Evaluation of the in vitro activity of cefprozil relative of other oral antimicrobial agents against bacteria in clinical specimens from patients in Säo Paulo with respiratory tract infections

RESUMO

Cefprozil is a new oral second generation cephalosporin. Its in vitro antimicrobial activity was evaluated against 371 recent clinical isolates from patients with respiratory infections. We tested the susceptibility of 244 streptococci (96 Streptococcus pneumoniae, 105 group viridans streptococci, 32 Streptococcus agulactiae, and 11 group A ß-hemolitic streptococci) 107 Haemophilus influenfae, and 20 oxacilin-susceptible S.aureus (OSSA). The isolates were susceptibility tested cefprozil, cefactor and amoxicillin/clavulanic acid by the E-test method; and against cefadroxil, cefuroxime, cefetamet, erythromycin, and azythromycin by disk diffusion. The methods and the susceptibility categorization followed the National Committee for Clinical Laboratory Standards (NCCLS) procedures. Amoxicillin/clavulanic acid was slightly more active against H.influenzae (MIcs900.5µg/mL) than cefprozil or cefaclor(MICs90 4 and 2µg/mL respectively). Cefprozil demonstrated potent activity against streptococci. Against S. pneumoniae, cefprozil was 2-4 fold more active than cefaclor (MICs90 0.125 and 0.38µg/mL, respectively). S.pneumoniae susceptibility was 84 percent to penicillin, 95 percent to erythromycin and 97 percent to azithromycin by disk diffusion. Viridans streptococci showed higher MICs for cefprozil and cefaclor (MICs90 4 and 2µg/mL respectively). Cefprozil demonstrated potent activity against streptococci. Against S.pneumoniae, cefprozil was 2-4 fold more active than cefaclor (MICs90 0.125 and 0.38 µg/mL, respectively). S.pneumoniae susceptibility was 84 percent to penicillin, 95 percent to erythromycin and 97 percent to azithromycin by disk diffusion. Viridans streptococci showed higher MICs for cefprozil and cefaclor (MICs90 4µg/mL and 8µg/mL, respectively) and only 50 percent susceptibility to the macrolides. Cefprozil was 4-fold more active than cefaclor and as active as amoxicillin /clavulanic acid against group A ß-hemolytic streptococci and S.agalactiae. These three comounds showed similar activity against OSSA. In conclusion, cefprozil demonstrated excellent in vitro activity against bacterial species responsible for respiratory infections in Säo Paulo.