Microbial profile and antibiotic sensitivity pattern in bile cultures from endoscopic retrograde cholangiography...

To identify the frequency of bacterial growth, the most commonly grown bacteria and their antibiotic susceptibility, and risk factors for bacterial colonization in bile collected from patients with different biliary diseases.

This prospective study was conducted between April 2010 and August 2011. Patients with various biliary disorders were included. Bile was aspirated by placing a single-use, 5F, standard sphincterotome catheter into the bile duct before the injection of contrast agent during endoscopic retrograde cholangiopancreaticography (ERCP). Bile specimens were transported to the microbiology laboratory in blood culture bottles within an anaerobic transport system. Bacteria were cultured and identified according to the standard protocol used in our clinical microbiology laboratory. The susceptibilities of the organisms recovered were identified using antimicrobial disks, chosen according to the initial gram stain of the positive cultures.

Ninety-one patients (27% male, mean age 53.7 ± 17.5 years, range: 17-86 years) were included in the study. The main indication for ERCP was benign biliary disease in 79 patients and malignant disease in 12 patients. The bile culture was positive for bacterial growth in 46 out of 91 (50.5%) patients. The most frequently encountered organisms were Gram-negative bacteria including Escherichia coli (28.2%), Pseudomonas (17.3%) and Stenotrophomonas maltophilia (15.2%). There were no significant differences between patients with malignant and benign disease (58% vs 49%, P = 0.474), patients with acute cholangitis and without acute cholangitis (52.9% vs 50%, P = 0.827), patients who were empirically administered antibiotics before intervention and not administered (51.4% vs 60.7%, P = 0.384), with regard to the bacteriobilia. We observed a large covering spectrum or low resistance to meropenem, amikacin and imipenem.

We did not find a significant risk factor for bacteriobilia in patients with biliary obstruction. A bile sample for microbiological analysis may become a valuable diagnostic tool as it leads to more accurate selection of antibiotics for the treatment of cholangitis.