Characteristics of Epidemic Multidrugresistant Salmonella enterica Serovar Typhimurium DT104 Strains First Isolated in Korea / 감염

ABSTRACT

BACKGROUND: Salmonella infections continue to cause gastrointestinal and systemic diseases throughout the world. S. Enteritidis and S. Typhimurium were traditionally known as typical food poisoning Salmonella agents, the isolation rate of which has been increased recently in Korea. S. Typhimurium phage type DT104 has become an important emerging pathogen. Isolates of this phage type often possess resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline (ACSSuT resistance). The mechanism by which DT104 has accumulated resistance genes is of interest, since these genes interfere with treatment of DT104 infections and might be horizontally transferred to other bacteria, even to unrelated organisms. METHODS: All the isolates included in this study were identified as S. enterica serovar Typhimurium according to the Kauffmann-White serotyping scheme and were definitive phage type DT104 according to the phage typing scheme described by Anderson, et al. A total of 63 isolates of S. enterica serovar Typhimurium DT104 were characterized by antimicrobial resistance analysis, pulsed-field gel electrophoresis (PFGE) with the restriction enzyme XbaI. RESULTS: Four hundred ninety six S. Typhimurium isolates were divided into 28 different phage types and DT104 was the second most common phage type in Korea. A total of 63 S. Typhimurium DT104 isolates were grouped into 7 resistance phenotypes. Fourty one (65.1%) isolates were resistant to the ACSSuTTic core alone or to additional drugs as well except twenty two (33.9%) isolates were resistant to the ASSuTeTic. Four PFGE subtypes A1, A2, B1, and B2 were observed among DT104 isolates and type A1 was prevalent. CONCLUSIONS: We concluded two distinct clones were present among Korea multidrug resistant S. enterica serotype Typhimurium DT104 and multidrug resistant S. Typhimurium phage type DT104 has been an important emerging pathogen in Korea.