Bacterial vaginosis: prevalence in outpatients, association with some micro-organisms and laboratory indices

Seven hundred and ninety three women were investigated, aged between 16 and 78 years, to evaluate the prevalence of bacterial vaginosis (BV) and some associated micro-organisms, and to discuss the significance of laboratory indices correlated to this pathology. BV was diagnosed on the basis of four distinct criteria: a positive result of the test for amines with 10% KOH (odour-test), the presence of clue cells on fresh microscopic examination, a pH greater than 4.5 and direct Gram stain positive (the presence of more than 40 Gram negative or Gram variable coccobacilli per microscopic field by 1000 magnifications under oil immersion). The total prevalence of BV was 20.5% (163); similar percentages were found in both fertile and pregnant women, whereas a lower percentage (12.7%) was found in menopausal women. Gardnerella vaginalis was present in 235 (29.6%) of the 793 women, in 144 (88.3%) of the 163 with BV and in 91 (14.4%) of the 630 women without BV. Mobiluncus species was present in 8.2% (65) of the total population, in 38.6% (63) of the women with BV and only in two (0.3%) of the women without BV. In the women with BV lower percentages were found for Trichomonas vaginalis, yeasts, Chlamydia trachomatis and Neisseria gonorrhoeae. The absence of a definite relationship between BV and cultural isolation of G vaginalis is confirmed whereas the role played by Mobiluncus spp still has to be clarified. It is concluded that it is not necessary to screen with all four laboratory indices. Two positive indices from a panel of three (excluding pH greater than 4.5 and direct Gram stain positive in the same panel) allows the correct diagnosis of BV in almost all cases.