Clinical Microbiology and Antimicrobial Chemotherapy. 2012; 14(1):38-50
In this paper, the evidence of broad geographic dissemination of Salmonella enterica serovar Typhimurium strains belonging to a single genetic lineage is presented. The isolates described possess resistance to oxiiminocephalosporines due to production of CTX-M-5 extended-spectrum b-lactamase. The genetic relatedness of the strains isolated during multiple outbreaks of nosocomial salmonellosis in various parts of Russia, Belarus and Kazakhstan was established by pulsed-field gel electrophoresis (PFGE) and multi-locus tandem repeat analysis (MLVA). Circulation of the clone was first noticed in 1994 and is currently ongoing according to the data presented. The resistance to multiple antibiotics including penicillininhibitor combinations and various non-b-lactam drugs is mediated by large conjugative plasmids, while blaCTX-M-5 gene is associated with ISEcp1 element and carried by small non-conjugative plasmid. Some isolates express resistance to nalidixic acid owing to mutations in QRDR of gyrA gene.