Multilab evaluation of delafloxacin MIC Test Strip against Gram-negative and Gram-positive organisms

Abstract

The performance of the delafloxacin MIC Test Strip (MTS) was evaluated. Three testing sites collected/tested clinical isolates, and 1 site tested challenge isolates that together total 224 S. aureus, 36 S. haemolyticus, 23 S. lugdunensis, 105 E. faecalis, 308 Enterobacteriales, and 140 P. aeruginosa. MIC testing was performed by broth microdilution (BMD) and MTS. Each site also tested 20 common isolates in triplicate on 3 days by MTS and 20 replicates of 4 QC strains by MTS and BMD. MTS results for consolidated clinical/challenge isolates were within 1 doubling dilution of the BMD MIC for 96.9% of S. aureus; 100% of S. haemolyticus, S. lugdunensis, and E. faecalis; 98.4% of Enterobacteriales; and 97.9% of P. aeruginosa. All reproducibility results were within 1 dilution of the modal MIC. All BMD and MTS results for the QC strains were within expected ranges. Overall, the delafloxacin MTS performed similar to BMD.