[Value of the score for Gram strains in the diagnosis of bacterial vaginosis].
The interpretation of Gram-stained slides of vaginal swab specimens is evaluated for the diagnosis of bacterial vaginosis and correlated with the isolation bacteria and clinical signs: thin homogeneous vaginal discharge, pH > or = 4.7, amine odor and presence of clue cells. Gram stained smears were scored following a morphotype classification: (a)-Lactobacillus morphotypes (scored 4 to 0), (b)-small Gram negative (G. vaginalis, scored 0 to 4), (c)-curved Gram variable rods (Mobiluncus morphotypes, scored 0 to 2). The scoring system (0 to 10) was a weighted combination of these morphotypes: a+b+c. The criterion for bacterial vaginosis was a score > or = 7, a score of 0 to 6 was considered as no bacterial vaginosis. Samples of 709 women, aged 18 to 84 (mean age = 39.7) were examined. The prevalence of G. vaginalis culture was 12.5%, and Mobiluncus infection occurred in 1.5%. The frequency of M. hominis was diagnosed in 2.8% of women. A score of 7 to 10 on Gram stain was observed in 9.7% in the population. Compared to G. vaginalis culture, Gram stained smear was more sensitive (0.71) than clinical signs of bacterial vaginosis (0.46). The specificity was similar with the two methods. The assessment of G. vaginalis morphotypes was highly correlated with the G. vaginalis culture (p < 0.001, OR = 248). The infection of T. vaginalis or Candida sp. was never associated with a score > or = 7. The Gram-stained smear is a cheap, fast and easy method. It provides good results for diagnosis of bacterial vaginosis.