The THAI Journal of SURGERY 2008; 29:77-80. Official Publication of the Royal College of Surgeons of Thailand Mono- or Poly- Antimicrobial Prophylaxis in Colorectal Surgery Varut Lohsiriwat, MD Atthaphorn Trakarnsanga, MD Thawatchai Akaraviputh, MD Vitoon Chinswangwatanakul, MD, PhD Darin Lohsiriwat, MD Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand Abstract Objective: The use of prophylactic antibiotics in colorectal surgery is well established. Type of antibiotics, however, varies significantly among surgeons. The aim of this study was to determine whether mono- antimicrobial regimen is as effective as poly-antimicrobial regimen in the prevention of surgical wound infections following elective colorectal cancer surgery. Materials and Methods: The medical records of 56 patients with colorectal cancer undergoing elective oncological resection from January 2004 to September 2006 at Siriraj Hospital, Bangkok, were retrospectively reviewed. Patients were divided into two groups according to the regimen of prophylactic intravenous anti- biotics; group A: monotherapy (cefminox-Meicelin®) and group B: polytherapy (ceftriaxone plus metronidazole). The duration of antibiotics administration was up to 24 hours in colonic surgery and up to 3 days in rectal surgery. Patient characteristics and rate of wound infection within 30 days after the operation were compared between the two groups. Results: This study included 25 males and 31 females, with a mean age of 63 years (range 27-86). There were 18 patients in group A and 38 patients in group B. There was no significant difference in patient characteristics between the two groups. Overall rate of wound infection was 14.3%. Rate of wound infection was not significantly different between the two groups (group A 11.1% vs group B 15.8%, P = 1.00). No adverse drug reaction was found in this study. Conclusions: Based on this study, there was no significant difference in the rate of wound infection following elective colorectal cancer surgery with mono-antimicrobial regimen, compared to that with poly- antimicrobial regimen. Thus, single drug regimen could be a feasible alternative in antibiotic prophylaxis for the prevention of wound infection following elective lower gastrointestinal tract surgery. Correspondence address : Varut Lohsiriwat, MD, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Prannok Road, Bangkok 10700, Thailand. Phone: 02 419 8077, 081 427 9474, Fax: 02 411 5009, E-mail address: [email protected] 77 78 Lohsiriwat V, et al. Thai J Surg Jul. - Sept. 2008 INTRODUCTION MATERIALS AND METHODS The use of prophylactic antibiotics in colorectal Medical records of patients with colorectal cancer surgery is well established as it significantly reduces the undergone elective oncological resection between incidence of surgical wound infection. According to January 2004 and September 2006 at the Department the Centers for Disease Control and Prevention (CDC) of Surgery, Faculty of Medicine Siriraj Hospital, guideline in 19991, prophylactic antibiotics should Bangkok, Thailand were reviewed. The enrollment have a bacteriocidal activity against the most probable criteria included patient receiving either cefminox or intraoperative contaminants. In the case of colorectal ceftriaxone plus metronidazole as prophylactic surgery, expected pathogens are both aerobic and antibiotics. Patients were excluded if they had non- anaerobic organisms, mainly gram-negative bacilli and primary wound closure, underwent emergency Bacteroides fragilis. Therefore, the antibiotics selected operations or died within the first 48 hours after should be effective against all of them. surgery. Patients with document of intraoperative Practically, type of prophylactic antibiotics could gross contamination resulting in receiving longer vary significantly among surgeons2. Some prefer period of antibiotics administration (therapeutic combined administration of two antibiotics (poly- intention) were also excluded. Written informed antimicrobial regimen or polytherapy), whereas some consent was obtained from all patients. prefer administration of single antibiotic (mono- All patients with rectal cancer and most patients antimicrobial regimen or monotherapy). Although with colon cancer underwent preoperative mechanical monotherapy has been reported to be equivalent in bowel preparation. Prophylactic intravenous anti- safety and efficacy to polytherapy for antibiotic biotics, either cefminox 1 gm or ceftriaxone 1 gm plus prophylaxis, there is very limited study regarding this metronidazole 500 mg, were administrated by subject in Thailand, particularly in major colorectal anesthesiologist after induction of general anesthesia. operations.3 In case of operation time longer than 4 hours or with Ceftriaxone, one of the third generation cephalo- massive blood loss, additional dose of antibiotics may sporin, offers broad-spectrum antimicrobial coverage be given during the operation. Standard oncological with activity against gram-positive and gram-negative resection was performed either laparoscopically or bacteria. It is one of the most common prophylactic through open approach. Duration of antibiotics antibiotics used in intra-abdominal surgery because of administration was determined by the surgeon’s its bacteriocidal activity, long half life, easy administra- discretion, mostly up to 24 hours in colonic surgery tion and lack of nephrotoxicity. However, ceftriaxone and up to 3 days in rectal surgery. Wound infection was does not have an activity against anaerobes. Thus, it is defined based on CDC criteria.7 usually used in combination with metronidazole for Patients with surgical wound infection were lower gastrointestinal surgery.4,5 Meanwhile, the new discharged after the wound was well controlled and generation cephalosporin, cefminox (Meicelin®, Thai could be managed in the outpatient setting safely. All Meiji Pharmaceutical, Thailand) meets the require- patients were scheduled for follow-up at 30 days ment of a single broad-spectrum antibiotic being active postoperatively. against a wide range of gram-positive, gram-negative The data collected included age and gender, and anaerobic bacteria.6 Therefore, it has been chosen body mass index (BMI), American Society of to be used as a mono-antimicrobial regimen for anti- Anesthesiologist (ASA) status, location of the tumor biotic prophylaxis in colorectal surgery, and to be and the development of wound infection. Patients compared with a poly-antimicrobial regimen (ceftria- were divided into two groups according to the regimen xone plus metronidazole). of intravenous antibiotics administration; group A: The aim of this study was to determine whether monotherapy (cefminox - Meicelin®) and group B: mono-antimicrobial regimen was as effective as poly- polytherapy (ceftriaxone plus metronidazole). antimicrobial regimen in the prevention of surgical All data were prepared and compiled using SPSS wound infections following elective colorectal cancer software (version 10.0 for Windows). Mean and surgery. standard deviation were assessed. The Kolmogorov- Vol. 29 No. 3 Mono- or Poly- Antimicrobial Prophylaxis in Colorectal Surgery 79 Samirnov test was used to test for the pattern of data lin-resistant Staphylococcus aureus.9 Therefore, the distribution. Unpaired t-test was used to compare data ideal prophylactic antibiotics should cover common between the two groups when they were in normal pathogens, but has a minimal effect on the patient’s distribution pattern. Mann-Whitney U test was used normal flora and has minor adverse drug reactions. when this was not the case. Pearson chi-square test or Cephalosporins meet the aforementioned principles, Fisher’s exact test was used for categorical data. A P- therefore, many guidelines have recommended them value of less than 0.05 was considered statistically as a first line agent.10 However, many cephalosporins significant. do not have an activity against anaerobes. Thus, they are usually used in combination with metronidazole for lower gastrointestinal surgery.4,5 RESULTS Considering the convenience of drug administra- This study included 25 males and 31 females with tion and the concern of drug compliance, the current a mean age of 63 years (range 27-86). There were 18 trend toward the use of broad-spectrum single drug for patients in group A and 38 patients in group B. Patient antibiotic prophylaxis in colorectal surgery has characteristics in both groups were well-matched (Table continued. Our findings suggested that there was no 1). Overall rate of wound infection was 14.3%. The significant difference in the rate of wound infection rate of wound infection was not significantly different between mono- and poly- antimicrobial regimen. between the two groups (group A 11.1% vs group B Several studies have demonstrated that single drug 15.8%, P = 1.00). No adverse drug reaction was found regimen is equivalent in safety and efficacy to combined in this study. drug regimen for antibiotic prophylaxis in elective colon and rectal surgery.11-13 A prospective randomized trial of 422 patients in Germany revealed that three DISCUSSION different types of antibiotics (ampicillin/sulbactam, Wound infection is a common but potentially cefoxitin and piperacillin/ metronidazole) are of equal preventable complication following colorectal surgery. value.11 Administration of prophylactic antibiotics inhibits the A systematic review of 147 randomized controlled growth