Acanthamoeba is known to interact with a plethora of microorganisms such as bacteria, fungi and viruses. In these interactions, the amoebae can be predatory in nature, transmission vehicle or an incubator. Amoebae consume microorganisms, especially bacteria, as food source to fulfil their nutritional needs by taking up bacteria through phagocytosis and lysing them in phagolysosomes and hence play an eminent role in the regulation of bacterial density in the nature and accountable for eradication of around 60% of the bacterial population in the environment. Acanthamoeba can also act as a "Trojan horse" for microbial transmission in the environment. Additionally, Acanthamoeba may serve as an incubator-like reservoir for microorganisms, including those that are pathogenic to humans, where the microorganisms use amoebae's defences to resist harsh environment and evade host defences and drugs, whilst growing in numbers inside the amoebae. Furthermore, amoebae can also be used as a "genetic melting pot" where exchange of genes as well as adaptation of microorganisms, leading to higher pathogenicity, may arise. Here, we describe bacteria, fungi and viruses that are known to interact with Acanthamoeba spp.

College of Arts and Sciences American University of Sharjah Sharjah United Arab Emirates

Department of Clinical Sciences College of Medicine University of Sharjah Sharjah United Arab Emirates

Research Institute for Medical and Health Sciences University of Sharjah University City Sharjah United Arab Emirates

Zobrazit více v PubMed

Abd H, Johansson T, Golovliov I, Sandström G, Forsman M. Survival and growth of Francisella tularensis in Acanthamoeba castellanii. Appl Environ Microbiol. 2003;69(1):600–606. doi: 10.1128/aem.69.1.600-606.2003. PubMed DOI PMC

Abrahão JS, Dornas FP, Silva LC, Almeida GM, Boratto PV, Colson P, La Scola B, Kroon EG. Acanthamoeba polyphaga mimivirus and other giant viruses: an open field to outstanding discoveries. Virol J. 2014;11(1):1–12. doi: 10.1186/1743-422x-11-120. PubMed DOI PMC

Aherfi S, Colson P, La Scola B, Raoult D. Giant viruses of amoebas: an update. Front Microbiol. 2016;7:349. doi: 10.3389/fmicb.2016.00349. PubMed DOI PMC

Akya A, Pointon A, Thomas C. Mechanism involved in phagocytosis and killing of Listeria monocytogenes by Acanthamoeba polyphaga. Parasitol Res. 2009;105(5):1375. doi: 10.1007/s00436-009-1565-z. PubMed DOI

Albert-Weissenberger C, Cazalet C, Buchrieser C. Legionella pneumophila—a human pathogen that co-evolved with fresh water protozoa. Cell Mol Life Sci. 2007;64(4):432. doi: 10.1007/s00018-006-6391-1. PubMed DOI PMC

Albuquerque P, Nicola AM, Magnabosco DAG, Derengowski LDS, Crisóstomo LS, Xavier LCG, Frazão SO, Guilhelmelli F, de Oliveira MA, Dias JDN, Hurtado FA, Teixeira MM, Guimarães AJ, Paes HC, Bagagli E, Felipe MSS, Casadevall A, Silva-Pereira I (2019) A hidden battle in the dirt: soil amoebae interactions with Paracoccidioides spp. Plos Negl Trop Dis 13(10) PubMed PMC

Allen PG, Dawidowicz EA (1990) Phagocytosis in Acanthamoeba: I. A mannose receptor is responsible for the binding and phagocytosis of yeast. J Cell Physiol 145(3):508–513. 10.1002/jcp.1041450317 PubMed

Alsam S, Jeong SR, Sissons J, Dudley R, Kim KS, Khan NA. Escherichia coli interactions with Acanthamoeba: a symbiosis with environmental and clinical implications. J Med Microbiol. 2006;55(6):689–694. doi: 10.1099/jmm.0.46497-0. PubMed DOI

Alsam S, Sissons J, Dudley R, Khan NA. Mechanisms associated with Acanthamoeba castellanii (T4) phagocytosis. Parasitol Res. 2005;96(6):402–409. doi: 10.1007/s00436-005-1401-z. PubMed DOI

Arslan D, Legendre M, Seltzer V, Abergel C, Claverie JM. Distant Mimivirus relative with a larger genome highlights the fundamental features of Megaviridae. Proc Natl Acad Sci USA. 2011;108(42):17486–17491. doi: 10.1073/pnas.1110889108. PubMed DOI PMC

Avery SV, Harwood JL, Lloyd D. Quantification and characterization of phagocytosis in the soil amoeba Acanthamoeba castellanii by flow cytometry. Appl Environ Microbiol. 1995;61(3):1124–1132. doi: 10.1128/aem.61.3.1124-1132.1995. PubMed DOI PMC

Balczun C, Scheid PL. Free-living amoebae as hosts for and vectors of intracellular microorganisms with public health significance. Viruses. 2017;9(4):65. doi: 10.3390/v9040065. PubMed DOI PMC

Barker J, Humphrey TJ, Brown MW. Survival of Escherichia coli 0157 in a soil protozoan: implications for disease. FEMS Microbiol Lett. 1999;173(2):291–295. doi: 10.1111/j.1574-6968.1999.tb13516.x. PubMed DOI

Boratto PVM, Oliveira GP, Machado TB, Andrade ACSP, Baudoin JP, Klose T, Schulz F, Azza S, Decloquement P, Chabrière E, Colson P, Levasseur A, La Scola B, Abrahão JS. Yaravirus: a novel 80-nm virus infecting Acanthamoeba castellanii. Proc Natl Acad Sci USA. 2020;117(28):16579–16586. doi: 10.1073/pnas.2001637117. PubMed DOI PMC

Bowers B, Olszewski TE. Acanthamoeba discriminates internally between digestible and indigestible particles. J Cell Biol. 1983;97(2):317–322. doi: 10.1083/jcb.97.2.317. PubMed DOI PMC

Boyer M, Yutin N, Pagnier I, Barrassi L, Fournous G, Espinosa L, Robert C, Azza S, Sun S, Rossmann MG, Suzan-Monti M, La Scola B, Koonin EV, Raoult D. Giant Marseillevirus highlights the role of amoebae as a melting pot in emergence of chimeric microorganisms. Proc Natl Acad Sci USA. 2009;106(51):21848–21853. doi: 10.1073/pnas.0911354106. PubMed DOI PMC

Chrisman CJ, Albuquerque P, Guimaraes AJ, Nieves E, Casadevall A. Phospholipids trigger Cryptococcus neoformans capsular enlargement during interactions with amoebae and macrophages. PLoS Pathog. 2011;7(5):e1002047. doi: 10.1371/journal.ppat.1002047. PubMed DOI PMC

Cirillo JD, Falkow S, Tompkins LS. Growth of Legionella pneumophila in Acanthamoeba castellanii enhances invasion. Infect Immun. 1994;62(8):3254–3261. doi: 10.1128/iai.62.8.3254-3261.1994. PubMed DOI PMC

Cirillo JD, Falkow S, Tompkins LS, Bermudez LE. Interaction of Mycobacterium avium with environmental amoebae enhances virulence. Infect Immun. 1997;65(9):3759–3767. doi: 10.1128/iai.65.9.3759-3767.1997. PubMed DOI PMC

Colson P, de Lamballerie X, Fournous G, Raoult D. Reclassification of giant viruses composing a fourth domain of life in the new order Megavirales. Intervirology. 2012;55(5):321–332. doi: 10.1159/000336562. PubMed DOI

Colson P, Pagnier I, Yoosuf N, Fournous G, La Scola B, Raoult D. “Marseilleviridae”, a new family of giant viruses infecting amoebae. Arch Virol. 2013;158(4):915–920. doi: 10.1007/s00705-012-1537-y. PubMed DOI

Corsaro D, Müller KD, Michel R. Molecular characterization and ultrastructure of a new amoeba endoparasite belonging to the Stenotrophomonas maltophilia complex. Exp Parasitol. 2013;133(4):383–390. doi: 10.1016/j.exppara.2012.12.016. PubMed DOI

de Souza TK, Soares SS, Benitez LB, Rott MB. Interaction between methicillin-resistant Staphylococcus aureus (MRSA) and Acanthamoeba polyphaga. Curr Microbiol. 2017;74(5):541–549. doi: 10.1007/s00284-017-1196-z. PubMed DOI

Delafont V, Bouchon D, Héchard Y, Moulin L. Environmental factors shaping cultured free-living amoebae and their associated bacterial community within drinking water network. Water Res. 2016;100:382–392. doi: 10.1016/j.watres.2016.05.044. PubMed DOI

Dey R, Hoffman PS, Glomski IJ. Germination and amplification of anthrax spores by soil-dwelling amoebas. Appl Environ Microbiol. 2012;78(22):8075–8081. doi: 10.1128/aem.02034-12. PubMed DOI PMC

Drancourt M, Adékambi T, Raoult D. Interactions between Mycobacterium xenopi, amoeba and human cells. J Hosp Infect. 2007;65(2):138–142. doi: 10.1016/j.jhin.2006.10.006. PubMed DOI

Drozanski W. Fatal bacterial infection in soil amoebae. Acta Microbiol Pol. 1956;5(3–4):315–317. PubMed

Essig A, Heinemann M, Simnacher U, Marre R. Infection of Acanthamoeba castellanii by Chlamydia pneumoniae. Appl Environ Microbiol. 1997;63(4):1396–1399. doi: 10.1128/aem.63.4.1396-1399.1997. PubMed DOI PMC

Fritsche TR, Sobek D, Gautom RK (1998) Enhancement of in vitro cytopathogenicity by Acanthamoeba spp. following acquisition of bacterial endosymbionts. FEMS Microbiol Lett 166(2):231–236. 10.1111/j.1574-6968.1998.tb13895.x PubMed

Fuchs BB, O'Brien E, Khoury JB, Mylonakis E. Methods for using Galleria mellonella as a model host to study fungal pathogenesis. Virulence. 2010;1(6):475–482. doi: 10.4161/viru.1.6.12985. PubMed DOI

Gaze WH, Burroughs N, Gallagher MP, Wellington EM. Interactions between Salmonella typhimurium and Acanthamoeba polyphaga, and observation of a new mode of intracellular growth within contractile vacuoles. Microb Ecol. 2003;46(3):358–369. doi: 10.1007/s00248-003-1001-3. PubMed DOI

Ghergab A, Selin C, Tanner J, Brassinga AK, Dekievit T. Pseudomonas chlororaphis PA23 metabolites protect against protozoan grazing by the predator Acanthamoeba castellanii. PeerJ. 2021;9:e10756. doi: 10.7717/peerj.10756. PubMed DOI PMC

Gómez-Couso H, Paniagua-Crespo E, Ares-Mazás E. Acanthamoeba as a temporal vehicle of Cryptosporidium. Parasitol Res. 2007;100(5):1151–1154. doi: 10.1007/s00436-006-0377-7. PubMed DOI

Gonçalves DS, Ferreira MDS, Gomes KX, Rodríguez-de La Noval C, Liedke SC, da Costa GCV, Albuquerque P, Cortines JR, Saramago Peralta RH, Peralta JM, Casadevall A, Guimarães AJ. Unravelling the interactions of the environmental host Acanthamoeba castellanii with fungi through the recognition by mannose-binding proteins. Cell Microbiol. 2019;21(10):e13066. doi: 10.1111/cmi.13066. PubMed DOI

Greub G, Raoult D. Microorganisms resistant to free-living amoebae. Clin Microbiol Rev. 2004;17(2):413–433. doi: 10.1128/cmr.17.2.413-433.2004. PubMed DOI PMC

Grillot-Courvalin C, Goussard S, Huetz F, Ojcius DM, Courvalin P. Functional gene transfer from intracellular bacteria to mammalian cells. Nat Biotechnol. 1998;16(9):862–866. doi: 10.1038/nbt0998-862. PubMed DOI

Harb OS, Gao LY, Abu Kwaik Y. From protozoa to mammalian cells: a new paradigm in the life cycle of intracellular bacterial pathogens: Minireview. Environ Microbiol. 2000;2(3):251–265. doi: 10.1046/j.1462-2920.2000.00112.x. PubMed DOI

Hoffmann R, Michel R. Distribution of free-living amoebae (FLA) during preparation and supply of drinking water. Int J Hyg Environ Health. 2001;203(3):215–219. doi: 10.1078/s1438-4639(04)70031-0. PubMed DOI

Horn M, Fritsche TR, Gautom RK, Schleifer KH, Wagner M (1999) Novel bacterial endosymbionts of Acanthamoeba spp. related to the Paramecium caudatum symbiont Caedibacter caryophilus. Environ Microbiol 1(4):357–367. 10.1046/j.1462-2920.1999.00045.x PubMed

Horn M, Fritsche TR, Linner T, Gautom RK, Harzenetter MD, Wagner M (2002) Obligate bacterial endosymbionts of Acanthamoeba spp. related to the beta-Proteobacteria: proposal of 'Candidatus Procabacter acanthamoebae' gen. nov., sp. nov. Int J Syst Evol Microbiol 52(2):599–605. 10.1099/00207713-52-2-599 PubMed

Horn M, Harzenetter MD, Linner T, Schmid EN, Müller KD, Michel R, Wagner M. Members of the Cytophaga–Flavobacterium–Bacteroides phylum as intracellular bacteria of acanthamoebae: proposal of ‘Candidatus Amoebophilus asiaticus’. Environ Microbiol. 2001;3(7):440–449. doi: 10.1046/j.1462-2920.2001.00210.x. PubMed DOI

Humann J, Lenz LL. Bacterial peptidoglycan-degrading enzymes and their impact on host muropeptide detection. J Innate Immun. 2009;1(2):88–97. doi: 10.1159/000181181. PubMed DOI PMC

Huws SA, Morley RJ, Jones MV, Brown MR, Smith AW. Interactions of some common pathogenic bacteria with Acanthamoeba polyphaga. FEMS Microbiol Lett. 2008;282(2):258–265. doi: 10.1111/j.1574-6968.2008.01123.x. PubMed DOI

Iqbal J, Siddiqui R, Khan NA. Acanthamoeba and bacteria produce antimicrobials to target their counterpart. Parasit Vectors. 2014;7(1):56. doi: 10.1186/1756-3305-7-56. PubMed DOI PMC

Jousset A, Bonkowski M. The model predator Acanthamoeba castellanii induces the production of 2, 4, DAPG by the biocontrol strain Pseudomonas fluorescens Q2–87. Soil Biol Biochem. 2010;42(9):1647–1649. doi: 10.1016/j.soilbio.2010.05.018. DOI

Jürgens K, Matz C. Predation as a shaping force for the phenotypic and genotypic composition of planktonic bacteria. Antonie Van Leeuwenhoek. 2002;81(1–4):413–434. doi: 10.1023/a:1020505204959. PubMed DOI

Kahane S, Dvoskin B, Mathias M, Friedman MG (2001) Infection of Acanthamoeba polyphaga with Simkania negevensis and S. negevensis Survival within Amoebal Cysts. Appl Environ Microbiol 67(10):4789–4795. 10.1128/aem.67.10.4789-4795.2001 PubMed PMC

Kebbi-Beghdadi C, Greub G. Importance of amoebae as a tool to isolate amoeba-resisting microorganisms and for their ecology and evolution: the Chlamydia paradigm. Environ Microbiol Rep. 2014;6(4):309–324. doi: 10.1111/1758-2229.12155. PubMed DOI

Khan NA. Acanthamoeba: biology and increasing importance in human health. FEMS Microbiol Rev. 2006;30(4):564–595. doi: 10.1111/j.1574-6976.2006.00023.x. PubMed DOI

Khan NA (2009) Acanthamoeba: biology and pathogenesis. Caister Academic Press. 424. ISBN 978–1–904455–43–1

Khan NA, Siddiqui R. Predator vs aliens: bacteria interactions with Acanthamoeba. Parasitology. 2014;141(7):869–874. doi: 10.1017/s003118201300231x. PubMed DOI

Kilvington S, Price J. Survival of Legionella pneumophila within cysts of Acanthamoeba polyphaga following chlorine exposure. J Appl Bacteriol. 1990;68(5):519–525. doi: 10.1111/j.1365-2672.1990.tb02904.x. PubMed DOI

King CH, Shotts EB, Jr, Wooley RE, Porter KG. Survival of coliforms and bacterial pathogens within protozoa during chlorination. Appl Environ Microbiol. 1988;54(12):3023–3033. doi: 10.1128/aem.54.12.3023-3033.1988. PubMed DOI PMC

Korn ED, Weisman RA (1967) Phagocytosis of latex beads by Acanthamoeba: II. Electron Microscopic Study of the Initial Events. J Cell Biol 34(1):219–227. 10.1083/jcb.34.1.219 PubMed PMC

Kuburich NA, Adhikari N, Hadwiger JA. Acanthamoeba and Dictyostelium use different foraging strategies. Protist. 2016;167(6):511–525. doi: 10.1016/j.protis.2016.08.006. PubMed DOI PMC

La Scola B, Audic S, Robert C, Jungang L, de Lamballerie X, Drancourt M, Birtles R, Claverie JM, Raoult D. A giant virus in amoebae. Science. 2003;299(5615):2033–2033. doi: 10.1126/science.1081867. PubMed DOI

La Scola B, Raoult D. Survival of Coxiella burnetii within free-living amoeba Acanthamoeba castellanii. Clin Microbiol Infect. 2001;7(2):75–79. doi: 10.1046/j.1469-0691.2001.00193.x. PubMed DOI

Lambrecht E, Baré J, Van Damme I, Bert W, Sabbe K, Houf K. Behavior of Yersinia enterocolitica in the presence of the bacterivorous Acanthamoeba castellanii. Appl Environ Microbiol. 2013;79(20):6407–6413. doi: 10.1128/aem.01915-13. PubMed DOI PMC

Landers P, Kerr KG, Rowbotham TJ, Tipper JL, Keig PM, Ingham E, Denton M. Survival and growth of Burkholderia cepacia within the free-living amoeba Acanthamoeba polyphaga. Eur J Clin Microbiol Infect Dis. 2000;19(2):121–123. doi: 10.1007/s100960050442. PubMed DOI

Legendre M, Lartigue A, Bertaux L, Jeudy S, Bartoli J, Lescot M, Alempic JM, Ramus C, Bruley C, Labadie K, Shmakova L, Rivkina E, Couté Y, Abergel C, Claverie JM. In-depth study of Mollivirus sibericum, a new 30,000-y-old giant virus infecting Acanthamoeba. Proc Natl Acad Sci USA. 2015;112(38):E5327–E5335. doi: 10.1073/pnas.1510795112. PubMed DOI PMC

Lim WG, Tong T, Chew J. Chryseobacterium indologenes and Chryseobacterium gleum interact and multiply intracellularly in Acanthamoeba castellanii. Exp Parasitol. 2020;211:107862. doi: 10.1016/j.exppara.2020.107862. PubMed DOI

Lorenzo-Morales J, Coronado-Alvarez N, Martínez-Carretero E, Maciver SK, Valladares B. Detection of four adenovirus serotypes within water-isolated strains of Acanthamoeba in the Canary Islands. Spain Am J Trop Med Hyg. 2007;77(4):753–756. doi: 10.4269/ajtmh.2007.77.753. PubMed DOI

Ly TM, Müller HE. Ingested Listeria monocytogenes survive and multiply in protozoa. J Med Microbiol. 1990;33(1):51–54. doi: 10.1099/00222615-33-1-51. PubMed DOI

Marciano-Cabral F, Cabral G (2003) Acanthamoeba spp. as agents of disease in humans. Clin Microbiol Rev 16(2):273–307. 10.1128/cmr.16.2.273-307.2003 PubMed PMC

Mattana A, Serra C, Mariotti E, Delogu G, Fiori PL, Cappuccinelli P. Acanthamoeba castellanii promotion of in vitro survival and transmission of coxsackie b3 viruses. Eukaryot Cell. 2006;5(4):665–671. doi: 10.1128/ec.5.4.665-671.2006. PubMed DOI PMC

McCuddin ZP, Carlson SA, Rasmussen MA, Franklin SK. Klebsiella to Salmonella gene transfer within rumen protozoa: implications for antibiotic resistance and rumen defaunation. Vet Microbiol. 2006;114(3–4):275–284. doi: 10.1016/j.vetmic.2005.12.004. PubMed DOI

Medina G, Flores-Martin S, Fonseca B, Otth C, Fernandez H. Mechanisms associated with phagocytosis of Arcobacter butzleri by Acanthamoeba castellanii. Parasitol Res. 2014;113(5):1933–1942. doi: 10.1007/s00436-014-3842-8. PubMed DOI

Mella C, Medina G, Flores-Martin S, Toledo Z, Simaluiza RJ, Pérez-Pérez G, Fernández H (2016) Interaction between zoonotic bacteria and free living amoebas. A new angle of an epidemiological polyhedron of public health importance?. Austral J Vet Sci 48(1):1–10

Michalek M, Sönnichsen FD, Wechselberger R, Dingley AJ, Hung CW, Kopp A, Wienk H, Simanski M, Herbst R, Lorenzen I, Marciano-Cabral F, Gelhaus C, Gutsmann T, Tholey A, Grötzinger J, Leippe M. Structure and function of a unique pore-forming protein from a pathogenic Acanthamoeba. Nat Chem Biol. 2013;9(1):37–42. doi: 10.1038/nchembio.1116. PubMed DOI

Michel R, Hauröder B. Isolation of an Acanthamoeba strain with intracellular Burkholderia pickettii infection. Zentralbl Bakteriol. 1997;285(4):541–557. doi: 10.1016/s0934-8840(97)80116-8. PubMed DOI

Michel R, Müller KD, Amann R, Schmid EN (1997) Legionella-like slender rods multiplying within a strain of Acanthamoeba sp. isolated from drinking water. Parasitol Res 84(1):84–88. 10.1007/s004360050362 PubMed

Michel R, Steinert M, Zoeller L, Hauroeder B, Henning K. Free-living amoebae may serve as hosts for the Chlamydia-like bacterium Waddlia chondrophila isolated from an aborted bovine foetus. Acta Protozool. 2004;43(1):37–42.

Moliner C, Fournier PE, Raoult D. Genome analysis of microorganisms living in amoebae reveals a melting pot of evolution. FEMS Microbiol Rev. 2010;34(3):281–294. doi: 10.1111/j.1574-6976.2010.00209.x. PubMed DOI

Molmeret M, Horn M, Wagner M, Santic M, Abu Kwaik Y. Amoebae as training grounds for intracellular bacterial pathogens. Appl Environ Microbiol. 2005;71(1):20–28. doi: 10.1128/aem.71.1.20-28.2005. PubMed DOI PMC

Moreira D, Brochier-Armanet C. Giant viruses, giant chimeras: the multiple evolutionary histories of Mimivirus genes. BMC Evol Biol. 2008;8(1):12. doi: 10.1186/1471-2148-8-12. PubMed DOI PMC

Moreno-Mesonero L, Moreno Y, Alonso JL, Ferrús MA. DVC-FISH and PMA-qPCR techniques to assess the survival of Helicobacter pylori inside Acanthamoeba castellanii. Res Microbiol. 2016;167(1):29–34. doi: 10.1016/j.resmic.2015.08.002. PubMed DOI

Mylonakis E. Galleria mellonella and the study of fungal pathogenesis: making the case for another genetically tractable model host. Mycopathologia. 2008;165(1):1–3. doi: 10.1007/s11046-007-9082-z. PubMed DOI

Philippe N, Legendre M, Doutre G, Couté Y, Poirot O, Lescot M, Arslan D, Seltzer V, Bertaux L, Bruley C, Garin J, Claverie JM, Abergel C (2013) Pandoraviruses: amoeba viruses with genomes up to 2.5 Mb reaching that of parasitic eukaryotes. Science 341(6143):281–286. 10.1126/science.1239181 PubMed

Prasad BK. Gupta SK (1978) Preliminary report on the engagement and retention of Mycobacteria by trophozoites of exenically grown Acanthamoeba castellanii douglas. Curr Sci. 1930;47(7):245–247.

Proca-Ciobanu M, Lupascu GH, Al P, Ionescu MD. Electron microscopic study of a pathogenic Acanthamoeba castellani strain: the presence of bacterial endosymbionts. Int J Parasitol. 1975;5(1):49–56. doi: 10.1016/0020-7519(75)90097-1. PubMed DOI

Raghavan A, Baidwal S, Venkatapathy N, Rammohan R. The Acanthamoeba-Fungal Keratitis Study. Am J Ophthalmol. 2019;201:31–36. doi: 10.1016/j.ajo.2019.01.024. PubMed DOI

Reteno DG, Benamar S, Khalil JB, Andreani J, Armstrong N, Klose T, Rossmann M, Colson P, Raoult D, La Scola B. Faustovirus, an asfarvirus-related new lineage of giant viruses infecting amoebae. J Virol. 2015;89(13):6585–6594. doi: 10.1128/jvi.00115-15. PubMed DOI PMC

Rizzo J, Albuquerque PC, Wolf JM, Nascimento R, Pereira MD, Nosanchuk JD, Rodrigues ML. Analysis of multiple components involved in the interaction between Cryptococcus neoformans and Acanthamoeba castellanii. Fungal Biol. 2017;121(6–7):602–614. doi: 10.1016/j.funbio.2017.04.002. PubMed DOI

Rosenberg K, Bertaux J, Krome K, Hartmann A, Scheu S, Bonkowski M. Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana. The ISME J. 2009;3(6):675–684. doi: 10.1038/ismej.2009.11. PubMed DOI

Rowbotham TJ. Preliminary report on the pathogenicity of Legionella pneumophila for freshwater and soil amoebae. J Clin Pathol. 1980;33(12):1179–1183. doi: 10.1136/jcp.33.12.1179. PubMed DOI PMC

Rubeniņa I, Kirjušina M, Bērziņš A, Valciņa O, Jahundoviča I (2017) Relationships between free-living amoeba and their intracellular bacteria. In Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences, 71(4):259–265. 10.1515/prolas-2017-0044

Scheid P, Zöller L, Pressmar S, Richard G, Michel R (2008) An extraordinary endocytobiont in Acanthamoeba sp. isolated from a patient with keratitis. Parasitol Res 102(5):945–950. 10.1007/s00436-007-0858-3 PubMed

Scheid PL. Relevance of free-living amoebae as hosts for phylogenetically diverse microorganisms. Parasitol Res. 2014;113(7):2407–2414. doi: 10.1007/s00436-014-3932-7. PubMed DOI

Scheid PL. Viruses in close associations with free-living amoebae. Parasitol Res. 2015;114(11):3959–3967. doi: 10.1007/s00436-015-4731-5. PubMed DOI

Scheid PL. A strange endocytobiont revealed as largest virus. Curr Opin Microbiol. 2016;31:58–62. doi: 10.1016/j.mib.2016.02.005. PubMed DOI

Scheid PL, Schwarzenberger R. Free-living amoebae as vectors of cryptosporidia. Parasitol Res. 2011;109(2):499–504. doi: 10.1007/s00436-011-2287-6. PubMed DOI

Scheid PL, Schwarzenberger R (2012) Acanthamoeba spp. as vehicle and reservoir of adenoviruses. Parasitol Res 111(1):479–485. 10.1007/s00436-012-2828-7 PubMed

Segal G, Shuman HA. Legionella pneumophila utilizes the same genes to multiply within Acanthamoeba castellanii and human macrophages. Infect Immun. 1999;67(5):2117–2124. doi: 10.1128/iai.67.5.2117-2124.1999. PubMed DOI PMC

Siddiqui R, Khan NA. War of the microbial worlds: who is the beneficiary in Acanthamoeba–bacterial interactions? Exp Parasitol. 2012;130(4):311–313. doi: 10.1016/j.exppara.2012.01.021. PubMed DOI

Siddiqui R, Khan NA. War on terror cells: strategies to eradicate “novel coronavirus” effectively. ACS Chem Neurosci. 2020;11(9):1198–1199. doi: 10.1021/acschemneuro.0c00162. PubMed DOI

Siddiqui R, Khan NA. Centralized air-conditioning and transmission of novel coronavirus. Pathog Glob Health. 2020;114(5):228–229. doi: 10.1080/20477724.2020.1765653. PubMed DOI PMC

Siddiqui R, Yee Ong TY, Jung SY, Khan NA. Acanthamoeba castellanii interactions with Streptococcus pneumoniae and Streptococcus pyogenes. Exp Parasitol. 2017;183:128–132. doi: 10.1016/j.exppara.2017.08.005. PubMed DOI

Snelling WJ, McKenna JP, Lecky DM, Dooley JS. Survival of Campylobacter jejuni in waterborne protozoa. Appl Environ Microbiol. 2005;71(9):5560–5571. doi: 10.1128/aem.71.9.5560-5571.2005. PubMed DOI PMC

Sriram R, Shoff M, Booton G, Fuerst P, Visvesvara GS. Survival of Acanthamoeba cysts after desiccation for more than 20 years. J Clin Microbiol. 2008;46(12):4045–4048. doi: 10.1128/jcm.01903-08. PubMed DOI PMC

Steenbergen JN, Casadevall A. The origin and maintenance of virulence for the human pathogenic fungus Cryptococcus neoformans. Microbes Infect. 2003;5(7):667–675. doi: 10.1016/s1286-4579(03)00092-3. PubMed DOI

Steenbergen JN, Nosanchuk JD, Malliaris SD, Casadevall A. Interaction of Blastomyces dermatitidis, Sporothrix schenckii, and Histoplasma capsulatum with Acanthamoeba castellanii. Infect Immun. 2004;72(6):3478–3488. doi: 10.1128/iai.72.6.3478-3488.2004. PubMed DOI PMC

Steenbergen JN, Shuman HA, Casadevall A. Cryptococcus neoformans interactions with amoebae suggest an explanation for its virulence and intracellular pathogenic strategy in macrophages. Proc Natl Acad Sci USA. 2001;98(26):15245–15250. doi: 10.1073/pnas.261418798. PubMed DOI PMC

Taylor M, Ross K, Bentham R (2009) Legionella, protozoa, and biofilms: interactions within complex microbial systems. Microb Ecol 58(3):538-47. 10.1007/s00248-009-9514-z PubMed

Tezcan-Merdol D, Ljungström M, Winiecka-Krusnell J, Linder E, Engstrand L, Rhen M. Uptake and replication of Salmonella enterica in Acanthamoeba rhysodes. Appl Environ Microbiol. 2004;70(6):3706–3714. doi: 10.1128/aem.70.6.3706-3714.2004. PubMed DOI PMC

Thomas V, Herrera-Rimann K, Blanc DS, Greub G. Biodiversity of amoebae and amoeba-resisting bacteria in a hospital water network. Appl Environ Microbiol. 2006;72(4):2428–2438. doi: 10.1128/aem.72.4.2428-2438.2006. PubMed DOI PMC

Thomas V, McDonnell G, Denyer SP, Maillard JY. Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality. FEMS Microbiol Rev. 2010;34(3):231–259. doi: 10.1111/j.1574-6976.2009.00190.x. PubMed DOI

Thomaz L, García-Rodas R, Guimarães AJ, Taborda CP, Zaragoza O, Nosanchuk JD. Galleria mellonella as a model host to study Paracoccidioides lutzii and Histoplasma capsulatum. Virulence. 2013;4(2):139–146. doi: 10.4161/viru.23047. PubMed DOI PMC

Tomov AT, Tsvetkova ED, Tomova IA, Michailova LI, Kassovski VK. Persistence and multiplication of obligate anaerobe bacteria in amebae under aerobic conditions. Anaerobe. 1999;5(1):19–23. doi: 10.1006/anae.1999.0182. PubMed DOI

Tsai CM, Chen JW, Lin WC. Effects of Acanthamoeba castellanii on the dissolved oxygen and the microbial community under the experimental aquatic model. Exp Parasitol. 2020;218:107985. doi: 10.1016/j.exppara.2020.107985. PubMed DOI

Van Waeyenberghe L, Baré J, Pasmans F, Claeys M, Bert W, Haesebrouck F, Houf K, Martel A. Interaction of Aspergillus fumigatus conidia with Acanthamoeba castellanii parallels macrophage–fungus interactions. Environ Microbiol Rep. 2013;5(6):819–824. doi: 10.1111/1758-2229.12082. PubMed DOI

Wagner Y, Noack B, Hoffmann T, Jacobs E, Lück CP. Periodontopathogenic bacteria multiply in the environmental amoeba Acanthamoeba castellani. Int J Hyg Environ Health. 2006;209(6):535–539. doi: 10.1016/j.ijheh.2006.05.006. PubMed DOI

Watkins RA, Andrews A, Wynn C, Barisch C, King JS, Johnston SA. Cryptococcus neoformans escape from Dictyostelium amoeba by both WASH-mediated constitutive exocytosis and vomocytosis. Front Cell Infect Microbiol. 2018;8:108. doi: 10.3389/fcimb.2018.00108. PubMed DOI PMC

Wetzel MG, Korn ED (1969) Phagocytosis of latex beads by Acanthamoeba castellanii (Neff) III. Isolation of the phagocytic vesicles and their membranes. J Cell Biol 43(1):90–104. 10.1083/jcb.43.1.90 PubMed PMC

Winiecka-Krusnell J, Wreiber K, von Euler A, Engstrand L, Linder E. Free-living amoebae promote growth and survival of Helicobacter pylori. Scand J Infect Dis. 2002;34(4):253–256. doi: 10.1080/00365540110080052. PubMed DOI

Yousuf FA, Siddiqui R, Khan NA. Acanthamoeba castellanii of the T4 genotype is a potential environmental host for Enterobacter aerogenes and Aeromonas hydrophila. Parasit Vectors. 2013;6(1):169. doi: 10.1186/1756-3305-6-169. PubMed DOI PMC

Zhang J, Ormälä-Odegrip AM, Mappes J, Laakso J. Top-down effects of a lytic bacteriophage and protozoa on bacteria in aqueous and biofilm phases. Ecol Evol. 2014;4(23):4444–4453. doi: 10.1002/ece3.1302. PubMed DOI PMC

Induction of Programmed Cell Death in Acanthamoeba culbertsoni by the Repurposed Compound Nitroxoline