title: Usefulness of Gastric Biopsy-Based Real-Time Polymerase Chain Reaction for the Diagnosis of Helicobacter pylori Infection in Children.
abstract: OBJECTIVE
  The aim of the study was to assess the usefulness of gastric biopsy-based quantitative real-time polymerase chain reaction (qPCR) for the detection of Helicobacter pylori infection and the identification of clarithromycin-resistant strains in children.
  
  
  METHODS
  A gastric biopsy-based qPCR for the detection of H pylori infection and the identification of clarithromycin-resistant strains in children was evaluated in 62 children with infection and 341 children without infection. H pylori infection was considered by the "reference method" when culture was positive for both histology and rapid urease test (RUT). Results were compared with those obtained using the qPCR.
  
  
  RESULTS
  The reference method versus H pylori qPCR positivity showed 95% confidence interval sensitivity 100% versus 100%, specificity 93.2% (86.9-99.4) versus 100%, positive predictive value 59.7% (47.4-71.9) versus 100%, negative predictive value 100% versus 100%, and, finally, test accuracy of 59.6% (47.3-71.8) versus 100%. Sixty-two children were found to be H pylori positive, based on the qPCR results. Among those, 31 children had both positive qPCR and culture with concordant antimicrobial susceptibility testing results, whereas 31 children had negative culture and positive qPCR. The qPCR showed a bacterial load ≥10 copies per milliliter when culture, histology, and RUT were all positive (29/31 children) versus <10 copies per milliliter when culture, histology, and RUT were all negative (25/31 children). Grades 2 and 3 histological gastritis were associated with a bacterial load ≥10 copies per milliliter for 28/35 of children versus 27/27 of grade 0 to 1 <10 copies per milliliter.
  
  
  CONCLUSIONS
  H pylori qPCR positivity is a more precise test than the routine culture, histology, RUT alone and allows detecting low bacterial loads.
authors: *Clinique Pédiatrique St Antoine †Département d'Anatomopathologie, Hôpital St Vincent de Paul ‡Département de Microbiologie, Hôpital St Philibert, Groupement des Hôpitaux de l'Institut Catholique de Lille, Lille §Service de Gastroentérologie Pédiatrique, Hôpital Necker-Enfants-malades, AP-HP ||Service de Microbiologie, Hôpital Cochin, Université Paris V-René Descartes, Paris, France.
authors: Nicolas
authors: N
authors: Kalach
authors: Pierre
authors: P
authors: Gosset
authors: Eric
authors: E
authors: Dehecq
authors: Anne
authors: A
authors: Decoster
authors: Claire
authors: C
authors: Spyckerelle
authors: Stephan
authors: S
authors: Papadopolos
authors: Christophe
authors: C
authors: Dupont
authors: Josette
authors: J
authors: Raymond
mesh_terms: D000293:Adolescent; D058491:Bacterial Load / Q000379:methods* / Q000706:statistics & numerical data; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology* / Q000473:pathology; D005756:Gastritis / Q000382:microbiology; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D007223:Infant; D008297:Male; D011237:Predictive Value of Tests; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014510:Urease / Q000032:analysis
chemical_list: D004269:DNA, Bacterial; D014510:Urease