Prophylactic oral antibiotics may reduce surgical site infections

The administration of oral antibiotics – without mechanical bowel preparation – one day before colon surgery may reduce the risk of surgical site infections, according to results of the ORALEV* trial.

“[O]ral antibiotics reduce the incidence of surgical site infections significantly compared with no intervention,” said the researchers.

“[O]ur study suggests that surgeons should implement oral antibiotics when preparing patients for elective colon surgery,” they said.

Study participants were 565 individuals with neoplasia or diverticular disease scheduled for colon surgery (partial colon resection or total colectomy) at one of five hospitals in Spain. They were randomized 1:1 to receive oral antibiotics (experimental arm; ciprofloxacin [750 mg every 12 hours] and metronidazole [250 mg every 8 hours]) or not (control arm) the day prior to surgery. Patients did not receive mechanical bowel preparation. At anaesthesia induction, all patients received intravenous cefuroxime (1.5 g) and metronidazole (1 g). Patients were followed up for 1 month after surgery.

The results are based on the 267 and 269 patients in the experimental and control arms, respectively, who received the intervention (median age 71 years, 55 percent male).

The incidence of surgical site infection (including skin superficial, deep incisional, and organ-space infection) was significantly lower in the experimental compared with the control arm (5 percent vs 11 percent; p=0.013), with an odds ratio (OR) of 0.41 (95 percent confidence interval, 0.20–0.80; p=0.008). [Lancet Gastroenterol Hepatol 2020;doi:10.1016/S2468-1253(20)30075-3]

Complications were more common among patients in the control vs the experimental arm (28 percent vs 19 percent; p=0.017), though severity did not appear to differ between groups. Duration of hospitalization was comparable between groups (5 days each; p=0.088).

The study revealed two predictors of surgical site infection ie, type of surgery (open vs laparoscopic; OR, 2.29; p=0.018) and ASA** grade (grade I–II vs grade III–IV; OR, 2.05; p=0.028).

There were four deaths, two in each group, 1-month post-surgery. No adverse effects were deemed antibiotic-related.

According to the researchers, intervention recommendations prior to elective colon surgery vary widely, and include mechanical bowel preparation with or without oral antibiotics, oral antibiotics only, or no prophylaxis. Despite its use as standard of care, evidence suggests that mechanical bowel preparation does not reduce the risk of post-surgical complications including surgical site infections. In contrast, the combination of mechanical bowel preparation and oral antibiotics has shown some benefit. [Ann Surg 2018;267:734-742]

The choice of antibiotic prophylactic regimen is still undetermined, they added, noting that general requirements list activity against both aerobic and anaerobic bacteria in faeces and high serum levels at time of surgery as crucial qualities. This influenced the choice of ciprofloxacin and metronidazole in this study.