Clinical Study of using Prophylactic Antibiotics and Chemical Preparation for Elective Operation of Colorectal Cancer

Introduction: Antibiotic prophylaxis is an important measure for preventing postoperative surgical site infection (SSI) after colorectal operations. We attempted to confirm the optimal method of using prophylaxis for elective colorectal operations by performing a prospective study between January 1997 and August 2002. Methods: Mechanical preparation was used prior to operation in all cases. Preoperative chemical preparation was used for 0-2 days. Well-conditioned, non-contaminated primary resection cases were randomized into one of two groups in advance. In Arm A, antibiotics were given from just prior to the operation until one day after the operation. In Arm B, antibiotics were given from just prior to the operation until 3 days after the operation. The type of antibiotic was limited to PIPC, CEZ, CTM, or CMZ, administered intravenously. If the operation required more than 4 hours to perform, an additional dose of antibiotics was used. Results: In total, 521 cases were enrolled in the study. The rate of SSI was 5.7%(n=262) in arm A, and 5.4%(n=259) in arm B, and the rate of remote infection (RI) was 6.9% in arm A, and 5% in arm B. No relationship was observed between the duration of prophylaxis and the rate of SSI or RI. In Japan, many surgeons do not use preoperative chemical preparations to prevent superinfections, such as MRSA. However, the Centers for Disease Control and Prevention (CDC) recommends using a short period of chemical preparation before surgery. Unlike the results for colonic operation, the SSI controll level after performing a Miles'operation was poor when no chemical preparations were used. We believe that short period of chemical preparation is useful for preventing SSI after lower rectal operations. However, postoperative MRSA colitis or MRSA pneumonia occured only in the group where chemical preparations were given for 2 days. In these cases, an overdose of the chemical preparations may have induced antibiotic resistant bacteria to multiply. Conclusions: We recommend the following standard method of using antibiotic prophylaxis for colorectal operations. 1) The required duration of antibiotic prophylaxis for SSI and RI does not appear to differ according to the clinical stage or type of operation that is performed. 2) Using antibiotic prophylaxis from just before the operation to one day after the operation is sufficient to prevent SSI. 3) Short periods of administering chemical preparations are likely to be effective for preventing