Study of oral garenoxacin against respiratory tract infection and otrhinolaryngological infection caused by multidrug-resistant S. pneumoniae

Abstract number: 1733_1514

Kohno S., Kobayashi H., Baba S., Fujimaki K.

Objectives: Respiratory tract infections caused by multi-drug resistant S. pneumoniae (MDRSP) are increasing in frequency worldwide. The objective of this analysis was to evaluate the clinical response of garenoxacin (GRN) treatment against S. pneumoniae infection (including MDRSP) to examine GRN susceptibility against S. pneumoniae isolates, and to analyse the correlation between resistance and gene mutation in isolates of S. pneumoniae.

Methods: Eight studies conducted in Japan assessed the clinical and biological efficacy of GRN in subjects with respiratory tract and otorhinolaryngological infection caused by S. pneumoniae. Treatment consisted of oral GRN 400 mg QD for 7 to 10 days. The minimum inhibitory concentration (MIC) of GRN against 106 isolates of S. pneumoniae (27 PRSP, 28 PISP and 51 PSSP, including 3 quinolone-resistant, 47 cephalosporin-resistant, 84 macrolide-resistant, 85 tetracycline-resistant, 10 trimethoprim-resistant and 83 multi-drug resistant) was measured using the CLSI method. GRN was compared with levofloxacin (LVFX), gatifloxacin (GFLX), moxifloxacin (MFLX), cefroxime (CXM), erythromycin (EM), azithromycin (AZM), telithromycin (TEL), tetracycline (TC) and trimethoprim/sulfametozalole (TMP/SMX). In addition, the mutation of the penicillin-binding protein genes and macrolide-resistant genes of S. pneumoniae isolates was investigated using electrophoresis analysis.

Results: The clinical efficacy rate of GRN against S. pneumoniae in 106 subjects was 96.2%; the bacterial eradication rate was 100%. MIC₉₀ values of the 106 isolates were GRN 0.125, LVFX 2, GFLX 0.5, MFLX 0.25, CXM 8, EM >128, AZM >128, TEL 0.25, TC 64 and TMP/SMX 2 mg/mL. In the PRSP/PISP, pbp1a + pbp2x + pbp2b mutations for PBP and ermB presence for the macrolide-resistant gene were observed most frequently. There appeared to be a correlation between drug-resistance and gene mutation.

Conclusions: GRN showed high efficacy and eradication rates in the treatment of respiratory tract infection caused by S. pneumoniae including MDRSP.