title: 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.
authors: Department of Clinical Sciences, Infectious Diseases Unit, Lund University, Malmö, Sweden. anna.nilsson@med.lu.se
authors: Anna C
authors: AC
authors: Nilsson
authors: Kenneth
authors: K
authors: Persson
authors: Per
authors: P
authors: Björkman
authors: Robin
authors: R
authors: Brittain-Long
authors: Magnus
authors: M
authors: Lindh
authors: Lars-Magnus
authors: LM
authors: Andersson
authors: Johan
authors: J
authors: Westin
mesh_terms: D000293:Adolescent; D002648:Child; D016993:Chlamydophila pneumoniae / Q000235:genetics / Q000302:isolation & purification; D003371:Cough; D005260:Female; D006801:Humans; D008297:Male; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods*; D009177:Mycoplasma pneumoniae / Q000235:genetics / Q000302:isolation & purification; D009960:Oropharynx / Q000382:microbiology* / Q000821:virology*; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D012229:Rhinovirus / Q000235:genetics / Q000302:isolation & purification; D012574:Schools; D013548:Sweden; D014777:Virus Diseases / Q000453:epidemiology / Q000821:virology; D014780:Viruses / Q000235:genetics / Q000302:isolation & purification