Frequent detection of respiratory agents by multiplex PCR on oropharyngeal samples in Swedish school-attending adolescents

Abstract

Background: Respiratory agents may be detected in the oropharynx of healthy individuals. The extent of this condition and the reasons behind it are largely unknown. The objective of this study was to determine the factors associated with the presence of respiratory agents in the oropharynx of adolescents healthy enough to attend school activities. Methods: On a single day in December, samples from the posterior wall of the oropharynx of adolescents aged 10–15 y were obtained using cotton-tipped swabs. The samples were analyzed by real-time polymerase chain reaction (PCR) for the presence of 13 respiratory viruses and 2 bacteria (Mycoplasma pneumoniae and Chlamydophila pneumoniae). Results: Out of the 232 adolescents sampled, 67 (29%) had any respiratory symptom. A positive PCR result was found in 50 individuals (22%). Human rhinovirus was the most commonly found agent. Respiratory agents were significantly more frequent in the younger age group (10–13 y) than in the older age group (14–15 y): 26% (38/148) vs 14% (12/84), respectively; p = 0.04. Cough was the only symptom that was more common among individuals with a positive PCR test than among those with a negative PCR test: 8/50 (16%) vs 11/182 (6%); p = 0.02. Family size and class size were not associated with the likelihood of a positive PCR test. Conclusions: The presence of respiratory agents in the oropharynx is a frequent finding among adolescents healthy enough to attend school activities. The high prevalence was found to be associated with young age, but not with the size of the family or class.

Keywords::

• PCR
• respiratory viruses
• adolescents
• respiratory symptoms

Acknowledgements

The authors wish to thank all the adolescents who provided the oropharyngeal samples. We would also like to thank Eva Jönsson for excellent laboratory assistance and Pernilla Olsson for assistance in the sampling procedure, as well as the staff at the Detection Department of the Clinical Virology Laboratory at Sahlgrenska University Hospital, Gothenburg for technical assistance. The study was funded by the Region Skåne and Region Västra Götaland research funds and STRAMA (the Swedish Strategic Programme against Antibiotic Resistance).

Declaration of interest: The authors declare no conflict of interest.