Facts about chlamydia infection Chlamydia is a sexually transmitted infection (STI) caused by the bacteria Chlamydia trachomatis. It affects both men and women and can lead to serious health problems if left untreated. Symptoms of chlamydia may include an unusual discharge from the penis or vagina, pain when urinating, genital itching or burning, and/or rectal Read more about How often should you get tested for chlamydia?[…]