title: Rapid paper disk test for identification of Helicobacter pylori in mixed cultures of gerbil gastric homogenates.
abstract: A method denominated rapid paper disk test (RPDT) was developed to identify H. pylori colonies in complex cultures obtained from gerbil gastric homogenates. Identification is based on a characteristic reaction pattern (RP) for H. pylori colonies given by the combination of the urease-oxidase activities on a paper disk. Compared to the RPs obtained from gerbil's intestinal tract isolated bacteria, H. pylori RP is completely distinguishable, even from those of bacteria that share one or both activities as are Aerococcus urinae, Bacillus sphaericus, Bacillus brevis, Corynebacterium pseudogenitalium, and Staphylococcus simulans, as well as from those produced by collection strains Proteus vulgaris and Pseudomonas aeruginosa. This method allows the practical quantification of H. pylori colonies in highly contaminated plates. RPDT has the following advantages over other methodologies that use indicators in the medium: it employs two of the three routinely used H. pylori biochemical identification tests, the reagents do not interfere with bacterial viability, there are no restrictions in relation to the medium used, and it is a simple, fast, and low-cost method.
authors.affiliation: Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510, México, D.F., México.
authors.forename: Israel
authors.initials: I
authors.lastname: Castillo-Juarez
authors.forename: Adrian
authors.initials: A
authors.lastname: Rangel-Vega
authors.forename: Irma
authors.initials: I
authors.lastname: Romero
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis; D001431:Bacteriological Techniques / Q000379:methods*; D004195:Disease Models, Animal; D057075:Enzyme Assays / Q000379:methods*; D005849:Gerbillinae; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D010088:Oxidoreductases / Q000032:analysis; D013270:Stomach / Q000737:chemistry / Q000382:microbiology*; D014510:Urease / Q000032:analysis
chemical_list: D001426:Bacterial Proteins; D010088:Oxidoreductases; D014510:Urease