title: Multiplex-touchdown PCR assay for the detection and genotyping of Helicobacter pylori from artificially contaminated sheep milk.
abstract: Helicobacter pylori (Hp) is an organism commonly present worldwide in the human population, sometimes causing serious illnesses such as duodenal and gastric ulcers, adenocarcinoma of the stomach, and low-grade B-cell mucosa-associated lymphoid tissue lymphoma of the stomach. This article describes a multiplex-touchdown PCR method for the identification and genotyping (vacA-s1/m1, sl/m2, and s2/m2-and cagA genes) of Hp directly from sheep milk artificially contaminated with Hp strains from human gastric biopsies and with Hp ATCC 43504. The strains from humans carried sl/m2 cagA+ and s2/m2 cagA allelic combinations, while the ATCC strains carried an sl/ml cagA+ allelic combination. The technique showed a sensitivity of 15 CFU/ml for species identification and of 1,500 CFU/ml for the detection of genes encoding for VacA and CagA. It has proven to be specific and rapid, and the authors suggest that it be used as a rapid screening method to ensure that sheep milk is uncontaminated with this organism.
authors.affiliation: Department of Health and Animal Welfare-Faculty of Veterinary Medicine, Str. Prov. per Casamassima Km 3, 70010 Valenzano (Ba), Italy.
authors.forename: N C
authors.initials: NC
authors.lastname: Quaglia
authors.forename: G
authors.initials: G
authors.lastname: Normanno
authors.forename: A
authors.initials: A
authors.lastname: Dambrosio
authors.forename: G V
authors.initials: GV
authors.lastname: Celano
authors.forename: A
authors.initials: A
authors.lastname: Parisi
authors.forename: A
authors.initials: A
authors.lastname: Firinu
authors.forename: C
authors.initials: C
authors.lastname: Buonavoglia
mesh_terms: D000818:Animals; D001483:Base Sequence; D015169:Colony Count, Microbial; D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005838:Genotype; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification*; D008892:Milk / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D012756:Sheep
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial