Activity of JNJ-Q2, a new fluoroquinolone, tested against contemporary pathogens isolated from patients with community-acquired bacterial pneumonia.

JNJ-Q2 is a broad-spectrum fluoroquinolone with bactericidal activity against Gram-positive and Gram-negative pathogens and is currently in clinical development for the treatment of community-acquired bacterial pneumonia (CABP) and acute bacterial skin and skin-structure infections. This study determined the activity of JNJ-Q2 against a worldwide year 2010 collection (89 centres in 27 countries) of three common respiratory pathogens (3757 isolates) from patients with CABP. Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were tested by the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method, and susceptibility rates for comparators were assessed using CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoint criteria. JNJ-Q2 had activity against all three species, with 96.9% of strains inhibited at ≤0.015 mg/L. JNJ-Q2 [minimum inhibitory concentration for 50% and 90% of the organisms, respectively (MIC(50/90))=0.008/0.015 mg/L] demonstrated a 16-fold greater potency compared with moxifloxacin (MIC(50/90)=0.12/0.25 mg/L) and at least 128-fold greater activity compared with levofloxacin (MIC(50/90)=1/ 1 mg/L) and ciprofloxacin (MIC(50/90)=1/2 mg/L) against S. pneumoniae. Haemophilus influenzae isolates were 21.9-23.3% resistant to ampicillin, but JNJ-Q2 (MIC(50/90)≤0.004/0.015 mg/L) was at least two-fold more active than moxifloxacin (MIC(50/90)=0.015/0.03 mg/L) as well as being potent against M. catarrhalis (MIC(90)=0.015/0.015 mg/L). In conclusion, JNJ-Q2 demonstrated increased potency compared with other marketed fluoroquinolones that have been used to treat CABP pathogens, thus favouring further clinical development.