TYPING, ANTIMICROBIAL SUSCEPTIBILITY AND FREQUENCY OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS-STRAINS ON A SURGICAL INTENSIVE-CARE UNIT(ICU)

Over a period of three years, the frequency of the appearance of methi cillin-resistant S. aureus strains (MRSA) was observed on a surgical i ntensive care unit. During this above-mentioned period of investigatio n it came to a heaped occurence of nosocomial infections on this ICU w ith altogether 332 S. aureus-stems being isolated from different patie nt specimen. 204 (61,5%) of these were resistant against methicillin a nd could be divided into 48 first- and 156 follow-up-isolates. The the reupon accomplished differentiation of the 48 MRSA-first isolates by m eans of lysotyping and the pioneered GenePath Strain Typing System(R) for a standardized pulsed-field-gel-electrophoresis (PFGE) gave the pr oof of 7 different MRSX-types. Around 7 different, in part parallel ch ains of infection on this ICU were observed, which could be led back t o different strains. In reference to all analyzed S. aureus, an especi ally high rate (90%) of MRSA on this ICU could be isolated in taken wo und-swabs, followed by 83,3% MRSA at catheter tips and 71,9% in trache al and bronchial secretion. A consideration of the antibiotic suscepti bility yielded, that also gentamicin and the chinolones showed an in-v itro resistance against MRSA, while fosfomycin, fusidinic acid, chlora mphenicol and trimethoprim/sulfamethoxazole reached positive respondin g rates between 80 and 100%. On the other hand, presently still 100% o f the explored MRSA-strains are susceptible for glycopeprides such as vancomycin and teicoplanin. Because of intensive hospital hygienic mea sures the number of newly isolated MRSA could be reduced clearly on th is ward.