Characterization of Salmonella enterica serotype typhimurium from outpatients of 28 hospitals in Henan province in 2006.

OBJECTIVE To characterize the diarrheal patients with Salmonella typhimurium (S. typhimurium) infections and to set up the first baseline for S. typhimurium pulsed-field gel electrophoresis (PFGE) patterns in Henan province, thus laying a foundation for comprehensive surveillance of Salmonella in human as well as foods. METHODS S. typhimurium isolates recovered from outpatients with diarrhea in Henan province from May to October of 2006 were characterized. Antimicrobial susceptibility tests of 8 antimicrobial agents and PFGE were carried out to analyze the S. typhimurium isolates. RESULTS Twenty-four (0.9%) S. typhimurium isolates were identified from 2661 stool specimens of diarrheal cases. Eighty-eight percent of isolates showed resistance to at least one antimicrobial agent. The resistance to chloramphenicol (79%) was most common. Fifty-eight percent of isolates were resistant to ciprofloxacin. All the 14 ciprofloxacin-resistant isolates were resistant to more than five antimicrobial agents. Thirty-three percent of S. typhimurium isolates were resistant to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (R-type ACSSuT). Eight antimicrobia-resistant phenotypes were found among the 24 isolates in 16 PFGE patterns. CONCLUSION The rate of multidrug-resistant S. typhimurium is relatively high in S. typhimurium PFGE patterns of Henan province. Multidrug-resistant S. typhimurium should be considered a public health threat.