Prevalence, molecular fingerprinting and drug resistance profile of enterovirulent Escherichia coli isolates from free-ranging yaks of Tawang district, Arunachal Pradesh, India

Abstract

Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid, nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant for repeated occurrence of diarrhea in yaks.

Antibiotic resistance, serogroups, virulence genes, and phylogenetic groups of Escherichia coli isolated from yaks with diarrhea in Qinghai Plateau, China

“…The high prevalence of O91 and O145 identified was inconsistent with the findings of previous reports from patients with diarrhea [44, 45]. Serogroups O2, O8, O60, O61, O66, O91, O97, O117, O158, O159, O165, and O172 were earlier identified in humans and animals with diarrhea [2, 6, 46, 47]. However, the serogroups O2 and O60 were also reported in MDR uropathogenic isolates of E. coli from patients with prostatitis, simple UTI, pyelonephritis, and cystitis in India [29].…”

“…Conversely, all isolates were negative for the InPEC-associated toxin genes ( stx1, stx2, exhA, eltA, and estA), but positive for ExPEC-associated toxin genes ( cnf1 and hly A). Such observation has not been commonly described in previous reports of E. coli isolates of animal origin [2, 7, 10, 17]. This observed variation could be attributed to the existing climatic conditions which may account for the diverse occurrence of virulence-associated genes.…”

“…While Escherichia coli is an important part of the microbiota of the intestinal tract of animals and humans, certain E. coli pathotypes are implicated in different animal and human infections [1, 2]. The pathogenicity of E. coli is determined by particular virulence traits such as capsules, toxins, invasions, adhesions, haemolysins, cytotoxic necrotic factors, and effacement factors [3].…”

“…However, frequent outbreaks of fatal hemorrhagic diarrhea in yaks are a serious concern from both a veterinary and a human health perspective [2, 4]. As such, it is important to know, which virulence genes, phylogroups, serogroups, and antibiotic resistance patterns are present in commensal E. coli strains in yaks with diarrheic infections.…”

Shiga Toxin-Producing Escherichia coli in Yaks (Bos grunniens) from the Qinghai-Tibetan Plateau, China

“…Bandyopadhyay et al . [39] recovered 42 STEC isolates from 273 rectal swab samples (15.38%) in an STEC study of the yak Poephagus grunniens . Our results showed a similar rate of STEC isolation.…”