Addition of gentamicin to endoscopic retrograde cholangiopancreatography (ERCP) contrast medium towards reducing the frequency of septic complications of ERCP

OBJECTIVE: Bacteremia and sepsis are serious complications of endoscopic retrograde cholangiopancreatography (ERCP) and occur in between 0.5 and 3% of cases. Patients with obstructed bile ducts are at highest risk of developing septic complications. The purpose of this investigation was to determine whether the addition of gentamicin to the ERCP contrast medium prevents or reduces the growth of Pseudomonas aeruginosa in vitro. METHODS: Artificial bile ducts were fashioned out of dialysis tubing and suspended in flasks containing brain heart infusion (BHI) broth. The tubing contained BHI broth alone, with or without contrast medium or with contrast medium plus gentamicin. The artificial ducts were inoculated with gentamicin-sensitive or gentamicin-resistant P. aeruginosa and quantitative cultures were performed. RESULTS: The contrast medium alone was bacteriostatic to both sensitive and resistant P. aeruginosa isolates. The addition of gentamicin to the contrast medium eliminated the sensitive strain after 2 h and resulted in a reduction in the number of gentamicin-resistant P. aeruginosa after 4 h. Incubation of the resistant isolate in the presence of contrast and gentamicin for an additional 4 h led to a further reduction in viable bacteria but did not completely eliminate the organisms. CONCLUSION: These results support the use of gentamicin in the contrast medium injected into the biliary system as an ancillary method to prevent post-ERCP sepsis.