The anaerobic, gram-negative, curved, motile bacilli associated with bacterial vaginosis belong to which genus?

• A. Actinomyces
• B. Bifidobacterium
• C. Lactobacillus
• D. Mobiluncus

Answer: (D)

Mobiluncus fits this description because these organisms are slender, curved Gram-negative rods that are obligately anaerobic and motile. In bacterial vaginosis, the vaginal flora shifts away from lactobacilli toward anaerobes, and Mobiluncus species are a classic example of the curved, motile, gram-negative bacilli associated with BV. This distinguishes them from other BV-associated organisms: Actinomyces are gram-positive and filamentous, Bifidobacterium are gram-positive rods, and Lactobacillus are gram-positive rods that are typically non-curved and less associated with the BV-associated spectrum. So, the genus described by such morphological and growth characteristics is Mobiluncus.