Open AccessProduction and release of heat‐labile toxin by wild‐type human‐derived enterotoxigenic Escherichia coli
Author(s) -
Lasaro Melissa Ang Simões,
Rodrigues Juliana Falcão,
MathiasSantos Camila,
Guth Beatriz Ernestina Cabílio,
RéguaMangia Adriana,
Ferreira Antônio José Piantino,
Takagi Mickie,
CabreraCrespo Joaquin,
SbrogioAlmeida Maria Elisabete,
Ferreira Luís Carlos de Souza
Publication year - 2006
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1111/j.1574-695x.2006.00134.x
Subject(s) - enterotoxigenic escherichia coli , toxin , microbiology and biotechnology , biology , escherichia coli , in vivo , secretion , in vitro , intracellular , enterotoxin , biochemistry , gene
Production and release of heat‐labile toxin (LT) by wild‐type enterotoxigenic Escherichia coli (ETEC) strains, isolated from diarrheic and asymptomatic Brazilian children, was studied under in vitro and in vivo conditions. Based on a set of 26 genetically diverse LT + enterotoxigenic E. coli strains, cell‐bound LT concentrations varied from 49.8 to 2415 ng mL −1 . The amounts of toxin released in culture supernatants ranged from 0% to 50% of the total synthesized toxin. The amount of LT associated with secreted membrane vesicles represented <5% of the total toxin detected in culture supernatants. ETEC strains secreting higher amounts of LT, but not those producing high intracellular levels of cell‐bound toxin, elicited enhanced fluid accumulation in tied rabbit ileal loops, suggesting that the strain‐specific differences in production and secretion of LT correlates with symptoms induced in vivo . However, no clear correlation was established between the ability to produce and secrete LT and the clinical symptoms of the infected individuals. The present results indicate that production and release of LT by wild‐type human‐derived ETEC strains are heterogeneous traits under both in vitro and in vivo growth conditions and may impact the clinical outcomes of infected individuals.