OUTBREAK OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS IN A TEACHINGHOSPITAL - EPIDEMIOLOGIC AND MICROBIOLOGICAL SURVEILLANCE

An outbreak of methicillin-resistant S. aureus (MRSA) in a large unive rsity teaching hospital occurred between December 1991 and May 1992, i nvolving 7 different wards and more than 30 patients. Epidemiological typing was performed to control the epidemic and to identify the MRSA carriers. By a combination of various classical methods (antimicrobial susceptibility, phage typing) and molecular typing procedures (SDS-PA GE of extracellular proteins, plasmid DNA. profile, restriction enzyme fragment pattern of chromosomal DNA), three different clones of MRSA could be discriminated. The epidemic clone A was recovered from 30 pat ients and from 3 staff members. By strict microbiological monitoring t ogether with hygienic measures, the epidemic could be successfully con trolled. It is concluded that a combination of phenotypic markers and DNA-based epidemiological markers is extremely useful in the microbiol ogical surveillance of MRSA outbreaks.