合成セファロスポリンCefazolinの細菌学的評価

抄録

Cefazolin is a new synthetic cephalosporin derivative developed at Central Research Laboratories of Fujisawa Pharmaceutical Co. in 1969.
Presented in this report are the results of our study where this new antibiotic was compared with two known antibiotics of the cephalosporin family, Cephalothin and Cephaloridine, as to in vitro antimicrobial activity including antimicrobial spectrum, sensitivity of clinically isolated strains of Staphylococci, E. coli, etc., the effect of culture pH on the antimicrobial activity, stability against beta-lactamase, bactericidal activity, and development of resistance and in vivo therapeutical effect in experimentally induced infections in mice with Staphylococcus aureus, Diplococcus pneumoniae, E. coli and Klebsiella pneumoniae.
Results :
1. Cefazolin is virtually the same antimicrobial spectrum as that of Cephalothin and Cephaloridine. In the antimicrobial activity, Cephaloridine was found superior to the other two, these latter two being virtually equal, when tested with Gram-positive organisms, while the three were comparable to each other when tested with Gram-negative ones.
2. Clinically isolated staphylococcal strains were sensitive in the range of 6.25-0.05mcg/ml to Cephaloridine, in the range of 6.25-0.2mcg/ml to Cefazolin, and in the range of 0.78-4.2 mcg/ml to Cephalothin. Clinically isolated E. coli strains, on the other hand, were sensitive in the range of 50-3.12mcg/ml to Cephaloridine, in the range of 25-0.78mcg/ml to Cefazolin, and in the range of 100-0.78mcg/ml to Cephalothin.
3. The antimicrobial activity tended to increase when the pH of culture increased in relative acidity.
4. As was the case with Cephalothin and Cephaloridine, Cefazolin was found stable against betalactamase produced by Staphylococci.
5. In therapeutical effect on infections in mice induced by Gram-positive organisms such as Staphylococci and Diplococcus pneumoniae, Cephaloridine was found best, followed by Cefazolin, then by Cephalothin. The same order of effectiveness resulted when cephalosporins were tested on the infections induced by Gram-negative organisms including E. coli and Klebsiella pneumoniae.