METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS STRAINS IN THE GREATER DUSSELDORF AREA

Over a period of three years the incidence of methicillin resistant St aphylococcus aureus (MRSA) isolates in II hospitals in the greater Dus seldorf area was observed. From a total of 7,814 S. aureus isolates, 4 89 (6.3%) were methicillin resistant. From 198 different patients, MRS A first isolates and 291 second isolates could be cultured. Methicilli n resistance among all S. aureus isolates from 11 hospitals in the gre ater Dusseldorf area, ranged from 0.5 to 7.8% dependant on the size of the hospital. The highest incidence (7.8%) was found in a 1,500 bed h ospital and the lowest incidence in a smaller 200 bed hospital (0.5%). With respect to the distribution among clinical departments the highe st incidence of MRSA isolates was found on intensive care units and su rgical wards, 25.5% and 13.0% respectively. The commonest specimen fro m which the MRSA isolates were cultured were respiratory secretions (1 7.6%) followed by central venous catheter tips (12.8%). In terms of th e drug resistance pattern: all isolates were resistant to the aminogly cosides and gyrase inhibitors, whereas between 80% and 90% were sensit ive to fusidic acid, chloramphenicol and pyrimethamine-sulfamethoxazol e. All the strains were sensitive to the glycopeptide antibiotics, van comycin and teicoplanin. Strain typing of 181 available first isolates (from a total of 198 first isolates) by PFGE and phage lysotyping pro duced identical results in more than 90% of all cases. Twenty-eight di fferent MRSA strain types were identified by PFGE and in total 23 lyso types could be determined. During the period of investigation an incre ased incidence of MRSA on an intensive care unit was observed, in whic h a total of 204 MRSA (42% of the total number) were isolated. The str ain typing using both methods showed that on that ICU eight different MRSA types were involved in this outbreak. A hygiene plan was implemen ted on the unit with considerable success in reducing the incidence an d spread of MRSA.