engleski

The survival of Legionella in Human Polymorphonuclear Granulocytes

Polymorphonuclear granulocytes (PMN) are primary antimicrobial effectors cells of the innate immune system and represent a first line of defense against harmful bacteria. Although most ingested microorganisms are killed inside PMN, several obligate or facultative intracellular pathogens are able to survive inside this cells. Phagocytosis and intracellular growth and multiplication of Legionella in phagocytic cells are key moment in the pathogenesis of legionellosis. It has been proven that Legionella replicate in macrophages, while knowledge of the other cells are insufficient. Therefore, the aim of this study was to establish a primary culture of human polymorphonuclear leukocytes, namely neutrophils and to examine and compare the survival of Legionella pneumophila and Legionella longbeachae. After establishing the primary culture of polymorphonuclear granulocytes, these cells were infected with Legionella at a ratio of 0.01. After a 24-hour co-infection bacterial number was determined. The results showed that in 24 hours there was a reduction in the number of both species of Legionella and co-infection with polymorphonuclear granulocytes survived 25% of L. pneumophila and 55% of L. longbeachae. In conclusion, both species of Legionella fail to proliferate in neutrophils although they resist killing by these cells. L. longbeachae better survives co-infection with polymorphonuclear granulocytes than L. pneumophila.

neutrophils; legionelosis; co-infection

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