The effect of Candida albicans on the isolation of N. gonorrhoeae

Recently, several studies have reported that strains of Candida albicans and perhaps other noraml bacterial flora are capable of inhibiting the growth of Neisseria gonorrhoeae in vitro, and it is possible that this may occur in vivo as well. This possible antagonism between N. gonorrhoeae and normal flora microorganisms poses many questions regarding the reliable laboratory diagnosis of gonorrhea. Mixed cultures of C. albicans and N. gonorrhoeae were grown together on GC base agar plates with varying concentrations of nystatin. Recovery of N. gonorrhoeae was improved as nystatin concentration was increased to 25 IU/ml, while growth of C. albicans was effectively inhibited. At concentrations of 50 and 100 IU/ml nystatin also began to inhibit N. gonorrhoeae. There was a noticeable decrease of nystatin bioactivity against C. albicans when the GC plates were stored at 4 C, thus making it more difficult to isolate N. gonorrhoeae. Growth curves of C. albicans and N. gonorrhoeae grown together in liquid medium did not significantly differ from growth curves of the individual organisms. Statistical analysis of our findings does not support the theory that strains of C. albicans produce a soluble diffusible factor that is inhibitory to N. gonorrhoeae.