engleski

Relationships between free living amoebae Hartmanella vermiformis and Legionella

Legionella pneumophila and Legionella longbeachae belongs to the Legionellaceae family. While L. pneumophila is an inhabitant of freshwater, L. longbeachae is isolated from potting soil. The amoebae of the genus Hartmanella are frequently recovered from freshwater and wet soils. The present work investigates the relationships between the amoeba Hartmanella vermiformis and Legionella. The bacterial strains (L. pneumophila and L. longbeachae) were grown on buffered charcoal-yeast extract (BCYE) agar. H. vermiformis cells were seeded into 24-well tissue culture trays at a density of 10(5) cells/well. Stationary-phase bacteria was added at an MOI of 0.01 and incubated at 27°C and 35°C. At specific time points, entire coculture wells were collected and plated onto BCYE agar for viable counts. Our results showed that at 37°C, both bacteria were able to replicate within H. vermiformis and 72 hours p.i. we isolated~10(7) CFU/ml L. pneumophila and ~10(5) CFU/ml L. longbeachae. In contrast, at lower temperature (27°C) the significantly lower number of both Legionella was recovered. In conclusion, both Legionella are able to infect and replicate in amoeba H. vermiformis and temperature has a significant impact on their relationship.

amoeba; Legionella; cocultivation

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