While the presence of malodor is an important symptom in the diagnosis of BV, it can inadvertently lead to a false diagnosis. About 50% of women experience unwanted vaginal odor at some point in their lives. Because of the complexity of BV diagnosis, some women who are experiencing feminine odor are misdiagnosed with BV and over-treated with antibiotics.
Complicating things is the recent discovery that baseline bacteria population differ by race. Some women seem to normally have less lactic acid producing bacteria in their vaginal ecosystem, even though they have no symptoms of any disease. The type of vaginal population present in women is called their Community State Types (CSTs). So far, 5 CSTs have been well identified. However, even within your CST, the bacteria in the vagina is always changing. A woman’s period, her ovulation, and her sexual activities can change the types of bacteria in the vagina at a given time. And as a woman ages and her hormone levels change (after about 30 years of age), her vaginal ecosystem also changes. These naturally occurring CSTs and changes in bacteria population make it difficult to predict the effectiveness of broad spectrum antibiotics during a bout with BV.
We now know that the bacteria that causes BV is often present in the vaginas of normal, healthy women in low numbers. It is not yet well understood why these bad bacteria start to take over and displace the “good” lactic acid bacteria, which ultimately leads to BV. BV occurs only when “bad” bacteria species out-compete the healthy lactic acid producing bacteria, and a biofilm or coating of bad bacteria occurs. A single Gram Stain swab of vaginal secretions taken just before the bad bacteria tilts the balance may lead to an inaccurate diagnosis.