Antimicrobial therapy of gram-negative bacteremia at two university-affiliated medical centers

Purpose To describe antimicrobial prescribing practices and patient outcomes associated with the treatment of aerobic gram-negative rod bacteremia at two university-affiliated medical centers. Subjects and methods All adult patients with gram-negative bacteremia (N = 326) who were at Stanford and University of California, San Francisco (UCSF) Hospitals from September 1, 1996 through August 31, 1997 were evaluated via retrospective review of medical records. Results Most patient characteristics were similar between institutions; however, patients at Stanford were more likely to have had a diagnosis of bone marrow transplantation, liver failure, or poor nutritional status, while more patients at UCSF had solid organ transplant, diabetes, pulmonary disease, or hypotension. The bacteriology was similar at both sites, with Escherichia coli the predominant pathogen (139 [43%] of 326). The majority of episodes were community acquired (67% [218/326]). Patients at Stanford were more likely to have been treated empirically with aminoglycosides (28% vs. 7%, P<0.001) and noncephalosporin β-lactams (31% vs. 11%, P<0.001), while patients at UCSF were more likely to have received cephalosporins (62% vs. 29%, P<0.001) and fluoroquinolones (21% vs. 11%, P = 0.02). These patterns continued for definitive therapy. Overall mortality was 60 (19%) of 326. Several risk factors were associated with 14-day mortality, including severity of illness, neutropenia, diabetes mellitus, use of vasopressors, and empiric use of a noncephalosporin β-lactam. Conclusion Prescribing practices for the treatment of gram-negative bacteremia differed significantly in the two institutions despite similar patients and pathogens.