Viral and bacterial organisms associated with acute pharyngitis in a school-aged population.

To investigate the causes and clinical characteristics of acute pharyngitis among school-aged children (4 to 18 years), we obtained throat cultures for respiratory viruses, Mycoplasma pneumoniae, group A streptococcus, and Chlamydia trachomatis from 320 patients with sore throat and 308 controls without respiratory complaints. The study was conducted from January to April 1985 in a private pediatric practice in central New York State. Sixty percent of the patients and 26% of the control subjects had positive cultures for at least one organism. Forty percent of patients had positive cultures for group A streptococcus, compared with 11.9% of the controls. Fifty (16%) patients had positive viral cultures, compared with eight (2.6%) controls; the predominant viral isolate was influenza A Philippines. Patients infected with influenza A were significantly more likely to complain of cough and hoarseness, and were less likely to have pharyngeal exudate or tender cervical adenopathy, than were patients who had positive cultures for group A streptococcus. Although 49 (15.8%) patients with acute pharyngitis had cultures positive for M. pneumoniae, 53 (17.6%) asymptomatic controls were also had M. pneumoniae-positive cultures. Thus detection of M. pneumoniae in the throat of school-aged children with pharyngitis may not be sufficient to establish a diagnosis of disease caused by this organism. C. trachomatis was not isolated from any patient or control.