Gram-negative rod bacteremia after cardiovascular surgery: Clinical features and prognostic factors

Background/PurposeOur aim was to describe the clinical features and prognostic factors of Gram-negative rod bacteremia (GNRB) after cardiovascular surgery (CVS).MethodsThis retrospective observational study included adults with GNRB onset within 100 days after CVS at a single institution from April 2004 to May 2013. Clinical data regarding episodes of GNRB were collected from patients' medical charts. Those having polymicrobial bacteremia with a bacterium other than a GNR were excluded.ResultsAmong 2017 CVS patients, GNRB occurred in 78. Klebsiella, Pseudomonas aeruginosa, Enterobacter, and Escherichia coli were the most commonly isolated organisms. Graft replacement was the most common surgical procedure in patients with GNRB after CVS (44.9%). Prophylaxis antibiotics were ampicillin/sulbactam (76.9%), and vancomycin (12.8%). The crude 90-day mortality rate was 21.8%, and the mean Acute Physiology and Chronic Health Evaluation II score was 15.6 (range, 3-39). In 34.6% of patients, the same GNR species were isolated from other samples within 30 days of GNRB occurrence. Multivariate analysis indicated that P. aeruginosa bacteremia [odds ratio (OR), 175; confidence interval (CI), 2.40-1270; p = 0.0182], Acute Physiology and Chronic Health Evaluation II scores of ≥ 25 (OR 76.2; CI 1.04-5580; p = 0.0479), and vancomycin for prophylaxis (OR 45.4; CI 1.02-202; p = 0.0488) were significant independent prognostic factors associated with death due to GNRB after CVS.ConclusionGraft replacement was the most common surgical procedure in patients with GNRB after CVS. Empirical antibiotics covering Gram-negative rods including P. aeruginosa should be considered if bacteremia is suspected in unstable patients after CVS.