Bile duct bacterial isolates in primary sclerosing cholangitis and certainother forms of cholestasis - A study of bile cultures from ERCP

Background/Aims: The pathogenesis of the inflammatory lesion in primary scl erosing cholangitis is unknown. We have recently demonstrated a high positi vity rate of bacterial cultures in bile and bile ducts of explanted livers from primary sclerosing cholangitis patients compared with patients with pr imary biliary cirrhosis. In particular, alpha-hemolytic Streptococci was a frequent finding, suggesting an etiopathogenic role of that particular bact eria in primary sclerosing cholangitis. We therefore wanted to study naive primary sclerosing cholangitis patients and compare them with primary scler osing cholangitis patients that have previously undergone endoscopic retrog rade cholangiopancreatography, in order to evaluate the potential role of t hese bacteria in the etiopathogenesis in primary sclerosing cholangitis. Methodology: Samples for bacterial cultures were obtained during a diagnost ic endoscopic retrograde cholangiopancreatography. Participants: 12 naive p rimary sclerosing cholangitis patients, 10 patients with primary sclerosing cholangitis, previously investigated using endoscopic retrograde cholangio pancreatography, 47 patients with choledocholithiasis, 19 patients with can cer obstructing the common bile duct, and 29 patients with other forms of b iliary disorders. Results: Positive cultures were obtained from 3 of the naive primary sclero sing cholangitis patients and from 6 of the primary sclerosing cholangitis patients with previous endoscopic retrograde cholangiopancreatography (NS). The most frequent finding in all the primary sclerosing cholangitis patien ts was alpha-hemolytic Streptococci. Bacteria were cultured from the bile i n 64% of the patients with choledocholithiasis, higher than the 25% in the naive primary sclerosing cholangitis patients (P<0.03), and in 56% of patie nts with obstructing cancer (NS) but in only 24% of patients with other for ms of biliary disorders, all of whom, except 4, had normal cholangiograms. In the 22 patients with primary sclerosing cholangitis, 75% of the positive bacterial cultures consisted of Gram-positive isolates and 25% were enteri c bacteria, which differed statistically from the 74% enteric bacteria and 26% Gram-positive bacteria in the patients with common duct stone (P<0.01). Conclusions: Alpha-hemolytic Streptococci do not seem to play a primary rol e in the etiopathogenesis of primary sclerosing cholangitis since most naiv e primary sclerosing cholangitis patients were found to have negative bacte rial cultures. This does not exclude the possibility that they play a role in the progression of primary sclerosing cholangitis following infection in conjunction with the first endoscopic retrograde cholangiopancreatography.