Vibrio Strain Selection

Sequence data will be generated for 17 strains that are classified into four major categories, described below. The first three categories consist of V. cholerae strains and the fourth group consists of strains from other Vibrio spp.

First, we have chosen an O1 serogroup strain of the classical biotype (O395), two strains of the O139 serogroup (MO10, an early isolate and AS244, an isolate from the later resurgence of the O139 epidemic), and a strain recently responsible for epidemic disease in Mozambique (M1). These strains represent the last of the classical strains to cause epidemic disease (and therefore precede the emergence of El Tor strains in the 7th pandemic) and the most recently emerged epidemic strains. Identification of sequence differences among all these strains will provide a more complete picture of the genomic composition of a pathogen and potentially reveal novel genes that account for epidemic and endemic success. In addition, these data may also help define genes important for aquatic survival.

Second, we are generating sequence data for several non-O1/non-O139 strains. While array analysis suggests that O1 and O139 strains are highly similar and are missing only ~1% of genes when compared to strain N16961, similar analysis of non-O1/non-O139 strains suggests that they are more highly divergent and are missing ~6% of genes compared to strain N16961. In some cases, atypical non-O1/non-O139 strains have caused only sporadic disease (strains AM-19226 and MZO-3), while in other cases they have been responsible for localized, limited epidemics (strains 1587 and V52). They have not been able to establish endemicity in any locale, and have not spread globally with the exception of strains belonging to the O141 serogroup (strain V46). Presumably, sequence data will help to identify the mechanism(s) by which atypical strains cause disease and also confirm genomic differences that may contribute to aquatic fitness, endemic and epidemic potential.

Third, we are sequencing two environmental isolates of V. cholerae (strains RC385 and 2740-80). We expect sequence information from these strains to provide information regarding their environmental fitness and perhaps also contribute to our understanding of their lack of pathogenic potential.

Finally, we have included a number of Vibrio spp. that appear to be environmental isolates having some similarity to V. cholerae (EX25, V. fluvialis), isolates pathogenic for non-human hosts (i.e. shrimp, V. harveyi), or species only rarely pathogenic for humans (V. mimicus and V. alginolyticus). Identifying the genomic content of this broad representation of Vibrio spp. will contribute towards a broad understanding of the genus and potentially reveal common genes that are perhaps shared and transferred among diverse strains.