Resistance of staphylococci to penicillin-G and cloxacillin.

Staphylococcus aureus and epidermidis species from patient cultures and hospital environmental samples were studied for resistance to Penicillin-G and Cloxacillin, a penicillinase resistant penicillin. Only 4--7% of the 232 Staphylococcus aureus strains were sensitive to Penicillin-G; 40--41% were sensitive to Cloxacillin. Patient strains (57) of Staphylococcus epidermidis were sensitive to Penicillin-G in 29% and to Cloxacillin in 53% of the cases. The incidence of sensitivity of the hospital strains (50) of Staphylococcus epidermidis to Penicillin-G was 78% and to Cloxacillin was 93%. In view of their high resistance to Cloxacillin, the strains were evaluated for sensitivity to Gentamicin, an alternate choice for antibiotic therapy. Approximately 90% of the Staphylococcus aureus strains were sensitive to Gentamicin while 99% of the Staphylococcus epidermidis strains were sensitive. This study indicates that differences may exist in regard to antibiotic resistance patterns in various localities and this should be evaluated.