Observations on multiple drug resistance in coagulase-negative staphylococci isolated in hospitals from 1975 to 1985.

Drug resistance in coagulase-negative staphylococci (CNS) isolated in hospitals since 1975 was analysed using routine laboratory data registered on a microcomputer. Resistance increased substantially in CNS during the years, especially in Staphylococcus epidermidis isolates, of which more than 50% were multiply drug resistant by 1985. Among the methicillin-resistant CNS strains, resistance to gentamicin rose from 0% in 1975 to 76% in 1985. Co-resistance to kanamycin, gentamicin, and in some cases netilmicin seemed to replace co-resistance to kanamycin and streptomycin in S. epidermidis. Gentamicin and netilmicin usage in hospital increased tenfold from 1976 to 1985.