Evaluation of the Microcult system for isolating and identifying Neisseria gonorrhoeae.

Abstract

SUMMARY Specimens from 95 patients attending a venereal diseases clinic were examined for gonococci by three methods-a conventional culture technique using modified Thayer-Martin medium, microscopy of a Gram-stained direct smear, and the Microcult system. For 56?' of the specimens the results by all three methods agreed. Assuming the results obtained by culture on Thayer-Martin medium to be correct, the largest source of error was due to false-positive results: microscopy gave 26 and Microcult gave 15 such results. False-negative results were less common: Microcult gave 14, microscopy six. Microcult gave positive results more quickly than the conventional Thayer-Martin cultural method, but the gonococci were difficult to isolate by subculture from the Microcult culture pads. The Microcult medium was not absolutely specific for Neisseria gonorrhoeae. Nevertheless, the Microcult test may well prove to be a useful adjunct to the diagnosis of gonorrhoea, especially when laboratory facilities are not readily available.

An assessment of the Microcult-GC culture test.

“…We agree with Willcox and John (1976) and Williams et al (1978) that Microcult-GC may be useful in areas or countries which lack laboratory facilities. In addition, the test allows subculture of gonocococci without the need to incorporate antibiotics into the medium used, which might be an advantage in some laboratories.…”

“…Unlike Williams et al (1978) we found that subculture from Microcult-GC was easy and the results correlated completely with those of VCNT culture. Our method of subculture delivered a heavier inoculum and we minimised delay after oxidase-testing.…”