Controversies in Perioperative Antimicrobial Prophylaxis

Controversies in Gastrointestinal Procedures: Bowel and Biliary Tract Prophylaxis

The idea of utilizing oral antibiotics to decrease perioperative infections began shortly after penicillin was discovered and was combined with purgatives to decrease microbial colonization. When the formal combination of mechanical bowel preparation and neomycin and erythromycin was introduced, surgical site infection rates were reduced from 43 to 9%.^[86] In a review of 5,800 colorectal surgery patients, no significant difference with mechanical bowel preparation versus no preparation in terms of leakage or surgical site infection were found.^[87] Whether to use mechanical bowel preparation, oral antibiotics alone, or in combination with systematic antibiotics has remained controversial. A review of the results of the 2012 to 2015 American College of Surgeons National Surgical Quality Improvement Program database addressed the question as to what extent mechanical bowel preparation and antibiotic bowel preparation decreased infection after elective colorectal resection.^[88] The combined mechanical bowel preparation/antibiotic bowel preparation when compared with no preparation had fewer surgical site infection (odds ratio, 0.39), organ space infection (odds ratio, 0.56), wound dehiscence (odds ratio, 0.43), and anastomotic leak (odds ratio, 0.54), all significantly lower. A 2014 Cochrane review found high quality evidence that antibacterial therapy targeting colonic pathogens reduced the risk of surgical site infection but could not determine whether this was attenuated by mechanical bowel preparation.^[89] Antibiotic bowel preparation alone compared with no preparation also has significant benefits, whereas mechanical bowel preparation alone did not. As such, for patients undergoing elective colon or rectal resection, both mechanical agents and oral agents are recommended whenever feasible.^[90,91]

Unlike open cholecystectomy, the benefits of antibiotic prophylaxis in patients undergoing planned elective laparoscopic cholecystectomy is controversial,^[92] although some studies have suggested a decline in postoperative infection.^[93,94] Patients who undergo more complex biliary, hepatic, or pancreatic surgery may have special considerations with respect to surgical site infection risk. Aside from the typical risk factors, these patients may have had recent contact with the healthcare system via procedures to further clarify their underlying anatomy/disease. Through endoscopic or transhepatic procedures, they may introduce or encourage potential future colonizing or infecting pathogens in the setting of partially obstructed biliary drainage systems. There appears to be a correlation between intraoperative biliary cultures and future pathogens identified at the time of infection.^[95]

In a randomized controlled trial of 126 patients with planned hepatobiliary pancreatic surgery, patients received targeted prophylaxis based on known pathogens in biliary cultures versus standard prophylaxis, which was with either a second-generation cephalosporin or up to three antibiotics targeted for the resistant pathogens. Infection rates were high in both groups (43.5% in the targeted group and 71% in the standard group). This study suggests that multidrug-resistant colonization should be considered when using perioperative prophylaxis in high-risk hepatobiliary pancreatic surgery.^[96]

Duration of prophylaxis has also been controversial in liver surgery. Four randomized controlled trials have examined the issue of extended duration under the premise that ongoing contamination related to bile leakage may occur after surgery and would incur added risk of surgical site infection. One study suggested that prophylaxis for up to 5 days postoperatively was beneficial,^[97] whereas another study reported that 2 days were as effective as 5 days.^[98] A recent consecutive series of patients having a hepatic resection without biliary reconstruction reported no difference in postoperative infection rates.^[99] Last, a small randomized controlled trial that included major hepatectomy with extrahepatic bile duct resection and reconstruction compared 2 days versus 4 days of antibiotics and found no difference in infectious complications between the two groups (30.2% in the 2-day group vs. 32.6% in the 4-day group).^[100] These studies show diligence is required in identifying infectious complications given the high rate of occurrence, but extending antibiotic duration does not appear to confer benefit. No studies in this high-risk population have limited antibiotics to the operating room only, as recommended in recent guidelines.