Susceptibilidad antimicrobiana y patrones de resistencia de Staphylococcus aureus aislados de pacientes y portadores en la ciudad de Valdivia, Chile / Antimicrobial susceptibility and resistance patterns of Staphylococcus aureus isolated from patients and carriers in Valdivia city, Chile

RESUMEN

La susceptibilidad in vitro de Staphylococcus aureus adquirido, tanto en el ambiente hospitalario como en la comunidad, debe ser monitorizada periódicamente por su continua evolución. Objetivos: Conocer la susceptibilidad antimicrobiana de cepas de S. aureus aisladas en Valdivia, determinar la prevalencia de cepas resistentes a meticilina y sus respectivos patrones de resistencia, analizar la evolución de esta susceptibilidad a través de los años. Material y Métodos: Se evaluaron 278 cepas de S. aureus 136 obtenidas de pacientes hospitalizados, 50 de pacientes ambulatorios y 92 de portadores. Los antimicrobianos ensayados fueron penicilina, oxacilina, vancomicina, gentamicina, ciprofloxacina, lincomicina y eritromicina.

ABSTRACT

In vitro susceptibility of nosocomial and community acquired strains of Staphylococcus aureus must be periodically evaluated because of its continuous evolution. Aim: To know the antimicrobial susceptibility of S. aureus isolated in Valdivia, to determine the prevalence of methicillin resistance and global patterns of resistance and to compare the evolution of the susceptibility along the years. Material and Methods: A total of 278 S. aureus strains were evaluated 136 obtained from hospitalized patients, 50 belonged to outpatients and 92 to healthy carriers. Antimicrobial agents tested were penicillin, oxacillin, vancomycin, gentamycin, ciprofloxacin, lincomycin and erythromycin. Results: Thirty three, 28 and 1.1 percent of strains isolated from hospitalized, outpatients and carriers, respectively, were methicillin-resistant. Six resistance patterns were found. No vancomycin resistant strain was isolated. Comment: It is worrisome that 2 percent of S. aureus strains obtained from hospitalized patients showed intermediate resistance to vancomycin.