title: Evaluation of methods for H. pylori detection in PPI consumption using culture, rapid urease test and smear examination.
abstract: BACKGROUND
  Culture, rapid urease test (RUT) and smear examination have been used as reliable methods for diagnosis of H. pylori infection. Accurate performance of these tests requires good quality biopsies with considerable number of bacterial cells. However, consumption of proton pump inhibitors (PPIs) affects growth and urease activity of H. pylori, leading to false negative results. In this study the efficacy of culture, RUT and smear examination was assessed and the effect of PPI consumption was evaluated.
  
  
  METHODS
  Two antral biopsies from 530 dyspeptic patients with and without PPI consumption were used for RUT, culture and smear examination. Statistical analysis was used to determine the association between results of culture, RUT or smear examination and PPI consumption. Sensitivity and specificity of three tests were calculated by standard methods.
  
  
  RESULTS
  H. pylori infection was detected in 40% of patients by culture, 48.3% by RUT and 21.1% by smear examination and the overall detection rate was 54%. A strong correlation was found between PPI consumption and negative results of culture and RUT (P<0.05) but not smear examination. The sensitivity of RUT was reduced as a result of PPI consumption. This reduction was more profound in 1-hr RUT (92.2% to 74.4%) compared with 24-hr RUT (93.9% to 81.6%).
  
  
  CONCLUSIONS
  Prevalence of H. pylori was declined, compared with previous studies. This decrement could be due to false negative results of H. pylori diagnostic tests, among which culture and RUT are mostly affected by PPI. Accordingly, PPI consumption should be stopped before performance of endoscopy.
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Farideh
authors.initials: F
authors.lastname: Siavoshi
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Parastoo
authors.initials: P
authors.lastname: Saniee
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Saman
authors.initials: S
authors.lastname: Khalili-Samani
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Farideh
authors.initials: F
authors.lastname: Hosseini
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Malakutikhah
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Mamivand
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Shahreza
authors.affiliation: 1 Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran 14176-14411, Iran ; 2 Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.
authors.forename: Amir Houshang
authors.initials: AH
authors.lastname: Sharifi
keywords: H. pylori; culture; diagnosis; rapid urease test (RUT); smear