Purification and characterization of Klebsiella pneumoniae cytotoxins

Isolation, purification and characterization of 3 new cytotoxins of a K. pneumoniae strain isolated from ready to eat pork sausage are reported. Purification process involved extraction of cytotoxins with polymyxin B sulphate, salt precipitation, gel filtration and anion exchange chromatography. Klebsiella cytotoxin (KCT) I, a glycoprotein of about 65 kDa was verocytotoxic, enterotoxic and dermonerotic. KCT II was erythemogenic, verocytotoxic and enterotoxic protein of co 55 kDa, while KCT III was about double in MW (110 kDa) hadverocytotoxicity but neither enterotoxicity nor dermatotoxicity. KCT I and II caused granulation, conglomeration, shrinkage, detachment and lysis of MDBK and Vero cells, while KCT III induced enlargement, vacuolation, granulation, multinucleolation and syncytia formation in exposed cells. All the three cytotoxins induced specific neutralizing antibodies and cytotoxins were detectable in nanogram quantities with enzyme-linked immunosorbant assay using homologous antibodies. None of the anticytotoxin cross-reacted with either heterologous Klebsiella cytotoxins or with verocytotoxic preparations of Shigella dysenteriae.