Despite concerted efforts in the laboratory and clinic to combat the staphylococcus, this organism remains the most important bacterial pathogen. The ability to produce deep-seated infections in almost any tissue of the body and to develop resistance to the majority of antimicrobials makes it particularly difficult to eradicate. To date no antibiotic has been uniformly successful in inhibiting its growth.
A previous report from this laboratory described the use of tube-dilution sensitivity tests to evaluate the activity of 10 antibiotics against 200 strains of hemolytic staphylococci.1 One hundred of these strains were isolated from patients with serious infections and the remainder from carriers hospitalized for other reasons. The majority of cultures were obtained in 1955.
The studies to be reported here consist of antimicrobial sensitivity tests performed on 300 additional strains of staphylococci isolated between July 1, 1958, and April 1, 1959. The same tube-dilution technique which measures bacteriostatic