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Colonization resistance of the digestive tract--mechanism and clinical consequences
1Laboratory for Medical Microbiology, University Hospital, Groningen, The Netherlands.
Abstract:
Potentially pathogenic bacteria and yeasts meet a number of resistance factors. These colonization resistance (CR) determining factors control the growth density of potentially pathogenic microorganisms in the various parts of the alimentary canal. The CR of the digestive tract is to be seen partially of host origin but to a greater extent due to direct and indirect activity of the (anaerobic) indigenous microflora. This implies that the CR mechanism is vulnerable to antibiotics which affect the indigenous flora during treatment. A decreased CR enhances colonization by microorganisms that are resistant to the antibiotic(s) used for therapy. Increased population densities of potentially pathogenic bacteria ("overgrowth") may correlate with invasion of the mucosal tissues often followed by translocation to remote lymphatic organs. Overgrowth also may correlate with development or acquisition of resistance to the antibiotic applied. By screening in experimental animals antibiotics have been selected which do not affect the CR. Such antimicrobial drugs have successfully been used to selectively eliminate potentially pathogenic bacteria and yeast in neutropenic patients.
Insights
Antibiotics can disrupt gut colonization resistance (CR), allowing harmful bacteria and yeasts to overgrow. Researchers identified specific antibiotics that preserve CR, effectively eliminating pathogens in vulnerable patients.
Area of Science:
- Microbiology
- Immunology
- Pharmacology
Background:
- Colonization resistance (CR) protects the host from pathogenic microorganisms.
- CR is influenced by the indigenous gut microflora and host factors.
- Antibiotics can compromise CR by altering the gut microbiota.
Purpose of the Study:
- To investigate the impact of antibiotics on CR.
- To identify antibiotics that do not affect CR.
- To evaluate the efficacy of CR-sparing antibiotics in eliminating pathogens.
Main Methods:
- Screening of antibiotics in experimental animal models.
- Evaluation of antibiotic effects on indigenous microflora and CR.
- Clinical application in neutropenic patients.
Main Results:
- Antibiotics can decrease CR, leading to pathogen overgrowth and potential resistance.
- Specific antibiotics were identified that preserve CR.
- CR-sparing antibiotics successfully eliminated pathogenic bacteria and yeasts in neutropenic patients.
Conclusions:
- Maintaining CR is crucial for preventing pathogen colonization.
- Antibiotics that spare CR offer a therapeutic strategy against infections in immunocompromised individuals.
- Targeted antibiotic selection can mitigate the risks associated with CR disruption.