RESUMO
BACKGROUND: Gallbladder stone is recently increased among the Iraqi society due to many risk factors such as bacterial infection and some HLA class II antigens. AIM(S): This study investigates the types of bacterial infection and HLA-DRB1 antigens' ratio that may be correlated with gallbladder stone formation. Setting and Design: The study included 45 patients and the same number of healthy individuals as a control group. Patients were with multiple gallstones. Gallstone bacterial culture was demonstrated to diagnose viable bacteria. HLA-DRB1 alleles' frequency was investigated using sequence-specific oligonucleotide probes (PCR-SSOP). RESULTS: Irrespective of gallstone type and size, different types of living viable bacteria were isolated from the cores of the studied gallstones in 80% of the studied cases versus 20% of sterile gallstones. Gram-negative bacteria cultures were the dominant (89.3%), including Escherichia coli, Klebsiella spp., Proteus spp., Acinetobacter spp., and Enterobacter spp. Mixed infection of Gram-positive and negative bacteria was noted: Escherichia coli and Enterococus spp. and the others of Escherichia coli and Acitobacter spp., and Klebsiella spp. and Pseudomonas spp. Gram-positive bacteria cultures were also detected at lower rate (10.7%) including Staphylococci spp. The frequency of HLA-DRB1*03:01, HLA-DRB1*4:03, HLA-DRB1*13:22, and HLA-DRB1*15:10 alleles was significantly elevated in patients compared to the healthy control group. CONCLUSION: Results ensured the viability of the bacteria isolated from the core of gallstones and showed positive correlation between gallbladder stone and different bacterial infection. In addition, HLA-DRB1 alleles were significantly high in patients compared to healthy control group suggesting them as risk factors (P < 0.05).