Genetic diversity of Helicobacter pylori indexed with respect to clinical symptomatology, using a 16S rRNA and a species‐specific DNA probe

Abstract

DNA probes are described which identify group and fingerprint strains of the human gastric pathogen Helicobacter pylori, on the basis of well-defined band homologies. A 544 bp internal fragment of the 16S ribosomal RNA gene was generated by polymerase chain reaction (PCR) with primers derived from the Escherichia coli rRNA gene sequence. In genomic Southern blots this probe detected restriction site variation around these loci, generating simple but strain-specific molecular fingerprints. A small conserved chromosomal fragment of 1.2 kbp, Hps, species-specific for H. pylori, was obtained by cloning random HindIII fragments into pUC19. It was useful for dot-blot identification, and also separated isolates into one major and two minor groups. When results for these two probes were combined, a baseline characterization of genotype was obtained. A band-matching database of molecular fingerprints for the type strain and 63 clinical isolates of H. pylori from asymptomatic, ulcer and gastritis contexts is presented. No significant association between the genotypes at this level of definition and the associated clinical symptomatology of the isolates was detected.

Panmictic structure ofHelicobacter pyloridemonstrated by the comparative study of six genetic markers

“…We identified 38 ribotypes among the 39 strains. This high degree of diversity in rRNA gene patterns and the lack of a significant association between ribotype and clinical symptoms are consistent with data published before [9, 29].…”

“…We studied the polymorphism of total DNA using the ribotyping method. Ribotyping seems to be a highly sensitive method for H. pylori strain identification [28, 29] even if only two copies of the rDNA operon are present [30]. We identified 38 ribotypes among the 39 strains.…”

Identification methods for campylobacters, helicobacters, and related organisms

“…jejuni (87,137,166,170), C. coli (170), C. hyointestinalis (60,61), C. mucosalis (60), C. helveticus (162), H. canis (165), and Lawsonia intracellularis (59,103). A number of randomly generated, species-specific probes for identifying H. pylori have also been developed (32,93,178,196), some of which (32,93,178) may also be used for epidemiological typing of this organism in Southern hybridization assays. Finally, Wesley et al (194) described the development of an oligonucleotide probe that recognized only C. fetus subsp.…”

Genetic diversity ofBacillus thuringiensis serovars revealed by RFLP using random DNA probes

“…Alternatively, a method where Southern blots were probed with random chromosomal DNA fragments was developed and proved effective at differentiating subspecies or closely-related strains, as exemplified in Bacteroides thetaitaomicron (SALYERS et al 1983), Salmonella typhimurium (TOMPKINS et al 1986), Candida albicans (SCHERER and STEVENS 1988), Aspergillus fumigatus (GIRARDIN et al 1993), Helicobacter pylori (Desai et al 1993) and Listeria monocytogenes (SWAMINATHAN et al 1996).…”