Snapshot A 22-year-old man presents to the clinic with a complaint of a dysuria and itching with urination. He admits that he has been engaging in unprotected sexual intercourse with several females. On physical exam, there is yellow mucopurulent discharge from his urethra with dried secretions on the walls of the meatus. Introduction Classification Chlamydia trachomatis obligate intracellular bacteria Pathogenesis transmission sexual intercourse passage through birth canal trachoma transmitted by hand-to-eye contact and flies location of infection genital tract eyes molecular biology obligate intracellular organism cannot make their own ATP requires live cells for growth in laboratory 2 forms reticulate body intracellular, metabolically active, replicating form "Reticulate Replicates" collections of reticulate bodies can be seen in the cytoplasm under light microscopy and are called "inclusion bodies" elementary body infectious, inactive, extracellular form small, dense "Elementary is Enfectious and Enters cell via Endocytosis" infection of mucosal surfaces leads to granulomatous response and damage cell wall lacks peptidoglycan beta-lactam antibiotics are thus ineffective Diseases trachoma most common cause of preventable blindness serotypes A-C chlamydia the most common bacterial STD in the United States serotypes D-K lymphogranuloma venereum serotypes L1-3 ("L for lymphogranuloma") Associated conditions co-infection with Neisseria gonorrhoeae pelvic inflammatory disease (PID) Presentation Trachoma itching and irritation of the eyes and eyelids discharge from the eyes containing mucus or pus eyelid inflammation blepharospasm conjunctival scarring trichiasis (inward-growing eyelashes) Chlamydia in females dysuria yellow mucopurulent discharge from the urethra vaginal discharge abnormal vaginal bleeding dyspareunia cervicitis fever (in pelvic inflammatory disease) asymptomatic in 80% of patients in males dysuria yellow mucopurulent discharge from the urethra unilateral pain and swelling of the scrotum fever asymptomatic in 50% of patients in newborns symptoms of conjunctivitis beginning at 1-2 weeks eye discharge eyelid swelling symptoms of pneumonia beginning at 1-3 months cough fever Lymphogranuloma venereum painful, localized inguinal adenopathy (buboes) genital ulceration Studies Laboratory diagnosis polymerase chain reaction (PCR) nucleic acid amplification test (NAAT) cytology for diagnosing infant conjunctivitis and trachoma visualization of intracytoplasmic inclusions Histology cytoplasmic inclusions (reticulate bodies) seen on Giemsa or fluorescent antibody-stained smear Additional studies pregnancy test for females with suspected chlamydial infection doxycycline contraindicated in pregnancy strongly consider testing sexual partners for Chlamydia Differential Bacterial vaginosis distinguishing factor gray vaginal discharge with a fishy smell Trichomonas vaginitis distinguishing factor frothy, yellow-green discharge motile trichomonads on wet mount Urinary tract infection distinguishing factor lack of cytoplasmic inclusions seen on Giemsa or fluorescent antibody-stained smear Treatment Medical azithromycin (one-time treatment) doxycycline add ceftriaxone for possible concomitant N. gonorrhoeae infection topical and oral erythromycin for neonatal chlamydial conjunctivitis Complications Pelvic inflammatory disease (PID) may include salpingitis endometritis hydrosalpinx tubo-ovarian abscess risk factor for ectopic pregnancy, infertility, chronic pelvic pain, and adhesions