Microbial epidemiology and risk factors for relapse in gram-negative bacteria catheter-related bloodstream infection with a pilot prospective study in patients with catheter removal receiving short-duration of antibiotic therapy

Background: Infectious Diseases Society of America (IDSA) guidelines suggest 7-14days' duration of antibiotic treatment for uncomplicated Gram-negative bacteria (GNB) catheter-related bloodstream infection (CRBSI). The objectives of this study were to review microbial epidemiology, to determine rate and risk factors for relapse, and to compare clinical outcomes in patients receiving long- versus short-duration antibiotic therapy. Methods: A retrospective phase 1 study was conducted between January 2010 and October 2016 to review microbial epidemiology and to determine the incidence of and risk factors for relapse in patients with GNB CRBSI, according to the IDSA guidelines diagnostic criteria. In phase 2 of the study, patients without risk factors for relapse between November 2016 and October 2017 were prospectively recruited to receive antibiotic therapy for 7days after catheter removal. Matched patients from the retrospective phase 1 study who had received antibiotic therapy for >= 14days were selected as a phase 2 control group to compare outcomes. Results: In phase 1, three most common pathogens identified among 174 cases were Pseudomonas aeruginosa (22.0%), Klebsiella pneumoniae (16.7%), and Stenotrophomonas maltophilia (13.4%). Eighty-nine episodes of infection occurred while patients were receiving antibiotic therapy. Of 140 cases, the relapse rate was 6.4%. Catheter retention was the only risk factor strongly associated with relapse (odds ratio=145.32; 95% confidence interval 12.66-1667.37, P