Site of action of a gonococcal growth inhibitor produced by Staphylococcus haemolyticus

The inhibitory substance produced by Staphylococcus haemolyticus strain no. 7 acts on growing as well as resting gonococcal cells, as shown by reductions in viable counts. The optical density of these cell suspensions was only slightly reduced. The inhibitor caused lysis of gonococcal spheroplasts at 24 degrees C and 37 degrees C, but was much less active at 4 degrees C. Acting on intact gonococcal cells, the inhibitor caused a temperature-dependent release of radioactive cytoplasmic material. Electronmicroscopy showed that treated suspensions contained ghost cells with the cell envelope relatively intact. Our results suggest that the inhibitor may act on the cytoplasmic membrane of the gonococcal cell causing cytoplasmic leakage and, eventually, death.