Cefoxitin, an antibiotic developed from the cephamycin family, was examined as to its in vitro activity against clinically isolated bacteria, its serum level and urinary excretion after intramuscular or intravenous injection, tissue concentration in rats as well as its effectiveness in clinical cases. The results obtained were as follows:
1) Antibacterial activity: Cefoxitin (CFX) was found to be more active against most of E. coli, Klebsiella and Proteus vulgaris strains than cephalothin and cephaloridine. The MICs of CFX against those bacteria were lowered when the inoculum concentration was reduced to 106 cell/ml.
2) Serum level and urinary excretion in human: The drug showed a serum peak level as high as 148μg/ml 30 minutes after 1μg/ml injection, followed by a steep decline. The urinary excretion rate was about 80%.
3) Distribution into rat organs: The highest tissue concentration of CFX in rat organs after i.m. administration was found in kidneys, followed by liver, blood, lungs, muscles and spleen. This distribution pattern was similar to that of cefazolin, though CFX showed higher peak concentrations and a steeper decline than the latter. No remarkable inactivation of CFX was observed after overnight storage in the icebox mixed with rat organ homogenates.
4) Clinical trials: Six clinical cases (pneumonia, sepsis, purulent arthritis, perityphlitis, pyelonephritis and fever of unknown origin all of them having underlying diseases) were treated with CFX intravenously or by drip infusion. All of the patients responded favorably to the treatment. No side effects were observed.
