Abstract
In order to investigate the cause of antibiotic-associated acute hemorrhagic colitis, the bacterial flora of the feces from 13 patients with bloody diarrhea induced by treatment with synthetic penicillins (ABPC and AMPC) and CEX were determined by quantitative cultu-ral method.
Klebsiella oxytoca were isolatea in 10 cases (77%) from bloody diarrhea but only in 4 cases did this species predominate the fecal flora. Although much attention has been paid to Clostridium difficile as a probable causative agent for pseudomembranous colitis, it was not isolated in any fecal specimen. Any specific species was not detected com-monly including some pathogenic enteric organisms such as Salmonella, Shigella, Yersinia species, Bacillus cereus and Campylobacter jejuni.
Fecal bacterial toxin was examined from the standpoint of both cytopathic effect and permeability factor in 9 cases. Any toxic factor was not detected in bloody loose stool in all cases.
The bacterial flora showed a marked decrease both in numbers and in kinds of species of obligate anaerobes. To clarify the significance of the changes in bacterial flora, fecal short chain fatty acids were measured in coecal contents of guinea pigs. Short chain fatty acids decreased markedly in watery contents of ABPC treated animals compared to greasy contents of untreated animals.
These studies revealed that a single bacterial species may not be solely incriminated as the cause of acute hemorrhagic colitis and suggested the change of intestinal environment including the decrease of short chain fatty acids as the cause of diarrhea. The patho-physiological mechanism of intestinal bleeding was not yet clarified.
