1844. Eravacycline is Active against Carbapenem-resistant Enterobacteriaceae and Acinetobacter baumannii Isolates in the FDA-CDC Antimicrobial Resistance Isolate Bank Panels
Session: Poster Abstract Session: Antibacterial Susceptibility Surveillance
Saturday, October 29, 2016
Room: Poster Hall
Background:  Eravacycline (ERV) is a novel, fully-synthetic fluorocycline antibiotic of the tetracycline class with in vitro activity against Gram-negative pathogens, including extended-spectrum β-lactamase and carbapenemase-producing Enterobacteriaceae (ENT) as well as multidrug-resistant strains of Acinetobacter baumannii.  To further characterize its activity in vitro, ERV was tested against new reference panels made available by the FDA and CDC for the testing of new antibacterial agents.   Methods:  Using Clinical Laboratory Standards Institute methodology, minimal inhibitory concentration (MIC) values for antibiotics were determined for isolates in the FDA-CDC Antimicrobial Resistance Isolate Bank (AR Bank) panels:  1) ENT Carbapenem Breakpoint  Panel (“Breakpoint”), 2) Gram Negative Carbapenemase Detection Panel (“Detection”) and 3) ENT Carbapenemase Diversity Panel (“Diversity”).  The Breakpoint panel contained 31 ENT of which 7 were meropenem-resistant, including 5 blaKPC isolates.  The Detection panel was comprised of 80 isolates total; a 52 ENT subset contained carbapenemase genes blaIMP (n=1), blaKPC (n=8), blaNDM (n=10), blaOXA (n=5), blaSME (n=2), blaVIM (n=3).  The Diversity panel contained 53 ENT with carbapenemase genes blaIMI (n=2), blaIMP (n=1), blaKPC (n=18), blaNDM (n=20), blaOXA (n=5), blaSME (n=6), and blaVIM (n=2).  There were 14 A. baumannii isolates across all panels, of which 4 isolates had blaNDM and 8 had blaOXA genes.    Results:   The ERV MIC50/90 values and ranges against the Breakpoint, Detection (ENT subset), Diversity panels and A. baumannii isolates are shown in the Table.   

FDA-CDC Panel

n

ERV MIC50 (µg/mL)

ERV MIC90 (µg/mL)

ERV Range (µg/mL)

Breakpoint

31

0.25

1

0.031-2

Detection (ENT subset)

52

0.5

2

0.031-4

Diversity

53

0.5

1

0.031-8

Acinetobacter baumannii

14

0.25

1

0.031-2

  Conclusion:   ERV maintained potency against carbapenem-resistant ENT and A. baumannii isolates in the AR Bank, including those containing carbapenemase genes prevalent in contemporary clinical isolates.  
Corey Fyfe, MS1, Gabrielle Leblanc, BS1, Joyce Sutcliffe, PhD2 and Trudy Grossman, PhD2, (1)Tetraphase Pharmaceuticals, Watertown, MA, (2)Biology, Tetraphase Pharmaceuticals, Watertown, MA

Disclosures:

C. Fyfe, Tetraphase Pharmaceuticals: Employee , Salary

G. Leblanc, Tetraphase Pharmaceuticals: Employee , Salary

J. Sutcliffe, Tetraphase Pharmaceuticals: Employee , Salary

T. Grossman, Tetraphase Pharmaceuticals: Employee , Salary

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