Abstract: Objective To investigate the bacteriology characteristics and drug resistance of post-operative infections of wounds in the patients with colorectal cancer and to provide the basis for the reasonable application of antibiotics.Methods A retrospective analysis of the pathogenic bacteria distribution and drug resistance in112 colorectal cancer patients,who underwent surgeries in the hospital from Sep 2012 to Dec 2015,was performed. Results A total of 121 strains of pathogenic bacteria were isolated from wound secretions and abdominal puncture fluids. Gram-negative bacterias accounted for 83.47% （101/121）, including Escherichia coli,Pseudomonas aeruginosa,Klebsiella pneumoniae,and Enterobacter cloacae. Gram-positive cocci accounted for 13.22% （16/121）,that dominated by Enterococcus. It was found that E. coli and K. pneumoniae had a low resistance rate to carbapenems,β-lactamase inhibitor compound agents,cephamycins and fourth generation Cephalosporins （less then 30%）,whereas P.aeruginosa showed higher sensitivity to antibacterial agents in vitro. Enterococcus had a high resistance rate to erythromycin and tetracycline,while no drug-resistant strains to vancomycin,linezolid,tigecycline and nitrofurantoin were found. Conclusion The most common pathogenic bacterias causing surgical site infections are gram-negative bacilli. It is necessary to energetically prevent and treat postoperative infections in colorectal cancer patients based on the Results of drug susceptibility testing.

Key words: Colorectal cancer, Surgical site infection, Etiology, Drug sensitivity test