Multiplex MassTag-PCR for respiratory pathogens in pediatric nasopharyngeal washes negative by conventional diagnostic testing shows a high prevalence of viruses belonging to a newly recognized rhinovirus clade.

BACKGROUND

Respiratory infections are the most common infectious diseases in humans worldwide and are a leading cause of death in children less than 5 years of age.

OBJECTIVES

Identify candidate pathogens in pediatric patients with unexplained respiratory disease.

STUDY DESIGN

Forty-four nasopharyngeal washes collected during the 2004-2005 winter season from pediatric patients with respiratory illnesses that tested negative for 7 common respiratory pathogens by culture and direct immunofluorescence assays were analyzed by MassTag-PCR. To distinguish human enteroviruses (HEV) and rhinoviruses (HRV), samples positive for picornaviruses were further characterized by sequence analysis.

RESULTS

Candidate pathogens were detected by MassTag PCR in 27 of the 44 (61%) specimens that previously were rated negative. Sixteen of these 27 specimens (59%) contained picornaviruses; of these 9 (57%) contained RNA of a recently discovered clade of rhinoviruses. Bocaviruses were detected in three patients by RT-PCR.

CONCLUSIONS

Our study confirms that multiplex MassTag-PCR enhances the detection of pathogens in clinical specimens, and shows that previously unrecognized rhinoviruses, that potentially form a species HRV-C, may cause a significant amount of pediatric respiratory disease.