Aerobic vaginitis: Abnormal vaginal flora entity that is distinct from bacterial vaginosis

Abstract

Due to shortcomings in the current systems of classifying pathology of the vaginal bacterial flora we aimed to define a new entity of abnormal vaginal flora: aerobic vaginitis. Six hundred thirty-one women were studied for clinical signs of vaginitis during routine prenatal visits and vaginitis clinic visits in the University Hospital Gasthuisberg, Leuven, Belgium. Samples were taken for fresh wet mount microscopy of vaginal fluid and for vaginal cultures. In order to study the difference between aerobic vaginitis and bacterial vaginosis, lactate and succinate levels were measured in vaginal rinsing fluids, and 243 samples were tested for cytokine levels. Smears deficient in lactobacilli and positive for clue cells were considered to indicate a diagnosis of bacterial vaginosis (BV). Aerobic vaginitis (AV) was diagnosed if smears were deficient in lactobacilli, positive for cocci or coarse bacilli, positive for parabasal epithelial cells, and positive for vaginal leukocytes (plus their granular aspect). We conclude that AV is a condition of abnormal vaginal flora that differs from BV. Genital complaints are those of a real vaginitis (red inflammation, yellow discharge, vaginal dyspareunia). Group B streptococci, Escherichia coli , Staphylococcus aureus and Trichomonas vaginalis are frequently cultured. As in BV, vaginal lactate concentration is severely depressed in patients with AV. Unlike patients with BV, vaginal succinate is not produced in AV. Also in contrast to BV, AV produces a host immune response that leads to high production of interleukin-6, interleukin-1-β and leukemia inhibitory factor in the vaginal fluid. Therefore, AV is an entity describing vaginitis associated with aerobic microorganisms, mainly group B streptococci and E. coli . Its characteristics are different from those of BV and elicit an important host response. In theory, AV is a better candidate than BV to be involved in the causation of pregnancy complications, such as ascending chorioamnionitis, preterm rupture of the membranes and preterm delivery.