title: Serogroups, atypical biochemical characters, colicinogeny and antibiotic resistance pattern of Shiga toxin-producing Escherichia coli isolated from diarrhoeic calves in Gujarat, India.
abstract: This study was designed to investigate the antibiotic resistance, colicinogeny, serotyping and atypical biochemical characteristics of 41 Shiga toxin-producing Escherichia coli (STEC) strains detected using polymerase chain reaction from 90 E. coli strains isolated from 46 diarrhoeic calves. The STEC strains belonged to 14 different serogroups. Seventeen per cent of the STEC strains carried the eaeA gene while 14.28% of the 49 non-STEC strains were eaeA positive. Twenty eight (68.29%) of the 41 STEC strains were rhamnose non-fermentors. All the STEC strains revealed resistance to at least three of the antibiotics tested. 100% resistance was found against kanamycin and cephalexin followed by cephaloridine, enrofloxacin, amikacin, ampicillin, tetracycline, ceftiofur, ciprofloxacin, colistin and co-trimoxazole. Eighteen (44%) of the STEC strains produced colicin and all these colicinogenic strains were resistant to three or more antibiotics. Eleven STEC strains (26.82%) showed urease activity. The results of this study suggest that diarrhoeic calves are an important reservoir of STEC strains that are potentially pathogenic for farm animals and humans. Moreover, rhamnose fermentation, colicinogeny and atypical biochemical behaviour, such as urease activity, may serve as important markers or diagnostic tools for epidemiological surveys to trace the source of infection in disease outbreaks.
authors.affiliation: Department of Veterinary Microbiology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand 388 001, Gujarat, India. gitanjali.arya@mail.mcgill.ca
authors.forename: G
authors.initials: G
authors.lastname: Arya
authors.forename: A
authors.initials: A
authors.lastname: Roy
authors.forename: V
authors.initials: V
authors.lastname: Choudhary
authors.forename: M M
authors.initials: MM
authors.lastname: Yadav
authors.forename: C G
authors.initials: CG
authors.lastname: Joshi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D004197:Disease Reservoirs / Q000382:microbiology / Q000662:veterinary; D024881:Drug Resistance, Bacterial; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D011634:Public Health; D012703:Serotyping; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000187:drug effects; D015047:Zoonoses
chemical_list: D000900:Anti-Bacterial Agents