Relative Contributions of Host and Microbial Factors in Bacterial Translocation

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.