Purpose: To investigate and analyze the clinical and etiological characteristics of community-acquired intraabdominal infections (CIAIs) and hospital-acquired or nosocomial intraabdominal infections (NIAls) in a comprehensive hospital, to understand the characteristics, pathogen composition, and drug resistance of CIAIs as well as NIAIs, and to provide a reference for clinical treatment.Methods: We collected the clinical data of patients with intraabdominal infections admitted to our hospital from June 2013 to June 2014.In vitro drug sensitivity tests were conducted to separate pathogens, and the data were analyzed using the WHONET 5.4 software and SPSS 13.0 software.Results: A total of 221 patients were enrolled in the study, including 144 with CIAIs (55 mild-moderate and 89 severe) and 77 with NIAIs.We isolated 322 pathogenic strains, including 234 strains of gramnegative bacteria, 82 strains of gram-positive bacteria, and 6 strains of fungi.Based on clinical features, NIAIs and severe CIAIs presented significantly higher values in age, length of hospital stay, mortality, and the incidence of severe intra-abdominal infection than mild-moderate CIAIs (p ＜ 0.05).There was no significant difference in the prognosis between NIAIs and severe CIAIs.Primary diseases leading to CIAIs and NIAIs mostly were hepatobiliary diseases and gastrointestinal diseases respectively.Bacteria isolated from various types of IAIs mainly were Enterobacteriaceae;mild-moderate CIAIs mostly were mono-infection of gram-negative bacteria;NIAIs mostly were mixed infections of gram-negative and gram-positive bacteria;and severe CIAIs were from either type of infection.The rate of Extended Spectrum β-Lactamase-producing Escherichia coli and Klebsiella pneumoniae was much higher in NIAIs than in CIAls (p ＜ 0.05).The antimicrobial drug sensitivity of gram-negative bacteria isolated from NIAIs was significantly lower than that of CIAIs.Conclusion: CIAIs and NIAls have their own unique clinical features and epidemiological features of pathogens which should be considered during the initial empiric therapy for the rational use of antimicrobial drugs.Regional IAIs pathogenic bacteria have their own features in drug resistance, slightly different from some recommendations of 2010 Infectious Diseases Society of America guidelines.