ADULT BACTERIAL NASOPHARYNGITIS - A CLINICAL ENTITY

Objective: To investigate bacterial nasopharyngitis as a cause of adul t upper respiratory infection. Design: Prospective case series. Settin g: Walk-in medical clinic of a university hospital. Patients: 507 pati ents with cold or flu symptoms, sore throat, or recent cough; 21 contr ol subjects without symptoms of upper respiratory infection. Measureme nts and main results: After thorough history and physical examination, the patients underwent nasopharyngeal aspiration and throat culture. Nasopharyngeal specimens were cultured for both bacteria and viruses; antigens for influenza, parainfluenza, and respiratory syncytial virus were sought by enzyme-linked immunosorbent assay (ELISA); serum antib odies to viral respiratory pathogens were determined. Group A beta-hem olytic streptococci grew from the throat specimens of 39 of the 507 pa tients (8%) or 38 of 3 34 patients (11%) who had clinical diagnoses of pharyngitis. Thirty-three cases of influenza A, 20 cases of influenza B, and seven cases of parainfluenza infections were diagnosed. Bacter ia were cultured from the nasopharyngeal secretions of 284 patients (5 6%). In contrast to pharyngeal culture, commensal mixed flora were rar ely found in nasopharyngeal culture. Nasopharyngeal culture of bacteri a usually considered to be respiratory pathogens was significantly ass ociated with the presence of leukocytes. Streptococcus pneumoniae (odd s ratio 6.0, 95% confidence interval 2.6-14.2), Moraxella catarrhalis (odds ratio 12.9, 95% confidence interval 3.1-79.5), and Hemophilus in fluenzae (odds ratio 3.0, 95% confidence interval 1.2-7.4) were all as sociated with the presence of leukocytes. In contrast, nasopharyngeal culture of coagulase-negative staphylococci, mixed flora, and the docu mentation of a viral infection were not associated with the presence o f leukocytes. For none of 21 control subjects were ''pathogenic'' bact eria found.Conclusions: These data suggest that potentially pathogenic bacteria may have a causal role in adult nasopharyngitis, although fu rther data are needed to confirm this hypothesis.