Helicobacter pylori in the etiology of cholesterol gallstones

GOALS: We aimed to investigate the presence of bacterial structures in cholesterol gallstones and particularly presence of Helicobacter spp/H. pylori in gallstones by microbiologic cultivation, histopathologic staining, and polymerase chain reaction (PCR). BACKGROUND: Many studies suggest that different mechanisms are responsible for the formation of pigmented gallstones and cholesterol gallstones. Recently, studies showed that infection could have an important role in the formation of cholesterol gallbladder stones. STUDY: We examined 77 mixed cholesterol gallstones. After cholecystectomy, gallbladder cultures were done for H. pylori and other bacterium. Gallbladder has also been examined by three histopathologic staining methods (Warthin-Starry, hematoxylin eosin, and gram staining) for Helicobacter spp. In addition, 16S rRNA-PCR amplification was performed for Helicobacter spp in gallstones. Twenty postmortem gallbladders without gallstones were investigated by the same histopathologic and PCR methods for Helicobacter spp. as a control group. RESULTS: Different bacterium were isolated from 22 gallbladder samples (12 Escherichia coli, 8 Pseudomonas, and 2 clostridium) and H. pylori was isolated in 6 gallbladder samples. Helicobacter spp was found in 7 gallstones by PCR amplification. Helicobacter-like organisms were demonstrated in 18 samples by three different histopathologic methods. Helicobacter-like organisms were also found in five samples by the same histopathologic methods (Warthin-Starry, hematoxylin-eosin, and gram staining). Only four samples were found positive for Helicobacter spp/H. pylori by all methods. CONCLUSIONS: Bacterial population including H. pylori could have a possible role in the formation of cholesterol gallstones.