Effect of Preoperative Oral Antibiotics and Mechanical Bowel Preparations on the Intestinal Flora of Patients Undergoing Laparoscopic Colorectal Cancer Surgery: A Single-Center Prospective Pilot Study

Introduction: In the last few decades, considerable progress has been made in controlling surgical site infections (SSIs) using a combination of mechanical and oral antibiotic bowel preparation. However, the number of bacteria present after bowel preparation has not been clarified. In this study, we investigated the bacterial cultures of intestinal fluid samples from patients undergoing laparoscopic surgery for colorectal cancer after preoperative bowel preparation. Methods: This prospective observational study was designed as a pilot study at a single center. We enrolled 25 consecutive patients who underwent laparoscopic surgery for colorectal cancer between March 2021 and February 2022 at our institution. Results: The rate of bacterial culture positivity was 56.0%. The most abundant bacterium was Escherichia coli (44.0%). The positivity rates for E. coli on the right and left sides were 54.5% and 35.7%, respectively (P = 0.60). Moreover, there was a significant relationship between a low American Society of Anesthesiologists Physical Status score and E. coli positivity on the right side (P = 0.031). In the left -sided group, female sex and large tumor size were significantly associated with E. coli positivity (P = 0.036 and 0.049, respectively). Superficial SSI occurred in the patient in the left -sided group, but E. coli was negative. Conclusion: This study emphasizes the importance of understanding intestinal fluid contamination and its relationship to infection risk. Future prospective multicenter studies should be conducted to determine the association between intestinal bacteria and different types of preoperative preparation.