Occurrence and distribution of various genetic structures of class 1 and class 2 integrons in Salmonella enterica isolates from foodborne disease patients in Korea for 16 years.

Abstract We have investigated the distribution of integrons among 752 multidrug-resistant Salmonella isolates from human febrile and/or diarrheal patients during 1992–2007 and analyzed their genetic characteristics. Here, we report extensive integron analysis results within human isolates during the last 16 years. The gene or gene cassette(s) in the class 1 integrons found in the isolates were dfrA7, dfrA12-orfF-aadA2, aadA2, blaPSE1, dfrA1-aadA1, dfrA17-aadA5, blaOXA1-aadA1, aadB-aadA1, aadA22, aadA1, and aac6'Ib-blaOXA1-aadA2. Class 2 integrons harboring dfrA1-sat2-aadA1 gene cassette were also found in four isolates. Twenty-nine isolates including one Salmonella Schleissheim isolate had two integrons harboring aadA2 and blaPSE1 in their variable regions of 1.0 and 1.2 kb amplicons, respectively, which have been also found in Salmonella genomic island 1 (SGI1) of multidrug-resistant Salmonella Typhimurium DT104. The presence of SGI1 in Salmonella Schleissheim isolate was proved by SGI1-specific polymera...