%0 Journal Article %A Ross, G. W. %A Davies, M. Jean %A Kirby, Susan M. %A Ryan, D. M. %T Degradation Of Selected Cephalosporins By Homogenates Of The Alimentary Tract Of Rats %D 1970 %J Journal of Medical Microbiology, %V 3 %N 3 %P 511-519 %@ 1473-5644 %R https://doi.org/10.1099/00222615-3-3-511 %I Microbiology Society, %X SUMMARY In-vitro tests with homogenates of rat intestine showed that cephaloridine, cephalexin and 7-(thienyl-2′-acetamido)-3-methylceph-3-em-4-carboxylic acid were degraded more quickly in the caecum and rectum than in other parts of the alimentary tract; even after 4 hr at 37°C at least 57 per cent. of the low dose of cephalosporin used remained intact in other portions of intestine. The extent of breakdown in the caecum varied with the structure of the cephalosporin. Cephalexin was more stable than cephaloridine to biological degradation. Different parts of rat intestine were assayed for β-lactamase and acylase activity and the effect of proteolytic enzymes on the cephalosporins was studied. The only degrading activity found was due to β-lactamase-producing bacteria in the caecum. %U https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-3-3-511