Background Previous researches about necrotic pancreatic tissue infections are numerous,but the study on systemic infection related to the severe acute pancreatitis (SAP) treatment period is limited.This study aimed to investigate the distribution and drug resistance of pathogenic bacteria in patients who had hepatobiliary surgery for SAP during the past three years.Methods A retrospective study was conducted on the distribution,category and drug resistance of pathogenic bacteria in patients who had hepatobiliary surgery for SAP from 2008 to 2011.Results A total of 594 pathogenic bacteria samples were isolated.Among them 418 isolates (70.4％) were Gram bacteria negative,142 isolates (23.9％) were Gram bacteria positive,and 34 isolates (5.7％) were found fungi.The most common Gram negative bacteria were Escherichia coli (19.8％),and the dominant Gram positive pathogenic bacteria were Enterococcus faecium.The distribution of SAP-related infectious pathogens was mainly in peritoneal drainage fluid,sputum,bile,and wound secretions.Almost all the Gram negative pathogenic bacteria were sensitive to carbapenum.Extended-spectrum β-lactamases (ESBLs) producing strains were more resistant to penicillins and cephalosprins than the ESBLs non-producing strains.Staphylococcus was sensitive to vancomycin and linezolid.The drug resistance of meticillin-resistant staphylococcus (MRS) to commonly used antibiotics was higher than meticillin-sensitive streptococcus (MSS).Enterococcus sp.exhibited lower drug-resistance rates to vancomycin and linezolid.Conclusions Gram negative bacteria were the dominant SAP-related infection after hepatobiliary surgery.A high number of fungal infections were reported.Drug resistant rates were high.Rational use of antibiotics according to the site of infection,bacterial species and drug sensitivity,correctly executing the course of treatment and enhancing hand washing will contribute to therapy and prevention of SAP-related infection and decrease its mortality.