Vaginitis: Bacterial (Nonspecific) and Bacterial Vaginosis

Introduction

• Description: Bacterial vaginitis is a vaginal infection that is caused by an overgrowth of normal or pathogenic bacteria, resulting in a rise in pH (>4.5), irritation, inflammation, and clinical symptoms. Bacterial vaginosis is a change in the vaginal ecology caused by an overgrowth of anaerobic bacteria, often with an absence of clinical symptoms. It should be noted that bacterial vaginosis does not engender an inflammatory response and, thus, is technically not a type of vaginitis.

• Prevalence: Approximately 6 million cases per year; accounts for 50% of “vaginal infections” and up to 50% of asymptomatic women in some studies. There is a higher prevalence in Black, Hispanic, and Mexican American women compared with White non-Hispanic women.

• Predominant Age: 15–50 years (may occur at any age).

• Genetics: No genetic pattern.

Etiology and Pathogenesis

• Causes: Bacterial vaginitis—overgrowth of normal or pathologic bacteria with an inflammatory response (which distinguishes this from bacterial vaginosis). Bacterial vaginosis—a polymicrobial process that involves the loss of normal lactobacilli, an increase in anaerobic bacteria (especially Gardnerella vaginalis, Bacteroides sp., Peptococcus sp., Mobiluncus sp., and others), and a change in the chemical composition of the vaginal secretions. There is a 1000-fold increase in the number of bacteria present and a 1000:1 anaerobic/aerobic bacteria ratio (normally 5:1), high levels of mucinases; phospholipase A ₂ , lipases, proteases, arachidonic acid, and prostaglandins are all present. Amines (cadaverine and putrescine) are made through bacterial decarboxylation of arginine and lysine. These amines are more volatile at an alkaline pH, such as that created by the addition of 10% potassium hydroxide (KOH) or semen (approximately a pH of 7), giving rise to odor found with the “whiff test” or as reported by these patients after intercourse.

• Risk Factors: Systemic processes—diabetes, pregnancy, and debilitating disease. Anything that alters the normal vaginal flora—smoking, numbers of sexual partners, vaginal contraceptives used, some forms of sexual expression such as oral sex, antibiotic use, hygiene practices and douching, menstruation, and immunologic status.

Signs and Symptoms