| Abstrakt: |
7-[a-(1-Methyl-4-pyridiniothio)-acetamido] cephalosporanic acid, referred to herein as BL-S 217, is a new broad-spectrum semisynthetic cephalosporin that offers several advantages over cephalothin. A comparison of the activity in vitro of these antibiotics indicates that BL-S 217 is about eightfold more effective against Streptococcus pyogenesand Diplococcus pneumoniae. Against gram-negative bacteria, BL-S 217 possesses a broader antibacterial spectrum than cephalothin, particularly against members of the Enterobacteriaceaefamily; e.g., BL-S 217 inhibited over 20% more strains of both Escherichia coliand Klebsiellathan cephalothin and also showed some advantage in tests against Salmonellaand Enterobacter. Overall, of 208 strains of Enterobacteriaceaetested, 172 were susceptible to BL-S 217 compared to 149 for cephalothin. BL-S 217 was less bound to human serum proteins than cephalothin and gave higher peak blood levels in mice after intramuscular administration. The LD50of BL-S 217 in mice after subcutaneous administration was in excess of 4,000 mg/kg. When administered by the same route to mice experimentally infected with cephalothin-sensitive bacterial strains, this new cephalosporin was 20 times more effective than cephalothin in S. pyogenesand D. pneumoniaeinfections and 3 to 4 times more efficacious in an E. coliinfection. Its therapeutic efficacy was comparable to that of cephalothin in infections produced by strains of Staphylococcus aureus, Klebsiella pneumoniae, and Proteus mirabilis. |
