Lactobacillus iners, the unusual suspect.

Lactobacillus iners is an unusual Lactobacillus species which does not grow on de Man Rogosa Sharpe agar, does not produce d-lactic acid, and only limited amounts of hydrogen peroxide. Its production of inerolysin, a cytotoxin, is also unusual for a lactobacillus. Epidemiological studies point to an ambiguous role for this species, which is quite often recovered in high numbers from vaginal dysbiosis and offers limited protection against vaginal dysbiosis and, subsequently, against sexually transmitted infections and adverse pregnancy outcome. Several data indicate that L. iners might even contribute to the onset and maintenance of vaginal dysbiosis and be a risk factor for adverse pregnancy outcome.