Vibrio cholerae O1 biotype El Tor, the causative agent of the seventh pandemic, has recently been replaced by strains carrying classical and Haitian ctxB in India, Haiti and other parts of the world. We conducted phenotypic and genetic tests to characterize V. cholerae O1 isolated between 2012 and 2014 from Silvassa, India, to examine the presence of virulence and regulatory genes, seventh pandemic marker, ctxB type and biofilm formation and to study genomic diversity. Of the 59 V. cholerae O1, eight isolates belong to El Tor prototype, one to classical prototype and the remaining isolates have attributes of both classical and El Tor biotypes. PCR and ctxB gene sequencing revealed the presence of classical ctxB in four strains and Haitian ctxB in 55 isolates; indicating that isolates were either an El Tor or hybrid variant. All isolates carried virulence, regulatory, adherence, Vibrio seventh pandemic pathogenicity island I and seventh pandemic group-specific marker VC2346, in addition to tcpA ET and rstR ET , the features of seventh pandemic strains, and produced cholera toxin and biofilm. PFGE analysis showed that the majority of isolates are clonal and belong to fingerprint pattern A; however, pattern B is unrelated and patterns C and D are distinct, suggesting considerable diversity in the genomic content among them. These data thus show that isolates from Silvassa are genetically diverse and that Haitian ctxB and hybrid phenotypes are undergoing global dissemination.
Overall, these data suggest that classical ctxB-positive V. cholerae O1 El Tor strains that appeared in 2003 continue to cause infection in 2005 in Puri, India, and belong to identical ribotype(s) and/or pulsotype(s). There is need to continuous monitor the emergence of variant of El Tor because it will improve our understanding of the evolution of new clones of variant of V. cholerae.
This study thus indicates that multiple clones (ribotypes/pulsotypes) of V. cholerae O1 carrying pre-CTXΦ and/or CTXΦ and ctx-negative strains were present in the water of the River Ganga, Varanasi, India.
Vibrio alginolyticus, a halophilic Gram-negative bacterium, which is found in temperate marine and estuarine environments, is known to cause infections in humans and other organisms. We sequenced the genome of sulfamethoxazole-trimthoprim-positive V. alginolyticus strain 4-19 isolated from the mucus of the coral Fungia danai in the Andaman Sea, India.
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