Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems
ABSTRACT The engulfment of Legionella pneumophila by free-living amoebae (FLA) in engineered water systems (EWS) enhances L. pneumophila persistence and provides a vehicle for rapid replication and increased public health risk. Despite numerous legionellosis outbreaks worldwide, effective tools for...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2022-08-01
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| Series: | Microbiology Spectrum |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/spectrum.02210-22 |
| _version_ | 1828319742893490176 |
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| author | Sujani Ariyadasa Craig Billington Mohamed Shaheen Nicholas J. Ashbolt Conan Fee Liping Pang |
| author_facet | Sujani Ariyadasa Craig Billington Mohamed Shaheen Nicholas J. Ashbolt Conan Fee Liping Pang |
| author_sort | Sujani Ariyadasa |
| collection | DOAJ |
| description | ABSTRACT The engulfment of Legionella pneumophila by free-living amoebae (FLA) in engineered water systems (EWS) enhances L. pneumophila persistence and provides a vehicle for rapid replication and increased public health risk. Despite numerous legionellosis outbreaks worldwide, effective tools for studying interactions between L. pneumophila and FLA in EWS are lacking. To address this, we have developed a biopolymer surrogate with a similar size, shape, surface charge, and hydrophobicity to those of stationary-phase L. pneumophila. Parallel experiments were conducted to observe the engulfment of L. pneumophila and the surrogate by Acanthamoeba polyphaga in dechlorinated, filter-sterilised tap water at 30°C for 72 h. Trophozoites engulfed both the surrogate and L. pneumophila, reaching maximum uptake after 2 and 6 h, respectively, but the peak surrogate uptake was ~2-log lower. Expulsion of the engulfed surrogate from A. polyphaga was also faster compared to that of L. pneumophila. Confocal laser scanning microscopy confirmed that the surrogate was actively engulfed and maintained within vacuoles for several hours before being expelled. L. pneumophila and surrogate phagocytosis appear to follow similar pathways, suggesting that the surrogate can be developed as a useful tool for studying interactions between L. pneumophila and FLA in EWS. IMPORTANCE The internalization of L. pneumophila within amoebae is a critical component of their life cycle in EWS, as it protects the bacteria from commonly used water disinfectants and provides a niche for their replication. Intracellularly replicated forms of L. pneumophila are also more virulent and resistant to sanitizers. Most importantly, the bacteria’s adaptation to the intracellular environments of amoebae primes them for the infection of human macrophages, posing a significant public health risk in EWS. The significance of our study is that a newly developed L. pneumophila biopolymer surrogate can mimic the L. pneumophila engulfment process in A. polyphaga, a free-living amoeba. With further development, the surrogate has the potential to improve the understanding of amoeba-mediated L. pneumophila persistence in EWS and the associated public health risk management. |
| first_indexed | 2024-04-13T18:00:49Z |
| format | Article |
| id | doaj.art-8e7501d72d244bf3b3bda35084d7acd3 |
| institution | Directory Open Access Journal |
| issn | 2165-0497 |
| language | English |
| last_indexed | 2024-04-13T18:00:49Z |
| publishDate | 2022-08-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | Microbiology Spectrum |
| spelling | doaj.art-8e7501d72d244bf3b3bda35084d7acd32022-12-22T02:36:15ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972022-08-0110410.1128/spectrum.02210-22Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water SystemsSujani Ariyadasa0Craig Billington1Mohamed Shaheen2Nicholas J. Ashbolt3Conan Fee4Liping Pang5Institute of Environmental Science and Research, Christchurch, New ZealandInstitute of Environmental Science and Research, Christchurch, New ZealandSchool of Public Health, University of Alberta, Edmonton, Alberta, CanadaFaculty of Science & Engineering, Southern Cross University, Lismore, New South Wales, AustraliaSchool of Product Design and Biomolecular Interaction Centre, University of Canterbury, Christchurch, New ZealandInstitute of Environmental Science and Research, Christchurch, New ZealandABSTRACT The engulfment of Legionella pneumophila by free-living amoebae (FLA) in engineered water systems (EWS) enhances L. pneumophila persistence and provides a vehicle for rapid replication and increased public health risk. Despite numerous legionellosis outbreaks worldwide, effective tools for studying interactions between L. pneumophila and FLA in EWS are lacking. To address this, we have developed a biopolymer surrogate with a similar size, shape, surface charge, and hydrophobicity to those of stationary-phase L. pneumophila. Parallel experiments were conducted to observe the engulfment of L. pneumophila and the surrogate by Acanthamoeba polyphaga in dechlorinated, filter-sterilised tap water at 30°C for 72 h. Trophozoites engulfed both the surrogate and L. pneumophila, reaching maximum uptake after 2 and 6 h, respectively, but the peak surrogate uptake was ~2-log lower. Expulsion of the engulfed surrogate from A. polyphaga was also faster compared to that of L. pneumophila. Confocal laser scanning microscopy confirmed that the surrogate was actively engulfed and maintained within vacuoles for several hours before being expelled. L. pneumophila and surrogate phagocytosis appear to follow similar pathways, suggesting that the surrogate can be developed as a useful tool for studying interactions between L. pneumophila and FLA in EWS. IMPORTANCE The internalization of L. pneumophila within amoebae is a critical component of their life cycle in EWS, as it protects the bacteria from commonly used water disinfectants and provides a niche for their replication. Intracellularly replicated forms of L. pneumophila are also more virulent and resistant to sanitizers. Most importantly, the bacteria’s adaptation to the intracellular environments of amoebae primes them for the infection of human macrophages, posing a significant public health risk in EWS. The significance of our study is that a newly developed L. pneumophila biopolymer surrogate can mimic the L. pneumophila engulfment process in A. polyphaga, a free-living amoeba. With further development, the surrogate has the potential to improve the understanding of amoeba-mediated L. pneumophila persistence in EWS and the associated public health risk management.https://journals.asm.org/doi/10.1128/spectrum.02210-22amoebaLegionella pneumophilapublic healthsurrogatewaterborne pathogens |
| spellingShingle | Sujani Ariyadasa Craig Billington Mohamed Shaheen Nicholas J. Ashbolt Conan Fee Liping Pang Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems Microbiology Spectrum amoeba Legionella pneumophila public health surrogate waterborne pathogens |
| title | Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems |
| title_full | Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems |
| title_fullStr | Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems |
| title_full_unstemmed | Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems |
| title_short | Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems |
| title_sort | use of a novel dna loaded alginate calcium carbonate biopolymer surrogate to study the engulfment of legionella pneumophila by acanthamoeba polyphaga in water systems |
| topic | amoeba Legionella pneumophila public health surrogate waterborne pathogens |
| url | https://journals.asm.org/doi/10.1128/spectrum.02210-22 |
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