PATHOGENESIS OF ANTIBIOTIC-INDUCED DIARRHEA NOT DUE TO CLOSTRIDIUM DIFFICILE (CD)

We wished to identify, in the in vitro rabbit intestine, the pathogenesis of post-antibiotic non CD-mediated diarrhea. Out of 25rabbits which were given Ampicillin (A) 14 developed diarrhea and were in vestigated. Results: 1)CD and its cytotoxin (absent in all control rabbits)were found in the ileum and/or caecum of 8 rabbits (CD+), while only other enterobacterial species were found in 5(CD-).Clostridium spiroforme was found in one. 2) Ileal and caecal transepithelial ion fluxes were measured in Ussing chambers: secretory charges in Na and Cl transport developed in both segments and were more marked (by about 2µEq/hr.cm2) inCD--. 3)Influx of 5mM Glucose, 1mM Phenylalanine and 2mM Glycyl-Phenylalanine across the brush border of jejunal mucosa was not affected in CD-rabbits, while it was markedly reduced in CD+(respectively, 1.5±.06, .27±.05, .55±.07µmoles/hr.cm2, means ±SE in controlG vs.1.12±.08,.32±.01, .59±.08 in CD-and .51±.06,.09±.01, .15±.03 in CD+). In conclusion: 1) both CD+ and CD-animals show secretory changes in the small and large intestine, more pronounced in CD-; 2)jejunal influx of nutrients is hampered only in CD+ animals. Thus, the pathogenesis of post-antibiotic CD-mediated diarrhea appears essentially invasive, while that not due to CD appears essentially secretory.