RESUMEN
Salmonella enterica serovar Typhimurium DT104 (Salmonella Typhimurium DT104 or DT104) has been emerging as a common pathogen for human in Korea since 1997. In order to compare the genomic relationship and to search for the dominant strains in Korea, we conducted pulsed-field gel electrophoresis (PFGE) and IS200 fingerprinting of 25 epidemiological unrelated isolates from human and animals from Korea and cattle from America. Two Salmonella Typhimurium DT104 isolates from human in Korea and all 8 isolates from American cattle had indistinguishable patterns from the PFGE and IS200 fingerprinting but multidrug-resistant Salmonella Typhimurium isolates, including DT104, from Korean animals had diverse genetic patterns. The data suggest that a dominant DT104 strain might have circulated between Korean and American cattle and that it had a high level of clonality.
Asunto(s)
ADN Bacteriano/análisis , Genoma Bacteriano , Salmonelosis Animal/microbiología , Infecciones por Salmonella/microbiología , Salmonella typhimurium/genética , Salmonella typhimurium/aislamiento & purificación , Animales , Bovinos , Análisis por Conglomerados , Dermatoglifia del ADN , Elementos Transponibles de ADN , ADN Bacteriano/aislamiento & purificación , ADN Bacteriano/metabolismo , Desoxirribonucleasas de Localización Especificada Tipo II/metabolismo , Farmacorresistencia Bacteriana Múltiple , Electroforesis en Gel de Campo Pulsado , Variación Genética , Humanos , Corea (Geográfico)/epidemiología , Epidemiología Molecular , Polimorfismo de Longitud del Fragmento de Restricción , Infecciones por Salmonella/epidemiología , Salmonelosis Animal/epidemiología , Salmonella typhimurium/clasificación , Estados Unidos/epidemiologíaRESUMEN
A total of 74 isolates of Salmonella enterica serovar London were collected through the Laboratory-Based Diarrheal Diseases Surveillance in 2000-2001. In order to characterize the isolates and investigate the source of the epidemic, we performed antimicrobial susceptibility tests and XbaI Pulsed-field gel electrophoresis (PFGE) of 44 Salmonella London isolates. Forty isolates were from feces of infants and four isolates were from adults aged 30, 52, 54, and 59 yr. Two subtypes were identified: a tetracycline-susceptible A 0 PFGE pattern and a tetracyclineresistant A 1 PFGE pattern. Interestingly, the isolates from all infants and one 30-yr-old adult were A 0 PFGE pattern and tetracycline-susceptible. Furthermore, the A 0 PFGE pattern strain was approximately 2 times more virulent than the A 1 PFGE pattern strain, according to the results of in vitro invasion assay using J774A.1 macrophage-like cells. These results indicate that the active surveillance with molecular epidemiological tools would be valuable for promptly finding new epidemic strains. Our results also suggested that the virulent Salmonella London strain might infect the infants through a common contaminated source.