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Relative contributions of host and microbial factors in bacterial translocation
C L Wells1, R P Jechorek, K J Gillingham
1Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455.
Abstract:
To study the relative contributions of host and microbial factors in bacterial translocation, germfree mice were mono-associated with either Proteus mirabilis, Escherichia coli, or Enterococcus faecalis. Germfree mice included T-cell-deficient nude mice and normal littermates, natural killer cell-deficient beige mice and normal littermates, and triply immunodeficient mice with beige, T-cell, and B-cell mutations and their littermates. Each bacterial species colonized the cecum in similarly high numbers. Bacteria were recovered from the mesenteric lymph node of every mouse in inconsistent numbers, eg, greater numbers of P mirabilis and E coli were recovered from T-cell-deficient nude mice than from their normal littermates, but the opposite was observed with E faecalis. Comparing the three bacterial species resulted in relatively consistent observations, eg, the incidence of E faecalis translocation to the liver was greater than that of E coli or P mirabilis translocation. Thus, the identity of the translocating microbe significantly affected the recovery of viable translocating bacteria.
Insights
Host and microbial factors influence bacterial translocation. The specific bacterial species, like Enterococcus faecalis, significantly impacted translocation rates and recovery in germfree mice models.
Area of Science:
- Microbiology and Immunology
- Host-Microbe Interactions
- Gastrointestinal Health
Background:
- Bacterial translocation is a critical factor in various infections and inflammatory conditions.
- Understanding the interplay between host immunity and microbial characteristics is essential for managing bacterial translocation.
Purpose of the Study:
- To investigate the distinct roles of host immune status and microbial species in bacterial translocation.
- To quantify bacterial translocation of Proteus mirabilis, Escherichia coli, and Enterococcus faecalis in different germfree mouse models.
Main Methods:
- Germfree mice, including immunodeficient (T-cell, NK cell, and triple-deficient) and normal littermates, were mono-associated with specific bacterial species.
- Cecal colonization levels and bacterial recovery from mesenteric lymph nodes and liver were assessed.
- Comparative analysis of translocation incidence across different bacterial species and host genotypes.
Main Results:
- All three bacterial species (P. mirabilis, E. coli, E. faecalis) colonized the cecum effectively.
- Significant differences in bacterial recovery from the mesenteric lymph node were observed based on host immune status and bacterial species.
- Enterococcus faecalis exhibited a higher incidence of translocation to the liver compared to E. coli and P. mirabilis.
Conclusions:
- The microbial species identity is a significant determinant of bacterial translocation and recovery.
- Host immune status modulates bacterial translocation, with variations observed between different immune deficiencies and bacterial types.
- These findings highlight the complex, multifactorial nature of bacterial translocation.