The predominant type of bacteria in a healthy vagina, which secretes lactic acid to maintain an acidic pH, belongs to the genus:

1. The vagina normally hosts a protective population of microorganisms. 2. The most predominant genus of these healthy bacteria directly. 3. That genus is Lactobacillus, which secretes lactic acid. 4. This lactic acid keeps vaginal pH below 4.5, making it inhospitable to many pathogens, so Candida (a yeast, not the protective bacteria) is ruled out. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 27 "The Reproductive System", p.1293 §Vagina_