Transmitted by close contact, Chlamydia trachomatis is the causative agent of a common sexually transmitted infection, with 200,000 new cases per year in the United States. More than 15% of pregnant women and 10% of men with chlamydial infections are asymptomatic. Chlamydia can be transmitted by a pregnant woman to her newborn during delivery, resulting in pneumonia or conjunctivitis in the infant.
Chlamydial infections in humans include trachoma, inclusion conjunctivitis, nongonococcal urethritis, epididymitis, mucopurulent cervicitis, proctitis, salpingitis, infant pneumonia syndrome, and lymphogranuloma venereum. Genital C trachomatis infection can cause pelvic inflammatory disease, tubal infertility, and ectopic pregnancy. Diagnostic techniques include culture, direct immunofluorescence antibody testing of exudates, enzyme immunoassay, and DNA PCR probe assay.
Chlamydial infections are readily treated with tetracycline, erythromycin, or one of the quinolones or macrolides. Although single-dose azithromycin therapy for urethritis and cervicitis has proved effective in some studies, it is usually recommended that patients continue treatment for at least 7 days to ensure complete eradication. Sexual partners of patients with chlamydial infections or other sexually transmitted infections should be examined and counseled for consideration of antibiotic treatment as well.
Neonatal chlamydial conjunctivitis is treated with oral erythromycin (50 mg/kg divided, 4 times daily) for 14 days. See BCSC Section 8, External Disease and Cornea, for more information.
LeFevre ML; US Preventive Services Task Force. Screening for chlamydia and gonorrhea: US Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;161(12):902–910.
Workowski KA, Bolan GA; Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2015. MMWR Recomm Rep. 2015; 64(RR-03):1–137.
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.