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Dey R, Rieger A, Banting G, Ashbolt NJ. Role of amoebae for survival and recovery of 'non-culturable' Helicobacter pylori cells in aquatic environments. FEMS Microbiol Ecol 2021; 96:5902844. [PMID: 32897313 PMCID: PMC7494403 DOI: 10.1093/femsec/fiaa182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022] Open
Abstract
Helicobacter pylori is a fastidious Gram-negative bacterium that infects over half of the world's population, causing chronic gastritis and is a risk factor for stomach cancer. In developing and rural regions where prevalence rate exceeds 60%, persistence and waterborne transmission are often linked to poor sanitation conditions. Here we demonstrate that H. pylori not only survives but also replicates within acidified free-living amoebal phagosomes. Bacterial counts of the clinical isolate H. pylori G27 increased over 50-fold after three days in co-culture with amoebae. In contrast, a H. pylori mutant deficient in a cagPAI gene (cagE) showed little growth within amoebae, demonstrating the likely importance of a type IV secretion system in H. pylori for amoebal infection. We also demonstrate that H. pylori can be packaged by amoebae and released in extracellular vesicles. Furthermore, and for the first time, we successfully demonstrate the ability of two free-living amoebae to revert and recover viable but non-cultivable coccoid (VBNC)-H. pylori to a culturable state. Our studies provide evidence to support the hypothesis that amoebae and perhaps other free-living protozoa contribute to the replication and persistence of human-pathogenic H. pylori by providing a protected intracellular microenvironment for this pathogen to persist in natural aquatic environments and engineered water systems, thereby H. pylori potentially uses amoeba as a carrier and a vector of transmission.
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Affiliation(s)
- Rafik Dey
- School of Public Health, University of Alberta,11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada.,Deparment of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Aja Rieger
- Deparment of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Graham Banting
- School of Public Health, University of Alberta,11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada
| | - Nicholas J Ashbolt
- School of Public Health, University of Alberta,11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada.,Deparment of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.,Provincial Laboratory for Public Health (ProvLab), Alberta Health Services, Edmonton, Canada.,School of Environmental, Sciense and Engineering, Southern Cross University, Lismore NSW, Australia
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2
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Mannan T, Rafique MW, Bhatti MH, Matin A, Ahmad I. Type 1 Fimbriae and Motility Play a Pivotal Role During Interactions of Salmonella typhimurium with Acanthamoeba castellanii (T4 Genotype). Curr Microbiol 2020; 77:836-845. [PMID: 31932998 DOI: 10.1007/s00284-019-01868-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/30/2019] [Indexed: 12/13/2022]
Abstract
Amoebic bacterial interactions are the most ancient form of host pathogen interactions. Here, we investigate the fate of Salmonella typhimurium and Acanthamoeba castellanii T4 genotype upon mutual interactions in a nutrition free environment. The role of type 1 fimbriae and motility of S. typhimurium during interactions with A. castellanii has also been investigated. Deletion of genes encoding the type 1 fimbriae subunit FimA, type 1 fimbriae tip protein FimH, chemotaxis regulatory proteins CheA and CheY and major flagella subunits FliC and FljB was performed through homologous recombination. In vitro association, invasion and survival assays of S. typhimurium wild-type and mutant strains were performed upon co-incubation of bacteria with A. castellanii trophozoites in a nutrition free environment. The deletion gene encoding type 1 fimbriae subunit FimA reduced, whereas the deletion of genes encoding flagella subunits FliC and FljB of flagella enhanced the association capability of S. typhimurium with A. castellanii. Invasion of A. castellanii by Salmonella was significantly reduced upon the loss of type 1 fimbriae subunit FimA and type 1 fimbriae tip protein FimH. Co-incubation of S. typhimurium with A. castellanii in phosphate buffered saline medium stimulated the growth of S. typhimurium wild-type and mutant strains. Viable A. castellanii trophozoites count became significantly reduced upon co-incubation with S. typhimurium within 48 h. Type 1 fimbriae play a pivotal role in the adherence of S. typhimurium to the A. castellanii cell surface. Subsequently, this interaction provides S. typhimurium an advantage in growth.
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Affiliation(s)
- Talha Mannan
- Institute of Biomedical and Allied Health Sciences, University of Health Sciences Lahore, Lahore, 54600, Pakistan
| | - Muhammad Wasim Rafique
- Institute of Biomedical and Allied Health Sciences, University of Health Sciences Lahore, Lahore, 54600, Pakistan
| | - Muhammad Haroon Bhatti
- Institute of Biomedical and Allied Health Sciences, University of Health Sciences Lahore, Lahore, 54600, Pakistan
| | - Abdul Matin
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Majmaah, 11952, Saudi Arabia.,Department of Medical Laboratory Technology, University of Haripur, Hattar Road, Haripur, Khyber Pakhtunkhwa, 22620, Pakistan
| | - Irfan Ahmad
- Institute of Biomedical and Allied Health Sciences, University of Health Sciences Lahore, Lahore, 54600, Pakistan.
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3
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Bunsuwansakul C, Mahboob T, Hounkong K, Laohaprapanon S, Chitapornpan S, Jawjit S, Yasiri A, Barusrux S, Bunluepuech K, Sawangjaroen N, Salibay CC, Kaewjai C, de Lourdes Pereira M, Nissapatorn V. Acanthamoeba in Southeast Asia - Overview and Challenges. THE KOREAN JOURNAL OF PARASITOLOGY 2019; 57:341-357. [PMID: 31533401 PMCID: PMC6753290 DOI: 10.3347/kjp.2019.57.4.341] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 07/18/2019] [Accepted: 07/18/2019] [Indexed: 12/21/2022]
Abstract
Acanthamoeba, one of free-living amoebae (FLA), remains a high risk of direct contact with this protozoan parasite which is ubiquitous in nature and man-made environment. This pathogenic FLA can cause sight-threatening amoebic keratitis (AK) and fatal granulomatous amoebic encephalitis (GAE) though these cases may not commonly be reported in our clinical settings. Acanthamoeba has been detected from different environmental sources namely; soil, water, hot-spring, swimming pool, air-conditioner, or contact lens storage cases. The identification of Acanthamoeba is based on morphological appearance and molecular techniques using PCR and DNA sequencing for clinico-epidemiological purposes. Recent treatments have long been ineffective against Acanthamoeba cyst, novel anti-Acanthamoeba agents have therefore been extensively investigated. There are efforts to utilize synthetic chemicals, lead compounds from medicinal plant extracts, and animal products to combat Acanthamoeba infection. Applied nanotechnology, an advanced technology, has shown to enhance the anti-Acanthamoeba activity in the encapsulated nanoparticles leading to new therapeutic options. This review attempts to provide an overview of the available data and studies on the occurrence of pathogenic Acanthamoeba among the Association of Southeast Asian Nations (ASEAN) members with the aim of identifying some potential contributing factors such as distribution, demographic profile of the patients, possible source of the parasite, mode of transmission and treatment. Further, this review attempts to provide future direction for prevention and control of the Acanthamoeba infection.
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Affiliation(s)
- Chooseel Bunsuwansakul
- School of Allied Health, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat, Thailand
| | - Tooba Mahboob
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kruawan Hounkong
- Department of Microbiology, Princess of Naradhiwas University, Narathiwat, Thailand
| | | | | | - Siriuma Jawjit
- School of Public Health, Walailak University, Nakhon Si Thammarat, Thailand
| | - Atipat Yasiri
- Chulabhorn International College of Medicine, Thammasat University, Pathum Thani, Thailand
| | - Sahapat Barusrux
- School of Allied Health, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat, Thailand
| | - Kingkan Bunluepuech
- School of Allied Health, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat, Thailand
| | | | - Cristina C. Salibay
- College of Science and Computer Studies, De La Salle University-Dasmarinas, Dasmarinas City, Cavite, Philippines
| | - Chalermpon Kaewjai
- Faculty of Medical Technology, Rangsit University, Pathum Thani, Thailand
| | - Maria de Lourdes Pereira
- Department of Medical Sciences & CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal
| | - Veeranoot Nissapatorn
- School of Allied Health, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat, Thailand
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4
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The cellulose synthase BcsA plays a role in interactions of Salmonella typhimurium with Acanthamoeba castellanii genotype T4. Parasitol Res 2018; 117:2283-2289. [PMID: 29797083 DOI: 10.1007/s00436-018-5917-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/09/2018] [Indexed: 12/13/2022]
Abstract
Pathogenic bacteria share their natural habitat with many other organisms such as animals, plants, insects, parasites and amoeba. Interactions between these organisms influence not only the life style of the host organisms, but also modulate bacterial physiology. Adaptation can include biofilm formation, capsule formation, and production of virulence factors. Although biofilm formation is a dominant mode of bacterial life in environmental settings, its role in host-pathogen interactions is not extensively studied. In this work, we investigated the role of molecular pathways involved in rdar biofilm formation in the interaction of Salmonella typhimurium with the Acanthamoeba castellanii genotype T4. Genes coding for the rdar biofilm activator CsgD, the cellulose synthase BcsA, and curli fimbriae subunits CsgBA were deleted from the genome of S. typhimurium. Assessment of interactions of wild-type and mutant strains of S. typhimurium with A. castellanii revealed that deletion of the cellulose synthase BcsA promoted association and uptake by A. castellanii, whereas the interactions with csgD and csgBA mutants were not changed. Our findings suggest that cellulose synthase BcsA inhibits the capabilities of S. typhimurium to associate with and invade into A. castellanii.
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Chavatte N, Lambrecht E, Van Damme I, Sabbe K, Houf K. Free-living protozoa in the gastrointestinal tract and feces of pigs: Exploration of an unknown world and towards a protocol for the recovery of free-living protozoa. Vet Parasitol 2016; 225:91-8. [DOI: 10.1016/j.vetpar.2016.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 01/26/2023]
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Isolation and identification of Acanthamoeba species from natural water sources in the northeastern part of Thailand. Parasitol Res 2016; 115:1705-9. [PMID: 26779920 DOI: 10.1007/s00436-016-4911-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 01/08/2016] [Indexed: 10/22/2022]
Abstract
Acanthamoeba are found in the environment, particularly in water, all over the world. The genus is currently classified into 20 different genotypes, T1-T20. In this study, 63 natural water samples from 11 provinces in northeast Thailand were collected and cultured on non-nutrient agar plates. Positive samples by culture were subsequently analyzed by molecular methods. The identification of Acanthamoeba was based on morphological features and molecular techniques using PCR and DNA sequencing. The results showed that 10 samples out of 63 were positive (15.9 %). Phylogenetic analysis revealed that seven samples were T4, one sample was similar to T3, and the other two samples were similar to T5. This is the first report demonstrating the contamination of Acanthamoeba species in natural water sources in northeast Thailand.
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Wannasan A, Uparanukraw P, Songsangchun A, Morakote N. Potentially pathogenic free-living amoebae in some flood-affected areas during 2011 Chiang Mai flood. Rev Inst Med Trop Sao Paulo 2014; 55:411-6. [PMID: 24213194 PMCID: PMC4105089 DOI: 10.1590/s0036-46652013000600007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 03/13/2013] [Indexed: 11/21/2022] Open
Abstract
SUMMARY The survey was carried out to investigate the presence of potentially
pathogenic free-living amoebae (FLA) during flood in Chiang Mai, Thailand in 2011.
From different crisis flood areas, seven water samples were collected and tested
for the presence of amoebae using culture and molecular methods. By monoxenic
culture, FLA were detected from all samples at 37 °C incubation. The FLA growing
at 37 °C were morphologically identified as Acanthamoeba spp.,
Naegleria spp. and some unidentified amoebae. Only three
samples (42.8%), defined as thermotolerant FLA, continued to grow at 42 °C. By
molecular methods, two non-thermotolerant FlA were shown to have 99% identity to
Acanthamoeba sp. and 98% identity to Hartmannella
vermiformis while the two thermotolerant FLA were identified as
Echinamoeba exundans (100% identity) and
Hartmannella sp. (99% identity). This first report of the
occurrence of FLA in water during the flood disaster will provide information to
the public to be aware of potentially pathogenic FLA.
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Affiliation(s)
- Anchalee Wannasan
- Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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8
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Mortazavi PN, Goldsworthy G, Kirk R, Khan NA. Novel model for the in vivo study of central nervous system infection due to Acanthamoeba spp. (T4 genotype). J Med Microbiol 2009; 58:503-508. [DOI: 10.1099/jmm.0.005462-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study it was shown for what is believed to be the first time that the African migratory locust can be used as a model for the study of Acanthamoeba pathogenesis. Mature adult locusts were injected intra-abdominally with 10 μl suspension of 106
Acanthamoeba (a clinical isolate of the T4 genotype) in culture medium, or with the same volume of sterile culture medium. Locusts injected with Acanthamoeba showed significant weight loss and reduced production of faeces compared with control locusts. Furthermore, injection of amoebae killed all of the locusts within 17 days at room temperature, although the speed of kill was temperature and dose dependent. When samples of faecal pellets and various tissues of infected locusts were cultured on non-nutrient agar plates containing bacterial lawns, live amoebae were recovered from haemolymph, flight muscle and fat body samples, but not from faeces. When brains dissected from locusts were incubated with an anti-amoebic drug (100 μM chlorhexidine) to kill extracellular amoebae, and then washed, homogenized and cultured on bacteria-seeded non-nutrient agar plates, only lysates from amoebae-infected locusts were positive for Acanthamoeba. This strongly suggests that amoebae invade the locust brain and, indeed, trophozoites of Acanthamoeba could be identified within the brain in histological sections of brains from infected locusts, but not from uninfected locusts. These findings support the view that locusts can be used as a model for the study of Acanthamoeba pathogenesis in vivo.
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Affiliation(s)
| | - Graham Goldsworthy
- School of Biological and Chemical Sciences, Birkbeck, University of London, London, UK
| | - Ruth Kirk
- School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, UK
| | - Naveed Ahmed Khan
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, England, UK
- School of Biological and Chemical Sciences, Birkbeck, University of London, London, UK
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Rahman M, Abd H, Romling U, Sandstrom G, Möllby R. Aeromonas-Acanthamoeba interaction and early shift to a viable but nonculturable state of Aeromonas by Acanthamoeba. J Appl Microbiol 2008; 104:1449-57. [PMID: 18194253 DOI: 10.1111/j.1365-2672.2007.03687.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS To investigate the hypothesis that amoeba may comprise a significant environmental reservoir for Aeromonas, Acanthamoeba-Aeromonas interaction experiments were performed. METHODS AND RESULTS Acanthamoeba were grown in monoculture and co-cultures with three different species of Aeromonas. Survival, invasion and viable but nonculturable state experiments were performed. We showed that at a low initial bacterial cell density, growth of Aeromonas spp. was inhibited by Acanthamoeba castellanii, while A. castellanii growth was unaffected. In contrast, a high initial bacterial cell density, Aeromonas hydrophila AEW44 and Aeromonas veronii biovar sobria AEW104 suppressed the growth of A. castellanii. Fluorescent and phase-contrast microscopic observations of GFP tagged Aer. hydrophila AEW44 demonstrated that the bacterial cells aggregated on A. castellanii cells after 15 min of incubation and internalized. Aeromonas hydrophila AEW44 cells were found to be actively moving. Interestingly, Aer. hydrophila AEW44 cells shifted more rapidly to a viable but nonculturable form when co-cultured with A. castellanii than in monoculture. CONCLUSIONS We demonstrated that Aeromonas spp. are able to interact with and to infect the protozoan A. castellanii under laboratory conditions. SIGNIFICANCE AND IMPACT OF THE STUDY Free-living amoeba might play a role as reservoir for Aeromonas, and thus may increase the transmission of Aeromonas by acting as a vehicle.
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Affiliation(s)
- M Rahman
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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Schuster FL, Visvesvara GS. Free-living amoebae as opportunistic and non-opportunistic pathogens of humans and animals. Int J Parasitol 2004; 34:1001-27. [PMID: 15313128 DOI: 10.1016/j.ijpara.2004.06.004] [Citation(s) in RCA: 497] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Revised: 05/31/2004] [Accepted: 06/01/2004] [Indexed: 10/26/2022]
Abstract
Knowledge that free-living amoebae are capable of causing human disease dates back some 50 years, prior to which time they were regarded as harmless soil organisms or, at most, commensals of mammals. First Naegleria fowleri, then Acanthamoeba spp. and Balamuthia mandrillaris, and finally Sappinia diploidea have been recognised as etiologic agents of encephalitis; Acanthamoeba spp. are also responsible for amoebic keratitis. Some of the infections are opportunistic, occurring mainly in immunocompromised hosts (Acanthamoeba and Balamuthia encephalitides), while others are non-opportunistic (Acanthamoeba keratitis, Naegleria meningoencephalitis, and cases of Balamuthia encephalitis occurring in immunocompetent humans). The amoebae have a cosmopolitan distribution in soil and water, providing multiple opportunities for contacts with humans and animals, as evidenced by antibody titers in surveyed human populations. Although, the numbers of infections caused by these amoebae are low in comparison to other protozoal parasitoses (trypanosomiasis, toxoplasmosis, malaria, etc.), the difficulty in diagnosing them, the challenge of finding optimal antimicrobial treatments and the morbidity and relatively high mortality associated with, in particular, the encephalitides have been a cause for concern for clinical and laboratory personnel and parasitologists. This review presents information about the individual amoebae: their morphologies and life-cycles, laboratory cultivation, ecology, epidemiology, nature of the infections and appropriate antimicrobial therapies, the immune response, and molecular diagnostic procedures that have been developed for identification of the amoebae in the environment and in clinical specimens.
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Affiliation(s)
- Frederick L Schuster
- Viral and Rickettsial Disease Laboratory, California Department Health Services, 850 Marina Bay Parkway, Richmond, CA 94804, USA.
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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; 70:3706-14. [PMID: 15184177 PMCID: PMC427739 DOI: 10.1128/aem.70.6.3706-3714.2004] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The ability of salmonellae to become internalized and to survive and replicate in amoebae was evaluated by using three separate serovars of Salmonella enterica and five different isolates of axenic Acanthamoeba spp. In gentamicin protection assays, Salmonella enterica serovar Dublin was internalized more efficiently than Salmonella enterica serovar Enteritidis or Salmonella enterica serovar Typhimurium in all of the amoeba isolates tested. The bacteria appeared to be most efficiently internalized by Acanthamoeba rhysodes. Variations in bacterial growth conditions affected internalization efficiency, but this effect was not altered by inactivation of hilA, a key regulator in the expression of the invasion-associated Salmonella pathogenicity island 1. Microscopy of infected A. rhysodes revealed that S. enterica resided within vacuoles. Prolonged incubation resulted in a loss of intracellular bacteria associated with morphological changes and loss of amoebae. In part, these alterations were associated with hilA and the Salmonella virulence plasmid. The data show that Acanthamoeba spp. can differentiate between different serovars of salmonellae and that internalization is associated with cytotoxic effects mediated by defined Salmonella virulence loci.
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Affiliation(s)
- Dilek Tezcan-Merdol
- Microbiology and Tumor Biology Center, Karolinska Institute, 171 77 Stockholm, Sweden
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Nwachuku N, Gerba CP. Health effects of Acanthamoeba spp. and its potential for waterborne transmission. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2004; 180:93-131. [PMID: 14561077 DOI: 10.1007/0-387-21729-0_2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Risk from Acanthamoeba keratitis is complex, depending upon the virulence of the particular strain, exposure, trauma, or other stress to the eye, and host immune response. Bacterial endosymbionts may also play a factor in the pathogenicity of Acanthamoeba. Which factor(s) may be the most important is not clear. The ability of the host to produce IgA antibodies in tears may be a significant factor. The immune response of the host is a significant risk factor for GAE infection. If so, then a certain subpopulation with an inability to produce IgA in the tears may be at greatest risk. There was no sufficient data on the occurrence or types of Acanthamoeba in tapwater in the U.S. Published work on amoebal presence in tapwater does not provide information on the type of treatment the water received or the level of residual chlorine. Assessment of the pathogenicity by cell culture and molecular methods of Acanthamoeba in tapwater would also be useful in the risk assessment process for drinking water. The possibility that Acanthamoeba spp. might serve as vectors for bacterial infections from water sources also should be explored. The bacterial endosymbionts include an interesting array of pathogens such as Vibrio cholerae and Legionella pneumophila, both of which are well recognized waterborne/water-based pathogens. Work is needed to determine if control of Acanthamoeba spp. is needed to control water-based pathogens in water supplies.
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Affiliation(s)
- Nena Nwachuku
- Office of Science and Technology, Office of Water, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave. N.W., Mc 4304T, Washington, DC 20460, USA
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