[In vitro comparative activity of moxifloxacin and other antimicrobials against respiratory pathogens].
BACKGROUND
Respiratory pathogens are becoming increasingly resistant to antimicrobials. A new group of drugs, called respiratory quinolones have been synthesized to overcome this problem.


OBJECTIVE
To study the in vitro susceptibility of respiratory pathogens to old and new antimicrobials.


METHODS
Forty five strains of S pneumoniae, 44 strains of H influenzae, 21 strains of M catarrhalis, 10 strains of methicillin susceptible S aureus and 20 strains of methicillin resistant S aureus were studied. All were isolated from community acquired respiratory infections during 1999. Minimal inhibitory concentrations of moxifloxacin, amoxicillin, amoxicillin/clavulanic acid, clarithromycin, azithromycin, ciprofloxacin and levofloxacin were determined using the Etest method. Beta-lactamase production by H influenzae and M catarrhalis was also studied.


RESULTS
S pneumoniae strains were 100% susceptible to quinolones and cotrimoxazole, 2% were resistant to macrolides, 11% were resistant to amoxicillin/clavulanic acid and 47% were resistant to cefuroxime. H influenzae was 100% susceptible to quinolones, azithromycin and amoxicillin/clavulanic acid. There was a 53% resistance to cotrimoxazole, 21% to amoxicillin, 9% to clarithromycin and 7% to cefuroxime. M catarrahalis was 100% susceptible to quinolones and 100% resistant to amoxicillin, 5% resistant to macrolides, 14% resistant to amoxicillin/clavulanic acid, 20% to cefuroxime and 30% to cotrimoxazole. Methicillin susceptible S aureus was susceptible to all antimicrobials and methicillin resistant S aureus was resistant to all.


CONCLUSIONS
Maxifloxacin and the new respiratory quinolones can be useful in the treatment of respiratory infections.
Unidad de Microbiología, Oriente, Programa de Microbiología y Micrología, ICBM, Facultad de Medicina, Universidad de Chile. vprado@machi.med.uchile.cl
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D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D005260:Female; D024841:Fluoroquinolones; D006193:Haemophilus influenzae / Q000187:drug effects*; D006801:Humans; D007769:Lactams; D018942:Macrolides; D008297:Male; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects*; D012141:Respiratory Tract Infections / Q000188:drug therapy / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects*; D013296:Streptococcus pneumoniae / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D007769:Lactams; D018942:Macrolides