AIM: To analyzed the species of bacteria and antibiotic susceptibility in the conjunctival sac of non- diabetic patients and diabetic patients, to decrease the rate of postoperative endophthalmitis through the proper use of antibiotic drop and preoperative disinfection.

METHODS: Totally 124 patients(124 eyes)underwent cataract operation in Yangsi Hospital during November 2013 to January 2017 were divided into two groups: diabetic group(37 patients 37 eyes)and control group(87 patients 87 eyes). Bacterial culture in the conjunctival sac and antibiotic susceptibility test was operated in three time-points: before preoperative disinfection(T0), after preoperative disinfection(T1)and after operation(T2).

RESULTS: The bacterial culture rate in the conjunctival sac of diabetic patients was significantly higher than that in non-diabetic patients. Most of strains of bacteria were sensitive to vancomycin, levofloxacin and tobramycin. For penicillin, azithromycin and tetracycline, the rate of antibiotic resistance was much higher than other antibiotic.

CONCLUSION: Due to the change of the microenvironment of ocular surface, the bacterial culture rate of the conjunctival sac was significantly increased in diabetic patients. The main cultured bacteria in conjunctival sac were staphylococcus epidermidis and acnes propionate. Most of cultured bacteria in conjunctival sac were sensitive to levofloxacin and tobramycin. Levofloxacin and tobramycin can be used as preoperative antibiotic eye drop.