Detection of cnf1 gene in the local human uropathogenic E. coli isolate and study some immunological and histopathological effects in vivo

Abstract EN

Uropathogenic Escherichia coli produce cytotoxic necrotizing factor-1 (CNF-1).

Which is mediates its effects on epithelial cells, and acts as one of uropathogenic E.

coli virulence factors .

Therefore this study was aimed to know the behavior of peripheral blood lymphocytes during the intravenous injection of CNF-1toxin , which has been poorly investigated in vivo .By using flow cytometery and light microscope, the effect of CNF1 was explored in rabbits, after certified the chromosomal cnf1 gene is found in the bacterial isolate.

PCR analysis confirmed the foundation of the chromosomal cnf1 gene in the selected uropathogenic isolate.

Whereas the assays of lymphocytes apoptosis and necrosis, revealed different effects, which were correlated with the investigated doses (1.82,3.65,5.47, and 7.3 µg/kg).The last two doses shown severe effects on some vital organs (liver, kidneys, and lungs )of rabbits.

Histological evaluation of rabbits treated with the dose 3.65 µg/kg revealed different changes occurred grossly due to the cytotoxic effect of CNF1.

They ranged between severe congestion in liver and lung tissues to paleness of kidney with changing in their textures.

Microscopic examination showed, infiltration of inflammatory cells with fibrin network and cellular necrosis were observed.

A conclusion of study revealed that,CNF1of uropathogenic E.

coli , coded by chromosomal cnf1 gene with 498bp ,has cytotoxic effects on immune system represented by lymphocytes apoptosis and necrosis.

As well as, different histopathological effects in some vital organs have been observed.