Abstract
We have previously demonstrated that isolates of the Burkholderia cepacia complex can survive intracellularly in murine macrophages and in free-living Acanthamoeba. In this work, we show that the clinical isolates B. vietnamiensis strain CEP040 and B. cenocepacia H111 survived but did not replicate within vacuoles of A. polyphaga. B. cepacia-containing vacuoles accumulated the fluid phase marker Lysosensor Blue and displayed strong blue fluorescence, indicating that they had low pH. In contrast, the majority of intracellular bacteria within amoebae treated with the V-ATPse inhibitor bafilomycin A1 localized in vacuoles that did not fluoresce with Lysosensor Blue. Experiments using bacteria fluorescently labelled with chloromethylfluorescein diacetate demonstrated that intracellular bacteria remained viable for at least 24 h. In contrast, Escherichia coli did not survive within amoebae after 2 h post infection. Furthermore, intracellular B. vietnamiensis CEP040 retained green fluorescent protein within the bacterial cytoplasm, while this protein rapidly escaped from the cytosol of phagocytized heat-killed bacteria into the vacuolar lumen. Transmission electron microscopy analysis confirmed that intracellular Burkholderia cells were structurally intact. In addition, both Legionella pneumophila- and B. vietnamiensis-containing vacuoles did not accumulate cationized ferritin, a compound that localizes within the lysosome. Thus, our observations support the notion that B. cepacia complex isolates can use amoebae as a reservoir in the environment by surviving without intracellular replication within an acidic vacuole that is distinct from the lysosomal compartment.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.