JAC Advance Access originally published online on October 14, 2009
Journal of Antimicrobial Chemotherapy 2009 64(6):1226-1229; doi:10.1093/jac/dkp370
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Original research |
In vitro activity of nemonoxacin (TG-873870), a novel non-fluorinated quinolone, against clinical isolates of Staphylococcus aureus, enterococci and Streptococcus pneumoniae with various resistance phenotypes in Taiwan
1 Department of Internal Medicine, Chung-Ho Memorial Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan 2 Department of Internal Medicine, Far Eastern Memorial Hospital, Taipei County, Taiwan 3 Division of Clinical Pathology, Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan 4 TaiGen Biotechnology Co. Ltd, Taipei, Taiwan 5 Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan 6 Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
Received 8 August 2009; returned 27 August 2009; revised 20 September 2009; accepted 22 September 2009
* Corresponding author. Tel: +886-2-23123456, ext. 65355; Fax: +886-2-23224263; E-mail: hsporen{at}ntu.edu.tw
Objectives: The aim of this study was to assess the in vitro activities of nemonoxacin against Gram-positive cocci with various resistance phenotypes.
Methods: MICs of nemonoxacin were determined for 798 recently collected (2005–07) and non-duplicate isolates of Gram-positive cocci by the agar dilution method. These isolates included: methicillin-susceptible Staphylococcus aureus (MSSA; n = 100); methicillin-resistant S. aureus (MRSA), including ciprofloxacin-susceptible (n = 50), ciprofloxacin-resistant (n = 100), vancomycin-intermediate (n = 50) and daptomycin-non-susceptible (DNS-MRSA; n = 5) isolates, and community-acquired MRSA (CA-MRSA; n = 101); invasive Streptococcus pneumoniae isolates (n = 150); levofloxacin-non-susceptible (MICs of 4–64 mg/L) S. pneumoniae isolates (n = 30); and enterococci (n = 212), including vancomycin-resistant enterococci (VRE; n = 112).
Results: Nemonoxacin had potent activity against MSSA (MIC90 of 
0.03 mg/L), ciprofloxacin-susceptible MRSA (MIC90 of 0.03 mg/L) and CA-MRSA (MIC90 of 0.06 mg/L). For all invasive S. pneumoniae isolates, the activity of nemonoxacin (MIC90 of 0.06 mg/L) was similar to that of gemifloxacin and much better than that of levofloxacin (MIC90 of 2 mg/L) and moxifloxacin (MIC90 of 0.25 mg/L). Nemonoxacin had a 32- to 64-fold higher activity than levofloxacin against levofloxacin-non-susceptible isolates. Nemonoxacin exerted limited activity against ciprofloxacin-resistant MRSA (MIC90 of 1 mg/L), vancomycin-intermediate MRSA (MIC90 of 2 mg/L), DNS-MRSA (MIC90 of 1 mg/L), vancomycin-susceptible enterococci (MIC90 of 2 mg/L for Enterococcus faecalis and 4 mg/L for Enterococcus faecium) and VRE (MIC90 of 4 mg/L for E. faecalis and 16 mg/L for E. faecium).
Conclusions: Our findings point to a potentially useful role for nemonoxacin in the treatment of infections caused by MSSA, ciprofloxacin-susceptible MRSA and S. pneumoniae with various resistance phenotypes.
Keywords: gemifloxacin , levofloxacin , moxifloxacin , vancomycin-intermediate , daptomycin-non-susceptible