Vaginitis

The vagina is not sterile. In many people of reproductive age, Lactobacillus species dominate the microbial community and produce lactic acid, keeping vaginal pH normally around 4.5 or lower. Lactobacillus crispatus is the most stable, health-associated community state. L. iners can appear after antimicrobial treatment or during transition between microbiome states; it is less protective and is associated with relapse. Bacterial vaginosis (BV) occurs when lactobacilli decline and anaerobic and facultative organisms expand. Gardnerella vaginalis, Prevotella, Fannyhessea vaginae, Megasphaera, and BV-associated bacteria can attach to the vaginal epithelium and form a polymicrobial biofilm. This explains why BV is better understood as community dysbiosis than as infection by a single organism—and why symptoms frequently return after treatment. Douching can disturb this acidic, lactobacillus-associated environment and is associated with BV. Commercial “microbiome-restoring” products should not replace diagnostic evaluation or antimicrobial treatment. Live biotherapeutics such as LACTIN-V, vaginal microbiota transplantation, targeted endolysins, and precision antimicrobials remain investigational.