1044. Aztreonam (AZT) versus cephalosporin (CEP) therapy for the treatment of gram-negative bacteremia
Session: Poster Abstract Session: Bacteremia and Endocarditis
Friday, October 5, 2018
Room: S Poster Hall
Background: The IDSA recommends use of AZT in patients with a confirmed beta-lactam allergy for nosocomial gram-negative infections. Despite this recommendation, there is limited data to suggest AZT is inferior to cephalosporins (CEP) for the treatment of gram-negative infections. This study aims to evaluate clinical outcomes in bacteremic patients treated with either AZT or CEP therapy.

Methods: A single-center, retrospective chart review of adult patients with positive blood cultures for Escherichia coli, Klebsiella pneumoniae or Pseudomonas aeruginosa was conducted to compare clinical outcomes between those who received ≥ 48 hours of AZT or CEP therapy (cefepime or ceftriaxone). The following clinical outcomes were assessed: clinical cure, in-hospital mortality, post-infection length of stay (LOS), post-infection intensive care unit LOS, microbiologic cure and leukocytosis resolution.

Results: One-hundred and twenty-nine patients met criteria for evaluation: 41 received AZT and 88 received CEP therapy. At baseline, patients who received AZT were more likely to have renal dysfunction (34.1% vs. 18.2%, p= 0.046), receive synergistic antimicrobials (61% vs. 28.4%, p < 0.001) and had a longer pre-infection LOS (1 day [0-2] vs. 0 [0-1], p=0.032) compared to those who received CEP. Although in-hospital mortality rates were similar between both groups (2.4% vs. 3.4%, p=1.000), there was a statistically significant difference in clinical cure rates (70.7% vs. 90.9%, p=0.003), post-infection length of stay (7 days [5-10] vs. 5 [4-8], p=0.007), and time to clinical cure (2.8 days (1.6-5.8) vs. 2.0 (1.2-2.9), p=0.018) in the AZT and CEP groups respectively. In a multivariate logistic regression model, patients who received AZT were significantly less likely to achieve clinical cure (OR=0.187, 95% CI (0.058-0.597). In a pre-determined subgroup analysis, clinical cure rates varied in E. coli (72% vs. 94.4%, p=0.009), K. pneumoniae (70% vs. 90.5%, p=0.296) and P. aeruginosa (66.7% vs. 76.9%, p=1.000) in the AZT and CEP group respectively.

Conclusion: Patients who receive aztreonam for gram-negative bacteremia may be more likely to experience clinical failure. Larger, prospective studies are warranted to confirm these findings.

Sunish Shah, PharmD, Hahnemann University Hospital, Philadelphia, PA, Kyle Krevolin, MT, Hahnemann Univ. Hosp., Philadelphia, PA and Tiffany Bias, PharmD, BCPS, AAHIVP, Nabriva Therapeutics US, King of Prussia, PA


S. Shah, None

K. Krevolin, None

T. Bias, None

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