Gallbladder stone formation in Iraqi patients is associated with bacterial infection and HLA class II-DRB1 antigens

Gallbladder stone is recently increased among the Iraqi society due to many risk factors such as bacterial infection and some HLA class II antigens.

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).

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.

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).