cholerae RC385,

TMA21 and MZO-3 yielded expected amplification patterns. In addition, seven carried the V. cholerae RC385 VSP-II (Table 3). Among these, two were isolated from Chesapeake Bay, MD, the same location as V. cholerae RC385, and one also carried a new variant of VSP-I (Grim et al., 2010). Of the remainder, one was isolated from a sewage sample collected in Brazil, one was from Czechoslovakia, two were from Japan and one was from Bangladesh. It should be noted that four of 15 Vibrio mimicus strains were also positive for the V. cholerae RC385 VSP-II variant. Interesting results emerged from screening buy Navitoclax of the collection of V. cholerae isolates from two cholera-endemic sites in Bangladesh, collected from

2004 to 2007. Among the clinical V. cholerae O1 El Tor, a total of 96 carried the V. cholerae CIRS101 VSP-II variant and only one harbored the typical seventh pandemic VSP-II (Table 3). Moreover, three isolates did not contain VSP-II and one was positive for V. cholerae RC385 VSP-II (Table 3), which was negative for VSP-I and ctxA (Grim et al., 2010). A similar result was obtained for environmental V. cholerae O1 isolates, because these were all ctx- and tcpA-positive strains and therefore likely related to the clinical strains. That is, all carried V. cholerae selleck CIRS101 VSP-II, except one strain, which did not have V. cholerae VSP-II or VSP-I (Table 3) (Grim et al., 2010). In contrast, all V. cholerae O139, both clinical and environmental, contained the canonical seventh pandemic VSP-II (Table 3), suggesting that this serogroup is genetically isolated from the dominant V. cholerae O1 pandemic clones. Among V. cholerae non-O1/non-O139 isolates, 70% did not harbor VSP-II, 26% contained V. cholerae RC385 VSP-II and two contained the V. cholerae TMA21 VSP-II (Table

3), showing that these are the most common variants in the nonepidemic V. cholerae population. Comparative genomic analysis of 23 V. cholerae strains belonging to different serotypes, widely distributed geographically and isolated over an extended period of time, has led to the discovery of three new variants of the VSP-II genomic island. This is remarkable, because VSP-I Thiamine-diphosphate kinase and VSP-II were originally considered to be conserved genetic markers of seventh pandemic V. cholerae (Dziejman et al., 2002; O’Shea et al., 2004). To date, two other examples of sequence variation within V. cholerae VSP-II have been described (Dziejman et al., 2005; Nusrin et al., 2009). Our analysis provides further knowledge of this genomic cluster and its evolution in V. cholerae. From the standpoint of genetic comparison, it is clear that the island has undergone significant genetic rearrangement. Two loci, at the 3′ end of the VC0498 and VC0511, may represent hot spots for recombination events within the conserved genomic backbone of the island.