HIV-1 INFECTION ASSOCIATED WITH ABNORMAL VAGINAL FLORA MORPHOLOGY ANDBACTERIAL VAGINOSIS

Background In-vitro research has suggested that bacterial vaginosis ma y increase the survival of HIV-1 in the genital tract. Therefore, we i nvestigated the association of HIV-1 infection with vaginal flora abno rmalities, including bacterial vaginosis and depletion of lactobacilli , after adjustment for sexual activity and the presence of other sexua lly transmitted diseases(STDs). Methods During the initial survey roun d of our community-based trial of STD control for HIV-1 prevention in rural Rakai District, southwestern Uganda, we selected 4718 women aged 15-59 years. They provided interview information, blood for HIV-1 and syphilis serology, urine for detection of Chlamydia trachomatis and N eisseria gonorrhoeae, and two self-administered vaginal swabs for cult ure of Trichomonas vaginalis and gram-stain detection of vaginal flora , classified by standardised, quantitative, morphological scoring. Sco res 0-3 were normal vaginal flora (predominant lactobacilli). Higher s cores suggested replacement of lactobacilli by gram-negative, anaerobi c microorganisms (4-6 intermediate; 7-8 and 9-10 moderate and severe b acterial vaginosis). Findings HIV-1 frequency was 14.2% among women wi th normal vaginal flora and 26.7% among those with severe bacterial va ginosis (p<0.001). We found an association between bacterial vaginosis and increased HIV-1 infection among younger women, but not among wome n older than 40 years; the association could not be explained by diffe rences in sexual activity or concurrent infection with other STDs. The frequency of bacterial vaginosis was similar among HIV-l-infected wom en with symptoms (55.0%) and without symptoms (55.7%). The adjusted od ds ratio of HIV-1 infection associated with any vaginal flora abnormal ity (scores 4-10) was 1.52 (95% CI 1.22-1.90), for moderate bacterial vagniosis (scores 7-8) it was 1.50 (1.18-1.89), and for severe bacteri al vaginosis (scores 9-10) it was 2.08 (1.48-2.94). Interpretation Thi s cross-sectional study cannot show whether disturbed vaginal flora in creases susceptibility to HIV-1 infection. Nevertheless, the increased frequency of HIV-1 associated with abnormal flora among younger women , for whom HIV-1 acquisition is likely to be recent, but not among old er women, in whom HIV-1 is likely to have been acquired earlier, sugge sts that loss of lactobacilli or presence of bacterial vaginosis may i ncrease susceptibility to HIV-1 acquisition. If this inference is corr ect, control of bacterial vaginosis could reduce HIV-1 transmission.