ABSTRACT
<p><b>OBJECTIVE</b>To explore the relationship of bacteria identified in cholesterol gallstones and gallstone formation.</p><p><b>METHODS</b>Observe the bacteria activity in model bile and the influence of bacteria on the cholesterol nucleation time (NT).</p><p><b>RESULTS</b>(1) Model bile were suitable for the growth of E. coli, Pseudomonas aeruginosa, staphylococcus aureus, enterococcus faecalis, clostridium difficile and Clostridium. Propionibacterium acne grew weakly and the growth of Bacteroides fragilis was restrained in model bile. (2) Only pseudomonas aeruginosa and enTerococcus faecalis could ly shorten the cholesterol nucleation time. (3) With pseudomonas aeruginosa or enTerococcus faecalis added in model bile, the formation of cholesterol crystals presented a progressive course of evolution.</p><p><b>CONCLUSIONS</b>Pseudomonas aeruginosa and enterococcus faecalis, not propionibacterium acne, have pro-nucleating ability in model bile.</p>