Anaerobic Culture Yield in Interventional Radiologic Drainage Procedures

Abstract

This study was designed to determine the yield of anaerobic cultures from percutaneous radiologic drainage procedures. Anaerobic culture results in 317 patients from June 1992 to May 1994 were retrospectively examined. Anaerobic specimens were placed in specially designed anaerobic culture tubes and not blood culture media. Patients had undergone the following procedures: percutaneous nephrostomy (105 patients), biliary drainage (65 patients), and abdominal abscess drainage (147 patients). Aerobic culture results were tabulated in those patients with positive anaerobic cultures. Overall, 10% of patients (n = 32) had positive anaerobic cultures (Bacteroides species, n = 25; Clostridium, n = 6; other organisms, n = 4). Anaerobes were isolated in 13% (n = 19) of abdominal abscess drainages, 8% (n = 8) of nephrostomy drainages, and 8% (n = 5) of biliary drainages. Aerobic isolates were present in 78% (n = 25) of patients with anaerobic infection. The yield for anaerobic cultures varies for different types of percutaneous drainage procedures from 8% to 13%. When isolated, anaerobic bacteria are frequently mixed with aerobic bacteria. Anaerobic culture usage is recommended with abdominal abscess and biliary drainages. Anaerobic bacterial cultures are not recommended for percutaneous nephrostomy unless the patient has a urinary tract malignancy or has undergone urinary instrumentation.