ABSTRACT
It has been shown that it is possible to investigate the colonization resistance in individual mice by determining the concentration of a certain contaminant (S.R.-E. coli) in the faeces during the first 4 days after contamination. Experimental contamination is contra-indicated in many cases such as in individuals with decreased resistance to infection. Particularly in this group, the value of the colonization resistance should be determined. It appeared to be possible to determine the colonization resistance in such individuals by quantitative biotyping of the Enterobacteriaceae species in the faeces on several consecutive days.
Subject(s)
Bacteria/pathogenicity , Intestines/microbiology , Administration, Oral , Animals , Bacitracin/administration & dosage , Biological Assay , Enterobacteriaceae/classification , Enterobacteriaceae/isolation & purification , Escherichia coli/isolation & purification , Feces/microbiology , Female , Mice/radiation effects , Natamycin/administration & dosage , Neomycin/administration & dosage , Radiation Effects , Streptomycin/administration & dosageABSTRACT
During systemic treatment of mice with ampicillin or streptomycin, oral contaminations with exogenous bacterial species resulted in an abnormal colonization pattern. The contaminants persisted much longer and in much higher concentrations in the caecum of systemically treated mice than in control animals. Spread of the contaminant into the mesenteric lymph nodes and the spleen was found much more often in the antibiotic treated group. This, however, was only seen when the contaminant was ;resistant' to the antibiotic injected. The experiments suggest that the ;CR-inducing species' of the microflora live in close contact with the mucosa and therefore could be identical with the anaerobic tapered rods described by Savage & Dubos (1968).
