Inhibition of growth of N. gonorrhoeae by bacterial interference.

Observations made in our laboratory during the past 3 years showed that the growth of some Neisseria gonorrhoeae cultures was inhibited in the presence of various bacterial contaminants of urogenital specimens. A total of 647 cultures confirmed as containing N. gonorrhoeae were examined in this study. The first part of the study was carried out on 520 N. gonorrhoeae cultures. Of these 520 cultures, 110 (21.1%) showed contamination on purity plates (GC medium, antibiotic-free). When further subcultured, 96 (87.3%) of the N. gonorrhoeae strains grew in pure culture, but 14 (12.7%) failed to grow. Subsequently, experiments were carried out on 127 pure N. gonorrhoeae cultures. The bacterial species that inhibited the growth of N. gonorrhoeae are listed in order of frequency: Neisseria meningitidis, Staphylococcus epidermidis, Corynebacterium species, Staphylococcus aureus, Streptococcus group A, and Neisseria subflava.