Garenoxacin activity and potency against S. pneumoniae and H. influenzae respiratory tract isolates (20042005): report from a Worldwide Surveillance Network
Abstract number: p1573
Jones R., Strabala P., Fritsche T., Sader H.
To evaluate the comparative activity of garenoxacin (GRN), a novel des-F(6) quinolone, tested by reference methods against recent community-acquired respiratory tract (CARTI) and CA pneumonia (CAP) isolates. S. pneumoniae (SPN) and H. influenzae (HI) strains from Latin America (10 sites), USA (23), Europe (20), and the Far East (11) were sampled in 20042005.
Consecutive, non-duplicate cultures of SPN (3,042) and HI (965) were tested by CLSI reference broth microdilution methods with concurrent QC and interpretative criteria (M7-A7 and M100-S16, 2006). Comparison antimicrobials numbered >25, including: penicillin (PEN), clarithromycin (CLAR), ceftriaxone (CTRI), and 4 fluoroquinolones (FQ), ciprofloxacin (CIPRO), levofloxacin (LEVO), gatifloxacin (GATI), and moxifloxacin (MOXI). GRN susceptibility (S) was defined as MIC at <=1 mg/L for comparison purposes only. CARTI isolates came from 23 nations and CAP strains from hospitalized patients (HCAP) in 9 countries.
The following table lists key study results: (See table) GRN activity remained unchanged compared to 19992003 results (2005 ECCMID abstract 1555 and 1565) with 99.9 and 100.0% inhibition at <=1 mg/L for SPN and HI, respectively. GRN was more potent than LEVO (16-fold), GATI (8-fold) and MOXI (4-fold) against SPN, and HCAP isolates were slightly more S than CARTI strains to nearly all agents. CTRI (96.098.8% S), cefepime (92.896.4%) and amoxicillin/clavulanate (90.591.8%) were the most active beta-lactams against SPN. PEN- and macrolide (CLAR)-R was elevated (26.937.3%) in SPN and nearly 24% of HI produced a beta-lactamase (ampicillin-R). Possible QRDR mutations (CIPRO MIC, >=4 mg/L) in SPN were noted for 1.22.8% of isolates.
GRN continues to exhibit the greatest activity (4- to 16-fold) compared to FQs tested against an updated (20042005) collection of CARTI and CAP isolates of SPN and HI. As FQ resistance evolves due to QRDR mutations, GRN MIC values generally remain well below potentially R levels, minimizing further selective pressure.
|Session name:||XXIst ISTH Congress|
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