title: Evidence of bacterial metabolic activity in culture-negative otitis media with effusion.
abstract: BACKGROUND
  Otitis media with effusion (OME) can lead to significant hearing loss in children. Although previous studies have shown that bacterial DNA is present in a significant percentage of effusions sterile by culture, whether the DNA represents viable organisms or "fossilized remains" is unknown.
  
  
  OBJECTIVE
  To determine if bacterial messenger RNA (mRNA), as detected by a reverse transcriptase-polymerase chain reaction (RT-PCR)-based assay, is present in chronic pediatric middle ear effusions that contain bacterial DNA but are sterile by standard cultural methods. Bacterial mRNAs have a half-life measured in seconds to minutes; therefore, detection of bacteria-specific mRNAs would be evidence that metabolically active organisms are present.
  
  
  METHODS
  Blinded comparative study.
  
  
  METHODS
  A total of 93 effusions from pediatric outpatients seen for myringotomy and tube placement for chronic (>3 months) OME (median age of children, 17 months).
  
  
  METHODS
  Tertiary care pediatric hospital.
  
  
  METHODS
  Percentage of positive test results for RT-PCR-based assays compared with culture for Haemophilus influenzae and concordance between RT-PCR and PCR-based findings for bacterial nucleic acids.
  
  
  RESULTS
  Eleven (11.8%) of the 93 specimens tested positive by culture, PCR, and RT-PCR for H influenzae. A total of 29 specimens (31.2%) were positive by PCR but negative by culture for H influenzae. All 29 specimens were positive by RT-PCR for H influenzae-specific mRNA.
  
  
  CONCLUSIONS
  The RT-PCR-based assay system can detect the presence of bacterial mRNA in a significant percentage of culturally sterile middle ear effusions, establishing the presence of viable, metabolically active, intact organisms in some culture-negative OME.
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, Pa, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Rayner
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: M C
authors.initials: MC
authors.lastname: Gorry
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: J C
authors.initials: JC
authors.lastname: Post
authors.forename: G D
authors.initials: GD
authors.lastname: Ehrlich
mesh_terms: D018441:Biofilms; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D004269:DNA, Bacterial / Q000302:isolation & purification; D005122:Exudates and Transudates / Q000737:chemistry / Q000382:microbiology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006192:Haemophilus Infections / Q000378:metabolism* / Q000382:microbiology; D006193:Haemophilus influenzae / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D010034:Otitis Media with Effusion / Q000378:metabolism / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000302:isolation & purification*; D012333:RNA, Messenger / Q000302:isolation & purification*; D012194:RNA-Directed DNA Polymerase
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012333:RNA, Messenger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D012194:RNA-Directed DNA Polymerase