Chemical and biological characterization of a gonococcal growth inhibitor produced by Staphylococcus haemolyticus isolated from urogenital flora.

The purified antigonococcal substance produced by Staphylococcus haemolyticus no. 7 has shown a broad antigonococcal spectrum and a narrow antibacterial spectrum. The inhibitor produced in vitro was also active in the guinea pig subcutaneous chamber. The inhibitor has shown hemolytic activity; the human, horse, and mouse erythrocytes were the most susceptible. Hemolytic and antigonococcal activities were inhibited in the presence of phosphatidylcholine. The amino acid composition of the antigonococcal substance was characterized by the absence of proline, tyrosine, histidine, cysteine, and tryptophan. The molecular weight was found to be 2,565, and the major isoelectric points were 4.8 and 4.9 in the presence of 8 M urea and 4.6 without urea. The inhibitor has some properties similar to those of the delta toxin of Staphylococcus aureus, although the two substances are different based mainly on their chemical characteristics. Also an antiserum directed against the gonococcal inhibitor did not give a precipitation line with the delta toxin, indicating that the two substances are antigenically unrelated.