Frequency of resistance to trimethoprim among isolates of Staphylococcus epidermidis and Staphylococcus saprophyticus.

Four hundred and forty-nine strains of staphylococci, 386 Staphylococcus epidermidis and 63 Staph. saprophyticus were tested by MIC and disc for susceptibility to trimethoprim. About 30% of clinically significant strains of Staph. epidermidis were resistant to trimethoprim; this fell to 12.6% in strains from normal flora. The frequency of resistance among clinically significant strains did not alter from 1976 to 1980. Strains of Staph. saprophyticus were uniformly sensitive to trimethoprim.