Frequency of Chlamydia trachomatis as the cause of pharyngitis.

We evaluated the incidence of Chlamydia trachomatis as the etiologic agent of uncomplicated pharyngitis by the cell culture procedure recommended by the Centers for Disease Control, Atlanta, Ga., and by the MicroTrak direct immunofluorescent stain (Syva Co., Palo Alto, Calif.) for elementary bodies on throat swabs collected from 126 symptomatic patients. Of the 126 cultures, 8% were positive for group A beta-hemolytic streptococci. Of 126 chlamydia cultures, none was positive. The MicroTrak test gave one borderline positive result. In contrast to a previously published report that C. trachomatis is the most frequent nonviral cause of adult pharyngitis (A. L. Komaroff, M. D. Aronson, T. M. Pass, C. T. Ervin, and W. T. Branch, Jr., Science 222:927-929, 1983), our data indicated an infection rate of less than 1%.