Atopobium vaginae is a bacterium commonly found in the vaginal microbiome. While its mere presence does not always signal a health concern, this bacterium has garnered attention due to its close association with certain vaginal conditions. Understanding Atopobium vaginae provides important insights into vaginal health and the factors influencing its balance.
Understanding Atopobium vaginae
Atopobium vaginae is an anaerobic, Gram-positive bacterium and a common resident in the vaginal flora. However, its presence differs from beneficial Lactobacillus species, which normally dominate the vaginal environment and produce lactic acid to maintain a healthy, slightly acidic pH. An overgrowth of Atopobium vaginae can disrupt this balance.
Is Atopobium a Sexually Transmitted Infection?
Atopobium vaginae is not classified as a traditional sexually transmitted infection (STI). Traditional STIs are typically acquired through sexual contact and are directly transmitted from one person to another. Atopobium vaginae is considered an opportunistic bacterium.
While its prevalence might be influenced by sexual activity, it is primarily an organism that can overgrow within the vaginal environment. Bacterial vaginosis, a condition strongly associated with Atopobium vaginae, is often considered a sexually associated condition. This distinction highlights that while sexual behaviors may affect the vaginal microbiome, Atopobium vaginae is not solely transmitted through sexual intercourse.
Atopobium’s Role in Bacterial Vaginosis
Atopobium vaginae plays a significant role in bacterial vaginosis (BV), which is a common imbalance of the vaginal microbiome. In BV, the typical dominance of Lactobacillus species is reduced, leading to an overgrowth of various anaerobic bacteria. Atopobium vaginae is frequently found in high numbers in women diagnosed with BV.
It often coexists with Gardnerella vaginalis, another bacterium strongly linked to BV. These bacteria can form polymicrobial biofilms on the vaginal epithelium, contributing to the persistence of BV and making it more challenging to treat. The presence of Atopobium vaginae, especially alongside Gardnerella vaginalis, is notably associated with recurrent BV cases.
Diagnosis and Management
Identification of Atopobium vaginae typically occurs as part of a broader assessment of the vaginal microbiome, often when diagnosing bacterial vaginosis. Clinicians diagnose BV using several methods, including evaluating symptoms, performing a pelvic exam, and using Amsel’s criteria. Amsel’s criteria involve checking for:
- A characteristic discharge
- Vaginal pH above 4.5
- A “fishy” odor after adding potassium hydroxide
- The presence of “clue cells” on a microscopic examination of vaginal discharge
The Nugent score, derived from a Gram stain of vaginal fluid, is another common diagnostic tool that assesses bacterial morphotypes. Molecular techniques, such as PCR, are increasingly utilized for more precise identification of Atopobium vaginae and other bacteria. Treatment for BV, which aims to restore the balance of the vaginal microbiome, commonly involves antibiotics such as metronidazole or clindamycin. Recurrence of BV, particularly when Atopobium vaginae is present, can be a challenge, partly because some strains of Atopobium vaginae may show reduced sensitivity to metronidazole.