Clinical Pearls & Morning Reports
Published December 5, 2018
Most investigators have concluded that bacterial vaginosis is a polymicrobial disorder of the vaginal microbiome that is characterized by the absence of vaginal lactobacilli. The disorder is also characterized by the absence of clinically significant vaginal inflammation as indicated by an absence of neutrophils. The predominant bacterial vaginosis–associated organisms include Gardnerella vaginalis, Atopobium vaginae, and mobiluncus species. Read the Latest NEJM Review Article here.
Q: What characterizes the microbiome in a healthy vagina?
A: Hydrogen peroxide–producing lactobacilli predominate in normal vaginal flora, typically accounting for 70 to 90% of the total microbiome in a healthy vagina. L. crispatus, L. gasseri, and L. jensenii usually occur as a single or predominant microorganism in the vaginal microbiome, whereas L. iners commonly occurs as a component of a polymicrobial vaginal flora, often transitioning to bacterial vaginosis. L. crispatus excludes other organisms through low pH due to robust lactic acid production together with hydrogen peroxide and specific host antimicrobial proteins called defensins.
Q: Does bacterial vaginosis affect the transmission of other sexually transmitted diseases?
A: Bacterial vaginosis is associated with not only the acquisition but also the transmission of other sexually transmitted infections, especially human immunodeficiency virus (HIV) infection. Among HIV-infected women, the quantity of HIV in vaginal secretions from women with bacterial vaginosis is increased substantially, as compared with HIV in vaginal secretions from women without bacterial vaginosis.
A: Bacterial vaginosis has a large variety of sequelae in the upper genital tract, including increased risks of preterm birth, first-trimester miscarriage in women undergoing IVF, amniotic-fluid infection, chorioamnionitis, endometritis after childbirth or abortion, and infections after hysterectomy, as well as pelvic inflammatory disease, both in general and after abortion. The attributable proportion of these sequelae has not been universally quantified. Overall, bacterial vaginosis is associated with only a modest increase, by a factor of 2, in the risk of preterm birth. The risks of endometritis after cesarean section, vaginal-cuff cellulitis after hysterectomy, and postpartum endometritis are increased by up to a factor of 6 among women with bacterial vaginosis. The link between bacterial vaginosis and pelvic inflammatory disease has been more consistently replicated than the association of bacterial vaginosis with adverse pregnancy outcomes. Laparoscopic studies have shown that microorganisms that are prevalent in high concentrations in the vagina in women with bacterial vaginosis are also observed in the endometrium and fallopian tubes in women with proven pelvic inflammatory disease.
A: Desquamative inflammatory vaginitis is a clinical syndrome characterized by persistent purulent vaginal discharge and vaginal erythema, often with submucosal cervicovaginal petechiae. Inflammation is the cardinal feature of this disorder. The exact cause of desquamative inflammatory vaginitis is unknown but appears to be a dysbiosis of the normal vaginal microbiome associated with inflammation. In desquamative inflammatory vaginitis, the vagina is colonized with facultative bacteria, not the obligate anaerobic bacteria that colonize the vagina in bacterial vaginosis. The microflora in desquamative inflammatory vaginitis typically consist of Escherichia coli, Staphylococcus aureus, group B streptococcus, or Enterococcus faecalis. The microbiome associated with desquamative inflammatory vaginitis is less well understood than the bacterial vaginosis microbiome. The disease burden caused by desquamative inflammatory vaginitis has not been well studied. The disorder has been linked to an increased risk of preterm birth, premature rupture of membranes, chorioamnionitis, and other adverse pregnancy outcomes, such as miscarriage. Metronidazole is not effective in desquamative inflammatory vaginitis, and treatment failure with metronidazole in women with bacterial vaginosis may suggest desquamative inflammatory vaginitis.