Comparison of bacteriostatic and bactericidal inhibitors of Neisseria gonorrhoeae growth produced in vitro by urogenital staphylococci

: Coagulase-negative staphylococci are known to produce bactericidal and bacteriostatic antigonococcal activities. Out of 12 staphylococci, Staphylococcus haemolyticus (four isolates) was identified as the principal source of bactericidal activity, whereas Staphylococcus epidermidis (six isolates) was primarily responsible for producing bacteriostatic activity. A comparison of the bacteriostatic substance produced by S. epidermidis isolate 66 with the bactericidal substance produced by S. haemolyticus isolate 7, which had been previously purified, showed that they were similar lipoproteins or lipid-associated proteins. However, these two inhibitors migrated differently under electrophoresis on agarose gel. The protein component of the bacteriostatic inhibitor was more difficult to separate from the lipid component when chromatographed on Ultrogel AcA 54 in the presence of urea (4 M) than the protein component of the bactericidal inhibitor. The protein component of both types of inhibitors was responsible for the antigonococcal activity and was dissociable into subunits of approximately 1,400 daltons. However, these protein components had different migration patterns on agarose gel. The bacteriostatic substance displayed a bactericidal effect when dissociated from its lipidic component suggesting that the lipids might play a role in the type of inhibitory activity produced. All of the bactericidal and bacteriostatic substances contained in the different crude preparations were antigenically related.