BACKGROUND Infection in liver recipients is related to high risk of transplantation failure and mortality. Infectious agents isolated from 55 liver recipients from January 2003 through June 2005 were studied to improve the anti-infectious therapy. METHODS Pathogens were isolated from routine culture. K-B method was used to examine the drug susceptibility. Extended spectrum beta-lactamase, AmpC beta-lactamase and Van gene in E.coli were examined by the agar-dilution susceptibility test and Nitrocefin test. RESULTS Thirty-nine of the 55 recipients got infection. The 513 strains of pathogens isolated from 1861 specimens were predominantly Gram negative bacteria and over 40% of them showed resistance to more than 4 drugs. The positive rates of extended spectrum beta-lactamse and AmpC beta-lactamse production in E.cloacae were 32.4% and 36.8%, in E.coli were 33.8% and 10.5%, but the rates of these 2 bacteria producing both lactamses were 24.3% and 7.0%. The beta-lactamse production rates of Enterococcus faecalis and Enterococcus faecium were 8.8% and 11.1%, and the resistance rates to vancomycin were 11.2% and 18.5%, respectively. CONCLUSIONS Infectious pathogens isolated from liver recipients are potent and multiple drug resistant. ESBLs and AmpC beta-lactamases are the major factors associated with Gram negative drug resistance. The infection of Enterococcal species presents as a particular challenge.