OUTBREAK OF NOSOCOMIAL INFECTIONS WITH 2 DIFFERENT MRSA-STRAINS INVOLVED - SIGNIFICANCE OF GENOMIC DNA FRAGMENT PATTERNS IN STRAINS OTHERWISE DIFFICULT TO TYPE

Methicillin-resistant Staphylococcus aureus isolates from an outbreak of 17 cases of wound infection in a municipal hospital were typed by c onventional methods, phage typing by three sets of phages, reverse pha ge typing and plasmid profiles, as well as by genomic DNA fragment pat terns obtained after Sma-I digestion and pulsed-field electrophoresis. These isolates were non-typable by phages, only some were typable by reverse phage typing and were not uniform in plasmid profile. Only the genomic DNA fragment patterns resulted in a clear discrimination of 2 strains (12 isolates for the first and 7 isolates for the second). Bo th strains were disseminated in different wards of the same hospital a nd one strain had obviously spread to another clinic in the same city.