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Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates
Published on: May 30, 2017
Multiresistant Vibrio cholerae non-O1/non-O139 from waters in South India: resistance patterns and
Sankar Jagadeeshan1, Praveen Kumar, Wilson Peter Abraham
1Cholera and Environmental Microbiology Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, Kerala, India.
Abstract:
From different aquatic locations in Alleppey district, Kerala, South India a number (n = 36) of multiresistant non-O1, non-O139 V. cholerae strains were isolated. Water samples were filtered through 0.22 mum membrane filters, enriched in alkaline peptone water and plated onto thiosulfate-citrate-bile salts-sucrose (TCBS) agar. The isolates were resistance to cefotaxime (50%), nalidixic acid (44.4%), streptomycin and tetracycline (41.6%), trimethoprim (38.8%), co-trimoxazole (33.3%), furazolidone (27.7%), neomycin and ofloxacin (19.4%), ciprofloxacin, norfloxacin and spectinomycin (16.6%), gentamicin (8.3%) and chloramphenicol (2.7%). To our knowledge, this is the first report from Kerala, South India on the emergence of multiple drug resistance in V. cholerae isolates belonging to serogroup other than O1 and O139. Virulence-associated gene profiling of the isolates by PCR revealed the presence of toxR (100%), rtxA (61.1%), hlyA (50%), mshA (33.3%), tcpA-acfB (13.8%) and st (2.7%) genes. The virulence gene clusters ctxA, ompU, ace, and zot were not detected. This study demonstrates the presence of a wide array of critical virulence factors in diverse strains of Vibrio cholerae non-O1/non-O139. Hence, this serogroup can no longer be ignored as an environmental reservoir of virulence genes.
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