In Vitro Activity of Delafloxacin against Contemporary Bacterial Pathogens from the United States and Europe, 2014.

M. A. Pfaller,R. K. Flamm,P. R. Rhomberg,H. S. Sader

doi:10.1128/aac.02609-16

Abstract

ABSTRACTThe in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested. Delafloxacin was the most potent agent tested against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus, Streptococcus pneumoniae, viridans group streptococci, and beta-hemolytic streptococci and had activity similar to that of ciprofloxacin and levofloxacin against certain members of the Enterobacteriaceae. Overall, the broadest coverage of the tested pathogens (Gram-positive cocci and Gram-negative bacilli) was observed with meropenem and tigecycline in both Europe and the United States. Delafloxacin was shown to be active against organisms that may be encountered in acute bacterial skin and skin structure infections, respiratory infections, and urinary tract infections.

Highlights

The in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested
The fluoroquinolone class of antibiotics is currently used as standard empirical therapy in health care-associated infections and community-acquired infections; antibiotics of this class are indicated for the treatment of urinary tract infections (UTI), respiratory tract infections (RTI), acute bacterial skin and skin structure infections (ABSSSI), and intra-abdominal infections [1,2,3,4,5,6]
In the face of such broad utilization, the emergence of fluoroquinolone resistance has been observed in both Gram-positive cocci (GPC) and Gram-negative bacilli (GNB) [1, 6, 8]

Summary

Introduction

The in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested. Resistance to fluoroquinolones is primarily caused by target mutations (e.g., mutations in chromosomal genes that encode the subunits of DNA gyrase and topoisomerase IV), efflux pumps, and reduced target expression [9] These mechanisms may occur in various combinations in resistant strains of staphylococci, Pseudomonas aeruginosa, and Enterobacteriaceae [1, 6]. Unlike other quinolones, which usually have a binding affinity for either DNA gyrase or topoisomerase IV, delafloxacin is potent against both enzymes [1, 11,12,13] This dual targeting is believed to help reduce the selection of resistant mutants in vitro and in vivo [11, 12, 14]. Cin may enhance its potency in acidic environments, characteristic of the milieu at an infection site [1, 13, 15]

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Results