Vibrio cholerae O1 El Tor and O139 Bengal strains carrying ctxBET, Bangladesh

摘要: To the Editor. Cholera, caused by Vibrio cholerae, continues to affect millions of persons in disease-endemic areas where safe drinking water is scarce and sanitation poor. Of 7 cholera pandemics recorded since 1817, V. cholerae serogroup O1 classical (CL) biotype was associated with sixth, whereas seventh (ongoing) pandemic initiated El Tor (ET), which displaced CL early 1960s (1). During 1992–1993, a non-O1 serogroup, designated O139 synonym Bengal, epidemics India Bangladesh transiently displacing ET (2). less frequently than 1994 years following, until 2005 (3); it has been undetected then. Meanwhile, shown genetic changes 2001, isolates carry ctxB gene (ctxBCL) (4). Although transition from ctxBET ctxBCL observed during 1998–1999 for (5), strains carrying were considered extinct, i.e., about decade. During June 2010–December 2012, International Centre Diarrheal Disease Research, (ICDDR,B) systematically conducted ongoing epidemiologic ecologic surveillance Dhaka, Chhatak, Mathbaria isolated (n = 500 [clinical/environmental]: Dhaka [n 110/94], 90/79], Chhatak 111/16]). isolates, 496 confirmed as 4 on basis serologic, phenotypic, properties (3,6–8). All positive ctxA, tlc, ace, zot possessed biotype–specific markers tcpAET, hlyAET, rtxC. Mismatch amplification mutation assay–PCR (9) demonstrated allele 492 (altered ET), found 8 (4 O139). Nucleotide sequencing showed that translated sequences identical those reference strain N16961 (GenBank accession no. {"type":"entrez-nucleotide","attrs":{"text":"NC_002505","term_id":"15640032"}}NC_002505), tyrosine isoleucine at positions 39 68, respectively, opposed altered ET, possesses histidine threonine respectively PCR additionally Bengal had RS1 element rstC repressor rstRET, suggesting prototype attributes (7). Three first 2011 surface water: one Chhatak. In patients 1 each). Also, 3 Dhaka. The particular interest because have deemed cause endemic 2001 (4) globally (10). V. closely related pre-2001 ctxBET, ctxBET. Two lines evidence support this close relationship. First, antimicrobial drug resistance patterns 2012 resistant trimethoprim/sulfamethoxazole (25 µg), remaining susceptible all drugs tested, including azithromycin (15 ciprofloxacin (5 gentamicin (10 ampicillin tetracycline (30 erythromycin µg). Second, pulsed-field gel electrophoresis (PFGE) NotI-digested genomic DNA banding strains, N16961, pattern differed (Figure). typical patterns, PFGE, except an extra band Comparison PFGE previously (1993–2005) recently (2011–2012) belonged ancient clones, present 1993 (Figure). Figure DNA fingerprinting cholerae. Dendrogram prepared Dice similarity coefficient UPGMA (unweighted pair-group method arithmetic mean) clustering methods using images Not ... In conclusion, we provide coexistence shows not approximately decade Bangladesh, again (3). importance change yet be understood, finding association following year may another turning point, considering global changing rapidly.