CLONAL HETEROGENEITY, DISTRIBUTION, AND PATHOGENICITY OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS

Four thousand eighty-eight Staphylococcus aureus isolates obtained fro m patients hospitalised in a university clinic and four community hosp itals over a period of one year were screened for methicillin resistan ce, A resistance rate of 5% was detected among initial isolates. Distr ibution of methicillin-resistant Staphylococcus aureus (MRSA) and ii m ethicillin-sensitive Staphylococcus aureus showed an increased prevale nce of MRSA in clinically significant specimens such as blood, central venous catheter tips, bronchial secretions, and wound secretions. Typ ing of 110 MRSA strains (initial isolates) by macrorestriction analysi s of chromosomal DNA revealed 26 different genotypes that could be div ided into five epidemic and 21 sporadic strains. More than 50% of all isolates belonged to one type that was confirmed to be closely related to the ''southern-German'' epidemic strain, Production of virulence f actors such as enterotoxin A-D and toxic shock syndrome-toxin 1 among MRSA strains (initial isolates) occurred in ten of 26 different MRSA t ypes, A strong correlation between genotype and toxin production was d emonstrated.