Identificación por PCR-SSCP de genes de cefotaximasas en aislamientos hospitalarios de Enterobacteriaceae

CTX-M cefotaximases are the most widely distributed extended-spectrum beta-lactamases among Enterobacteriaceae and they are an important cause of microbial resistance in nosocomial infection-causing isolates. The object of this work was to identify group 1 CTX-M cefotaximase variants from PCR amplified blaCTX-M genes by single-stranded conformational polymorphism of restriction fragments (RF-SSCP). We analysed 49 Enterobacteria isolates using the RF-SSCP procedure standardised in this work; isolates were collected from eight hospitals attached to the Bogota Health Secretariat (Secretaría Distrital de Salud). CTX-M-12, CTX-M-15, CTX-M-12a and CTX-M-1 variants were detected as well as a new one, designated CTX-M-60. All variants were detected in hospital and community isolates thereby indicating these genes' possible high mobility from and towards hospital centres. This study represents the first report in Colombia of CTXM-12a and of the new evolutionary variant: CTX-M-60.