598. Activity of JNJ-Q2 and Comparators against Genetically Defined MRSA Clones
Session: Poster Abstract Session: Novel Antimicrobial Agents
Friday, October 21, 2011
Room: Poster Hall B1

Background: JNJ-Q2 is a broad-spectrum bactericidal fluoroquinolone (FQ) with potent activity against Gram-positive pathogens including methicillin-resistant (MR) S. aureus (SA), Gram-negative pathogens, atypical respiratory pathogens, and anaerobic pathogens and is in clinical development for the treatment of acute bacterial skin and skin structure infection (ABSSSI) and community-acquired bacterial pneumonia. In this study, the in vitro activity of JNJ-Q2 and other FQ agents was evaluated against a panel of genetically defined strains representative of global MRSA clones.

Methods: A collection of 111 genetically defined SA strains (predominantly MRSA [103/111, 92.8%]) representative of the major circulating global clones were evaluated. Along with the groups specified in the table (below), USA PFGE types 100 to 1100 (not 900), SCCmec types I to IV (and IV-a), agr types I to IV, and PVL-positive strains were all represented. Isolates were tested against JNJ-Q2, moxifloxacin (MOX), levofloxacin (LEV), and other comparator agents per the CLSI broth microdilution method (M07-A8; M100-S21).

Results: Overall, JNJ-Q2 inhibited all 111 major circulating S. aureus clones at ≤1 g/ml. MOX and LEV demonstrated high levels of resistance (R) to these strains (69.4 and 74.8%, respectively). JNJ-Q2 inhibited all ten VRSA strains at a MIC of ≤1 g/ml and all ten were R to MOX and LEV. JNJ-Q2 was also very active against strains R to comparator agents (n strains): daptomycin (7), linezolid (5), tetracycline (32), trimethoprim-sulfamethoxazole (13), erythromycin (86) and clindamycin (41).

Conclusion: JNJ-Q2 retained activity against these sub-sets of challenging strains regardless of antimicrobial resistance phenotype, ST or PFGE clonal types, PVL positivity, and agr or SCCmec type. These JNJ-Q2 in vitro results against major global MRSA clones are very promising and support further clinical development of this new FQ for treatment of ABSSSI.

Subject Category: A. Antimicrobial agents and Resistance

David J. Farrell, Ph.D.1, Lisa C. Liverman2, Rodrigo E. Mendes, Ph.D.1, Douglas Biedenbach, BS, MT1 and Ronald Jones, MD1, (1)Microbiology, JMI Laboratories, North Liberty, IA, (2)Furiex, Wilmington, NC


D. J. Farrell, None

L. C. Liverman, None

R. E. Mendes, None

D. Biedenbach, None

R. Jones, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.