Background: We have shown previously that the PA-I lectin of Pseudomonas aeruginosa plays
a key role in gut-derived sepsis during surgical stress. The aims of this study were to determine
if the intestinal tract lumen of a stressed host contained soluble factors that could induce
the expression of PA-I.
Methods: Mice were subjected to either 30% surgical hepatectomy or sham-laparotomy, and
P. aeruginosa was introduced into the cecum. Twenty-four hours later, feces were recovered,
and PA-I and exotoxin A were determined by real-time polymerase chain reaction (PCR). In
reiterative experiments, fecal filtrates from both hepatectomy and sham-operated mice were
tested for their ability to induce PA-I expression in cultures of P. aeruginosa. Finally, the media
from cultured human intestinal epithelial (Caco-2) cells stressed with excess glutamine
was tested for its ability to induce the expression of PA-I in cultures of P. aeruginosa.
Results: Both PA-I and exotoxin A mRNA were increased in vivo in the intestinal tract of
mice subjected to 30% hepatectomy. Soluble fecal filtrates from hepatectomy mice induced
PA-I in vitro. Media from epithelial cells exposed to excess glutamine alone induced PA-I expression.
Conclusions: The intestinal environment of a stressed host contains soluble factors capable
of inducing lethal virulence traits in human opportunistic pathogen P. aeruginosa.
