Bacterial interference of Neisseria gonorrhoeae by α-hemolytic streptococci

Abstract

Fifty pharyngeal isolates of α-hemolytic streptococci were tested against 20 cervical isolates of Neisseria gonorrhoeae for bacterial interference in vitro using the lawn-spotting method. Forty-seven (94%) isolates of streptococci showed inhibitory activity toward N. gonorrhoeae, although nine of these were inhibitory to only one isolate of N. gonorrhoeae. Isolates of N. gonorrhoeae varied widely in their sensitivity to streptococci; the most sensitive were inhibited by 40 isolates of streptococci and the least sensitive by only 14 isolates. Species of Streptococcus found to inhibit growth of N. gonorrhoeae were S. mitis, SO MG intermedius, S. sanguis II, S. mutans, and S. morbillorum.