The use of proton pump inhibitors and the spectrum and number of biliary pathogens in patients with acute cholangitis

Background Knowledge of the bacterial spectrum for acute cholangitis is essential for adequate empiric antibiotic treatment. Aim To analyse the relation of proton pump inhibitors (PPI) with biliary pathogens in patients with acute cholangitis. Methods This retrospective study identified 278 patients with 318 acute cholangitis episodes using an endoscopic database. The relationship between PPI and microbiological outcomes was assessed by logistic and poisson regression analysis for binary and count data. Results In total, 882 pathogens were isolated, of which, 120 cholangitis episodes occurred with PPI; 198 cholangitis episodes without PPI. Multivariate poisson regression analysis showed that PPI use resulted in a 23% increase in the number of biliary pathogens [3.14 vs. 2.55 (Delta=0.59), P<0.01], whereas stent therapy, previous interventional procedures (endoscopic retrograde cholangiography/percutaneous transhepatic cholangiography), genesis, age and sex showed no significant association with the number of biliary pathogens. Significantly, more cholangitis episodes with more than one pathogen isolated occurred during PPI treatment [103/120 (86%) vs. 151/198 (76%), P=0.04]. Analysis of intrinsic anti-microbial resistance patterns was performed: Anti-microbial combination therapies were significantly more required to cover all isolated pathogens in cholangitis episodes with PPI than in cholangitis episodes without PPI (44/120 vs. 46/198, P=0.01). Additionally, PPI use was associated with a significantly higher incidence of oropharyngeal flora in the biliary tract (53/120 vs. 61/198, P=0.02). Conclusions Proton pump inhibitors seem to influence biliary pathogens by increasing the number and broadening the spectrum of biliary pathogens. However, the findings of this hypothesis-generating study need to be tested by confirmatory studies.