Objective      To investigate epidemiological characteristics of Gram-negative bacilli (GNB) isolated from patients with non-recurrent intra-abdominal infections in our hospitals from 2008 to 2010

and to analyze antimicrobial resistance of GNB to common antibiotics and ESBLs-producing ratio of GNB.     Methods      A total of 290 cases of GNB were isolated from patients with intra-abdominal infections from 2008 to 2010. In antimicrobial susceptibility test

agar dilution method was applied for MIC determination according to NCCLS guidelines. All the data were analyzed using WHONET 5.4 and SPSS 13.0.     Results      In the total of 290 GNB

enterobacteriaceae accounted for 82.7% and non-fermentative bacteria accounted for 17.93%. There were six types of common bacteria in which E. coli accounted for 55.3%

and the ratio of Acinetobacter baumannii complex increased apparently (7.96%). The positive rates of ESBLs production in E. coli and Klebsiella spp were 74.38% and 55.56%

respectively. E. coli was highly sensitive to carbapenems

piperacillin/tazobaetam and amikacin

but not to the third-generation cephalosporins and cefepime. The non-ESBLs-producing Klebsiella spp was sensitive to the twelve common anti-GNB antibiotics

while ESBLs-producing Klebsiella spp was sensitive to amikacin

piperacillin/tazobaetam and carbapenems. The susceptibility rates of Pseudomonas aerltgillosa to imipenem

piperacillin/tazobaetam and amikacin were all above 90% and to cefepime and two quinolones were 80%to 90%

but the susceptibility rate to ceftazidime decreased below 80%. The drug resistance rate of Acinetobacter baumannii to carbapenems was above 80%. Multidrug resistant (MDR) strains accounted for 32%

mainly including Acinetobacter baumannii complex and Pseudomonas aerltgillosa. Eighty percent MDR strains were resistant to almost all commonly used antibiotics.     Conclusion      The antimicrobial resistance of GNB isolated from patients with intra-abdominal infections increases apparently during the past three years in the region

especially with a high proportion of ESBLs-producing enterobacteriaceae. Enterobacteriaceae and Pseudomonas aerltgillosa are highly sensitive to carbapenems

piperacillin/tazobaetam and amikacin

while Acinetobacter baumannii is resistant to all common antibiotics with an increased proportion of MDR strains.