Journal of Bacteriology & Parasitology

Abstract

Effects of Salmonella enteritidis serovar typhimurium Infection in Adenocarcinomic Human Alveolar Basal Epithelial Cells A549 In vitro: Bacteria Induce Apoptosis in Adenocarcinomic Cell

Izidoro MS Jr, Varela JN, Alves DA, Pereira RFC, Brocchi M, Lancellotti M and Hollanda LM

Salmonella enterica serovar typhimurium is a facultative anaerobic bacterium, gram-negative, flagellated which generally develops and grows preferably in a wide variety of tumor cells. Until now, several factors for this predilection have been described, such as: an increase in number of nutrients favorable for bacterial growth due to rapid growth of the tumor cells, adaptation of S. typhimurium, loss of macrophages and neutrophils bactericidal activity in areas of hypoxia, the absence of antibodies and complement factors around the tumor. This study analyzed the infection in vitro of Salmonella enteritidis serovar typhimurium in A549 cell lineage, in three different aspects: morphological characterization of the infection, analysis of cellular DNA degradation and production of cytokines such as TNFα. The morphological assay showed tumor cell shrinkage, nuclear fragmentation with DNA degradation and chromatin condensation suggesting that these bacteria were inducing apoptosis on these cells. The cytokines production showed great variations among the strains analyzed and some predictable results, for example, bacterial strains isolated from diarrhoea which was more virulent against the tumor cells than others. In conclusion, we have shown some data proving that Salmonella enteritidis serovar typhimurium is able to adhere and infect adenocarcinomic cells causing programmed cellular death. A pattern was established, the more virulent the strain, the higher the quantity of cytokines produced in the inflammatory process.