Parasitología al día
Print version ISSN 0716-0720
COSTAMAGNA, SIXTO RAUL and PRADO FIGUEROA, MARIA. VALIDATION TEST OF CONVENTIONAL WET MOUNT EXAMINATION, MAY GRUNWALD-GIEMSA AND GRAM STAINING, AND CULTURE MEDIUM TESTS FOR THE DIAGNOSIS OF Trichomonas vaginalis. Parasitol. día [online]. 2001, vol.25, n.1-2, pp. 60-64. ISSN 0716-0720. doi: 10.4067/S0716-07202001000100011.
The goal of the present study was to determine the validity of the following five methods used for the diagnosis of Trichomonas vaginalis in vaginal secretions at the clinical laboratory: Gram staining; Conventional wet mount examination; May Grunwald-Giemsa staining; Culture in a modified Diamond (Menarini®) medium; Culture in an OXOID® CM 161 medium. We used 89 vaginal-secretion samples extracted with sterile cotton swabs of female subjects between the ages of 25 and 55 at the laboratory of the Hospital de Evacuación 181 of the city of Bahía Blanca, Province of Buenos Aires, Argentina. The samples were stained with Gram and May Grunwald-Giemsa; observed by conventional wet mount examination; and cultured in Diamond (Menarini®) and OXOID® CM 161 media and incubated for 5 days at 37ºC in an anaerobic condition. Results showed that, for a prevalence of disease (Trichomonosis) of 29.21%, the Diamond (Menarini®) culture medium and the immediate conventional wet mount examination at our diagnostic lab have similar sensitivities, predictive negative values, and global values: 80.7%, 92.64%, and 94.38%, respectively. When the four tests were conducted in parallel, the resulting sensitivity was 99.76% with a predictive negative value of 99.90%. As for the OXOID® CM 161 medium, even though the global value of the test was similar, its sensitivity was 76.92%, slightly lower than the results from the conventional wet mount examination, but without a significant statistical difference. The Gram staining showed a diagnostic sensitivity of 19.23%. We conclude that the Diamond (Menarini®) and the OXOID® CM 161 culture media do not improve the etiological diagnosis of Trichomonas as compared to the conventional wet mount examination and May Grunwald-Giemsa staining tests. While we do not recommend using Gram staining for the study of T. vaginalis, we consider that, if the flagellate were to be identified by this method, its finding could be reported without further testing
Keywords : Trichomonas vaginalis; Trichomonosis; Culture of Trichomonas; Diagnostic.