[Typing of methicillin-resistant Staphylococcus aureus by antibiotic resistance phenotypes as an epidemiological marker in nosocomial infections].

A total of 129 clinical isolates of methicillin-resistant Staphylococcus aureus was tested for the susceptibility to 28 antibiotics, antiseptics and heavy metal salts, according to the method of Gillespie et al. The strains showed resistance ranging from 20% to 80%, to 10 agents, such as amikacin, chloramphenicol, clindamycin, gentamicin, neomycin, streptomycin, tobramycin, acriflavine, cadmium nitrate, ethidium bromide. These agents were finally chosen for typing in this study. Strains resistant to 10 agents were distributed into 55 phenotypes. Most strains isolated from one ward belonged to the specified phenotype, whereas strains isolated from other wards were divided into a variety of phenotypes. It seemed to be the occurrence of nosocomial infection in this hospital. This typing method gives the merit to be easy, economical, rapid and reproducible for the epidemiological investigations in the clinical bacteriological laboratory.