Correlation Between the Crude Extracellular Secretion by Shigella dysenteriae and Destruction of RD and L20B Cell Lines, A Simple Sign as Alternative Treatments for Cancer Tumors through Cytotoxicity

摘要

The clinical pathogenic strains of S. dysenteriae in this study were initially diagnosed as enteroinvasive E. coli dueto the high similarity in characterization and pathogenic mechanism. The clinical samples were collected previouslyfrom patients of diarrheic stool. Confirmation was done by API 20 NE and API 20 E systems in central public healthlaboratory in Baghdad. The three clinical strains of S. dysenteriae had shown weakness in their ability to produce serineprotease autotransporters (Sat), showing small clear zone (about 1-1.4 mm in diameter) around the colonies. No clearhemolysis pattern on blood agar was shown but, the lysis of human Erythrocytes was observed by hemagglutinationtest in twofold dilution 1/10-1/320 for non-heated bacterial supernatant. When treated with heated supernatanthowever, agglutination appeared, which indicates that RBCs did not lyse. The biofilm formation was evaluated in thisstudy by Congo red plate Method which had shown weak strength in formation. The clinical strains of S. dysenteriaehave different antibiogram analyses; it was strong sensitive against ceftriaxone, ciprofloxacin, and co-trimoxazole;while, resistant to Tetracycline, ampicillin and chloramphenicol and finally, Nalidixic acids shown intermediatesusceptibility. Both non-heated and heated (at boiling temperature for 60 min) supernatants had cytotoxic effecton shape and vitality of RD and L20B cell lines. Several changes in morphology include: size, shrinkage, segregation,rounding were noted as cytopathic effect. Cell death was shown, which caused either failure of cells in suspensionto attach (to a surface to form a monolayer) or detachment of cells from established monolayers within 120 hr.compared with non- treated cells as a control. There is a poor relation between cytotoxicity effect and Sat proteaseand hemolysin secretion of S. dysenteriae. But, other heat-stable toxins may involve in infectivity of S. dysenteriae onhuman cells. Also, the destruction and damage of above mentioned cell lines by extracellular production of clinicalpathogens may effect cancer cells when infected with S. dysenteriae and become weaker. Cytotoxicity of cancercells may leave them vulnerable and exposed to active immune cells leading to rapid death. Although the toxinsof S. dysenteriae are dangerous, they can be employed in treatment of cancer cells or developing anti-tumor drugthrough destruction of tumor mass.