasmentioned that these isolates were potential risks for public healthbecause a high proportion of these E. coli isolates (29%) carrieda pathotype set of virulence-related genes and 14% of the isolatescarried antimicrobial resistance genes.

Therefore, it is necessary to inactivate pathogenic and antibiotic-resistant bacteria in both point and non-point discharges with aneffective disinfection method and thus their entrance into therecreational waters may be reduced.

Chlorination is usually used for disinfection of water [22] butthere are serious safety concerns and great ecological risks involvedin the use of chlorine. It oxidizes certain types of organic matter inwater, resulting in the formation of carcinogenic compounds such astrihalomethanes. In the presence of high concentrations of chlorine-demanding substances, chlorine residual is unstable. Some parasiticspecies have shown resistance to low doses of chlorine. Further-more, long-term effect of discharging chlorinated compounds intothe environment is unknown [23,24]. Other methods, such asozonation and UV radiation, have not been widely utilized in waterdisinfection because of their high operational cost [22].

Although it has been reported that direct electric current disin-fection can destroy a variety of microorganisms in food, medical andindustrial applications [25–29], the inactivation effect of alternativeelectric current on fecal E. coli in polluted sea and river waters has notyet been reported. Therefore, the objective of this research was toevaluate the inactivation potential of alternative electric current onE. coli ATCC 25922 and fecal E. coli MAAG 1405 in sea and riverwaters. E. coli MAAG 1405 was selected as a test strain as itcommonly exists in sewage contaminated seawater.

Fig. 1. Schematic diagram of electroly

2. Experimental methods

2.1. Test strains

E. coli ATCC 25922 was used as a reference strain. The fecal E. coliMAAG 1405 was isolated from the seawater sample collected fromthe Marmara Sea close to the discharge point of a stream pollutedwith sewage and identified by API 20 E (bioMeruieux� SA, France)at 2005 [30]. It was selected to represent the pathogenic bacteriumdischarged to the sea along with non-disinfected sewage treatmentplant effluents and untreated sewage and surface run-offs.

2.2. Antibiotic susceptibility test

Kirby–Bauer method was used to examine antibiotic sensitivitiesof both E. coli ATCC 25922 and fecal E. coli MAAG 1405 [12,31].Antibiotic sensitivities of E. coli ATCC 25922 and fecal E. coli MAAG1405 strains were examined by spreading the bacterial suspensions(final concentration, 1 � 108 CFU [colony forming units]/mL) onplates containing Nutrient Agar (Merck, Darmstadt, Germany) andapplying antibiotic discs imipenem (10 mg/mL), cefuroxime (30 mg/mL), cefotaxime (30 mg/mL), ampicillin (10 mg/mL) and amoxicillin–clavulanic acid (30 mg/mL). The results were recorded as susceptibleor resistant after 24 h of incubation at 37 �C for E. coli ATCC 25922and 44.5 �C for E. coli MAAG 1405.

2.3. Inactivation of test strains

E. coli ATCC 25922 and E. coli MAAG 1405 were grown for 24 h inlauryl sulfate broth (Merck, Darmstadt, Germany) at 35 �C and44.5 �C, respectively. At the end of the exponential growth phase,the cells were suspended in sterile physiological saline solution toa density of 105 CFU/mL and 2 mL of the bacterial suspension wastransferred into an electrolysis cell containing 198 mL of the watersample. The electrolysis cell used was made of a glass beaker having2 internally attached platinum wire electrodes immersed in 200 mLof the test medium. The 2 electrodes were 1 mm in diameter and8 mm in length, at a separation of 40 mm. They were connected toa regulated alternative current (AC) source (Ruhstrat VDE Norma-dain Germany, f ¼ 50 Hz, Sec V ¼ 0–250 V, VA ¼ 2250 VA), whichhad an automatic variable output voltage range of 0–220 V anduser-selectable current range of 0–9 A (Fig. 1). Each test wasrepeated 3 times using 200 mL of the test media. The current levelswere set at 1 A, 1.5 A and 2 A and applied for 35 min [29,32]. Thewaters collected from the Ayamama River (Medium I), the SarısuRiver (Medium II), the Black Sea (Medium III), the Marmara Sea(Medium IV), the discharge points of the Ayamama (Medium V) and

sis cell system for test medium.

M. Birbir et al. / Journal of Electrostatics 67 (2009) 640–645642

the Sarısu Rivers (Medium VI) and lauryl sulfate broth (Medium VII;20 g l�1 tryptose, 5 g l�1 lactose, 5 g l�1 sodium chloride, 0.1 g l�1

lauryl sulfate sodium salt, 2.75 g l�1 dipotassium hydrogen phos-phate, 2.75 g l�1 potassium dihydrogen phosphate, pH 6.8) wereused as test media. A 100 mL quantity of the test media wasremoved from the electrolysis cell at 1, 3, 5, 10, 15, 20, 25, 30 and35 min. Each of the test media was plated onto Endo agar (Merck,Darmstadt, Germany) both directly and after serial dilutions. TheCFU of E. coli ATCC 25922 and E. coli MAAG 1405 were counted after24 h of incubation at 35 �C and 44.5 �C, respectively.

The pH values of the samples were measured before and after theapplication of alternative current (AC) using a pH meter (SartoriusPortable Meter PT-10P, Goettingen, Germany). All alternativecurrent disinfection tests were conducted at room temperature andthe temperature of the test media was 23 �C before the treatment.

3. Results and discussion

Untreated domestic wastewater discharged into a marineenvironment may carry millions of pathogenic microorganisms [1].During swimming, surfing, windsurfing and scuba diving bothforeign and local tourists may often be exposed to pathogenicmicroorganisms in coastal waters polluted by wastewater [1,2].

It was mentioned that the Kartodoma beach in Brazil contained4.3 � 106 fecal coliform bacteria/100 mL in March and 4.3 � 103

fecal coliform bacteria/100 mL in September. This level ofcontamination was due to highly polluted discharge of the Jacar-ecanga River [33].

Exposure to recreational waters contaminated with human andanimal waste may cause gastroenteritis, acute respiratory diseaseand eye, ear and skin infections in humans [4,7,34,35]. Theseillnesses are caused by enteric bacteria, viruses and protozoa [7].According to the World Health Organization (WHO) and someacademic researches, every year more than 120 million peoplesuffer from gastrointestinal diseases caused by swimming andbathing in wastewater-polluted coastal waters [1].

Bacteria which are resistant to a variety of antibiotics used incommon therapy of various infectious diseases in gut may be carriedwith untreated sewage into seawater. Researchers emphasized thatantibiotic-resistant coliform bacteria from effluents and land run-offeventually may enter into marine waters [36–39]. Human pathogenssuch as Escherichia, Salmonella, Shigella and Vibrio which are resis-tant to a variety of antibiotics are usually found in coastal waters andsediments [40–43]. The increase of antibiotic resistance amongmicroorganisms may increase morbidity and mortality [44,45].Therefore, domestic wastewater containing pathogenic bacteriashould be treated with a high level of disinfection.

Excessive and indiscriminant use of antibiotics in agriculturalapplications and metabolic excretion from humans and animalscontinuously release great amounts of antibiotics into the envi-ronment. It is known that some antibiotics are not completelydegraded in sewage treatment plants (STPs) and remain in thewater effluent. Researchers explained that antibacterials and anti-biotics such as trimethoprim, sulfamethoxazole, fluoroquinolones,chloramphenicol, erythromycin, roxithromycin, ofloxacin andtylosin, chlortetracycline and flumequine were found in STP efflu-ents, surface waters and sediments [10,11]. When sewage iscontinually discharged into seawater without any treatment, anti-biotics and antibiotic-resistant bacteria may accumulate inseawater and may cause an important threat for humans.

In the study’s antibiotics susceptibility tests, E. coli ATCC 25922(which was tested as a reference strain) was found to be susceptibleto imipenem (10 mg/mL), cefuroxime (30 mg/mL), cefotaxime(30 mg/mL) and resistant to ampicillin (10 mg/mL) and amoxicillin–clavulanic acid (30 mg/mL). As confirming the findings given above,

the fecal E. coli strain MAAG 1405, which was formerly isolatedfrom the discharge point of a stream polluted with sewage andsurface run-offs, was found resistant to all antibiotics tested.

It was mentioned that E. coli strains isolated from humanurinary tract infections in Turkey were sensitive to imipenem (98–100%) but resistant to ampicillin (60–97%) amoxicillin–clavulanicacid (35–65%) and cefuroxime (50–75%) [46]. On the contrary, theexperiment’s isolate E. coli MAAG 1405 was found to be imipenemresistant. If resistance to antibiotics used in the treatment of E. coliinfections in human becomes more widespread in environmentalisolates, treatment of E. coli infections may not be possible withexisting antibiotics in the near future.

In another study, researchers examined all currently describedvirulence genes and commonly found antimicrobial resistancegenes in environmental E. coli strains isolated from a beach of theGreat Lakes. It was found that a total of 43 isolates have at least oneantimicrobial resistance gene. The resistance genes against ampi-cillin, streptomycin, sulfonamide and tetracycline were found mostfrequently [47].

Inactivation of bacteria in the sewage, which are resistant toa variety of antibiotics by applying electric current, may prevent thetransmission of these bacteria to the environment and conse-quently to humans. Therefore, this method may be an importantapproach for public health.

In previous studies, researchers used different levels of direct oralternative electric currents to inactivate microorganisms found inseawater [29], milk [25], synthetic urine [48], salt solutions [49], onhuman skin [50], brine solutions [32,51], on catheter surface [52], inactivated sludge and biofilms [27], in effluent discharge into theseawater [53], drinking water [54], natural water [26], recirculatedbrine [28] and hide soak liquors [55].

In another study, 0.06 A direct electric current was used to killdifferent species of microorganisms such as E. coli IFO 3301 andPseudomonas aeruginosa IFO 2689 [56].

The lethal effects of low-amperage electric treatment onmicroorganisms in natural seawater and seawater inoculated withVibrio parahaemolyticus were investigated in Ref. [29]. In both cases,bacteria were completely inhibited within 100 ms by a 0.5 A, 12 Vdirect current.

Furthermore, Staphylococcus aureus, Staphylococcus epidermidis,E. coli, Klebsiella pneumoniae and Proteus mirabilis on intravascularcatheters were reduced by 0.01 A direct electric current [52].

In addition, V. parahaemolyticus in effluent seawater was inac-tivated by 3 A alternating current within 30 ms [53].

In the present study, both E. coli strains in the Medium I wereinactivated within 5–10 min by 1 A AC treatment. 1.5 A AC treatmentinactivated the test strains within 3–5 min, though 2 A AC treatmentinactivated these strains within 1–3 min. 0.5 A AC treatment wasenough to kill both test strains in the Medium II within 5 min. In theMedia III, IV and V, the inactivation of the test strains occurred within1 min by 1 A, 1.5 A and 2 A AC treatment. While both strains in theMedium VI were killed by 1 A AC treatment within 3 min,1.5 A and 2 AAC treatment killed both strains within 1 min. Although 1 A ACtreatment in the Medium VII inactivated E. coli ATCC 25922 within20 min, E. coli MAAG 1405 was inactivated within 35 min. Further-more, E. coli ATCC 25922 in the Medium VII was inactivated by 1.5 A ACtreatment within 10 min but long exposure time (20 min) of ACtreatment was necessary to inactivate E. coli MAAG 1405. Five minutesof 2 A AC treatment was enough to completely inactivate E. coli ATCC25922 whereas E. coli MAAG 1405 was inactivated within 10 mintreatment in the Medium VII. It was thought that long inactivationtimes of E. coli strains in the Medium VII were due to lower salinityandthus the lower conductivity of the medium (Fig. 2).

The pH of all the water samples was between 6 and 7, and didnot change during AC treatment.

Fig. 2. Time-based inactivation data of the E. coli strains tested in different media (I–VII). *log10(CFU/mL); **min.

M. Birbir et al. / Journal of Electrostatics 67 (2009) 640–645 643

M. Birbir et al. / Journal of Electrostatics 67 (2009) 640–645644

Although AC has bactericidal effect, little is known about theprecise mechanisms of inactivating effects of electric currentagainst bacteria. The mechanism of electric current activity mayinclude disruption of bacterial membrane integrity and electrolysisof molecules on cell surface [53,57,58]. Also, chlorides, after beingelectrolyzed to chlorine gas, are involved in the inactivationmechanism [57–59].

It was found that the concentration of Cl2 in the AC-treatedseawater was considerably less than that in seawater treated withDC. Thus, researchers mentioned that AC treatment which disin-fects seawater and resolves the problem of chlorine generation ismore suitable than DC treatment for practical applications. Disin-fection with DC is not suitable for large-scale treatment of seawaterbecause of the generation of chlorine gas. Because the AC polarityalternates periodically, the seawater undergoes less electrolysis,which results in reduced generation of chlorine [53].

4. Conclusion

AC treatment as a water disinfection method was proved to bea very effective way to kill E. coli strains in the polluted rivers,discharge points of rivers and water samples containing organicpollution. Our experimental results suggest that alternative electriccurrent may be used as a simple and effective method to inactivatefecal coliform bacteria in discharges of polluted open rivers andsewage. The low conductivity problem of the treated sewage maybe solved by addition of NaCl (less than 2%) into the water.

Furthermore, this system may be used to prevent transmissionof antibiotic-resistant bacteria to humans through contaminatedmarine water.

Acknowledgements

This work was supported by the Scientific Research ProjectCommission of Marmara University, Project No. FEN-YLS-200407-0084. We thank the Scientific Research Project Commission. Weexpress our appreciation to Michele Goebel, MSM and Dick Goebel,DVM for their helpful guidance and comments on this manuscript.We thank also Cennet Çelik, MSc, Didem Berber, MSc and Mr. HakanDemir for their assistance.

References

[1] H. Shuval, Estimating the global burden of thalassogenic diseases: humaninfectious diseases caused by wastewater pollution of the marine environ-ment, J. Water Health 1 (2) (2003) 53–64.

[2] World Health Organization (WHO), Swimming pools, spas and similar recre-ational-water environments, in: Guidelines for Safe Recreational Water Envi-ronments, vol. 2, WHO, Geneva, Switzerland, 2005.

[3] M.A. Yukselen, B. Calli, O. Gokyay, A. Saatci, Inactivation of coliform bacteria inBlack Sea waters due to solar radiation, Environ. Int. 29 (2003) 45–50.

[4] A. Pruss, Review of epidemiological studies on health effects from exposure torecreational water, Int. J. Epidemiol. 27 (1998) 1–9.

[5] K. Reynolds, Collateral damage: the chronic sequelae of waterborne patho-gens, Water Conditioning and Purification Magazine 45 (8) (2003) 3.

[6] K. Pond, Water Recreation and Disease. Plausibility of Associated Infections:Acute Effects, Sequelae and Mortality World Health Organization (WHO), IWAPublishing, London, 2005.

[7] R.H. Dwight, L.M. Fernandez, D.B. Baker, J.C. Semenza, B.H. Olson, Estimatingthe economic burden from illnesses associated with recreational waterpollution – a case study in Orange County, California, J. Environ. Manag. 76(2005) 95–103.

[8] A. Bruneau, H. Rodrigue, J. Ismael, R. Dion, R. Allard, Outbreak of Escherichiacoli O157:H7 associated with bathing at a public beach in the Montreal-Centreregion, Can. Commun. Dis. Rep. 30 (2004) 133–136.

[9] R.H.S.F. Vieira, D.P. Rodrigues, N.S.S. Evangelista, G.N.D. Teophilo, E.M.F. Reis,Colimetry of marine waters off Fortaleza, Brazil and detection of entero-pathogenic Escherichia coli strains, Int. Microbiol. 1 (1998) 221–224.

[10] R. Hirsch, T. Ternes, K. Haberer, K.-L. Kratz, Occurrence of antibiotics in theaquatic environment, Sci. Total Environ. 225 (1999) 109–118.

[11] M.D. Hernando, M. Mezcua, A.R. Fernandez-Alba, D. Barcelo, Environmentalrisk assessment of pharmaceutical residues in wastewater effluents, surfacewaters and sediments, Talanta 69 (2006) 334–342.

[12] M.T. Madigan, J.M. Martinko, P.V. Dunlap, D.P. Clark, Brock Biology ofMicroorganisms, 12th ed. Pearson Benjamin Cummings, San Francisco, USA,2009.

[13] K.M. Nielsen, M.D.M. Van Weerelt, T.N. Berg, A.M. Bones, A.N. Hagler, J.D. VanElsas, Natural transformation and availability of transforming DNA toAcinetobacter calcoaceticus in soil microcosms, Appl. Environ. Microbiol. 63(1997) 1945–1952.

[14] K.E. Wommack, R.R. Colwell, Virioplankton: viruses in aquatic ecosystems,Microbiol. Mol. Biol. Rev. 64 (2000) 69–114.

[15] H. Heuer, E. Krogerrecklenfort, E.M.H. Wellington, S. Egan, J.D. Van Elsas, L. VanOverbeek, J.-M. Collard, G. Guillaume, A.D. Karagouni, T.L. Nikolakopoulou,K. Smalla, Gentamicin resistance genes in environmental bacteria: prevalenceand transfer, FEMS Microbiol. Ecol. 42 (2002) 289–302.

[16] M. Furushita, T. Shiba, T. Maeda, M. Yahata, A. Kaneoka, Y. Takahashi, K. Torii,T. Hasegawa, M. Ohtal, Similarity of tetracycline resistance genes isolated fromfish farm bacteria to those from clinical isolates, Appl. Environ. Microbiol. 69(2003) 5336–5342.

[17] R.H. Kelsey, G.I. Scott, D.E. Porter, B. Thompson, L. Webster, Using multipleantibiotic resistance and land use characteristics to determine sources of fecalcoliform bacterial pollution, Environ. Monit. Assess. 81 (2003) 337–348.

[18] C.D. Miranda, C. Kehrenberg, C. Ulep, S. Schwarz, M.C. Roberts, Diversity oftetracycline resistance genes in bacteria from Chilean salmon farms, Anti-microb. Agents Chemother. 47 (2003) 883–888.

[19] G. Altug, I. Onac-Icoz, Antibiotic resistant strains and bacterial metabolicactivity in the Western Black Sea, Turkey, presented at the Black SeaEcosystem 2005 and Beyond, in: The 1st Biannual Scientific Conference,Istanbul, Turkey, 2006.

[20] G. Altug, M. Çardak, P.S. Ciftçi, The levels of indicator bacteria and antibioticresistance strains of the Western Black Sea region, Turkey, presented at the2nd Biannual and Black Sea Scene, in: EC Project Joint Conference, Sofia,Bulgaria, 2008.

[21] J.B. Kaper, J.P. Nataro, H.L.T. Mobley, Pathogenic Escherichia coli, Nat. Rev.Microbiol. 2 (2004) 123–140.

[22] H.F. Diao, X.Y. Li, J.D. Gu, H.C. Shi, Z.M. Xie, Electron microscopic investigationof bactericidal action of electrochemical disinfection in comparison withchlorination, ozonation and Fenton reaction, Process Biochem. 39 (2004)1421–1426.

[23] K.E. Longley, Manuals of Practice for Water Pollution Control, Water PollutionControl Federation, Alexandria, VA, USA, 1986.

[24] G.C. White, Handbook of Chlorination and Alternative Disinfectants, fourth ed.Wiley, New York, 1999.

[25] S.C. Prescott, The treatment of milk by an electrical method, Am. J. PublicHealth 17 (1927) 221–223.

[26] G. Patermaraxis, E. Fountoukidis, Disinfection of water by electrochemicaltreatment, Water Res. 24 (1990) 1491–1496.

[27] X.-G. Li, H.-B. Cao, J.-C. Wu, K.-T. Yu, Inhibition of the metabolism of nitrifyingbacteria by direct electric current, Biotechnol. Lett. 23 (2001) 705–709.

[28] I. Ye, H. Yang, H.K. Kim, Y. Li, Inactivation of Listeria monocytogenes inrecirculated brine for chilling thermally processed bacon using an electro-chemical treatment system, J. Food Sci. 66 (2001) 729–733.

[29] J.C. Park, M.S. Lee, D.H. Lee, B.J. Park, D.W. Han, M. Uzawa, K. Takatori,Inactivation of bacteria in seawater by low-amperage electric current, Appl.Environ. Microbiol. 69 (2003) 2405–2408.

[30] G. Altug, H.C. Yardımcı, Marmara Denizi kıyısal alanında (Avcılar-Sarıyer)bakteriyolojik kirlilik duzeyi ve Enterobacteriaceae uyelerinin bazı betalaktam antibiyotiklerine dirençlilik frekansı, presented at XIII, in: Ulusal SuUrunleri Sempozyumu, Çanakkale, Turkiye, 2005.

[31] CLSI, Antimikrobik Duyarlılık Testleri için Uygulama Standartları, OnsekizinciBilgi Eki, M100-S18, Cilt 28, Sayı 1, Turk Mikrobiyoloji Cemiyeti, 2008.

[32] Y. Birbir, M. Birbir, Inactivation of extremely halophilic hide-damagingbacteria via low-level direct electric current, J. Electrostat. 64 (2006) 791–795.

[33] T.D.M. Melo, R.S.F. Vieira, S. Saker-Sampaio, E. Hofer, Coliforms and Salmonellain seawater near to domestic sewage sources in Fortaleza (Ceara, Brazil),Microbiologia SEM 13 (1997) 463–470.

[34] L.J. Saliba, R. Helmer, Health risks associated with pollution of coastal bathingwaters, World Health Stat. Q. 43 (1990) 177–184.

[35] R.H. Dwight, D.B. Baker, J.C. Semenza, B.H. Olson, Health effects associatedwith recreational coastal water use: urban versus rural California, Am. J. PublicHealth 94 (2004) 565–567.

[36] H.W. Smith, Incidence in river water of Escherichia coli containing R factors,Nature 228 (1970) 1286–1288.

[37] H.W. Smith, Incidence of Rþ Escherichia coli in coastal bathing waters ofBritain, Nature 234 (1971) 155–156.

[38] T.W. Feary, A.B. Sturtevant, J. Lankford, Antibiotic-resistant coliforms in freshand salt water, Arch. Environ. Health 25 (1972) 215–220.

[39] P.R. Smith, E. Farrell, K. Dunican, Survival of Rþ Escherichia coli in sea water,Appl. Microbiol. 18 (1974) 983–984.

[40] M.D. Cooke, Antibiotic resistance among coliform and fecal coliform bacteriaisolated from sewage, seawater, and marine shellfish, Antimicrob. AgentsChemother. 9 (1976) 879–884.

[41] M. Denton, N.J. Todd, K.G. Kerr, P.M. Hawkey, J.M. Littlewood, Molecularepidemiology of Stenotrophomonas maltophilia isolated from clinical

M. Birbir et al. / Journal of Electrostatics 67 (2009) 640–645 645

specimens from patients with cystic fibrosis and associated environmentalsamples, J. Clin. Microbiol. 36 (1998) 1953–1958.

[42] NRC, From Monsoons to Microbes: Understanding the Ocean’s Role in HumanHealth, National Academy Press, Washington, DC, 1999.

[43] H. Hanberger, D. Diekema, A. Fluit, R. Jones, M. Struelens, R. Spencer, M. Wolff,Surveillance of antibiotic resistance in European ICUs, J. Hosp. Infect. 48(2001) 161–176.

[44] H.C. Neu, The crisis in antibiotic-resistance, Science 257 (1992) 1064–1073.[45] S.B. Levy, Antibiotic resistance: consequences of infection, Clin. Infect. Dis. 33

(2001) 124–129.[46] T. Hosbul, M. Ozyurt, A. Erdemoglu, B. Bektore, N. Ardıc, T. Haznedaroglu, Gata

Haydarpasa Egitim Hastanesi, Mikrobiyoloji ve Klinik Mikrobiyoloji Servisi E.coli Nedenli Komplike Olmamıs Uriner Sistem _Infeksiyonlarında FosfomisinTrometamol’un In vitro Etkinligi, in: The XXXIII Turkish MicrobiologyCongress, Bodrum, Turkey, 2008.

[47] K. Hamelin, G. Bruant, A. El-Shaarawi, S. Hill, T.A. Edge, S. Bekal,J.M. Fairbrother, J. Harel, C. Maynard, L. Mason, R.A. Brousxau, Virulence andantimicrobial resistance DNA microarray detects a high frequency of virulencegenes in Escherichia coli isolates from Great Lakes recreational waters, Appl.Environ. Microbiol. 72 (2006) 4200–4206.

[48] C.P. Davis, N. Wagle, M.D. Anderson, M.M. Warren, Bacterial and fungal killingby iontophoresis with long-lived electrodes, Antimicrob. Agents Chemother.35 (1991) 2131–2134.

[49] A. Pareilleux, N. Sicard, Lethal effects of electric current on Escherichia coli,Appl. Microbiol. 19 (1970) 421–424.

[50] L. Bolton, B. Foleno, B. Means, S. Petrucelli, Direct-current bactericidal effect onintact skin, Antimicrob. Agents Chemother. 18 (1980) 137–141.

[51] Y. Birbir, D. Degirmenci, M. Birbir, Direct electric current utilization indestruction of extremely halophilic bacteria in salt which is used in brinecuring of hide, J. Electrostat. 66 (2008) 388–394.

[52] W.K. Liu, S.E. Tebbs, P.O. Byrne, T.S. Elliot, The effects of electric current onbacteria colonizing intravenous catheter, J. Infect. 27 (1993) 261–269.

[53] J.-C. Park, M.S. Lee, D.-H. Han, D.H. Lee, B.J. Park, I.-S. Lee, D.W. Han, M. Uzawa,M. Aihara, K. Takatori, Inactivation of Vibrio parahaemolyticus in effluentseawater by alternating-current treatment, Appl. Environ. Microbiol. 70(2004) 1833–1835.

[54] T. Matsunaga, S. Nakasono, T. Takamuku, J.G. Burgess, N. Nakamura, K. Sode,Disinfection of drinking water by using a novel electrochemical reactoremploying carbon-cloth electrodes, Appl. Environ. Microbiol. 58 (1992)686–689.

[55] Y. Birbir, G. Ugur, M. Birbir, Inactivation of bacterial population in hide soakliquors via direct electric current, J. Electrostat. 66 (2008) 355–360.

[56] H. Tokuda, K. Nakanishi, Application of direct current to protectbioreactor against contamination, Biosci. Biotechnol. Biochem. 18 (1995)185–212.

[57] C.P. Davis, M.E. Shirtliff, N.M. Trieff, S.L. Hoskins, M.M. Warren, Quantification,qualification, and microbial killing efficiencies of antimicrobial chlorine-basedsubstances produced by iontophoresis, Antimicrob. Agents Chemother. 38(1994) 2768–2774.

[58] W.K. Liu, M.R.W. Brown, T.S.J. Elliot, Mechanism of the bactericidal activity of lowamperage electric current (DC), J. Antimicrob. Chemother. 39 (1997) 687–695.

[59] S.A. Jackman, G. Maini, A.K. Sharman, C.J. Knowles, The effects of direct electriccurrent on the viability and metabolism of acidophilic bacteria, EnzymeMicrob. Technol. 24 (1999) 316–324.