Methods: A total of 4,122 GP isolates were collected in 2016 from 30 USA medical centers and included 2,366 staphylococci, 1,252 streptococci and 504 enterococci. A single isolate/patient/infection episode was included. Identifications were confirmed by matrix-assisted laser desorption/ionization mass spectrometry and susceptibility (S) testing was performed using reference broth microdilution methods.
Results: OMC was equally active against methicillin-susceptible (55.1% MSSA) and -resistant (44.9% MRSA) Staphylococcus aureus (SA; MIC50/90, 0.12/0.25 µg/mL). All SA were S to daptomycin (DAP), linezolid (LZD) and vancomycin (VAN). In MRSA, S was lower for levofloxacin (LEV; 28.2%), clindamycin (CLI; 69.9%), and erythromycin (ERY; 10.9%). OMC (MIC50/90, 0.12/0.5 µg/mL) and tigecycline (TGC; MIC50/90, 0.06/12 µg/mL) were the most active agents against coagulase-negative staphylococci (CoNS) and methicillin-R CoNS. S. pneumoniae (including penicillin- [12.8% resistant], ceftriaxone- and ERY-resistant strains), viridans group streptococci (VGS) and β-hemolytic streptococci (including ERY and tetracycline resistant strains) were inhibited by low levels of OMC (MIC50/90 0.06/0.06-0.12 µg/mL) and TGC (MIC50/90 0.03-0.06/0.06-0.12 µg/mL). OMC was highly potent against enterococci (MIC50/90 0.12/0.25 µg/mL) including vancomycin-R isolates. Vancomycin resistance rates were 4.3% and 66.5% in E. faecalis and E. faecium, respectively.
Conclusion: OMC demonstrated potent activity against susceptible and resistant GP pathogens often associated with ABSSSI and CABP including staphylococci, S. pneumoniae, β-hemolytic streptococci, VGS and enterococci. These data support further omadacycline clinical studies, especially in infections where resistant GP isolates occur.
M. D. Huband,
Paratek Pharma, LLC:
H. S. Sader, Paratek Pharma, LLC: Research Contractor , Research grant
R. K. Flamm, Paratek Pharma, LLC: Research Contractor , Research grant
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