Bactericidal activity of moxifloxacin against multidrug-resistant Streptoccocus pneumoniae at clinically achievable serum and epithelial lining fluid concentrations compared with three other antimicrobials.
Time-kill studies compared the activities of moxifloxacin with those of levofloxacin, azithromycin and amoxicillin-clavulanate against 10 pneumococcal strains with various drug susceptibilities. Three Streptococcus pneumoniae strains were resistant to moxifloxacin: 6, 7 and 2 strains were resistant to levofloxacin, azithromycin and amoxicillin-clavulanate, respectively. Of these, 1 strain was resistant to all antimicrobial agents studied. Moxifloxacin and amoxicillin-clavulanate were bactericidal after 24h at serum Cmax levels against 9 and 8 strains, respectively, while levofloxacin and azithromycin were bactericidal against 3 and 2 strains, respectively. A higher activity was only observed for amoxicillin-clavulanate for logarithmic phase cultures at 1, 4 and 8h compared with stationary phase organisms. Amoxicillin-clavulanate and moxifloxacin were bactericidal at free serum levels (protein unbound) after 24h against 8 and 3 strains, respectively. Moxifloxacin was bactericidal at epithelial lining fluid levels against all strains at 24h, including one moxifloxacin, amoxicillin-clavulanate and azithromycin-resistant strain; lower levels of bactericidal activity was observed for levofloxacin, azithromycin and amoxicillin-clavulanate against 7, 2 and 4 strains, respectively. This demonstrated the importance of moxifloxacin tissue levels.
Cafini
Fabio
F
Departmento de Microbiología I, Facultad de Medicina, Avda Complutense s/n, 28040 Madrid, Spain.
Alou
Luis
L
Sevillano
David
D
Valero
Eva
E
Prieto
José
J
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001372:Aza Compounds / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D018432:Drug Resistance, Multiple; D024841:Fluoroquinolones; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D015242:Ofloxacin / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology*; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D064704:Levofloxacin; D017963:Azithromycin; D015242:Ofloxacin; D000077266:Moxifloxacin