Salmonella Genomic Island 1 Research Articles

Variant Salmonella genomic island 1 antibiotic resistance gene cluster in Salmonella enterica serovar Albany.

Salmonella genomic island 1 (SGI1) contains an antibiotic resistance gene cluster and has been previously identified in multidrug-resistant Salmonella enterica serovars Typhimurium DT104, Agona, and Paratyphi B. We identified a variant SGI1 antibiotic-resistance gene cluster in a multidrug-resistant strain of S. enterica serovar Albany isolated from food fish from Thailand and imported to France. In this strain, the streptomycin resistance aadA2 gene cassette in one of the SGI1 integrons was replaced by a dfrA1 gene cassette, conferring resistance to trimethoprim and an open reading frame of unknown function. Thus, this serovar Albany strain represents the fourth S. enterica serovar in which SGI1 has been identified and the first SGI1 example where gene cassette replacement took place in one of its integron structures. The antibiotic resistance gene cluster of serovar Albany strain 7205.00 constitutes a new SGI1 variant; we propose a name of SGI1-F.

Florfenicol resistance in Salmonella enterica serovar Newport mediated by a plasmid related to R55 from Klebsiella pneumoniae.

Florfenicol resistance has emerged over the past few years in multidrug-resistant Salmonella enterica serovars Typhimurium, Agona and Paratyphi B. The floR gene encoding florfenicol resistance is chromosomally located in these serovars within a genomic island of 43 kb called SGI1 (Salmonella genomic island 1). In the present study, we characterized florfenicol resistance in a strain of S. enterica serovar Newport isolated from a turkey in 1990 and that lacked SGI1. Florfenicol resistance was mediated by a conjugative plasmid related to R55 from Klebsiella pneumoniae, which was characterized initially in the 1970s and harbours a gene 95% identical to floR.