Clinical Review

BV update: eliminating diagnostic confusion

OBG Manag. 2002 June;14(6):67-79

In the absence of universally accepted data, 3 leading authorities review the evidence on bacterial vaginosis and discuss their approaches to diagnosing and treating this common vaginal affliction.

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References

1. Hawes SE, Hillier SL, Benedetti J, et al. Hydrogen peroxide-producing lactobacilli and acquisition of vaginal infections. JID. 1996;174:1058-1063.

2. Watts DH, Krohn MA, Hillier SL, et al. Bacterial vaginosis as a risk factor for post-cesarean endometritis. Obstet Gynecol. 1990;75:52-58.

3. Larsson PG, Bergman B, Forsum U, et al. Mobiluncus and clue cells as predictors of PID after first-trimester abortion. Acta Obstet Gynecol Scand. 1989;68:217-220.

4. Larsson PG, Platz-Christensen J, Thejls H, et al. Incidence of pelvic inflammatory disease after first-trimester legal abortion in women with bacterial vaginosis after treatment with metronidazole: a double-blind, randomized study. Am J Obstet Gynecol. 1992;166:100-103.

5. Hoyme U, et al. Results and potential consequences of the Thuringa prematurity preventional campaign 2000. Geburtsch Frauenheilk. 2002;62:257-263.

6. Paavonen J, Mangioni C, Martin MA, et al. Vaginal clindamycin and oral metronidazole for bacterial vaginosis: a randomized trial. Obstet Gynecol. 2000;96:256-260.

7. Sobel JD, Chaim W, Thomason J, Livengood C, et al. Comparative study of intravaginal metronidazole and triple-sulfa therapy for bacterial vaginosis. Infect Dis Obstet Gynecol. 1996;4:66-70.

8. Hill GB, Livengood CH. Bacterial vaginosis-associated microflora and effects of topical intravaginal clindamycin. Am J Obstet Gynecol. 1994;171:1198-1204.

9. Centers for Disease Control and Prevention. 1998 guidelines for treatment of sexually transmitted diseases. MMWR. 1998;47(No. RR-1).:

10. Hillier SL, Krohn MA, Watts DH, et al. Microbiologic efficacy of intravaginal clindamycin cream for the treatment of bacterial vaginosis. Obstet Gynecol. 1990;76:407.-

11. Ross RA, et al. Effect of Candida albicans infection and clotrimazole treatment on vaginal microflora in vitro. Obstet Gynecol. 1995;86:925-930.

12. Clissold SP, Heel RC. Tioconazole: a review of its antimicrobial and ther-apeutic use in superficial mycoses. Drugs. 1986;31:29-51.

13. Jones RN, Cali MJ, Hoban D, et al. In vitro antimicrobial activity of tioconazole and its concentration in vaginal fluids following topical (vagistat-1 6.5%) application. Diag Microbiol Infect Dis. 1993;17:45-51.

14. Sobel JD, Leaman D. Suppressive maintenance therapy of recurrent bac-terial vaginosis utilizing 0.75% metronidazole vaginal gel. Int J Gynecol Obstet. 1999;67:S41, abstract #010115

15. Hubacher D, et al. Use of copper intrauterine devices and the risk of tubal infertility among nulligravid women. N Engl J Med. 2001;345:561-567.

The panelists

William Ledger, MD, is chairman emeritus and professor of OBG at the New York Weill Cornell Medical Center in New York City.

Sharon Hillier, PhD, is professor of OBG and reproductive sciences at the University of Pittsburgh School of Medicine in Pennsylvania.

Sebastian Faro, MD, PhD, is clinical professor of OBG and reproductive sciences at the University of Texas-Houston Health Science Center in Houston.

Key points

Physicians should not diagnose BV with a culture. A standard culture will not identify the number of anaerobic bacteria.
In diagnosing BV, an Ob/Gyn must perform a microscopic exam, along with a whiff test and pH.
Metronidazole and clindamycin are only 66% effective in treating BV.
Topical clindamycin causes a temporary overgrowth of E. coli and Enterococcus in the vagina.
Women whose vaginal microflora is colonized with hydrogen peroxide-producing Lactobacillus are less likely to acquire BV.
All women should be screened for BV during an annual exam.

The number one reason women visit their gynecologists is for the treatment of vaginal infections. Yet a recent Gallup survey found that only 36% had ever heard of bacterial vaginosis (BV), the most common type of vaginal infection, affecting 1 in 4 American women. BV is a disease caused by an overgrowth of anaerobic bacteria and Gardnerella, all of which can be found in low numbers in the healthy vagina. In fact, women who have been diagnosed with BV have up to 1,000 times more anaerobic bacteria than normal women.

Studies have shown that many women confuse the symptoms of BV with a yeast infection and often self-medicate with over-the-counter preparations. Unlike Candida, however, BV has been associated with pelvic inflammatory disease (PID), as well as an increased risk of endometritis, cervicitis, and in pregnant women, premature delivery. Therefore, it is imperative that Ob/Gyns properly diagnose and treat BV while creating greater awareness of the signs and symptoms of this widespread disorder among their patients. Here, Sebastian Faro, MD, PhD, William Ledger, MD, and Sharon Hillier, PhD, respond to OBG Management editors’ questions on appropriate diagnosis, screening, and management modalities to combat this potentially dangerous yet treatable condition.

OBG Management: How does a woman contract BV? What are the predisposing factors?

Dr. Ledger: In many cases, it is related to sexual activity, though there are certainly women who are not sexually active who can get it. Basically, there’s a change in the bacterial flora of the vagina. Unfortunately, what triggers that change is unknown.

Dr. Faro: I think an alteration in pH levels stimulates a change in the vaginal microflora. We don’t know what causes that, but this alteration stimulates other bacteria such as Gardnerella to grow. Frequency of sexual intercourse does affect the pH and flora.

Dr. Hillier: In following a group of women without BV over time, we have found that women who use douching products and those with greater levels of sexual activity are more likely to acquire BV. However, there are many women who are monogamous and who do not douche who acquire BV. In our studies, it turned out that women who had H₂O₂-producing Lactobacillus vaginally were significantly less likely to acquire BV¹ (Figure 1). There is no way presently for a woman or her physician to tell whether the Lactobacillus colonizing the vagina produces H₂O₂. Nevertheless, we think that many women who acquire BV simply lack the most protective kind of normal flora.

OBG Management: If there is a positive whiff test when examining the patient, is it necessary to do a wet mount or a pH test?

Dr. Hillier: A positive whiff test indicates that there are high levels of anaerobic bacteria producing trimethylamine in the vaginal flora. In our experience, nearly every woman who has a positive whiff test will also have an elevated pH. It is still advisable to do a wet mount on a woman with a positive whiff test in order to evaluate for mixed infections with other agents such as Trichomonas vaginalis.

Dr. Ledger: Unfortunately, many physicians are trying to cut corners on things that are very simple to do. An Ob/Gyn cannot diagnose any vaginitis unless he or she knows how to do a microscopic exam, along with a whiff test and pH (Figure 2). The whole process takes seconds. If they are not doing these tests, they ought to be sending patients to someone who is.

Dr. Faro: I think it is critical to perform a microscopic analysis, a whiff test, and a pH. If you only rely on the whiff test, you often will miss BV. Individuals can have an elevated pH of 5, 5.5, or 6, and not have BV. This could signify a dominant flora with E. coli or some other bacteria. Furthermore, the Trichomonas patient will have a positive whiff test, a pH that’s 5 or greater, and not have BV.