The microbiology of bacterial vaginosis.

A group of microorganisms are present concurrently in high concentrations in the vaginas of women with bacterial vaginosis. The major members of the group are Gardnerella vaginalis, anaerobic gram-negative rods belonging to the genera Prevotella, Porphyromonas and Bacteroides, Peptostreptococcus species, Mycoplasma hominis, Ureaplasma urealyticum, and often Mobiluncus species. Facultative species of Lactobacillus are present in lower concentrations and are less prevalent in bacterial vaginosis than in women with a normal vaginal examination. The exact microbe(s) responsible for bacterial vaginosis is unknown whether among the organisms listed above or an unknown agent. The high concentrations of anaerobic gram-negative rods, peptostreptococci, and other opportunistic pathogens in the lower genital tract place women with bacterial vaginosis at increased risk for genital infections and adverse pregnancy outcomes.