Tracheal Colonization and Outcome After Major Abdominal Cancer Surgery

Inclusion Criteria: * Adult patients diagnosis of gastric cancer, or colorectal cancer or pancreatic cancer * Scheduled for major abdominal surgery with organ resections * Written informed consent * Nasopharyngeal smears taken in the preoperative area * Tracheal aspirates taken at the end of the surgical procedure Exclusion Criteria: * Patients unable to understand study protocol and patients who refused study participation at any time * patients with clinically or radiologically confirmed acute respiratory infections at admission * antibiotic therapy due to the respiratory infections a week prior to the surgery