Antimicrobial resistance in the Salmonella strains isolated from Shenzhen People's Hospital

Objective To investigate the antimicrobial resistance among the Salmonella strains isolated from Shenzhen People's Hospital.Methods The minimal inhibitory concentrations (MICs) of antibacterial agents were determined by agar dilution method against 95 strains of Salmonella. WHONET 5.3 software was used to analyze the data.Results S. typhi and S. paratyphi A remained highly susceptible to ampicillin,chloramphenicol and trimethoprim-sulfamethoxazole. About 96%-100% and 97%-100% of the strains were susceptible respectively. Multidrug-resistant isolate was not found. About 52% (13/25) of S. typhi isolates and 94% (62/66) of S. paratyphi A isolates were resistant to nalidixic acid,respectively. The prevalence of S. typhi and S. paratyphi A with decreased susceptibility to ciprofloxacin (MIC=0.125-1 mg/L) was 24% (6/25) and 92.4% (61/66),respectively. One strain of S. paratyphi B and one strain of S. typhimurium showed high resistance to ciprofloxacin (MIC≥16 mg/L),and resistance to ampicillin,chloramphenicol and trimethoprim-sulfamethoxazole too.Conclusions The S. typhi and S. paratyphi A with decreased susceptibility to ciprofloxacin were prevalent in our hospital. Ciprofloxacin-resistant S. paratyphi B and S. typhimurium were identified.