Tinción diferencial de fluorescencia modificada en el diagnóstico de N. gonorrhoeae y correlación clínico-tintorial del diplococo

The objective of this study was to evaluate the modified differential fluorescent staining method for diagnosing gonorrhea in perianal and urethral specimens, and to correlate the characteristics of the fluorescent dye of the diplococcus in smears with symptoms. The perianal and urethral specimens were collected from men with two swabs for both smear and bacteriological culture. The modified differential fluorescent staining identified diplococcus in perianal and urethral specimens with different dyes and intensities of fluorescence. Patients with rectal infection, showed no symptoms. The modified fluorescent staining was highly sensitive (100%) in identifying gonococcus in perianal smears, as well as Gram, and specificity was high (86%) as compared with Gram (36%), with statistically significant differences. 75% of symptomatic patients presented urethritis. Values for sensitivity and specificity of the modified differential fluorescent staining method in the latter were similar to Gram (100%). In asymptomatic individuals, sensitivity for both methods was similar (100%) and, although specificity values were low, the modified differential fluorescent staining method (67%)outperformed the Gram (50%), with statistically significant differences. Fluorescent staining has a more discriminatory capacity in asymptomatic patients (perianal=93%; urethral=83%) than Gram (perianal=68%; urethral = 75%). There was a statistically significant correlation between the observation green non-fluorescent diplococcus in urethral smears and the presence of symptoms. The modified differential fluorescent staining method is an excellent tool for the diagnosis of gonorrhea in perianal and urethral specimens, The use of ROC curves allowed the assessment of the best staining methods for diagnosing rectal and urethral gonorrhea, the modified differential fluorescent staining method showing more discriminatory capacity than Gram, especially in asymptomatic patients, which is very important for controlling the disease.