During the cholera epidemic of 2002 in and around Hubli, south India, Vibrio cholerae strains resistant to fluoroquinolones were isolated. Among the isolates of V. cholerae non-O1, non-O139 serogroups, 55.9% and 47.1% were resistant to norfloxacin and ciprofloxacin, respectively. However, only 12.5% of the O1 serogroup strains were resistant to both norfloxacin and ciprofloxacin. Though the O139 serogroup strains were susceptible to these antibiotics, they exhibited multidrug resistance. Emergence of fluoroquinolone-resistant V. cholerae that also exhibited multidrug resistance is of great significance in the epidemiology and control of cholera.
"Non-O1 non-O139 serotypes of V. cholerae are increasingly being reported as the causal agents of severe gastrointestinal disorders (Chatterjee et al., 1998; Das & Gupta, 2005). And the isolation of multidrug-resistant clinical isolates has focused the need for a vaccine (Das & Gupta, 2005; Krishna et al., 2006). The choice of prospective vaccine targets is linked to immunodominant structures engaged in cholera pathogenesis (Kabir, 2005; Levine, 2010). "
[Show abstract][Hide abstract] ABSTRACT: We studied T-cell immune responses to surface capsular polysaccharide (CPS) of Vibrio cholerae O135 and its protein conjugate. CPS and CPS-bovine serum albumin (BSA) activation and presentation are characterized with induced alterations in expression and upregulation of membrane antigens CD25, CD11b, CD16/32, MHCII and CD45 on blood- and spleen-derived T cells. Expression of the early activation marker CD25 revealed efficient CPS-BSA conjugate activation especially of CD4(+) CD3(+) and CD8(+) CD3(+) cells. Specific CPS-BSA-induced CD25(+) T-cell subsets in blood were observed after the first application, i.e. a 4.2-fold increase of CD4(+) CD25(+) and 7.6-fold increase of CD8(+) CD25(+) vs. preimmune levels was determined. The upregulation of surface antigens MHCII and CD45 involved in antigen presentation and cell activation of CD3(+) cells and their significant reciprocal correlation (R(2) = 0.92) observed only with CPS-BSA conjugate suggested efficient T-cell dependency and presentation. The pattern of accelerated T-cell activation and engagement of T cells as antigen-presenting cells throughout CPS-BSA immunization contrary to CPS alone was also confirmed in CD4(+) /CD8(+) /CD3(+) splenic cells. The results revealed different T-cell antigen presentation and activation following administration of CPS and CPS-BSA conjugates, as supported also by evaluation of CD45, MHCII and CD25 expression on CD19(+) B cells.
"Most strains also showed resistance to streptomycin and nalidixic acid (Table 1). Such a complex resistance profile is quite common in Indian V. cholerae strains, known to be resistant to cotrimoxazole , beta-lactams, fluoroquinolones, and aminoglycosides as previously described (Thungapathra et al., 2002; Krishna et al., 2006). "
[Show abstract][Hide abstract] ABSTRACT: Integrative conjugative elements (ICEs) of the SXT/R391 family are self-transmissible mobile elements mainly involved in antibiotic resistance spread among γ-Proteobacteria, including Vibrio cholerae. We demonstrated that the recently described ICEVchInd5 is prevailing in V. cholerae O1 clinical strains isolated in Wardha province (Maharashtra, India) from 1994 to 2005. Genetic characterization by ribotyping and multiple-locus SSR analysis proved the same clonal origin for V. cholerae O1 isolates in Wardha province over an 11-year period and was used to assess the correlation between strain and ICE content among ours and different Indian reference strains. In silico analysis showed the existence of at least 3 sibling ICEs of ICEVchInd5 in V. cholerae O1 El Tor reference strains, isolated in the Indian subcontinent after 1992.
International journal of medical microbiology: IJMM 04/2011; 301(4):318-24. DOI:10.1016/j.ijmm.2010.11.005 · 3.61 Impact Factor
"Multiple antibiotic resistance among V. cholerae has emerged as a major problem worldwide (Faruque et al. 2007). In India, there is a progressive increasing trend of antibiotic resistance towards common fluoroquinolone, i.e., ciprofloxacin and norfloxacin since 1996 (Garg et al. 2001; Krishna et al. 2006). In this study, however, strains are sensitive to ciprofloxacin and norfloxacin but resistant to nalidixic acid, a non-fluorinated quinolone. "
[Show abstract][Hide abstract] ABSTRACT: Forty-four Vibrio cholerae isolates collected over a 7-month period in Chennai, India in 2004 were characterized for gene traits, antimicrobial susceptibility and genomic fingerprints. All 44 isolates were identified as O1 El Tor Ogawa, positive for various toxigenic and pathogenic genes viz. ace, ctxB, hlyA, ompU, ompW, rfbO1, rtx, tcpA, toxR and zot. Nucleotide sequencing revealed the presence of cholera toxin B of classical biotype in all the El Tor isolates, suggesting infection of isolates by classical CTXΦ. Antibiogram analysis showed a broad-spectrum antibiotic resistance that was also confirmed by the presence of resistant genes in the genomes. All isolates contained a class 1 integron and an SXT constin. However, isolates were sensitive to chloramphenicol and tested negative for the chloramphenicol resistant gene suggesting a deletion in SXT constin. Fingerprinting analysis of isolates by ERIC- and Box PCR revealed similar DNA patterns indicating the clonal dissemination of a single predominant V. cholerae O1 strain throughout the 2004 outbreak in Chennai.
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World Journal of Microbiology and Biotechnology (Formerly MIRCEN Journal of Applied Microbiology and Biotechnology) 02/2010; 26(2):281-287. DOI:10.1007/s11274-009-0171-7 · 1.78 Impact Factor
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