Diagnosis
Mild inflammation, perivaginal irritation, dysuria, dyspareunia with an occasional fishy vaginal odor and a gray, thin, bubbly, homogeneous discharge.
Vaginal pH is > 4.5; 10 to 20% KOH added to the discharge produces a fishy odor.
A wet mount has clue cells.
Epidemiologic Risks
Usually in sexually active women, including women who have sex with women (PubMed). Risk factors are douching, new or multiple ex-partners, antibiotics use, and using an IUD.
Hormonal contraception is associated with relapse (PubMed).
Increases the risk of other STD's.
Microbiology
BV is primarily an ecologic/microbiome problem, "A careful analysis of the available data suggests that what we term BV is, in fact, a set of common clinical signs and symptoms that can be provoked by a plethora of bacterial species with pro-inflammatory characteristics, coupled to an immune response driven by variability in host immune function."(PubMed): there is a shift from a primarily Lactobacillus species (L crispatus, L. jensenii, and L. iners, different species than those found in yogurt or probiotics) of few types to a mixed microbiology of a wide variety of anaerobes, many of which can not be grown but can be detected by molecular techniques. It is not a problem with one bug, but a substitution of normal flora with multiple bugs.
and
"Bacterial vaginosis can be considered a biofilm infection, with a dense polymicrobial biofilm consisting primarily of G. vaginalis adhering to the vaginal epithelium (PubMed)."
One model suggests a role for "virulent strains of G. vaginalis, as well as Prevotella bivia and Atopobium vaginae (PubMed)" which may be spread as an STD,
G. vaginalis, Bacteroides, Prevotella, Mobiluncus, Mycoplasma hominis and Ureaplasma urealyticum have all been isolated. This disease is more of a change in the flora of the vagina than to any particular organism. Women who have sex with women may have different flora, Clostridiales bacteria, designated as BVAB1, BVAB2, or BVAB3m; Peptoniphilus lacrimalis; and Megasphaera phylotype 2 that is associated with increased failure of topical therapy (PubMed).
"G. vaginalis, P. bivia, A. vaginae, and Megasphaera type I may play significant roles in iBV. (PubMed)."
Empiric Therapy
Metronidazole 500 mg po bid for 7 d OR 250 mg po tid for 7 d OR 750 mg extended-release tablet po qd for 7 d OR 2 g po single dose
OR
clindamycin 300 mg PO bid for 7 d OR Clindamycin 2% vaginal cream 5 g vaginally q hs for 7 d
OR
Metronidazole 0.75% vaginal gel 5 g vaginally bid or q hs for 5 d.
Probiotics may hasten a return to normal flora (PubMed). Or it may not. One study showed no benefit of adding probiotics (PubMed).
Pearls
See http://www.cdc.gov/STD/treatment/ for complete information.
Rants
Last Update: 10/31/19.