Antimicrobial resistance in Salmonella strains clinically isolated in Hyogo, Japan (2009-2012)

The purpose of this study was to examine the in vitro susceptibilities to antimicrobial agents and genetic diversity of 195 clinical strains of Salmonella spp., which were isolated and examined for the extended-spectrum β-lactamase (ESBL) blaCTX-M gene and the presence of gyrA, gyrB, parC, and parE genes mutations in Hyogo, Japan, from 2009 to 2012. Forty-three of the 195 strains were antimicrobial resistant. Two Salmonella enterica subsp. enterica strains, 1 serovar Schwarzengrund, and 1 serovar Enteritidis were identified as ESBL-producing strains possessing blaCTX-M-15 and blaCTX-M-2, respectively. Among 8 nalidixic acid-resistant strains, 7 had mutations in gyrA alone or in gyrA and parC. In conclusion, we identified CTX-M ESBL-producing Salmonella clinical strains with multidrug resistance. Further studies are needed to monitor these serious drug-resistant Salmonella strains in Japan.