The Journal of Medical Microbiology, Vol 30, Issue 3 199-206, Copyright © 1989 by Society for General Microbiology
Effect of endotoxin on colonisation of Campylobacter jejuni in infant mice
M. L. Hanninen
College of Veterinary Medicine, Department of Food and Environmental Hygiene, Helsinki, Finland.
An infant mouse model has been used to investigate the colonisation of the
intestine by Campylobacter jejuni and the effect of endotoxin (Escherichia
coli O26: B6) on the initial stage of this process. Endotoxin injected 1 or
16 h before the bacterial challenge had no effect on the growth of
campylobacters but endotoxin injected 4 to 10 h before the bacterial
challenge caused a bacteriostatic effect on the growth of campylobacters
which lasted for one day. The bacteriostatic effect was evident both in the
small intestine and in the distal part of the intestine containing caecum
and colon. The mechanism of the bacteriostatic effect of endotoxin could
not be explained in the study, but is thought to be non-immunological
because it developed so rapidly. Oral and parenteral iron administered as
ammonium ferric citrate or iron dextran, respectively, were used in an
attempt to reverse the bacteriostatic effect. High oral doses of iron (0.5
mg per animal) were effective but small doses (0.5 mg per animal) were
ineffective. Parenteral iron administration had a delayed effect on the
reversal of the bacteriostatic effect of endotoxin. Transferrin
administered orally caused a clear bacteriostatic effect in both endotoxin
pretreated and untreated mice. Campylobacter counts were always lower in
the small intestine than in the large intestine both in control and in
endotoxin pretreated mice. This indicates that the large intestine is the
primary ecological niche where campylobacters colonise mice.
