[Microbiological evaluation of cefoxitin, a new beta-lactamase resistant cephamycin antibiotic, compared to cephalothin, cephaloridine and cefazolin].

Cefoxitin (Mefoxitin), Cephaloridin, Cephalothin and Cefazolin were tested in vitro against 380 clinical isolates of Staph. aureus and Enterobacteriaceae using the tube dilution procedure. Of the gramnegative microorganisms a selection of 150 strains was examined regarding susceptibility to the antibiotic combinations cefoxitin/gentamicin and cefoxitin/sisomicin in comparison to cephalothin/gentamicin and cephalothin/sisomicin. Cefoxitin has a broad antimicrobial spectrum and a high beta-lactamase-resistance. Cefoxitin was more active than the other antibiotics tested against E. coli, Klebsiella, Serratia, Enterobacter, indole-negative and -positive Proteus species. The high effectiveness of cefoxitin against anaerobic bacteria such as Bacteroides fragilis and Clostridium perfringens is discussed. Cefoxitin has an excellent bactericidal potency. Among the combinations tested cefoxitin/sisomicin was most active and obtained synergistic effects in most species. The resistance rate of cefoxitin of 8.7% was reduced to 0.7% with cefoxitin/sisomicin.