title: Atypical bacterial pathogen infection in children with acute bronchiolitis in northeast Thailand.
abstract: BACKGROUND
  Atypical bacterial pathogens--including Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Chlamydia trachomatis--are important infectious agents of the respiratory system. Most current information pertains to adults and little is known about the role of these organisms in lower respiratory tract infections among young children with acute bronchiolitis.
  
  
  METHODS
  This study detected these pathogens in the nasopharyngeal secretions of children between 1 month and 2 years of age admitted with acute bronchiolitis to hospitals in Khon Kaen, northeast Thailand. The M pneumoniae and C pneumoniae in the nasopharyngeal secretions were detected using multiplex and nested-polymerase chain reaction (PCR), whereas PCR and restriction fragment length polymorphism were used to investigate C trachomatis. These samples were also tested by multiplex reverse transcriptase PCR for respiratory viruses, including respiratory syncytial virus (RSV), influenza A, influenza B, and human metapneumovirus.
  
  
  RESULTS
  Of the 170 samples taken from hospitalized children with acute bronchiolitis, 12.9% were infected with atypical bacteria and 85.3% with respiratory viruses. RSV was the most common causative viral agents found in 64.7% of the samples. M pneumoniae was the most common atypical bacterial pathogen (14/170, 8.2%) and most of the patients infected with it were between 6 and less than 12 months of age (71 cases). Of the infected cases in this age group, 7 of 14 were infected with M pneumoniae and 4 of 4 with C pneumoniae. Both M pneumoniae (13/14) and C pneumoniae (4/4) had etiologies indicating viral coinfections. Four (2.4%) of all of the cases had C trachomatis infections and all of these were infected with RSV, including three patients less than 6 months of age.
  
  
  CONCLUSIONS
  These results suggest that in children with virus-induced acute bronchiolitis coinfection with M pneumoniae, C pneumoniae, or C trachomatis can be expressed differently in each age group. These atypical bacteria may be the important infectious agents that induce severe illness of acute bronchiolitis.
authors: Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. chapie@kku.ac.th
authors: Chamsai
authors: C
authors: Pientong
authors: Tipaya
authors: T
authors: Ekalaksananan
authors: Jamree
authors: J
authors: Teeratakulpisarn
authors: Sureeporn
authors: S
authors: Tanuwattanachai
authors: Bunkerd
authors: B
authors: Kongyingyoes
authors: Chulaporn
authors: C
authors: Limwattananon
mesh_terms: D000208:Acute Disease / Q000453:epidemiology; D001988:Bronchiolitis / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D002675:Child, Preschool; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D002692:Chlamydia trachomatis / Q000302:isolation & purification* / Q000472:pathogenicity; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification* / Q000472:pathogenicity; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D009177:Mycoplasma pneumoniae / Q000302:isolation & purification* / Q000472:pathogenicity; D011019:Pneumonia, Mycoplasma / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D016032:Randomized Controlled Trials as Topic; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D013785:Thailand / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial