The prevalence of Mycoplasma pneumoniae in ambulatory patients with nonstreptococcal sore throat.

Several studies have implicated Mycoplasma pneumoniae as an important cause of nonstreptococcal pharyngitis in certain clinical settings. This study was performed to determine the prevalence of M. pneumoniae infection in family practice patients with sore throats and to identify patient characteristics predictive of this infection. M. pneumoniae throat cultures were obtained from 419 patients aged five years or older who were seen in one of four family practice offices with a complaint of sore throat. The overall prevalence of M. pneumoniae infection was 13%. It was characterized by more frequent hoarseness and less frequent complaint of postnasal drip when compared with other nonstreptococcal infections. Compared to patients with streptococcal pharyngitis, M. pneumoniae patients revealed a strikingly dissimilar clinical presentation. In particular, while pharyngitis is predictive of streptococcal infections, its presence did not predict M. pneumoniae infection. Recently developed rapid office-based tests for M. pneumoniae may allow timely diagnosis of this common and formerly elusive pathogen. Further study is required to validate the utility of such methods and to evaluate the efficacy of treatment.