Helicobacter pylori is a gram-negative, microaerophilic bacterium that colonizes the human gastrointestinal tract. H. pylori infections occur worldwide, and the prevalence varies from 20% in the developed countries to more than 80% in the developing countries. The bacterium lives in the mucus layer lining the stomach, secretes proteins that interact with the epithelium, and attracts macrophages and neutrophils, causing inflammation.
Chronic infections with H. pylori are associated with peptic ulcers, atrophic gastritis, and gastric carcinoma. Heterogeneity of H. pylori is associated with its virulence, the ability to cause severe epithelial damage, and the efficacy of antimicrobial therapy. Antimicrobial resistance is a major threat for the efficacy of eradication therapy, and the prevalence of macrolide-resistant H. pylori strains is increasing.
Specific point mutations in the 23S rRNA of the bacterium are associated with macrolide resistance.
Detection of antibodies to H. pylori
- Based on detection of IgG and IgA by ELISA
- For detection of anti-CagA antibodies an ELISA is also available
Detection of H. pylori
- Based on the polymerase chain reaction (PCR)
- Targeting the vacA or 23S rRNA gene
- Simultaneous detection of several genotypes
- Based on PCR followed by a reverse hybridization line probe assay (LiPA)
- Targeting vacA (s1a, s1b, s1c, s2, m1, m2a, m2b), and cagA
Simultaneous detection of 23S rDNA mutations
- Based on PCR followed by LiPA
- Targeting the A2142G, A2142C, A2143G, A2143C, and A2143T mutations of the 23 rRNA gene
Samples
- Serological testing: serum, EDTA plasma. Minimal volume 1 ml. Store at -20°C.
- Molecular testing: cultured H. pylori strains, stool samples, freshly frozen gastric biopsy specimens, and (buffered) formalin-fixed, paraffin-embedded gastric biopsy specimens.
