Infectious Disease Compendium

Bacterial vaginosis


Mild inflammation, perivaginal irritation, dysuria, dyspareunia with a 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.


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 proinflammatory 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.

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).

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 qhs for 7 d OR Metronidazole 0.75% vaginal gel 5 g vaginally bid or qhs 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).


See for complete information.


Last Update: 05/09/18.