This article is written live from ID Week 2017 Annual Meeting in San Diego, CA. MPR will be reporting news on the latest findings from leading experts in infectious diseases. Check back for more news from IDWeek 2017.

SAN DIEGO— The investigational anionic fluoroquinolone delafloxacin (DLX) exhibits broad-spectrum in vitro activity against Gram-positive (GP) and -negative (GN) bacteria commonly found in community-acquired pneumonia and acute bacterial skin and skin structure infections (ABSSSI), according to findings presented at IDWeek 2017.

“DLX was active against a broad range of GP and GN bacteria, including MRSA and multidrug-resistant SPN [S. pneumoniae],” reported lead study author Robert K. Flamm, PhD, JMI Laboratories, North Liberty, IA. “DLX merits further study as therapy in infections in which these organisms may occur.”

“Overall, delafloxacin was more potent in vitro against S. aureus and CoNS [coagulase-negative staphylococci], including methicillin-resistant strains, and against S. pneumoniae and β-hemolytic streptococci than levofloxacin and moxifloxacin,” he explained.

A total of 36,683 GP and GN isolated during 2014–2016 were obtained from the U.S. and Europe for the study.

DLX was “very active” against S. aureus, with a total of 88.9% of isolates inhibited at ≤0.25μg/mL; 6.4% of isolates were DLX-resistant. “Delafloxacin was the most potent antimicrobial when tested against methicillin-susceptible S. aureus (MSSA),” added Dr. Flamm. Based on MIC90, DLX was 16 times more potent against MSSA than ceftaroline and 32 times more potent than levofloxacin, he noted. Against MRSA isolates, DLX was 32 times more potent (MIC50 criteria) and more than 4 times more potent (MIC90) than levofloxacin.

“The greatest coverage of all S. aureus (MSSA and MRSA) was provided by vancomycin (100% susceptible) and daptomycin, linezolid, and tigecycline, which all exhibited >99.9% susceptibility,” Dr. Flamm reported. DLX was the most active agent tested against S. pneumoniae

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Flamm R, Shortridge D, Huband M, McCurdy S, Pfaller M. Activity of Delafloxacin When Tested against Bacterial Surveillance Isolates Collected in the US and Europe During 2014-2016 as Part of a Global Surveillance Program. Poster presented at IDWeek; October 4–8, 2017; San Diego, CA.