Aerobic Vaginitis

An Aerobic Vaginitis (AV) Panel detects bacterial pathogens associated with aerobic vaginitis, a vaginal infection characterized by an imbalance in normal flora, inflammation, and disruption of the vaginal epithelium.

The bacterial isolates that are included in the panel includes:

• Enterococcus faecalis: A facultative anaerobic Gram-positive bacterium commonly found in the gastrointestinal tract but implicated in AV due to its ability to adhere to vaginal epithelial cells and trigger inflammation.
• Escherichia coli: A Gram-negative rod that can colonize the vagina from the rectal reservoir, leading to AV and increasing the risk of urinary tract infections.
• Staphylococcus aureus: A Gram-positive coccus capable of producing toxins and biofilms, contributing to vaginal dysbiosis and potential complications like toxic shock syndrome in rare cases.
• Streptococcus agalactiae (Group B Streptococcus, GBS): A Gram-positive bacterium associated with AV and adverse pregnancy outcomes, including preterm labor and neonatal infections if transmitted during childbirth.

Tempera et al. found that patients with AV have depressed levels of hydrogen-peroxide-producing lactobacilli, but increased levels of aerobic bacteria (group B streptococci, S. aureus, E. coli and enterococci). Compared with the normal vaginal microflora, these aerobes increased by three-to fivefold and were associated with inflamed vaginal mucosa and with evidence of local cytokine-mediated inflammation. Similarly, Wang et al. developed a bedside test for AV diagnosis. AV was diagnosed based on five enzymatic indicators:

1. Hydrogen peroxidase activity, which reflects the growth status of hydrogen peroxide-producing lactobacilli;
2. Leucocyte esterase (LE) activity, which indicates the presence of inflammation;
3. sialidase activity, which is produced in high quantities by BV and AV associated bacteria, S. agalactiae;
4. Beta-glucuronidase activity, specific for E. coli infection;
5. Coagulase activity, which indicates the presence of S. aureus and E. faecalis . The authors also found increased presence of E coli, but the methodology used for detection was not clear. The reported sensitivity of their test was 90%, but the study lacked analysis of specificity.

Detection of these bacteria in a vaginal swab using molecular or culture-based methods helps guide appropriate antibiotic treatment to restore vaginal microbiota balance and prevent complications.

Reference:

• Donders, G. G. G., Ruban, K., & Bellen, G. (2020). Aerobic vaginitis: No longer a stranger. Research in Microbiology, 171(1-2), 75-78. DOI: 10.1016/j.resmic.2019.11.006
• Donders, G. G., Vereecken, A., Bosmans, E., Dekeersmaecker, A., Salembier, G., & Spitz, B. (2002). Definition of a type of abnormal vaginal flora that is distinct from bacterial vaginosis: Aerobic vaginitis. BJOG: An International Journal of Obstetrics and Gynaecology, 109(1), 34-43. https://doi.org/10.1111/j.1471-0528.2002.01032.x