AIM: To investigate the microbiological characteristics and drug resistance in liver cirrhosis patients with spontaneous peritonitis.METHODS: We analyzed the data of patients with liver cirrhosis and abdominal infection at the First Affiliated Hospital of Zhejiang University between January 2011 and December 2013. Pathogens present in the ascites were identified,and their sensitivity to various antibiotics was determined. RESULTS: We isolated 306 pathogenic bacteria from 288 cases: In 178 cases,the infection was caused by gram-negative strains(58.2%); in 85 cases,grampositive strains(27.8%); in 9 cases,fungi(2.9%); and in 16 cases,more than one pathogen. The main pathogens were Escherichia coli(E. coli)(24.2%),Klebsiella pneumoniae(18.9%),Enterococcus spp.(11.1%),and Staphylococcus aureus(7.5%). Of the 306 isolated pathogens,99 caused nosocomial infections and 207 caused community-acquired andother infections. The E. coli and K. pneumoniae strains produced more extended-spectrum β-lactamases in cases of nosocomial infections than non-nosocomial infections(62.5% vs 38%,P < 0.013; 36.8% vs 12.8%,P < 0.034,respectively). The sensitivity to individual antibiotics differed between nosocomial and non-nosocomial infections: Piperacillin/tazobactam was significantly more effective against non-nosocomial E. coli infections(4% vs 20.8%,P < 0.021). Nitrofurantoin had stronger antibacterial activity against Enterococcus species causing non-nosocomial infections(36.4% vs 86.3%,P < 0.009).CONCLUSION: The majority of pathogens that cause abdominal infection in patients with liver cirrhosis are gram-negative,and drug resistance is significantly higher in nosocomial infections than in non-nosocomial infections. AIM: To investigate the microbiological characteristics and drug resistance in liver cirrhosis patients with spontaneous peritonitis. METHODS: We analyzed the data of patients with liver cirrhosis and abdominal infection at the First Affiliated Hospital of Zhejiang University between January 2011 and December 2013. Pathogens present in the ascites were identified, and their sensitivity to various antibiotics was determined. RESULTS: We isolated 306 pathogenic bacteria from 288 cases: In 178 cases, the infection was caused by gram- negative strains (58.2%); in 85 cases, grampositive strains The main pathogens were Escherichia coli (24.2%), Klebsiella pneumoniae (18.9%), Enterococcus spp. (27.8%); in 9 cases, fungi (11.1%), and Staphylococcus aureus (7.5%). Of the 306 isolated pathogens, 99 caused nosocomial infections and 207 caused community-acquired andother infections. The E. coli and K. pneumoniae strains produced more extended-spectrum β-lac tamases in cases of nosocomial infections than non-nosocomial infections (62.5% vs 38%, P <0.013; 36.8% vs 12.8%, P <0.034, respectively). The sensitivity to individual antibiotics differed between nosocomial and non-nosocomial infections: Piperacillin / tazobactam was significantly more effective against non-nosocomial E. coli infections (4% vs 20.8%, P <0.021). Nitrofurantoin had stronger antibacterial activity against Enterococcus species causing non-nosocomial infections (36.4% vs 86.3%, P <0.009) .CONCLUSION: The majority of pathogens that cause abdominal infection in patients with liver cirrhosis are gram-negative, and drug resistance is significantly higher in nosocomial infections than in non-nosocomial infections.