1052. Impact of Empiric Carbapenem Beta-Lactam (CBL) versus Non-Carbapenem Beta-Lactam (N-CBL) Treatment on Mortality and Microbiological Response Rates for Third-Generation Cephalosporin-Resistant (3GCR) Enterobacteriaceae Bloodstream Infections (BSI)
Session: Poster Abstract Session: Clinical Infectious Diseases: Bacteremia and Endocarditis
Friday, October 28, 2016
Room: Poster Hall
Background: Carbapenem β-lactams (CBLs) have been the class of choice for third generation cephalosporin-resistant (3GCR) Enterobacteriaceae infections, but emergence of carbapenemase-producing bacteria highlight the need to limit their use to prevent resistance. Current literature shows mixed evidence regarding the effectiveness of carbapenem-sparing β-lactam regimens. This study aimed to compare 30-day mortality and microbiological response for patients with 3GCR bloodstream infections (BSI) when treated empirically with CBLs or non-carbapenem β-lactams (N-CBLs; cefepime [FEP] or piperacillin/tazobactam [TZP]).

Methods: This retrospective study included patients with 3GCR Enterobacteriaceae BSI from 1/2009-9/2015 at two Boston teaching hospitals. Patients were included if 1) they had ≥1 blood culture positive for Escherichia coli, Enterobacter spp., and/or Klebsiella spp., 2) their culture was resistant to 3GC and susceptible to both CBLs and N-CBLs (either FEP or TZP), and 3) they received ≥ 48 hours of CBL or N-CBL therapy within 72 hours of the index culture. Patients with polymicrobial BSI or a BSI within the previous 30 days were excluded. The primary outcome was 30-day all-cause hospital mortality. Secondary outcomes included microbiological response, duration of BSI, and BSI length of stay (LOS; index date to discharge).

Results: Of 125 included patients, 90 received CBL and 35 received N-CBL (15 FEP; 20 TZP). Baseline characteristics of the groups were similar; median patient age and APACHE II scores were 66.2 years and 14.6, respectively. After 48 hours of treatment, a switch in therapy from empiric N-CBL to CBL was common (54.3%). There was no difference in 30-day mortality between CBL and N-CBL (8.9% vs. 14.3%; p =0.51) groups, respectively. Microbiological response rates were similar between groups (approx. 94% eradication) as well as duration of BSI (approx. 2 ± 1 days) and BSI LOS (11 ± 16 days [CBL] vs. 12 ± 22 [N-CBL]; p = 0.79).

Conclusion: No differences in 30-day mortality nor microbiological response were revealed among this cohort of 125 patients with 3GCR BSI treated empirically with CBL or N-CBL (FEP or TZP). While larger studies should be conducted to validate findings, N-CBLs may be an effective CBL-sparing strategy.

Melissa Kirejczyk, BS1,2, Srijana Jonchhe, PharmD3, Stephanie E. Giancola, PharmD1, Michael Hogan, PharmD1, Sunwoo Ahn, PharmD1, Monica V. Mahoney, PharmD, BCPS-AQ ID3, Graham M. Snyder, MD, SM3, Kirthana R. Beaulac, PharmD2 and Elizabeth B. Hirsch, PharmD, BCPS1,3, (1)Northeastern Univ., Boston, MA, (2)Tufts Med. Ctr., Boston, MA, (3)Beth Israel Deaconess Med. Ctr., Boston, MA


M. Kirejczyk, None

S. Jonchhe, None

S. E. Giancola, None

M. Hogan, None

S. Ahn, None

M. V. Mahoney, Forest Pharmaceuticals/Actavis: Grant Investigator , Research grant
Cubist Pharmaceuticals: Consultant , Consulting fee

G. M. Snyder, None

K. R. Beaulac, Actavis: Speaker's Bureau , Speaker honorarium

E. B. Hirsch, Durata Therapueitcs/Actavis: Grant Investigator , Research grant
Theravance Biopharma: Consultant , Consulting fee
The Medicines Company: Speaker's Bureau , Speaker honorarium

Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.