Isolation,molecular characterization and antibiotic resistance of Shiga Toxin–Producing Escherichia coli (STEC) from buffalo in India |
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| Authors: | A. Mahanti I. Samanta S. Bandopaddhay S.N. Joardar T.K. Dutta S. Batabyal T.K. Sar D.P. Isore |
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| Affiliation: | 1. Department of Veterinary Microbiology, West Bengal University of Animal and Fishery Sciences, , Kolkata, West Bengal, India;2. Eastern Regional Station, Indian Veterinary Research Institute, , Kolkata, West Bengal, India;3. College of Veterinary Science, Central Agricultural University, , Aizawl, Mizoram, India;4. Department of Veterinary Biochemistry, West Bengal University of Animal and Fishery Sciences, , Kolkata, West Bengal, India;5. Department of Veterinary Pharmacology & Toxicology, West Bengal University of Animal and Fishery Sciences, , Kolkata, West Bengal, India |
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| Abstract: | In total, 363 Escherichia coli were isolated from 165 faecal samples of healthy buffaloes in West Bengal, India. Twenty‐four of these isolates (6·61%) were found to carry at least one gene characteristic for Shiga toxin–producing Escherichia coli (STEC). These STEC strains belonged to 13 different O‐serogroups. The stx1 gene was present in 23 (95·8%) of total STEC isolates, whereas 20 (83·3%) STEC isolates carried the gene stx2. Twelve strains of E. coli (50% of total STEC isolates) possessed enterohaemolysin (ehxA) gene in combination with others. Fourteen (58·33%) isolates found to possess saa gene. However, no E. coli was detected harbouring gene for intimin protein (eaeA). Of 23 stx1‐positive isolates, seven (30·43%) were positive for genes of the stx1C subtype. Of the 20 isolates with the stx2 gene, 25% (5/20) possessed stx2C and 10% (2/20) possessed stx2d gene. The phylogenetic analysis after RAPD of STEC strains revealed six major clusters. The isolated STEC strains were resistant most frequently to erythromycin (95·83%), cephalothin (62·5%), amikacin (54·17%), kanamycin (45·83%) and gentamicin (41·67%) group of antibiotics. No ESBL‐producing (blaCTXM, blaTEM, blaSHV) or quinolone resistance gene (qnrA) was detected in the STEC isolates. Significance and Impact of the Study The buffaloes from different districts of West Bengal, India, are important reservoir of multidrug‐resistant Shiga toxin–producing Escherichia coli (STEC). India is home to more than 56% of world buffalo population, traditionally raised by farmers. So, there is a major risk of transmission of STEC among the human population of this part of the globe. However, there is no prevalence study of STEC from healthy or diarrhoeic buffalo in India. The present study reports for the first time in India about isolation, molecular characterization and antibiotic resistance pattern of STEC in healthy buffaloes. |
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| Keywords: | antibiotic resistance buffalo India Shiga toxin– producing Escherichia coli West Bengal |
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