Chlamydial organisms are small bacteria that need to be inside cells to multiply. There are three species, Chlamydia trachomatis, C psittaci, and C pneumoniae. Serotypes A, B, and C of C trachomatis are the cause of the blinding disease trachoma. Serotypes D to K are sexually transmitted and, world wide, are an important cause of morbidity in both men and women. In men chlamydial infection causes up to half of all acute non-gonococcal urethritis and at least one third of acute epididymitis.1 In women such infection causes up to half of all mucopurulent or follicular cervicitis, and in developed countries up to 60% of pelvic inflammatory disease,1 a condition associated with a substantial risk of subsequent infertility and ectopic pregnancy. C trachomatis infection may also trigger reactive arthritis in men and women.2 Transmission of the organisms to newborn infants from mothers, usually during birth, may lead to neonatal conjunctivitis and pneumonia.epididymitis.

Progress in understanding the pathogenesis of genital chlamydial infections has come with the recognition that some persistent or recurrent disease (including chronic non-gonococcal …