In Vitro Evaluation of BL-S640 Cephalosporin Antibiotic

Abstract

BL-S640, a new oral cephalosporin analogue, was evaluated in vitro against 102 gram-negative and 80 gram-positive bacteria. The antimicrobial spectrum was similar to that of previous cephalosporin analogues. Good antimicrobial activity against strains of Escherichia coli, Klebsiella , staphylococci, and streptococci was demonstrated. Relatively poor activity and/or resistance was noted among most strains of Proteus, Providencia, Pseudomonas , and Serratia . In comparative studies BL-S640 had better activity against strains of Hemophilus influenzae, Staphylococcus aureus , and Enterobacteriaceae than many cephalosporin analogues. Variation of susceptibility results was dependent upon the type of media and inoculum size. Cross-resistance between BL-S640 cephalexin, cephalothin, and cefazolin was demonstrated. Among strains of Klebsiella the more rapid selection of resistance ot other cephalosporins was in contrast to BL-S640. Experience in vitro with BL-S640 has documented its antimicrobial activity,and further studies of pharmacokinetics and therapeutic efficacy are indicated.