Estudio molecular de 6 episodios de infección intrahospitalaria causados por staphylococcus aureus meticilino-resistente / Molecular study of 6 episodes of intrahospitalary infection due to methicillin resistant staphylococcus aureus

ABSTRACT

A critical step in any epidemiologic research concerning nosocomial infections is the precise identification of the responsible pathogen. The present work utilized a molecular approach-plasmids identification, restriction lengght polymorphism DNA analysis and random amplified polymorphic DNA for the characterization of 6 nosocomial outbreaks due to 52 strains of methicillin-resistant staphylococcus aureus (MRSA). In these episodes, the clinic-epidemiologic and phenotipic analysis (antibiotype) pointed to a nosocomial infection. Through molecular analysis it was possible to establish in a very precise way, clonality due to MRSA strains in 2 of the studied outbreaks; the same type of analysis allowed to eliminate a MRSA clonal origin in the remainder 4 episodes. The antibiogram was not an useful analytic tool due to its poor discriminatory power. Also, through a PCR procedure, it was possible to identify the presence of the gen mecA in every of the 52 MRSA strains studied