INVITRO ANTI-BACTERIAL ACTIVITY OF A NEW 1-OXA CEPHALOSPORIN COMPOUND

  • 1 January 1980
    • journal article
    • research article
    • Vol. 53  (2) , 149-159
Abstract
The in vitro activity of a unique new 1-oxa cephalosporin .beta.-lactam antibiotic (LY 127935) was tested against clinical isolates of gram-positive and gram-negative bacteria and compared with the activities of cefoxitin, cefamandole, cephalothin, clindamycin, amikacin, tobramycin, gentamicin, ticarcillin and carbenicillin. The new compound was observed to have a broad spectrum of antibacterial activity which far exceeded the activity of older cephalosporins against aerobic gram-negative enteric bacilli. This new compound was the most active drug tested against Klebsiella, Serratia, Enterobacter, indole-negative and positive Proteus spp. and Escherichia coli. Against clinical isolates of Pseudomonas spp. the new compound was more active than cefoxitin, cefamandole, cephalothin and clindamycin, comparable to ticarcillin and carbenicillin, and less active than gentamicin, tobramycin and amikacin. Yet, most of the Pseudomonas isolates were inhibited by 16 .mu.g/ml of the new compound. Against both .beta.-lactamase and non-.beta.-lactamase producing Staphylococcus aureus isolates, the new 1-oxa compound was less active than the older cephalosporins, of which cephalothin and cefamandole were the most effective. The 1-oxa compound had no appreciable activity against isolates of Streptococcus faecalis. Activity of all 4 cephalosporins studied was decreased in the presence of an increased inoculum of Enterobacteriaceae in trypticase soy and Mueller-Hinton broth. The activity of the new compound against Pseudomonas spp. was also decreased by an increased inoculum in Mueller-Hinton but not in trypticase soy broth. This new 1-oxa compound may have great promise as a broad spectrum antibiotic and may warrant controlled clinical trials in man.