K. Hillman et al., INHIBITION OF ENTEROTOXIGENIC ESCHERICHIA-COLI BY THE MICROFLORA OF THE PORCINE ILEUM, IN AN IN-VITRO SEMICONTINUOUS CULTURE SYSTEM, Journal of Applied Bacteriology, 76(3), 1994, pp. 294-300
An in vitro fermentation system capable of maintaining at least part o
f the microbial population of the contents of the porcine ileum has be
en developed. The system was tested over the pH range 6.0-8.5, anaerob
ically and at dissolved oxygen concentrations within the ranges detect
ed in the ileum of piglets at weaning (50 and 100 mu mol l(-1)). The r
esults demonstrated that changes in pH and dissolved oxygen within the
se ranges had relatively little effect on the total numbers of aerobic
and anaerobic bacteria. Lactic acid bacteria, enumerated anaerobicall
y, showed changes in viable counts in response to pH changes but were
apparently unaffected by changes in dissolved oxygen, although the pro
portion of aerotolerant species within this group was increased at hig
h concentrations of dissolved oxygen. The relative proportions of lact
obacilli and coliforms were similar to those reported in vivo when dis
solved oxygen was present at a concentration of 50 mu mol l(-1). Under
these conditions the simulated population was consistently found to r
esist colonization by an enterotoxigenic Escherichia coli, of a seroty
pe known to cause weaning scours in the piglet.