ANTIBACTERIAL ACTIVITY OF CEPHALEXIN

Abstract

Antibacterial spectrum of cephalexin is similar to that of cephaloglycin. They are effective to both gram negative and positive bacteria except the strains of Pseudomonas, E. freundii and some of Proteus. species. Antibacterial activity of the drug to the strains of E. coli or Staphylococci which are either moderately resistant or sensitive to penicillin G, did not show any significant changes on the media at various pH. But in the Staphylococcal strains, highly resistant to penicillin G, the decrease of pH of the assay media caused the increase in antibacterial activity of the drug. This increase was seen only when Difco agar plate was used. When inoculum size was decreased to one hundredth, the level of drug resistance in most strains decreased to about one half. Prolongation of incubation time did not affect significantly the level of resistance except cephalexin resistant strains.