Imipenem/relebactam activity compared to other antimicrobials against non-MBL-producing carbapenem-resistant Enterobacteriaceae from an academic medical center.

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Imipenem/relebactam activity compared to other antimicrobials against non-MBL-producing carbapenem-resistant Enterobacteriaceae from an academic medical center.

Pathog Dis. 2019 Jul 31;:

Authors: Kulengowski B, Burgess DS

Abstract
BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) cause significant mortality and are resistant to most antimicrobial agents. Imipenem/relebactam, a novel beta-lactam/beta-lactamase inhibitor combination, and 16 other antimicrobials were evaluated against non-metallo-beta-lactamase-producing carbapenem-resistant Enterobacteriaceae clinical isolates from a United States tertiary academic medical center.
OBJECTIVES: To evaluate imipenem/relebactam and other commonly utilized antimicrobial agents against carbapenem-resistant Enterobacteriaceae.
METHODS: Clinical isolates (n = 96) resistant to ertapenem or meropenem by BD Phoenix™ and negative for metallo-beta-lactamase-production by an EDTA/phenylboronic acid disk diffusion assay were identified and collected from January 2012 to January 2017. In vitro susceptibility by broth microdilution was performed according to CLSI guidelines using CLSI susceptibility breakpoints for 17 antimicrobials.
RESULTS: CRE primarily produced KPC and consisted primarily of Klebsiella pneumoniae (55%) and Enterobacter spp. (25%), followed by Citrobacter spp. (10%), Escherichia coli (5%), and others (5%). CRE were most susceptible to imipenem/relebactam (100%), followed by amikacin (85%), tigecycline (82%), and polymyxin B/colistin (65%). The median reduction of imipenem minimum inhibitory concentrations (MICs) of non-MBL-producing CRE was 16-fold but ranged from 0.5 to > 512-fold. The MIC50, MIC90, and MIC range of imipenem/relebactam was 0.5/4 mg/L, 1/4 mg/L, and 0.06/4-1/4 mg/L, respectively.
CONCLUSIONS: Imipenem/relebactam exhibits excellent activity against CRE that produce KPC.

PMID: 31365075 [PubMed - as supplied by publisher]