
Methods: Clinical isolates (n=300) were collected from various body sites in patients in nine mainly European countries from 2005-2015. Antimicrobial susceptibility testing was performed by broth microdilution in cation-adjusted Mueller–Hinton broth according to CLSI guidelines. The concentration ranges tested in 2-fold dilutions were: ERV, 0.015–16 mg/L; amikacin, 1–128 mg/L; imipenem, 1-128 mg/L; levofloxacin, 0.25–32 mg/L; meropenem, 0.25–32 mg/L; minocycline, 0.125-16 mg/L; doxycycline, 0.125-16 mg/L; sulbactam, 0.25-32 mg/L; tigecycline, 0.126-16 mg/L; and tobramycin, 0.25-32 mg/L. Susceptibility was determined using CLSI 2015 breakpoints. Based on rep-PCR and MLST, isolates represented 8 worldwide clonal lineages and included 232 isolates with blaOXA-23-like, 18 isolates with blaOXA-40-like, 28 isolates with blaOXA-58-like and 22 isolates with overexpression of intrinsic blaOXA-51.
Results: The ERV MIC50/90 values for all isolates were 0.5/1 mg/L. Comparatively, tigecycline, minocycline and doxycycline MIC50/90 values were 1/2, 4/8, 32/>32 mg/L, respectively. One or 19 strains had susceptibility of ≥4 mg/L to eravacycline and tigecycline, respectively, while 28 strains had a MIC of 16 mg/L.
Organism (n) |
Eravacycline |
Tigecycline |
Minocycline |
||||
MIC50/90 |
MIC range |
MIC50/90 |
MIC range |
MIC50/90 |
MIC range |
|
|
A. baumannii (300) |
0.5/1 |
0.031 - 8 |
1/2 |
0.125-8 |
4/8 |
≤0.063-16 |
|
Conclusion: ERV had the best in vitro potency, including isolates that were pan-resistant to sulbactam, imipenem/meropenem, levofloxacin, and amikacin/tobramycin, compared to other compounds. ERV may be a therapeutic option for treatment of multidrug-resistant A. baumannii
.

H. Seifert,
Tetraphase Pharmaceuticals, Inc.:
Scientific Advisor
,
Consulting fee
P. Higgins, None
J. Sutcliffe, Tetraphase Pharmaceuticals: Employee , Salary