Methods: A total of 8,296 GP unique isolates were consecutively collected from 33 United States (USA; n=4,409) and 39 European (EUR; n=3,887) medical centers in 2015-2017 and susceptibility tested by reference broth microdilution methods.
Results: The most common organisms were SA (48.3% in USA, 44.3% in EUR), CoNS (14.3% in USA, 15.6% in EUR), and E. faecalis (EF; 11.5% in USA, 13.1% in EUR). All SA isolates were susceptible (S) to DALBA (MIC50/90, 0.03/0.03 mg/L), linezolid (LZD; MIC50/90, 1/2 mg/L), vancomycin (VAN; MIC50/90, 1/1 mg/L), and teicoplanin (TEI; MIC50/90, ≤0.5/≤0.5 mg/L); >99.9% were S to daptomycin (DAPTO; MIC50/90, 0.25/0.5 mg/L). Based on MIC50, DALBA was 8-fold more active than DAPTO and 32-fold more active than VAN against SA, and DALBA activity was not adversely affected by oxacillin (OXA) resistance (R). Among CoNS, 99.9% of isolates were inhibited at a DALBA MIC of ≤0.25 mg/L (MIC50/90, 0.03/0.06 mg/L); S to DAPTO (MIC50/90, 0.5/0.5 mg/L), LZD (MIC50/90, 0.5/1 mg/L), VAN (MIC50/90, 1/2 mg/L), and TEI (MIC50/90, 2/4 mg/L) were 99.9%, 97.6%, 100.0%, and 98.5%, respectively. Among EF, 97.7% were DALBA-S (96.4% in USA, 99.0% in EUR; MIC50/90, 0.03/0.06 mg/L), 97.5% were VAN-S (96.1% in USA, 99.0% in EUR; MIC50/90, 1/2 mg/L), and all isolates were S to ampicillin (MIC50/90, 1/1 mg/L), DAPTO (MIC50/90, 0.5/1 mg/L) and LZD (MIC50/90,1/2 mg/L). Among E. faecium isolates (n=656; 7.9% overall), 63.9% were inhibited at ≤0.25 mg/L of DALBA (33.4% in USA, 87.5% in EUR) and 61.6% were VAN-S (32.8% in USA, 84.0% in EUR). DALBA was highly active against β-hemolytic streptococci (BHS; n=686 [8.3%]; MIC50/90, 0.015/0.03 mg/L) and viridans group streptococci (VGS; n=432 [5.2%]; MIC50/90, 0.015/0.03 mg/L).
Conclusion: DALBA was very active against SA, CoNS, VAN-S enterococci, BHS, and VGS isolated from patients with bacteremia. Based on MIC50, DALBA was generally 8- to 32-fold more active than DAPTO and VAN against these organisms.
H. S. Sader,
U. Rappo, Allergan: Employee , Salary .
D. Debabov, Allergan: Employee , Salary .
M. Castanheira, Allergan: Research Contractor , Research support .
R. E. Mendes, Allergan: Research Contractor , Research support .