Diarrheogenic Escherechia coli in potable water sources of West Bengal, India (original) (raw)
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American Journal of Tropical Medicine and Hygiene, 2019
Although access to piped drinking water continues to increase globally, information on the prevalence and clonal composition of coliforms found in piped water systems in low-resource settings remains limited. From June to July 2016, we examined Escherichia coli isolates in domestic water from the distribution system in Alibag, a small town in India. We analyzed the isolates for drug resistance and genotyped them by multilocus sequence typing. Of 147 water samples, 51 contained coliforms, and 19 (37%) of the 51 were biochemically confirmed to contain E. coli. These samples contained 104 E. coli isolates-all resistant to ampicillin. Resistance to ceftazidime was observed in 52 (50%) isolates, cefotaxime in 59 (57%), sulfamethoxazole-trimethoprim in 46 (44%), ciprofloxacin in 30 (29%), and gentamicin in two (2%). Thirty-eight (36%) belonged to sequence types recognized as extraintestinal pathogenic E. coli (ExPEC); 19 (50%) of these 38 ExPEC belonged to known uropathogenic E. coli lineages. This exploratory field research shows the extent to which "improved" drinking water is a potential source of E. coli strains capable of causing extraintestinal infections. The prevalence of bacteria resistant to antimicrobial agents is a serious threat to global public health. Studies have shown that human activity is correlated with increased prevalence of genes conferring resistance to antimicrobial agents in the environment. 1 Specifically, this increase in resistance is correlated with the introduction of antimicrobial agents and bacteria resistant to antimicrobial agents into the environment through activities known to occur in low-resource settings, such as wastewater dumping. 2 When piped drinking water contains agents such as NDM-1, a metallo-beta-lactamase, even the highest rung of the Joint Monitoring Program's "im-proved" water ladder is not safe. 3,4 The risks are potentially high in small towns of the global South, where water treatment and water quality data are both limited. As Escherichia coli is easily eliminated from drinking water, researchers use it as an indicator bacterium to determine whether water has recently been exposed to feces and whether it is safe for consumption. Its presence in more than 5% of drinking water samples indicates that the water treatment (if any) is inadequate to eliminate more harmful bacteria such as Campylobacter or Salmonella. 5 Detection of E. coli can also indicate either treatment inadequacy or posttreat-ment contamination. When considering an intermittent system , the possibility of posttreatment contamination is high. Few researchers have conducted in-depth microbiological studies of drinking water distribution systems; their focus has largely been on general bacterial community analysis or calculating the number of colony-forming units of E. coli. 6-8 The use of E. coli solely as a fecal indicator bacterium prevents researchers from understanding the public health impact of its antimicrobial drug resistance and its potential to be a human pathogen. A subgroup of E. coli causes diarrhea and is responsible for foodborne diseases in both high-income and low-income countries. 9 Another group of E. coli causes extraintestinal infections, referred to as extraintestinal pathogenic E. coli (ExPEC). It is the leading cause of Gram-negative bacter-emia and the most common cause of urinary tract infections (UTI), an infection primarily affecting women; both are potentially lethal if left untreated. 10,11 This exploratory study in a "typical" small town in India sought to determine what proportion of E. coli strains used as an indicator bacterium in field drinking water tests are drug-resistant, and are potential human pathogens. Alibag, Maharashtra, is a coastal tourist city with a population of 20,743. 12 Its piped drinking water system is intermittently supplied with water by the Maharashtra Industrial Development Corporation (MIDC). The MIDC drinking water treatment plant sources drinking water from the Amba River and treats the raw water using liquid alum sul-fate, flash mixing, flocculation/settling, sand filtration, and chlorination with Cl 2 gas to 0.2 ppm. The treated water is then tested four times a day by an MIDC chemist for multiple contaminants. Water samples were collected from the water distribution system over an 8-week period from June to July 2016, which evenly captured the end of summer and the onset of the monsoon season. Samples were collected once a week from the treated water at the MIDC and from one of the three elevated storage reservoirs from which water is piped to households. Many households stored water in rooftop tanks connected to the distribution system to cope with its intermittent deliveries. Point-of-use samples were taken from households with in-home taps; for households collecting water from a public tap connected to the distribution system, points-of-collection samples were taken during their scheduled water allocations. Households were sampled such that the service area of the drinking water system was adequately covered. Water samples for quantification of bacteria were collected and processed with the compartment bag test (CBT) (Aqua-genx, Chapel Hill, NC), which uses a β-D-glucuronide E. coli indicator. 13 As per the CBT protocol, drinking water was collected in presterilized 100-mL pouches with a sodium thio-sulfate tablet to neutralize any residual chlorine-samples
Enterotoxigenic Escherichia coli (ETEC) is a causative agents of diarrhea. Humans and non humans can acquire infections primarily through consumption of contaminated water. In India, ETEC has been concerned as a foremost cause of diarrhea. The pathogen harbors LT1 signature gene responsible for its virulence. The prevalence of drug resistance ETEC in water is of great concern. The present paper aims to isolate and characterize drug resistant virulent isolates of ETEC in potable water collected from different locations (n=6) of urban settings in Gwalior city. Further the samples were characterized using conventional culture methods and molecular methods. All identified ETEC isolates were subjected to antibiotic susceptibility testing. Our study indicates the existence of pathogenic drug-resistant isolates in potable water of Gwalior. Site 1 exhibited maximum intermediate isolates for antibiotics which is alarming and of great concern where as site 4 exhibited maximum resistance isolates of ETEC. This study may help in risk assessment posed by the infections due to persistence of antibiotic resistant bacteria in potable waters. Keywords: Enterotoxigenic E. coli, Diarrhea, Drug resistance bacteria, Potable water, Virulence determinants.
Spectrum of Diarrheagenic Escherichia coli in Drinking and Wastewater in Rafha City of Saudi Arabia
Journal of Pharmaceutical Research International
Introduction: E coli is one of the most important etiologic agent of diarrhea in children and adults. Based on the clinical features and virulence determinants, there are five major E. coli strains which cause diarrhea; Enterohemorrhagic E. coli (EHEC), Enteropathogenic E. coli (EPEC), Enterotoxigenic E. coli (ETEC), Enteroinvasive E. coli (EIEC) and Enteroaggregative E. coli (EAEC). The PCR based identification proves to be a better choice as it can differentiate between different strains on the basis of genetic difference. Aim: The purpose of the current study was to isolate diarrheagenic E. coli from the drinking and wastewater from Rafha city of Saudi Arabia. Methodology: One 100 drinking and wastewater samples (50 each) were included in the study. The samples were cultured on MacConkey agar plates at 37 oC for 24 hours. Pink colonies were carefully picked and subjected to DNA isolation and PCR detection and identification of E. coli and Diarrheagenic E. coli. The detected PCR p...
Objective: To investigate the virulence factors including hemolysin production, β-lactamase production, and biofilm formation. Antimicrobial resistance and plasmid content of 20 Escherichia coli isolates obtained from feces and Tigris water were screened. Methods: Ten clinical and ten environmental E. coli isolates were collected from children diarrhea and swim areas on Tigris River in Baghdad city, Iraq, respectively. The bacterial isolates were identified by cultural characteristics, Gram stain, biochemical tests, and screened for the presence of E. coli O157:H7 serotype. Bacterial E. coli isolates were investigated for hemo-lysin production, biofilm formation, and β-lactamase production. Antibiotics susceptibility and plasmid content were determined. Results: A total of ten clinical and ten water E. coli isolates were studied. Results showed that all E. coli isolates give negative results for latex O157:H7. Virulence factors analysis showed that 6/10 water isolates and 2/10 clinical isolates were hemolytic, 5/10 water isolates and 3/10 clinical isolates were biofilm formation, and 7/10 water isolates and 4/10 clinical isolates were β-lactamase producer. Antibiotics profile showed that all bacterial isolates were multidrug resistant. All E. coli isolates (100%) were resistant to carbenicillin, cefodizime, imipenem, and piperacillin. The plasmid DNA analysis showed that all E. coli isolates contained plasmid with molecular weight range between 4.507 kbp and 5.07 kbp, but clinical isolates contained multiple small and mega plasmids. Conclusion: Our study revealed that E. coli isolates from river water exhibit a higher level of hemolysin production, β-lactamase production, and biofilm formation than feces isolates may be due to long adaptation. On the other hand, clinical E. coli isolates from feces showed higher level of antibiotic resistance and have multiple plasmids.
Journal of Laboratory Physicians, 2012
Background: Diarrheal diseases are a major cause of morbidity and mortality in resource-limited countries. Among the bacterial pathogens, diarrheagenic E. coli (DEC) are most frequently implicated in cases of epidemic and endemic diarrhea worldwide. The objective of this study was to determine the prevalence of DEC in stool specimens from patients with acute diarrhea using polymerase chain reaction (PCR). Materials and Methods: Escherichia coli stool samples were collected from 115 hospitalized children and adults with acute diarrhea in Mangalore, a coastal city, in southern India. PCR amplification of eae, bfp, stx, ehx genes were used for detection of enteropathogenic (EPEC) and shigatoxigenic E. coli (STEC), lt and st genes were used for enterotoxigenic E. coli (ETEC) and astA gene for enteroaggregative E. coli (EAEC). Results: During the 24 month study period, of the 115 stool samples, DEC type was detected in 20 (17.4%) using the PCR method. The most prevalent DEC was atypical ...
Environmental Science and Pollution Research, 2015
We evaluated the antibiogram profile of Escherichia coli (n=300) isolated from selected rivers in Osun State, Nigeria. The identities of the E. coli isolates were confirmed by polymerase chain reaction (PCR) technique. Susceptibility of the isolates to 20 antibiotics conventionally used in clinical cases was assessed in vitro by the standardized agar disc-diffusion method. All the isolates were susceptible to imipenem, meropenem, amikacin and gatilofloxacin. The isolates were variously susceptible to the other antibiotics as follows: ciprofloxacin (96 %), kanamycin (95 %), neomycin (92 %), streptomycin (84 %), chloramphenicol (73 %), nalidixic acid (66 %), nitrofurantoin (64 %), gentamycin (63 %), doxycycline (58 %), cefepime (57 %), tetracycline (49 %) and cephalothin (42 %). The multiple antibiotic resistance indexing ranged from 0.50 to 0.80 for all the sampling locations and exceeded the threshold value of 0.2, suggesting the origin of the isolates to be of high antimicrobial usage. Our findings signify an increase in the incidence of antimicrobial resistance of E. coli towards conventionally used antibiotics necessitating proper surveillance programmes towards the monitoring of antimicrobial resistance determinants in water bodies.
Journal of Bangladesh Academy of Sciences, 2012
A total of 21 isolates were included randomly on the basis of their initial identification by the appearance of metallic sheen and from the biochemical traits to detect virulent markers of diarrhoeagenic E. Coli isolated from surface water. The antibiotic susceptibility pattern of the isolates were determined against six most commonly used antibiotics. About 52% of the isolates showed resistance to at least one of the antibiotics. About 38% of the isolates were resistant to more than one antibiotics. However, all the isolates were sensitive to gentamicin (CN). Among the 21 isolates, a total of 5 randomly selected isolates were examined for the detection of virulent genes (elt, est and stx) by PCR based method. Among the 5 tested isolates, 3 harbored the gene stx encoding Shiga toxin (Stx) and 2 to elt encoding heat-labile enterotoxin (LT). None of the isolates contained est encoding heat-stable enterotoxin (ST). Data revealed that as the virulent marker genes were detected, diarrho...
The objectives of this study were to assess the bacteriological quality of tap water samples obtained from different markets of different upazillas of Mymensingh, Sherpur & Gazipur district. For achieving the above mentioned objectives, methods of heterotrophic plate count (HPC) and total coliform count (TCC) were applied. Moreover, isolated E. coli from tap water samples were characterized by using biochemical test, molecular method and antimicrobial susceptibility tests. HPC was highest in market tap water collected from Kaligonj and TCC was highest in market tap water of collected from Mymensingh sadar. The geometric mean of HPC of Mymensingh, Gazipur and Sherpur districts water was 8.4x105 , 2.5 x106 and 6.8 x105 C.F.U/100 ml. Out of 20 isolates of E. coli, 20 isolates were amplified by using 16S rRNA gene based PCR. In respect to antimicrobial susceptibility testing, most of the E. coli isolates were susceptible to norfloxacin, ampicilin, tetracycline, streptomycin and ciprofloxacin. Furthermore, a few E. coli isolates were intermediate resistant to gentamycin and ciprofloxacin. However, a few of the E. coli isolates were resistant to erythromycin and amoxycilin. Moreover, out of 20 E. coli isolates 3 (15%) isolates were detected as multidrug resistant. This study indicated the presence of multidrug resistant E. coli isolates in tap water in Mymensingh, Sherpur and Gazipur districts that warrants particular attention.
International Journal of Scientific Research in Biological Sciences, 2019
Diarrhea caused by E. coli has been recognized as an important health problem among children in developing countries particularly in India and is a research priority of the diarrheal disease control program of the World Health Organization. Despite progress in preventing diarrhea and the spread of medical facilities in India, diarrhea remains the second leading cause of death in children, killing an estimated 321 children every day in 2015. It is the aim of the present research to gather information on current definitions, detection and prevalence, characterization of genetic determinants, virulence mechanisms, antibiotic resistance and epidemiology of the major DEC pathotypes with emphasis on the case studies conducted in the Bikaner region of Rajasthan in India. It has been found that the incidence of diarrheal diseases to be very high during the summer months followed by rainy or winter months in the Bikaner region of Rajasthan. Mode of water transportation, poor handling of water (at the household level), the presence of wastewater and unhygienic conditions predisposed children to diarrhea. In addition, indiscriminate stool disposal by mothers, lack of hand-washing before feeding their children or handwashing without soap has also been observed to be associated with the increased threat of diarrheal infection. The health associated risks of diarrheagenic E. coli in under-five children and the possible solutions to prevent the same are discussed.
BioMed Research International, 2020
Background. Diarrhea has been reported as the leading cause of childhood mortality and morbidity globally but with disproportionate impacts in developing nations. Among bacterial etiologic agents of diarrhea, diarrheagenic Escherichia coli is the main cause of the disease among children under the age of 5 years. This study is aimed at determining the prevalence and antibiogram pattern of diarrheagenic Escherichia coli (DEC) pathotypes associated with diarrhea cases in the study area. Methods. A total of 120 presumptive isolates of E. coli were obtained from diarrheal stool samples from male and female patients below 12 years of age using chromogenic agar. Confirmation of the isolates and screening for virulence genes were determined by polymerase chain reaction (PCR) while antimicrobial susceptibility testing was performed using the disk diffusion method. The presence of antibiotic resistance genes to chloramphenicol and tetracycline among the confirmed isolates was also profiled by PCR based on the observed phenotypic resistance pattern. Results. Of the 120 presumptive isolates, 88.3% (106/120) were confirmed as E. coli through PCR. The molecular pathotyping of the confirmed isolates showed their distribution as 41% (43/106) of diffusely adhering E. coli (DAEC), 17% (18/106) of enterohemorrhagic E. coli (EHEC), 17% (18/106) of enteropathogenic E. coli (EPEC), and 10% (11/106) of enteroinvasive E. coli (EIEC), while enteroaggregative E. coli (EAEC) and enterotoxigenic E. coli (ETEC) were not detected, and the remaining 15% did not belong to any pathotype. Notably, high resistance of the isolates to commonly used antimicrobials was observed as follows: ampicillin (98%), chloramphenicol (94%), trimethoprimsulfamethoxazole (96%), and tetracycline (90.6%), while a relatively low number of the confirmed isolates were resistant to ciprofloxacin (45%) and imipenem (36%). In addition, 94% of the isolates that exhibited phenotypic resistance against chloramphenicol harbored the catA1 resistance gene while 89% that showed resistance to tetracycline had tetA genes. Conclusions. These findings showed that DEC could be considered as the leading etiologic bacterial agent responsible for diarrhea in the study community, and the observable high degree of resistance of the isolates to antimicrobial agents is of huge significance, calling for stakeholders to adopt and consolidate the existing antimicrobial stewardship scheme of the government, in order to ensure an uncompromised public health.