Study on structure of new CTXΥ and nct-CTXΥ genomes coexisted in 0139 serogroup Vibrio cholerae strains.

Objective To study the structure of new CTXφ and nct-CTXφ genomes coexisted in O139 serogroup Vibrio cholerae(VC) strains.Methods Genes including end of core region of CTXφ or nct-CTXφ and start of genome were gotten by using PCR method,and were digested with RsaI and BglII differentially,and tested with PCR using specific primers to indentify type of rstR-ig2.Genes including part of TLC and RS region,and genes including part of RTX and core region of CTXφ or nct-CTXφ,were gotten by using PCR method.Results The typical O139VC strains with rstR-ig2 types of CTXφ and/or nct-CTXφ were FJ9510 strain including CTXETφ,FJ98352 strain including CTXETφ and nct-CTX calcφ,FJ99364 strain including CTXETφ and nct-CTXnewO139φ and nct-CTXcalcφ,JS9803 strain including CTXETφ and nct-CTX newO139φ,and JX94484 strain including CTXETφ and nct-CTXnewETφ.46 bp of 3′ part of zot genes of CTXφ and nct-CTXφ were compared and 20 different sites were observed,and 11 of presumptive 15 AAA were different.Genes near CTXφ genomes of O139VC strains were TLC and RTX clusters,but genes near nct-CTXφ genomes were new or unidentified genes.Conclusions Changeable genes of CTXφ and nct-CTXφ of O139VC and insertion genes in chromosome were elucidated.