1934. Evaluation of a Prolonged β-Lactam Antibiotic Infusion Policy on Clinical Outcomes in Patients with Pseudomonas aeruginosa Bacteremia
Session: Poster Abstract Session: Clinical: Bacteremia and Endocarditis
Saturday, October 7, 2017
Room: Poster Hall CD
Background: Prolonged β-lactam antibiotic infusions achieve superior pharmacokinetic and pharmacodynamic goals, compared to intermittent infusions. In October 2009, our institution changed the standard infusion time for Gram negative β-lactam antibiotics from 30 minutes to 3 hours. The objective of this study was to evaluate the effect of this practice change on clinical outcomes in patients with Pseudomonas aeruginosa (PSA) bacteremia.

Methods: We collected data on all patients with PSA bacteremia treated with an intravenous β-lactam from 01/2004-12/2014, including demographics, microbiology results, treatment regimen, and clinical outcomes such as intensive care unit (ICU)/hospital length of stay and mortality. We excluded patients with polymicrobial bacteremia or β-lactam resistant PSA that required switching to an alternative antibiotic class within 24 hours of microbiology susceptibility results. We used multivariable linear and logistic regression analysis to compare clinical outcomes before and after the practice change, adjusting for potential confounders.

Results: In total, 183 patients were diagnosed with PSA bacteremia. The most common primary anti-PSA β-lactam was ceftazidime, followed by cefepime, in both the pre and post-intervention cohorts. Development of new β-lactam resistance after therapy and recurrence of bacteremia was rare in our cohort.


No. (%)

Pre-Prolonged Infusion


Post-Prolonged Infusion


P value

Patient Characteristics

Female gender

43 (51.2)

37 (37.4)


Age – years*

62.5 (48.9 – 72.3)

67.8 (56.6 – 77.4)


Pitt Bacteremia Score*

2 (1-4)

1 (0-2.5)


ICU Admission

50 (59.5)

35 (35.4)


Ceftazidime as primary β-lactam

63 (75.0)

52 (52.5)


Clinical Outcomes#

Hospital length of stay, days*

14 (8.8 – 29.3)

12 ( 5 – 21)


ICU length of stay, days*

6 (3-32)

3 ( 2-8.5)


30-day mortality

20 (23.8)

16 (16.2)


30-day readmission

24 (28.6)

24 (24.2)


*Data presented as median (IQR)

#Adjusted for age, Pitt bacteremia score, ICU admission, mechanical ventilation

Conclusion: Prolonged β-lactam infusion over 3 hours was associated with decreased ICU length of stay, with a trend towards decreased hospital length of stay compared to intermittent infusions in patients with PSA bacteremia.

Megan E. Barra, PharmD, BCPS1, Jillian Dempsey, PharmD, BCPS1, Eleanor Broadbent, BS1, Nour Ismail, MD2, Obadah Aloum, MBBS2, Paul Szumita, PharmD, BCPS, BCCCP, FCCM, FASHP1, Sophia Koo, MD, FIDSA2 and David W. Kubiak, PharmD, BCPS {AQ ID}2, (1)Department of Pharmacy, Brigham and Women's Hospital, Boston, MA, (2)Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA


M. E. Barra, None

J. Dempsey, None

E. Broadbent, None

N. Ismail, None

O. Aloum, None

P. Szumita, None

S. Koo, None

D. W. Kubiak, Shionogi: Consultant , Consulting fee
Astellas Pharma: Consultant , Consulting fee

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