Genetic diversity and antibiogram profile of diarrhoeagenic Escherichia coli pathotypes isolated from human, animal, foods and associated environmental sources

Abstract

IntroductionInfectious diarrhoea particularly due to pathogenic bacteria is a major health problem in developing countries, including India. Despite significant reports of diarrhoeagenic Escherichia coli (DEC) pathotypes around the globe, studies which address genetic relatedness, antibiogram profile and their correlation with respect to their isolation from different sources are sparse. The present study determines isolation and identification of DEC pathotypes from different sources, their genetic characterisation, antibiogram profile and their correlation if any.Materials and methodsA total of 336 samples comprising diarrhoeic stool samples from infants (n=103), young animal (n=106), foods (n=68) and associated environmental sources (n=59) were collected from Bareilly region of India. All the samples were screened by using standard microbiological methods for the detection of E. coli. The identified E. coli were then confirmed as DEC pathotypes using polymerase chain reaction–based assays. Those DEC pathotypes identified as Enteroaggregative E. coli (EAEC) were further confirmed using HEp-2 adherence assay. All the isolated DEC pathotypes were studied for their genetic diversity using pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing was performed by using disc diffusion method as per Clinical Laboratory Standards Institute guidelines.Results and discussionOf the four DEC pathotypes investigated, EAEC was found to be the predominant pathogen with an isolation rate of 16.5% from infants, 17.9% from young animals, 16.2% from foods and 3.4% from the associated environmental sources. These EAEC isolates, on further characterisation, revealed predominance of ‘atypical’ EAEC, with an isolation rate of 10.7% from infants, 15.1% from young animals, 16.2% from foods, and 3.4% from the associated environmental sources. On PFGE analysis, discrimination was evident within DEC pathotypes as 52 unique pulsotypes were observed for 59 recovered DEC pathotypes. However, a few EAEC isolates were found to be clonal (clusters A, B, C, D, F, G, and H) irrespective of their source of isolation, suggests sharing and/or circulation among different sources. Further, a high antibiotic resistance pattern was observed among isolated DEC pathotypes as almost 86.4% of isolates were found to be resistant against ≥3 tested drugs.

Human, animal and environmental contributors to antibiotic resistance in low-resource settings: integrating behavioural, epidemiological and One Health approaches

“…The only statistically significant similarities in ABR profiles of EAEC isolates were for ciprofloxacin (human versus environmental, and animal versus environmental). This was explained by the widespread use of fluoroquinolones for diarrhoea treatment which then leads to both human and animal ciprofloxacin-resistant EAEC isolates that contaminate the environment through faecal waste [73]. Goat carcasses, faeces, equipment and environmental samples were examined in a large abattoir in a pastoralist region of Ethiopia [74].…”

Prevalence and virulence gene profiles of Escherichia coli O157 from cattle slaughtered in Buea, Cameroon

“…This does not occur in cattle because they lack the toxin receptors in their blood vessels. In addition to toxin production, E. coli O157 produces numerous other putative virulence factors including a protein called intimin, which is responsible for intimate attachment of the bacteria to the intestinal epithelial cells, causing attaching and effacing lesions in the intestinal mucosa and aiding in the attachment and colonisation of the bacteria in the intestinal wall [13]. Intimin is encoded by the chromosomal gene eaeA, which is part of a pathogenicity island termed the locus of enterocyte effacement.…”

Prevalence and Antibiotic Resistance of <i>Escherichia coli</i> O157:H7 Isolated from Raw Meat Samples of Ruminants and Poultry

“…Food samples with animal origin and especially meat have been found to harbor E. coli 0157:H7 with high levels of resistance against commonly used groups of antibiotics including quinolones, aminoglycosides, macrolides, cephalosporins, sulfonamides, fluoroquinolones and tetracycline [9][10][11][12][13][14][15]. Some antibiotic resistance genes including the genes that encode resistance to ampicillin (CITM), fluoroquinolone (qnr), gentamicin (aac(3)-IV), cephalothin (blaSHV), trimethoprim (dfrA1), sulfonamide (sul1), tetracycline (tetA and tetB), chloramphenicol (cat1 and cmlA) and aminoglycosides (aadA1 have been found to be responsible for antibiotic resistance in STEC strains [9][10][11][12][13][14]16,17,18].…”