The vagina hosts a dense and distinct microbial ecosystem, comprising approximately 10¹⁰–10¹¹ bacteria. These microbiota, typically dominated by Lactobacillus species, engage in a symbiotic relationship with the host by producing antimicrobial compounds such as lactic acid, hydrogen peroxide, and bacteriocins. These metabolites help maintain an acidic pH and inhibit pathogen colonization, forming a critical component of the innate immune defense.
