Translocation of Lactobacillus murinus from the gastrointestinal tract

Bacterial translocation is defined as the passage of viable bacteria from the gastrointestinal tract to the mesenteric lymph nodes and other extraintestinal sites. The translocation rate of a newly described species of indigenous bacteria, Lactobacillus murinus, was compared with the translocation rates of indigenous Lactobacillus acidophilus and nonindigenous Salmonella enteritidis. Groups of germfree or antibiotic-decontaminated, specific pathogen-free mice were monoassociated with each of these bacterial strains and tested at various intervals for translocation to the mesenteric lymph nodes. The translocation rates of the various bacteria expressed in decreasing order as the numbers of translocating bacteria per gram mesenteric lymph node were S. enteritidis, L. murinus, and L. acidophilus. The degree of histologic damage to the gastrointestinal mucosa after monoassociation with these strains followed the same pattern. Thus, L. murinus translocates from the GI tract at a surprisingly high rate for an indigenous bacterial strain, and its translocation appears to be associated with mucosal alterations.