Serotype and antimicrobial resistance analysis of Salmonella isolates at Tachikawa hospital from 2007 to 2016: Results in the past 10 years

Abstract

We investigated the serotype and antimicrobial resistance of Salmonella isolates at our hospital located in Tachikawa City, Tokyo, from 2007 to 2016. Forty-two Salmonella strains were isolated. Those strains were classified into six O groups, namely, O4 (20 strains: 47.6%), O9 (15 strains: 35.7%), O7 (4 strains: 9.5%), O8 (1 strain: 2.4%), O3,10 (1 strain: 2.4%) and O21 (1 strain: 2.4%). The most prevalent serotype was Salmonella enterica subsp. enterica serovar Enteritidis (21.4%). Among the 42 strains, three showed resistance to one or more antimicrobial drugs. One showed resistance only to ABPC, one only to trimethoprim-sulfamethoxazole, and the remaining one to ABPC, third-generation cephalosporin and levofloxacin. Although the isolation rate of Salmonella has tended to decrease in recent years and our results did not show an increasing trend of the number of resistant strains in our hospital during this study period, there is a concern for the emergence of resistant Salmonella strains and multidrug-resistant strains these days. Further studies on the prevalence, antimicrobial susceptibility pattern and mechanisms of antibiotic resistance including the ability for ESBL, metallo-beta-lactamase and AmpC production by circulating strains of these species are recommended.