From the Guidelines
Bacterial vaginosis (BV) is most commonly caused by an imbalance in the vaginal microbiome, where beneficial lactobacilli bacteria decrease while harmful bacteria such as Prevotella sp., Mobiluncus sp., G. vaginalis, and Mycoplasma hominis overgrow, as noted in the 2002 CDC guidelines 1. The causes of this imbalance can be multifactorial, including:
- Douching, which washes away the protective lactobacilli
- Having multiple sex partners, although BV is not classified as a sexually transmitted infection
- Lack of vaginal lactobacilli, which can be due to various factors including antibiotic use, frequent vaginal cleansing with soap, wearing tight non-breathable underwear, and using scented feminine hygiene products
- Smoking, which has been linked to increased BV risk due to its effect on vaginal pH and immune function It's essential to note that the exact cause of the microbial alteration in BV is not fully understood, and more research is needed to determine the underlying mechanisms 1. In terms of diagnosis, BV can be identified using clinical or Gram-stain criteria, including the presence of a homogeneous, white, noninflammatory discharge, clue cells on microscopic examination, a pH of vaginal fluid >4.5, and a fishy odor of vaginal discharge before or after addition of 10% KOH (i.e., the whiff test) 1. Treatment typically involves antibiotics such as metronidazole or clindamycin, and prevention of recurrence can be achieved by avoiding douching, using condoms during sex, wearing cotton underwear, and considering probiotic supplements containing Lactobacillus species to help restore vaginal flora balance 1.
From the Research
Common Causes of Bacterial Vaginosis
The exact causes of bacterial vaginosis (BV) are not fully understood, but several factors are thought to contribute to its development.
- Persistence of residual infection
- Resistance to antibiotics
- Reinfection from male or female partners
- Formation of a biofilm that protects BV-causing bacteria from antimicrobial therapy 2
- Poor adherence to treatment among patients with genitourinary infections may lead to resistance 2
Risk Factors
Some studies suggest that the following may increase the risk of developing BV:
- Imbalance of the vaginal flora, with a decrease in lactobacillus-dominated commensal flora and an increase in polymicrobial biofilms 3
- High pH levels in the vagina, which can facilitate the growth of BV-causing bacteria 3
- Sexual activity, as BV is more common in sexually active women 2
Underlying Mechanisms
The underlying mechanisms of recurrent BV are not fully understood, but it is thought that the following may play a role: