Which of the following organisms is most likely to be implicated as a cause of urethritis that persists after antibiotic therapy for gonorrhea?
Actinomyces
Chlamydia
Mycobacteria
Nocardia
Chlamydia, Mycoplasma, and Ureaplasma are not effectively treated by penicillins and cephalosporins, and are impoant causes of post-gonococcal urethritis. Chlamydial urethritis can be diagnosed by using fluorescent antibodies to identify inclusions in epithelial cells. Actinomyces is a mouth commensal that rarely causes a deeper oral infection. Mycobacteria cause chronic granulomatous diseases such as tuberculosis and leprosy. Nocardia can cause necrotizing pneumonia and disseminated disease.