Immunohistochemistry and molecular detection of Helicobacter pylori infection and their virulent genes in gastric biopsies

An infection with Helicobacter pylori (H. pylori) can lead to chronic gastritis, which, if not treated, can cause serious gastroduodenal diseases such as gastric mucosa-associated lymphoid tissue lymphoma, gastric cancer, and peptic ulcer. H. pylori infection usually occurs during childhood, and if left untreated, it can persist throughout a person’s lifetime. The main objective of this study was to determine the occurrence of H. pylori infections and the presence of virulence genes such as vacA and cagA. Additionally, the study aimed to investigate the connection between virulence factors and gastroduodenal issues in patients. Several virulent factors play a crucial role in the development of diseases associated with H. pylori. A total of 1308 gastric biopsy specimens were collected from patients with a history of gastritis in 10% normal saline aseptically. Tissue size was measured, and gross examined, which were processed in an automated tissue processor. After processing, the embedding of tissues was done in paraffin wax. 2 to 3 μm sections were prepared using a rotary microtome. Hematoxylin and eosin staining, and immunohistochemistry were performed. DNA was extracted from the tissue of H. pylori and their virulence factors (cagA and vacA) through PCR. Of 1308 biopsies, 374 (28.5%) were H. pylori infections confirmed by hematoxylin and eosin stain and immunohistochemistry. The mean age was 39.5 (± 15.1) years, and the male-to-female ratio was 1:0.9. Among positive samples, gastric samples (260; 69.5%) were taken from the antrum, followed by antrum and body (68; 18.1%), gastric mucosa (26; 7.0%), and body (10; 2.6%). The colonization of H. pylori was classified into three levels: mild (270; 72.2%), moderate (64; 17.1%), and severe (40; 10.7%). Among the antrum, mild active gastritis (78; 30%), and mild chronic active gastritis (60; 23.1%), while in the antrum and body samples, 28 (41.1%) were mild active gastritis (P < 0.0001). 16 S rDNA in biopsy samples of H. pylori isolates. Additionally, in mild gastric colonisation, cagA (103; 27.5%) and vacA (143; 38.2%), and in moderate colonisation, 27 (7.2%) and 24 (6.4%) of cagA and vacA were identified, respectively. There was a high prevalence of H. pylori infection in gastric biopsies with mild colonization, and isolates carried the virulence genes.