title: Correlation of viral load of respiratory pathogens and co-infections with disease severity in children hospitalized for lower respiratory tract infection.
abstract: BACKGROUND
  The clinical significance of viral load and co-infections in children with respiratory infections is not clear.
  
  
  OBJECTIVE
  To evaluate the correlation of viral load as well as viral and bacterial co-infections with disease severity in hospitalized children with lower respiratory tract infections (LRTIs).
  
  
  METHODS
  This is a prospective study conducted in children admitted for LRTIs for two seasons. To determine viral and bacterial load of respiratory pathogens we performed multiplex real-time polymerase chain reaction and semiquantitative bacterial cultures on nasopharyngeal aspirates (NPA).
  
  
  RESULTS
  During the study period 244 (60%) children were hospitalized for LRTI with acute virus-induced wheezing and 160 (40%) for radiologic confirmed pneumonia. In the first NPA, viruses were identified in 315 (78%) of the 404 samples and bacteria in 198 (63.3%) of 311 samples. The viral load significantly decreased between the first and second NPA sample in most single and viral co-infections, except rhinovirus and human bocavirus infections. Viral load was inversely related to CRP in RSV infections, whereas a positive correlation was observed in adenovirus infections. Duration of hospitalization was significantly longer in RSV single infections compared to rhinovirus single infections whereas in the latter, leucocytosis and use of systemic steroids was more common. In RSV viral co-infections the presence of fever, leucocytosis, and the use of antibiotics was significantly more frequent. Positive cultures of Haemophilus influenzae dominated in RSV and rhinovirus single infections and Moraxella catarrhalis in RSV viral co-infections.
  
  
  CONCLUSIONS
  Specific viral single and co-infections as well as viral load contribute to disease severity in children with LRTIs.
authors.affiliation: Department of Pediatrics, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Franz
authors.forename: Ortwin
authors.initials: O
authors.lastname: Adams
authors.forename: Rhea
authors.initials: R
authors.lastname: Willems
authors.forename: Linda
authors.initials: L
authors.lastname: Bonzel
authors.forename: Nicole
authors.initials: N
authors.lastname: Neuhausen
authors.forename: Susanne
authors.initials: S
authors.lastname: Schweizer-Krantz
authors.forename: Jens U
authors.initials: JU
authors.lastname: Ruggeberg
authors.forename: Reinhart
authors.initials: R
authors.lastname: Willers
authors.forename: Birgit
authors.initials: B
authors.lastname: Henrich
authors.forename: Horst
authors.initials: H
authors.lastname: Schroten
authors.forename: Tobias
authors.initials: T
authors.lastname: Tenenbaum
mesh_terms: D000293:Adolescent; D001419:Bacteria / Q000302:isolation & purification; D001424:Bacterial Infections / Q000150:complications* / Q000382:microbiology / Q000473:pathology; D001988:Bronchiolitis / Q000382:microbiology / Q000473:pathology* / Q000821:virology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009305:Nasopharynx / Q000382:microbiology / Q000821:virology; D011014:Pneumonia / Q000382:microbiology / Q000473:pathology* / Q000821:virology; D016133:Polymerase Chain Reaction / Q000379:methods; D012189:Retrospective Studies; D012720:Severity of Illness Index; D019562:Viral Load; D014777:Virus Diseases / Q000150:complications* / Q000473:pathology / Q000821:virology; D014780:Viruses / Q000302:isolation & purification