21st European Congress of Clinical Microbiology and Infectious Diseases

Activity of JNJ-Q2, a new fluoroquinolone, tested against contemporary (2010) European pathogens isolated from patients with acute bacterial skin and skin-structure infections

Abstract number: P1138

Farrell D., Liverman L., Rhomberg P., Jones R.

Objectives: To determine the activity of JNJ-Q2 tested against contemporary (2010) European isolates of the most common bacterial species isolated from patients with acute bacterial skin and skin-structure infections (ABSSSI). JNJ-Q2 is a broad-spectrum bactericidal fluoroquinolone (FQ) with potent activity against Gram-positive and -negative pathogens, including methicillin-resistant (MR) Staphylococcus aureus (SA), and is in early clinical development for the treatment of ABSSSI and community-acquired bacterial pneumonia.

Methods: A total of 750 pathogens were collected from patients with ABSSSI in 25 medical centres in 12 European countries (including Turkey and Israel) in 2010. Species/organism group (number of isolates tested) were: SA (635) and b-hemolytic streptococci (BHS, 115; 33.0% S. pyogenes). Isolates were tested for susceptibility by CLSI broth microdilution methods (M07-A8 and M100-S20-U). Susceptibility interpretations for comparator agents were determined using EUCAST (2010) and CLSI breakpoints.

Results: The table shows the cumulative percentage MIC frequency against the species/groups tested. Against 635 SA, JNJ-Q2 (MIC_50/90, 0.008/0.25 mg/L) inhibited all isolates at a MIC 2 mg/L. Although activity was lower against MRSA (MIC₅₀, 0.25 mg/L) compared to methicillin-susceptible (MS) SA (MIC₅₀, 0.008 mg/L), 98.1% of MRSA were inhibited at a JNJ-Q2 MIC value of 0.5 mg/L. Against MRSA, JNJ-Q2 was four- to 16-fold more active than moxifloxacin (MOX; MIC_50/90, 4/8 mg/L) and at least 32-fold more active than levofloxacin (LEV; MIC_50/90, 8/8 mg/L) and ciprofloxacin (CIP; MIC_50/90, 8/8 mg/L). JNJ-Q2 demonstrated excellent activity (MIC_50/90, 0.008/0.015 mg/L) against BHS, inhibiting 100.0% of isolates at a MIC of 0.03 mg/L. JNJ-Q2 was 16-fold more active than MOX (MIC_50/90, 0.12/0.25 mg/L) and 64-fold more active than CIP (MIC_50/90, 0.5/1 mg/L) against BHS.

Conclusions: JNJ-Q2 demonstrated very potent activity against this collection of common bacterial pathogens isolated from patients with ABSSSI in European medical centers year 2010. JNJ-Q2 also exhibited four-fold or greater activity compared to CIP, LEV and MOX against these isolates. The JNJ-Q2 in vitro results were very promising and support further clinical development of this new FQ for treatment of ABSSSI, including cases caused by MRSA.