Comparative in vitro sensitivity to metronidazole of Trichomonas vaginalis with isolates and clones
Sithithaworn, P.; Sithithaworn, J.; Kitjaroen, K.; Pairojkul, C.; Ratananurakpong, S.; Sriswangwonk, T.
Southeast Asian Journal of Tropical Medicine and Public Health 20(2): 279-284
1989
ISSN/ISBN: 0125-1562 PMID: 2609217 Document Number: 337179
Isolates of Trichomonas vaginalis from a group of Thai women in Khon Kaen, Thailand were studies for their in vitro sensitivity to metronidazole. Forty-five isolates of T. vaginalis and futher 226 laboratory clones of these isolates were examined for drug sensitivity under anaerobic conditions using the CPLM (Cysteine-Peptone-Liver infusion-Maltose) medium. The in vitro sensitivity of T. vaginalis to metronidazole, recorded as MLC values revealed highly variable sensitivity profiles. Greater than 90% of the trichomonads studies were susceptible to relatively low concentrations of metronidazole in the range of 1-10 .mu.g/ml. The remaining fraction of trichomonads, appeared to be less sensitive and required higher concentration of drug to attain the MLCs. The highest recorded MLC was 60 .mu.g/ml. The geometric mean MLC of the 45 isolates was 7.99 .mu.g/ml while that of the 226 clones was 5.43 .mu.g/ml. The influence of the individual clones or subpopulations of T. vaginalis on the observed sensitivity of the isolates was also examined. A positive linear relationship was observed between the MLC of the isolate and the MLC of the least sensitive clone of the same isolate (p < 0.05). This suggests that the most resistant clone present within an isolate of T. vaginalis plays an important role in determining the overall drug sensitivity of the isolate.