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Table 1: Recommendations for antibiotic prophylaxis in patients undergoing gastrointestinal endoscopic procedures
Patients with bleeding esophageal varices also have high rates of bacteremia. Up to 20% of patients with cirrhosis and GI bleeding on admission develop an infection within 48 hours of presentation.8 There is evidence that the bacteremia may actually be related to the variceal bleeding rather than the procedure.9 Patients with bleeding esophageal varices treated with antibiotics have improved outcomes, including a decrease in mortality.10 Therefore, all patients with bleeding esophageal varices should be placed on antibiotic therapy regardless of whether an endoscopic intervention is planned.
Percutaneous Endoscopic Gastrostomy (PEG) Placement. Prophylactic antibiotics are recommended before placement of a PEG. The indication for prophylactic antibiotics is to prevent a gastrostomy site infection, not infective endocarditis. Gastrostomy site infection is unfortunately a fairly common infection, affecting 4% to 30% of patients who undergo PEG tube placement. There is significant evidence that antibiotics are beneficial in preventing peristomal infections. A meta-analysis showed that only eight patients need to be treated with prophylactic antibiotics to prevent a single peristomal infection.11 Since these infections are believed to be caused by contamination from the oropharynx, physicians should consider prophylaxis against pathogens from the oral flora.12
More recently, it has been noted that methicillin-resistant Staphylococcus aureus (MRSA) is increasingly cultured from infection sites.13 In centers with endemic MRSA, patients should be screened and then undergo decontamination prior to the PEG placement in positive cases.
Endoscopic Ultrasound with Fine Needle Aspiration (EUS-FNA). Antibiotic prophylaxis before EUS-FNA of a solid lesion in an organ is generally thought to be unnecessary because the risk of bacteremia with this procedure is low, comparable to routine GI endoscopy with biopsy. The recommendation for prophylactic antibiotics before biopsy of a cystic lesion is different. There is concern that puncturing cystic lesions may create a new infected fluid collection.2 A systematic review of more than 10,000 patients undergoing EUS-FNA with a full range of target organs revealed that, overall, 11.2% of patients experienced a fever and 4.7% of patients had a peri-procedural infection. While it was not possible in this study to determine which patients received prophylactic antibiotics, 93.7% of patients with pancreatic cystic lesions were reported to have been treated with antibiotics.14
A separate, single-center, retrospective trial produced different results. This study examined a population of 253 patients who underwent 266 EUS-FNA of pancreatic cysts and found that prophylactic antibiotics were associated with more adverse events and were not protective for the 3% of the patients with infectious symptoms.15 Despite the conflicting data, guidelines at this time recommend prophylactic antibiotics before drainage of a sterile pancreatic fluid collection that communicates with the pancreatic duct and also for aspiration of cystic lesions along the GI tract and the mediastinum.2
Endoscopic Retrograde Cholangiopancreatography (ERCP). In patients undergoing ERCP, the routine use of prophylactic antibiotics has not been found to be effective in decreasing the risk of post-procedure cholangitis.16 Guidelines recommend the use of prophylactic antibiotics only in those patients in which the ERCP may not completely resolve the biliary obstruction.2 In these patients, the thought is that ERCP can precipitate infection by disturbing bacteria already present in the biliary tree, especially with increased intrabiliary pressure at the time of contrast dye injection.17
Patients with incomplete biliary drainage, including those with primary sclerosing cholangitis (PSC), hilar cholangiocarcinoma, persistent biliary that were not extracted, and strictures that continue to obstruct despite attempted intervention, are thought to be at elevated risk of developing cholangitis post-ERCP. These patients should be placed on prophylactic antibiotics at the time of the procedure to cover biliary flora such as enteric gram negatives and enterococci. Antibiotics should be continued until the biliary obstruction is resolved.2
