Viral and Bacterial Etiology of Acute Pharyngitis in Children

Background: Acute pharyngitis accounts for a substantial portion of visits to pediatricians, but only few comprehensive studies have documented the microbiological etiology besides group A Streptococcus (GAS). The aim of this study was to determine the viruses, bacteria, and the discriminative potential of biomarkers in children with acute pharyngitis in an outpatient setting.

Methods: In this 14-month prospective study, oropharyngeal swab samples and serum samples were collected from children 1 to 16 years of age presenting to the emergency department with an acute pharyngitis (fever > 38°C and exudations or intense redness in the oropharynx). Throat culture, serology, antigen detection, and polymerase chain reaction (PCR) methods were used to investigate the microbiological etiology. Whole blood or plasma levels of C-reactive protein (CRP), procalcitonin (PCT), and paramyxovirus resistance protein A (MxA) were determined.

Results: Eighty-three children with the mean age of 7.4 years were included in the study. A potential causative agent was detected in 72 (87%) children. Sixty-five percent of children had viral infection, 22% had culture-confirmed GAS infection, and 11% had concomitant GAS and viral infection. Enteroviruses (23%), rhinovirus (17%), adenovirus (14%), and Epstein-Barr virus (11%) were the most common viruses associated with acute pharyngitis. Multiple viruses were detected in 17 children. Haemophilus influenzae, group C Streptococcus, group G Streptococcus, Streptococcus pneumoniae, and Moraxella catarrhalis were detected in the oropharynx of 10, 3, 2, 1, and 1 children, respectively. Mycoplasma pneumoniae was detected in none and Chlamydia pneumoniae in 1 child by PCR in oropharyngeal swabs. Blood MxA levels were higher in children with viral (584 ± 288 μg/L; mean ± SD) or concomitant GAS-viral (392 ± 278 μg/L) than in those with sole bacterial (149 ± 105 μg/L) infections. CRP or PCT levels were not discriminative.

Conclusion: Viruses cause the majority of cases with pharyngitis in children and adolescents. These data fortify the current practice to withhold antibiotic treatment in non-GAS illness. Blood MxA has potential as a biomarker of viral pharyngitis. The role of H. influenzae as a possible pharyngitis pathogen needs further investigations.