Antibiotic resistance of pathogenic staphylococci; study of five hundred strains isolated at Boston City Hospital from October, 1951, to February, 1952.

Abstract

SOON AFTER interest in Fleming's penicillin was reawakened through the work of Chain and Florey1and their associates, there appeared evidence of the occurrence of penicillin-resistant strains of pathogenic staphylococci after exposure to penicillin both in vitro and in vivo.2In 1945, North and Christie3obtained 128 strains of staphylococci (88 coagulase producers and 40 not coagulase producers) from one hospital where penicillin had not been used and compared them with 31 coagulase-positive strains isolated from patients in another hospital where penicillin was being used extensively. The coagulase-positive strains from the former hospital were all inhibited by 1/8 unit or less, while the coagulase-negative ones were all completely inhibited by 1/2 unit or less. By contrast, only 13 of the strains from the hospital where penicillin was widely used were inhibited by less than 1 unit, and 17 required 2 to 80 units. Since that time many