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Journal of Infection and Molecular Biology

Research Article
J. Inf. Mol. Biol. 1 (4): 58 - 63
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Md. Zohorul Islam*, Abdul Ahad, Paritosh Kumar Biswas
Department of Microbiology, Chittagong Veterinary and Animal Sciences University, Chittagong–4225, Bangladesh
*Corresponding author: zahir_vet@yahoo.com

ABSTRACT
Cattle and other ruminants are natural reservoir of sorbitol non–fermenting shiga toxin producing Escherichia coli (SNF–STEC), and human beings can be infected through food chain. Likewise, anti-microbial resistant strain of animal origin may be transmitted to human. The objectives of this study were to determine the antimicrobial resistance profile of SNF–STEC isolated from smallholdings cattle. A total of 57 SNF E. coli isolates were tested, of which 88%, 84% and 82% were sensitive to chloramphenicol, gentamicin and ciprofloxacin, respectively. All the isolates (100%) were resistant to penicillin, whereas, 53% were resistant to trimethoprim–sulfamethoxazole. Among the 57 SNF E. coli, 28 were shiga toxin producing (carrying stx1 or stx2 gene) which exhibited the highest resistance (57%) against trimethoprim–sulfamethoxazole and tetracycline, and the lowest (4%) against chloramphenicol. Of the Stx1 genotypic isolates, 60% and 40% were resistant to trimethoprim–sulfamethoxazole and ampicillin, respectively. On the other hand, 58% Stx2 genotypic isolates were resistant to tetracycline, whereas 44% both of hly and eae genotypic isolates were resistant to trimethoprim–sulfamethoxazole. About 60% isolates carrying all the three STEC virulent genes were resistant to ≥ 2 antimicrobials; among them one isolate was resistant to six antimicrobials – ceftriaxone, nalidixic acid, ciprofloxacin, tetracycline, doxycycline and trimethoprim–sulfamethoxazole. Isolates having no virulent gene, but harboring 54.2 kb sized plasmid were resistant to tetracycline. sulfamethoxazole, ampicillin and amoxicillin.

Key Words: STEC; Anti-microbials; Resistance; Plasmid