Purificação e caracterização de um citotoxina produzida por amostras de Enterobacter cloacae isoladas de pacientes com infecção hospitalar / Purification and characterization of a cytotoxin produced by Enterobacter cloacae strains isolated from patients with hospital infection

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The bacterium Enterobacter cloacae has been recognized as an important infectious agent in hospitaIs, sometimes leading patients to obit. Studying its virulence properties in our laboratory, 18% of the strains were characterized as cytotoxic against Vero cells. The cytotoxin was purified from the most cytotoxic strain (118.9) by means ionic exchange and molecular exclusion chromatography techniques respectively, increasing its relative activity in 62.5%. The purified toxin did not display either lethal activity nor did it cause fluid accumulation in neonatal mice intestine. Furthermore, no leukotoxic activity was detected and regarding its hemolytic activity, the purified toxin showed hemolytic activity against rabbit, bovine and sheep erythrocytes, but not against human erythrocytes, with or without beta-mercaptoethanol. The toxicity mechanism seems to be associated with a failure in the mitochondria s function, which would activate the apoptotic pathway and membrane lyses. When heated for 100°C for 30 minutes, the toxin lost completely its cytotoxicity. Despite the fact that the toxin displayed similar effects in Vero cells compared to verotoxins, PCR did not amplified the STXl and -2 and VTl and 2 genes, found in verotoxin expressing strains

ASSUNTO(S)

enterobacter cloacae vero cells apoptose cytotoxins celulas vero apoptosis citotoxinas

ACESSO AO ARTIGO

Documentos Relacionados