Serendipitous Isolation of Non-VibrioBacterial Strains Carrying the Cholera Toxin Gene from Environmental Waters in Indonesia

[摘要] We initially attempted to isolate aVibrio choleraeO1 El Tor biotype that carries a novel variant of the cholera toxin gene (ctxAB) from environmental waters of Indonesia, where the seventh cholera pandemic byV. choleraeO1 El Tor biotype began. Nested PCR targeting the gene revealed that a total of eight strains were found to carryctxAB. However, sequencing of the 16S rRNA genes of these isolates showed they were notV. choleraebut were eitherKlebsiella,Enterobacter,Pantoea, orAeromonas. Subsequent nested PCR assays targeting all genes known to be encoded on the CTX phage (i.e.,zot,ace,orfU,cep,rstB,rstA, andrstR) showed that one isolate belonged to theEnterobactergenus carried all the genes tested, while the other isolates lacked either 2, 3, or 5 of the genes. This evidence suggests that phages withctxABare genetically diverse and can infect not onlyV. choleraeandV. mimicusbut also other species and genera in the form of a pseudolysogen.

[学科分类] 微生物学和免疫学