Detection of cagA and vacA Virulence Genes in Helicobacter pylori Isolated from Gastric Biopsy Samples of Iraqi Patients

Abstract

Helicobacter pylori is a leading gastric pathogen that causes chronic gastritis, peptic ulcer disease, and is linked to an increased risk of gastric malignancy. Although its pathogenic potential is determined by numerous virulence factors, the cytotoxin-associated gene A (cagA) and the vacuolating cytotoxin gene (vacA) in particular exert important effects in antimicrobial resistance. The purpose of this study was to determine the prevalence of cagA and vacA virulence genes in relation to antimicrobial resistance among H. pylori isolates from gastric biopsy samples of Iraqi patients. A cross-sectional study was performed at Al-Husseini Teaching Hospital, Karbala, Iraq. A total of 66 H. pylori isolates from gastric biopsy specimens. Antimicrobial susceptibility testing was performed against clarithromycin, amoxicillin, metronidazole, tetracycline and levofloxacin. Both of the virulence genes explored were anticipated to be highly prevalent, with cagA defined in 47 (71.2%) isolates and vacA in 62 (93.9%) isolates. Resistances were mainly known to be high to metronidazole (80.3%), clarithromycin (53.0%) and levofloxacin (45.5%), but low towards amoxicillin (27.3%) and tetracycline (9.1%). We anticipated large associations between cagA positivity and metronidazole resistance (P=0.001), and vacA and resistance to the other antibiotics tested, for which no significant associations were hypothesized. These results show that a high proportion of important H. pylori virulence factors and high-level antimicrobial resistance can be found among Iraq isolates indicating continuous molecular and antimicrobial monitoring is necessary to assist in effective eradication attempts.