title: Culture of Helicobacter pylori from stool samples in children.
abstract: We evaluated two protocols for isolation of Helicobacter pylori in stool from biopsied and nonbiopsied children. Twenty-three child patients whose presumptive positivity or negativity was diagnosed by endoscopy and a rapid urease test at site were used to compare biopsy-based tests with stool-based tests (H. pylori stool antigen test and stool culture). Their gastric activity and bacterial density were graded by the updated Sydney system. Biopsy and stool specimens were cultured on Campy-blood and Belo horizonte agar plates after enrichment in selective Campy-Thio medium. To compare two stool culture protocols, stools from 20 nonbiopsied children were tested by the HpSA test and cultured either as above or after treatment with cholestyramine. Grown colonies were screened by Gram staining, slide agglutination using anti-H. pylori monoclonal IgG; positive isolates were tested by biochemical tests and polymerase chain reaction for H. pylori-specific ureA gene. Coccoid H. pylori was isolated in stool samples from the biopsied patients whose bacterial density was two to four in histology. Their oxidase was slightly positive but became positive after two subcultures, while additional biochemical tests confirmed the isolation of H. pylori. Similar coccoid but oxidase positive H. pylori was isolated from three nonbiopsied children with the protocol of cholestyramine treatment only. The density of bacteria in the stomach may influence the recovery of H. pylori from stool; inactivation of bile with cholestyramine improves the yield in culture and favors isolation of an enhanced metabolic form of bacteria.
authors.affiliation: Department of Biology Microbiology, Azzahra University, 1993891176 Tehran, Iran. tfalsafi@yahoo.com
authors.forename: Tahereh
authors.initials: T
authors.lastname: Falsafi
authors.forename: Nargess
authors.initials: N
authors.lastname: Valizadeh
authors.forename: Mehri
authors.initials: M
authors.lastname: Najafi
authors.forename: Azadeh
authors.initials: A
authors.lastname: Ehsani
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Khani
authors.forename: Zahra
authors.initials: Z
authors.lastname: Landarani
authors.forename: Zahra
authors.initials: Z
authors.lastname: Falahi
mesh_terms: D000293:Adolescent; D000924:Anticholesteremic Agents / Q000627:therapeutic use; D000942:Antigens, Bacterial / Q000032:analysis*; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D002792:Cholestyramine Resin / Q000627:therapeutic use; D003470:Culture Media; D004724:Endoscopy; D005243:Feces / Q000382:microbiology*; D016481:Helicobacter Infections / Q000188:drug therapy / Q000382:microbiology*; D016480:Helicobacter pylori / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007492:Iran; D011933:Reagent Kits, Diagnostic
chemical_list: D000924:Anticholesteremic Agents; D000942:Antigens, Bacterial; D003470:Culture Media; D011933:Reagent Kits, Diagnostic; D002792:Cholestyramine Resin