Bacterial Inoculum Preparation

E. coli (ATCC #25922) bacterial strains were obtained from microbiology laboratory, Renji Hospital, School of Medicine, Shanghai Jiao Tong University. An aliquot of E. coli was cultured in a 2 ml Luria Bertani broth (LB) for 24 h with a temperature of 37°C. The cultures were washed in saline. Spectrophotometry (OD600) was utilized to detect the culture concentration. Each culture was brought to the desired concentration (10² CFU/ml, 10⁴ CFU/ml, 10⁶ CFU/ml and 10⁸ CFU/ml) in 0.9% sterile saline and verified by plating serial ten-fold dilutions of the final solutions used during surgery.