RESUMEN
This study characterized a cephalosporin-resistant Salmonella enterica serovar Typhi isolate. The organism possessed a plasmid encoding the CTX-M-15 extended-spectrum-beta-lactamase. This plasmid is the determinant for the phenotype of cephalosporin resistance and is transferrable among Enterobacteriaceae.
Asunto(s)
Antibacterianos/farmacología , Cefalosporinas/farmacología , Plásmidos/genética , Farmacorresistencia Bacteriana/genética , Pruebas de Sensibilidad Microbiana , Salmonella typhi , beta-Lactamasas/genéticaRESUMEN
We identified seven distinct subtypes of enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates that were derived from sporadic cases and outbreaks from multiple prefectures in Japan in 2005. A surveillance system utilizing pulsed-field gel electrophoresis (PFGE), PulseNet Japan, was used. Some strains showed indistinguishable PFGE patterns using another restriction enzyme (BlnI or SpeI) in each subtype of EHEC O157:H7 isolates that were routinely subtyped by the XbaI PFGE pattern. In order to examine the genotypic relatedness of these strains, we carried out a multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA). By using the MLVA system, we found that three of seven subtypes of EHEC O157:H7 strains that were isolated from sporadic cases dispersed across multiple prefectures within a few months showed indistinguishable PFGE patterns and identical MLVA types. Strains belonging to the other four subtypes of EHEC O157:H7 in the PFGE analysis were further classified into different clusters of EHEC O157:H7. Therefore, compared to PFGE, MLVA showed greater discriminatory power with respect to analysis of the isolates in this study.
Asunto(s)
Escherichia coli Enterohemorrágica/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Escherichia coli O157/aislamiento & purificación , Repeticiones de Minisatélite , Alelos , Técnicas de Tipificación Bacteriana , Brotes de Enfermedades , Electroforesis en Gel de Campo Pulsado , Escherichia coli Enterohemorrágica/clasificación , Infecciones por Escherichia coli/microbiología , Escherichia coli O157/clasificación , Escherichia coli O157/genética , Humanos , Japón/epidemiologíaRESUMEN
We analyzed the resistance to cefotaxime of a Salmonella enterica serovar Enteritidis isolate from a stool culture of a 4-year-old boy. It produced a beta-lactamase CTX-M-14, encoded by two related R plasmids. The region surrounding the blaCTX-M-14 gene had an original mosaic structure containing insertion sequences (IS26 and IS903D).
Asunto(s)
Antibacterianos/farmacología , Cefotaxima/farmacología , Resistencia a las Cefalosporinas/genética , Salmonella enteritidis/enzimología , beta-Lactamasas/metabolismo , Preescolar , Heces/microbiología , Humanos , Japón , Masculino , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Factores R/genética , Infecciones por Salmonella , Salmonella enteritidis/efectos de los fármacos , Análisis de Secuencia de ADN , beta-Lactamasas/genéticaRESUMEN
We performed susceptibility testing with Shigella sonnei isolates from imported and domestic cases of infection in Japan during 2001 and 2002. Some S. sonnei isolates were resistant to nalidixic acid, tetracycline, and trimethoprim-sulfamethoxazole. Most of the nalidixic acid-resistant strains showed reduced susceptibility to fluoroquinolones but did not show fluoroquinolone resistance.