PurposeInfectious complications are as high as 30% in elective colorectal surgery. In recent years, several studies have discussed the topic of preoperative bowel decontamination prior to colorectal surgery in order to reduce postoperative infectious complications and have found significant effects of oral antibiotic administration with a large variety of drugs used. No study has evaluated the combination of oral paromomycin and metronidazole in this context.MethodsWe performed a prospective single-center study with a matched-pair retrospective cohort to evaluate postoperative infectious complications (superficial site infections, organ space abscess, anastomotic leakage) in elective colorectal surgery.PatientsA total of 120 patients were available for study inclusion; 101 gave informed consent and were included. A total of 92 patients were matched and subsequently analyzed. We could show a reduction in overall infectious complications in the intervention group (15.2% vs 30.8%, p = 0.018; odds ratio 0.333, 95% CI 0.142–0.784) as well as a reduction in superficial surgical site infections (8.7 vs 19.6%, p = 0.041, OR 0.333, 95% CI 0.121–0.917). The frequency of the other infectious complications such as intraabdominal abscesses and anastomotic leakage showed a tendency towards decreased frequencies in the intervention group (OR 0.714, 95% CI 0.235–2.169 and OR 0.571; 95% CI 0.167–1.952, respectively). Finally, the oral antibiotic administration led to an almost significantly reduced length of stay (12.24 days vs 15.25 days; p = 0.057).ConclusionsOral paromomycin and metronidazole with intravenous ertapenem effectively reduce infectious complications in elective colorectal surgery.Trial registrationThe study was registered at Clinicaltrials.gov (NCT03759886) December 17, 2018