The sample of biliary aspirate will be assessed as follows.~Its macroscopic appearance will be analyzed: yellow, black, or purulent.~Biliary culture will be performed; if bacterial growth is observed, its identification will be carried out by means of MALDI-TOF MS mass spectrometry and antibiotic susceptibility tests will be carried out, using the automated VITEK system.
Patients admitted to hospital due to obstructive biliary disease secondary to benign and malign etiologies, undergoing ERCP, will be selected. Bile sample will be taken in ERCP procedure with sterile technique. Its macroscopic appearance will be assessed and biliary culture will be performed.