In a patient with suspected bacterial vaginosis, which organism is typically isolated if lactobacilli are significantly decreased?

In cases of suspected bacterial vaginosis, a significant decrease in lactobacilli is a key indicator. Lactobacilli are normally the predominant flora in a healthy vaginal ecosystem, playing a crucial role in maintaining pH balance and preventing overgrowth of pathogenic organisms. When lactobacilli are depleted, it allows for an overgrowth of other microorganisms.

Gardnerella vaginalis is the organism that is commonly associated with bacterial vaginosis. It is a part of the polymicrobial flora that can expand when the balance of the vaginal microbiome is disrupted. The presence of Gardnerella vaginalis is often noted in the diagnosis of bacterial vaginosis, with diagnostic criteria that may include a “fishy” odor, clue cells on wet mount microscopy, and an increased vaginal pH.

In contrast, the other organisms listed do not typically present in cases of bacterial vaginosis to the same extent. Though Streptococcus agalactiae can be a pathogen in certain contexts, it is more commonly associated with group B streptococcal infections and does not specifically relate to bacterial vaginosis. Mycoplasma hominis can be present but is less specific and not solely indicative of bacterial vaginosis when lactobacilli