Comparative in vitro activities of amoxicillin-clavulanate against aerobicand anaerobic bacteria isolated from antral puncture specimens from patients with sinusitis

By an agar dilution method, the antimicrobial susceptibilities of antral si nus puncture isolates were studied. Pneumococci were generally susceptible to amoxicillin, azithromycin, and clarithromycin, but 17% of pneumococcal i solates were resistant to cefuroxime. Haemophilus influenzae isolates were resistant to amoxicillin and clarithromycin. beta-Lactamase production occu rred in 69% of Prevotella species. One-third of Peptostreptococcus magnus i solates were resistant to azithromycin and clarithromycin. Cefuroxime had l imited activity against Prevotella species and P. magnus. Levofloxacin was active against most isolates except peptostreptococci. Amoxicillin-clavulan ate was active against all isolates, with the MIC at which 90% of the isola tes were inhibited being less than or equal to 1 mu g/ml.