Helicobacter pylori vacA genes associated with gastric diseases in Trinidad and Tobago

Objectives: To delineate and understand the genetic variations among Helicobacter pylori strains from Trinidad and Tobago associated with gastric diseases.

Methods: One hundred (n = 100) patients who routinely presented with clinical features suggestive of peptic disease were enrolled in the study and underwent gastroscopy procedures. Biopsy specimens were analyzed using serological and molecular methods. Amplification of the variable vacuolating cytotoxin gene A (vacA), urease C (ureC), and 16S ribosomal RNA regions was performed by polymerase chain reaction; and then followed by sequencing and alignment. Phylogenetic analysis and DNA fragment alignment were carried out using DNA MEGA 7 version 7.

Results: Overall, 70 of the patients tested positive for H. pylori infection using an enzyme immune assay. All were 16S ribosomal RNA positive, with 8.6% (6/70) testing positive for S1 and 91.4% (64/70) for S2. The most prevalent vacA allelic combination was S2M1, with 87.1% (61/70) cases. All S1M1 strains were ureC-positive, while S1M2 strains were ureC-negative.

Conclusions: H. pylori strain variations are seen in the Trinidad and Tobago isolates and are most closely related to the ones from the USA, India, and Indonesia. However, the factors contributing to the emergence of S2/M1 being more prevalent will need to be further investigated.