Chlamydia trachomatis Genital Tract Infections: When Host Immune Response and the Microbiome Collide

Genital infections with Chlamydia trachomatis continue to be a major health problem worldwide. While some individuals clear their infection (presumed to be the result of an effective Th1/interferon-gamma response), others develop chronic infections and some are prone to repeat infections. In females in particular, chronic asymptomatic infections are common and can lead to pelvic inflammatory disease and infertility. Recent studies suggest that the genital tract micro biota could be a significant factor and explain person-to-person variation in C. trachomatis infections. One hypothesis suggests that C. trachomatis can use its trpBA genes to rescue tryptophan from indole, which is a product of anaerobic members of the genital tract microbiota. Women with particular microbiota types, such as seen in bacterial vaginosis, have increased numbers of anaerobes, and this would enable the chiamydia in these individuals to overcome the host's interferon-gamma attempts to eliminate it, resulting in more repeat and/or chronic infections.