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Amsri A, Pruksaphon K, Thammasit P, Nosanchuk JD, Youngchim S. Adaptation to an amoeba host drives selection of virulence-associated traits and genetic variation in saprotrophic Candida albicans. Front Cell Infect Microbiol 2024; 14:1367656. [PMID: 38550616 PMCID: PMC10976851 DOI: 10.3389/fcimb.2024.1367656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/27/2024] [Indexed: 04/02/2024] Open
Abstract
Amoebae are micropredators that play an important role in controlling fungal populations in ecosystems. However, the interaction between fungi and their amoebic predators suggests that the pressure from predatory selection can significantly influence the development of fungal virulence and evolutionary processes. Thus, the purpose of this study was to investigate the adaptation of saprotrophic Candida albicans strains during their interactions with Acanthamoeba castellanii. We conducted a comprehensive analysis of survival after co-culture by colony counting of the yeast cells and examining yeast cell phenotypic and genetic characteristics. Our results indicated that exposure to amoebae enhanced the survival capacity of environmental C. albicans and induced visible morphological alterations in C. albicans, particularly by an increase in filamentation. These observed phenotypic changes were closely related to concurrent genetic variations. Notably, mutations in genes encoding transcriptional repressors (TUP1 and SSN6), recognized for their negative regulation of filamentous growth, were exclusively identified in amoeba-passaged isolates, and absent in unexposed isolates. Furthermore, these adaptations increased the exposed isolates' fitness against various stressors, simultaneously enhancing virulence factors and demonstrating an increased ability to invade A549 lung human epithelial cells. These observations indicate that the sustained survival of C. albicans under ongoing amoebic predation involved a key role of mutation events in microevolution to modulate the ability of these isolates to change phenotype and increase their virulence factors, demonstrating an enhanced potential to survive in diverse environmental niches.
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Affiliation(s)
- Artid Amsri
- Office of Research Administration, Chiang Mai University, Chiang Mai, Thailand
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Kritsada Pruksaphon
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand
- Center of Excellence Research for Melioidosis and Microorganisms (CERMM), Walailak University, Nakhon Si Thammarat, Thailand
| | - Patcharin Thammasit
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Joshua D. Nosanchuk
- Department of Medicine (Division of Infectious Diseases), Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, United States
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Graham CI, MacMartin TL, de Kievit TR, Brassinga AKC. Molecular regulation of virulence in Legionella pneumophila. Mol Microbiol 2024; 121:167-195. [PMID: 37908155 DOI: 10.1111/mmi.15172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/15/2023] [Accepted: 09/17/2023] [Indexed: 11/02/2023]
Abstract
Legionella pneumophila is a gram-negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase-like metabolic changes via alternative sigma factors, and two-component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity.
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Affiliation(s)
- Christopher I Graham
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teassa L MacMartin
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teresa R de Kievit
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ann Karen C Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
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3
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Nugraha DK, Nishida T, Tamaki Y, Hiramatsu Y, Yamaguchi H, Horiguchi Y. Survival of Bordetella bronchiseptica in Acanthamoeba castellanii. Microbiol Spectr 2023; 11:e0048723. [PMID: 36971600 PMCID: PMC10100856 DOI: 10.1128/spectrum.00487-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/06/2023] [Indexed: 03/29/2023] Open
Abstract
The respiratory pathogenic bacterium Bordetella bronchiseptica can persistently survive in terrestrial and aquatic environments, providing a source of infection. However, the environmental lifestyle of the bacterium is poorly understood. In this study, expecting repeated encounters of the bacteria with environmental protists, we explored the interaction between B. bronchiseptica and a representative environmental amoeba, Acanthamoeba castellanii, and found that the bacteria resisted amoeba digestion and entered contractile vacuoles (CVs), which are intracellular compartments involved in osmoregulation, to escape amoeba cells. In prolonged coculture, A. castellanii supported the proliferation of B. bronchiseptica. The avirulent Bvg- phase, but not the virulent Bvg+ phase, of the bacteria was advantageous for survival in the amoebae. We further demonstrate that two Bvg+ phase-specific virulence factors, filamentous hemagglutinin and fimbriae, were targeted for predation by A. castellanii. These results are evidence that the BvgAS two-component system, the master regulator for Bvg phase conversion, plays an indispensable role in the survival of B. bronchiseptica in amoebae. IMPORTANCE The pathogenic bacterium Bordetella bronchiseptica, which causes respiratory diseases in various mammals, exhibits distinct Bvg+ and Bvg- phenotypes. The former represents the virulent phase, in which the bacteria express a set of virulence factors, while the role of the latter in the bacterial life cycle remains to be understood. In this study, we demonstrate that B. bronchiseptica in the Bvg- phase, but not the Bvg+ phase, survives and proliferates in coculture with Acanthamoeba castellanii, an environmental amoeba. Two Bvg+ phase-specific virulence factors, filamentous hemagglutinin and fimbriae, were targeted by A. castellanii predation. B. bronchiseptica turns into the Bvg- phase at temperatures in which the bacteria normally encounter these amoebae. These findings demonstrate that the Bvg- phase of B. bronchiseptica is advantageous for survival outside mammalian hosts and that the bacteria can utilize protists as transient hosts in natural environments.
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Affiliation(s)
- Dendi Krisna Nugraha
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Takashi Nishida
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yuki Tamaki
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yukihiro Hiramatsu
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Hiroyuki Yamaguchi
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yasuhiko Horiguchi
- Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka, Japan
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4
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Scheithauer L, Karagöz MS, Mayer BE, Steinert M. Protein sociology of ProA, Mip and other secreted virulence factors at the Legionella pneumophila surface. Front Cell Infect Microbiol 2023; 13:1140688. [PMID: 36936764 PMCID: PMC10017501 DOI: 10.3389/fcimb.2023.1140688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/17/2023] [Indexed: 03/06/2023] Open
Abstract
The pathogenicity of L. pneumophila, the causative agent of Legionnaires' disease, depends on an arsenal of interacting proteins. Here we describe how surface-associated and secreted virulence factors of this pathogen interact with each other or target extra- and intracellular host proteins resulting in host cell manipulation and tissue colonization. Since progress of computational methods like AlphaFold, molecular dynamics simulation, and docking allows to predict, analyze and evaluate experimental proteomic and interactomic data, we describe how the combination of these approaches generated new insights into the multifaceted "protein sociology" of the zinc metalloprotease ProA and the peptidyl-prolyl cis/trans isomerase Mip (macrophage infectivity potentiator). Both virulence factors of L. pneumophila interact with numerous proteins including bacterial flagellin (FlaA) and host collagen, and play important roles in virulence regulation, host tissue degradation and immune evasion. The recent progress in protein-ligand analyses of virulence factors suggests that machine learning will also have a beneficial impact in early stages of drug discovery.
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Affiliation(s)
- Lina Scheithauer
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Mustafa Safa Karagöz
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Benjamin E. Mayer
- Computational Biology & Simulation, Technische Universität Darmstadt, Darmstadt, Germany
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
- *Correspondence: Michael Steinert,
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Pruksaphon K, Nosanchuk JD, Thammasit P, Pongpom M, Youngchim S. Interaction of Talaromyces marneffei with free living soil amoeba as a model of fungal pathogenesis. Front Cell Infect Microbiol 2022; 12:1023067. [PMID: 36262181 PMCID: PMC9574045 DOI: 10.3389/fcimb.2022.1023067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Talaromyces (Penicillium) marneffei is an important dimorphic mycosis endemic in Southeast Asia and Southern China, but the origin and maintenance of virulence traits in this organism remains obscure. Several pathogenic fungi, including Cryptococcus neoformans, Aspergillus fumigatus, Blastomyces dermatitidis, Sporothrix schenckii, Histoplasma capsulatum and Paracoccidioides spp. interact with free living soil amoebae and data suggests that fungal pathogenic strategies may emerge from environmental interactions of these fungi with ubiquitous phagocytic microorganisms. In this study, we examined the interactions of T. marneffei with the soil amoeba Acanthamoeba castellanii. T. marneffei was rapidly ingested by A. castellanii and phagocytosis of fungal cells resulted in amoeba death after 24 h of contact. Co-culture also resulted in a rapid transition for conidia to the fission-yeast form. In addition, well-established virulence factors such as melanin and a yeast specific mannoprotein of T. marneffei were expressed during interaction with A. castellanii at 37°C. Our findings support the assumption that soil amoebae environmental predators play a role in the selection and maintenance of particular features in T. marneffei that impart virulence to this clinically important dimorphic fungus in mammalian hosts.
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Affiliation(s)
- Kritsada Pruksaphon
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Joshua D. Nosanchuk
- Departments of Microbiology and Immunology and Medicine, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Patcharin Thammasit
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Monsicha Pongpom
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Sirida Youngchim
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- *Correspondence: Sirida Youngchim,
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Ma L, Linz B, Caulfield AD, Dewan KK, Rivera I, Harvill ET. Natural History and Ecology of Interactions Between Bordetella Species and Amoeba. Front Cell Infect Microbiol 2022; 12:798317. [PMID: 35223538 PMCID: PMC8863592 DOI: 10.3389/fcimb.2022.798317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
A variety of bacteria have evolved the ability to interact with environmental phagocytic predators such as amoebae, which may have facilitated their subsequent interactions with phagocytes in animal hosts. Our recent study found that the animal pathogen Bordetella bronchiseptica can evade predation by the common soil amoeba Dictyostelium discoideum, survive within, and hijack its complex life cycle as a propagation and dissemination vector. However, it is uncertain whether the mechanisms allowing interactions with predatory amoebae are conserved among Bordetella species, because divergence, evolution, and adaptation to different hosts and ecological niches was accompanied by acquisition and loss of many genes. Here we tested 9 diverse Bordetella species in three assays representing distinct aspects of their interactions with D. discoideum. Several human and animal pathogens retained the abilities to survive within single-celled amoeba, to inhibit amoebic plaque expansion, and to translocate with amoebae to the fruiting body and disseminate along with the fruiting body. In contrast, these abilities were partly degraded for the bird pathogen B. avium, and for the human-restricted species B. pertussis and B. parapertussis. Interestingly, a different lineage of B. parapertussis only known to infect sheep retained the ability to interact with D. discoideum, demonstrating that these abilities were lost in multiple lineages independently, correlating with niche specialization and recent rapid genome decay apparently mediated by insertion sequences. B. petrii has been isolated sporadically from diverse human and environmental sources, has acquired insertion sequences, undergone genome decay and has also lost the ability to interact with amoebae, suggesting some specialization to some unknown niche. A genome-wide association study (GWAS) identified a set of genes that are potentially associated with the ability to interact with D. discoideum. These results suggest that massive gene loss associated with specialization of some Bordetella species to a closed life cycle in a particular host was repeatedly and independently accompanied by loss of the ability to interact with amoebae in an environmental niche.
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Affiliation(s)
- Longhuan Ma
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Bodo Linz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Amanda D. Caulfield
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Kalyan K. Dewan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Israel Rivera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Eric T. Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- *Correspondence: Eric T. Harvill,
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7
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Efficient nested-PCR-based method development for detection and genotype identification of Acanthamoeba from a small volume of aquatic environmental sample. Sci Rep 2021; 11:21740. [PMID: 34741041 PMCID: PMC8571327 DOI: 10.1038/s41598-021-00968-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 10/15/2021] [Indexed: 12/17/2022] Open
Abstract
Acanthamoeba spp. are opportunistic human pathogens that cause granulomatous amoebic encephalitis and keratitis, and their accurate detection and enumeration in environmental samples is a challenge. In addition, information regarding the genotyping of Acanthamoeba spp. using various PCR methods is equally critical. Therefore, considering the diverse niches of habitats, it is necessary to develop an even more efficient genotyping method for Acanthamoeba spp. detection. This study improved the sensitivity of detection to avoid underestimation of Acanthamoeba spp. occurrence in aquatic environmental samples, and to accurately define the pathogenic risk by developing an efficient PCR method. In this study, a new nested genotyping method was established and compared with various PCR-based methods using in silico, lab, and empirical tests. The in silico test showed that many PCR-based methods could not successfully align specific genotypes of Acanthamoeba, except for the newly designed nested PCR and real-time PCR method. Furthermore, 52 water samples from rivers, reservoirs, and a river basin in Taiwan were analysed by six different PCR methods and compared for genotyping and detection efficiency of Acanthamoeba. The newly developed nested-PCR-based method of genotyping was found to be significantly sensitive as it could effectively detect the occurrence of Acanthamoeba spp., which was underestimated by the JDP-PCR method. Additionally, the present results are consistent with previous studies indicating that the high prevalence of Acanthamoeba in the aquatic environment of Taiwan is attributed to the commonly found T4 genotype. Ultimately, we report the development of a small volume procedure, which is a combination of recent genotyping PCR and conventional real-time PCR for enumeration of aquatic Acanthamoeba and acquirement of biologically meaningful genotyping information. We anticipate that the newly developed detection method will contribute to the precise estimation, evaluation, and reduction of the contamination risk of pathogenic Acanthamoeba spp., which is regularly found in the water resources utilised for domestic purposes.
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Glueck NK, O'Brien KM, Seguin DC, Starai VJ. Legionella pneumophila LegC7 effector protein drives aberrant endoplasmic reticulum:endosome contacts in yeast. Traffic 2021; 22:284-302. [PMID: 34184807 DOI: 10.1111/tra.12807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 11/28/2022]
Abstract
Legionella pneumophila is a facultative intracellular bacterial pathogen, causing the severe form of pneumonia known as Legionnaires' disease. Legionella actively alters host organelle trafficking through the activities of "effector" proteins secreted via a type-IVB secretion system, in order to construct the bacteria-laden Legionella-containing vacuole (LCV) and prevent lysosomal degradation. The LCV is created with membrane derived from host endoplasmic reticulum (ER), secretory vesicles and phagosomes, although the precise molecular mechanisms that drive its synthesis remain poorly understood. In an effort to characterize the in vivo activity of the LegC7/YlfA SNARE-like effector protein from Legionella in the context of eukaryotic membrane trafficking in yeast, we find that LegC7 interacts with the Emp46p/Emp47p ER-to-Golgi glycoprotein cargo adapter complex, alters ER morphology and induces aberrant ER:endosome interactions, as measured by visualization of ER cargo degradation, reconstitution of split-GFP proteins and enhanced oxidation of the ER lumen. LegC7-dependent toxicity, disruption of ER morphology and ER:endosome fusion events were dependent upon endosomal VPS class C tethering complexes and the endosomal t-SNARE, Pep12p. This work establishes a model in which LegC7 functions to recruit host ER material to the bacterial phagosome during infection by driving ER:endosome contacts, potentially through interaction with host membrane tethering complexes and/or cargo adapters.
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Affiliation(s)
- Nathan K Glueck
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Kevin M O'Brien
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Danielle C Seguin
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Vincent J Starai
- Department of Microbiology, University of Georgia, Athens, Georgia, USA.,Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
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Fu MS, Liporagi-Lopes LC, Dos Santos SR, Tenor JL, Perfect JR, Cuomo CA, Casadevall A. Amoeba Predation of Cryptococcus neoformans Results in Pleiotropic Changes to Traits Associated with Virulence. mBio 2021; 12:e00567-21. [PMID: 33906924 PMCID: PMC8092252 DOI: 10.1128/mbio.00567-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 03/30/2021] [Indexed: 11/20/2022] Open
Abstract
Amoeboid predators, such as amoebae, are proposed to select for survival traits in soil microbes such as Cryptococcus neoformans; these traits can also function in animal virulence by defeating phagocytic immune cells, such as macrophages. Consistent with this notion, incubation of various fungal species with amoebae enhanced their virulence, but the mechanisms involved are unknown. In this study, we exposed three strains of C. neoformans (1 clinical and 2 environmental) to predation by Acanthamoeba castellanii for prolonged times and then analyzed surviving colonies phenotypically and genetically. Surviving colonies comprised cells that expressed either pseudohyphal or yeast phenotypes, which demonstrated variable expression of traits associated with virulence, such as capsule size, urease production, and melanization. Phenotypic changes were associated with aneuploidy and DNA sequence mutations in some amoeba-passaged isolates, but not in others. Mutations in the gene encoding the oligopeptide transporter (CNAG_03013; OPT1) were observed among amoeba-passaged isolates from each of the three strains. Isolates derived from environmental strains gained the capacity for enhanced macrophage toxicity after amoeba selection and carried mutations on the CNAG_00570 gene encoding Pkr1 (AMP-dependent protein kinase regulator) but manifested reduced virulence in mice because they elicited more effective fungal-clearing immune responses. Our results indicate that C. neoformans survival under constant amoeba predation involves the generation of strains expressing pleiotropic phenotypic and genetic changes. Given the myriad potential predators in soils, the diversity observed among amoeba-selected strains suggests a bet-hedging strategy whereby variant diversity increases the likelihood that some will survive predation.IMPORTANCECryptococcus neoformans is a ubiquitous environmental fungus that is also a leading cause of fatal fungal infection in humans, especially among immunocompromised patients. A major question in the field is how an environmental yeast such as C. neoformans becomes a human pathogen when it has no need for an animal host in its life cycle. Previous studies showed that C. neoformans increases its pathogenicity after interacting with its environmental predator amoebae. Amoebae, like macrophages, are phagocytic cells that are considered an environmental training ground for pathogens to resist macrophages, but the mechanism by which C. neoformans changes its virulence through interactions with protozoa is unknown. Our study indicates that fungal survival in the face of amoeba predation is associated with the emergence of pleiotropic phenotypic and genomic changes that increase the chance of fungal survival, with this diversity suggesting a bet-hedging strategy to ensure that some forms survive.
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Affiliation(s)
- Man Shun Fu
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Livia C Liporagi-Lopes
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Samuel R Dos Santos
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Jennifer L Tenor
- Division of Infectious Diseases, Department of Medicine and Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - John R Perfect
- Division of Infectious Diseases, Department of Medicine and Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA
| | - Christina A Cuomo
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, Massachusetts, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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Chauhan D, Shames SR. Pathogenicity and Virulence of Legionella: Intracellular replication and host response. Virulence 2021; 12:1122-1144. [PMID: 33843434 PMCID: PMC8043192 DOI: 10.1080/21505594.2021.1903199] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bacteria of the genus Legionella are natural pathogens of amoebae that can cause a severe pneumonia in humans called Legionnaires’ Disease. Human disease results from inhalation of Legionella-contaminated aerosols and subsequent bacterial replication within alveolar macrophages. Legionella pathogenicity in humans has resulted from extensive co-evolution with diverse genera of amoebae. To replicate intracellularly, Legionella generates a replication-permissive compartment called the Legionella-containing vacuole (LCV) through the concerted action of hundreds of Dot/Icm-translocated effector proteins. In this review, we present a collective overview of Legionella pathogenicity including infection mechanisms, secretion systems, and translocated effector function. We also discuss innate and adaptive immune responses to L. pneumophila, the implications of Legionella genome diversity and future avenues for the field.
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Affiliation(s)
- Deepika Chauhan
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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11
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Rayamajhee B, Subedi D, Peguda HK, Willcox MD, Henriquez FL, Carnt N. A Systematic Review of Intracellular Microorganisms within Acanthamoeba to Understand Potential Impact for Infection. Pathogens 2021; 10:pathogens10020225. [PMID: 33670718 PMCID: PMC7922382 DOI: 10.3390/pathogens10020225] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 12/20/2022] Open
Abstract
Acanthamoeba, an opportunistic pathogen is known to cause an infection of the cornea, central nervous system, and skin. Acanthamoeba feeds different microorganisms, including potentially pathogenic prokaryotes; some of microbes have developed ways of surviving intracellularly and this may mean that Acanthamoeba acts as incubator of important pathogens. A systematic review of the literature was performed in order to capture a comprehensive picture of the variety of microbial species identified within Acanthamoeba following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Forty-three studies met the inclusion criteria, 26 studies (60.5%) examined environmental samples, eight (18.6%) studies examined clinical specimens, and another nine (20.9%) studies analysed both types of samples. Polymerase chain reaction (PCR) followed by gene sequencing was the most common technique used to identify the intracellular microorganisms. Important pathogenic bacteria, such as E. coli, Mycobacterium spp. and P. aeruginosa, were observed in clinical isolates of Acanthamoeba, whereas Legionella, adenovirus, mimivirus, and unidentified bacteria (Candidatus) were often identified in environmental Acanthamoeba. Increasing resistance of Acanthamoeba associated intracellular pathogens to antimicrobials is an increased risk to public health. Molecular-based future studies are needed in order to assess the microbiome residing in Acanthamoeba, as a research on the hypotheses that intracellular microbes can affect the pathogenicity of Acanthamoeba infections.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
- Department of Infection and Immunology, Kathmandu Research Institute for Biological Sciences (KRIBS), Lalitpur 44700, Nepal
- Correspondence: or
| | - Dinesh Subedi
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia;
| | - Hari Kumar Peguda
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
| | - Mark Duncan Willcox
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
| | - Fiona L. Henriquez
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland (UWS), Paisley PA1 2BE, UK;
| | - Nicole Carnt
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia; (H.K.P.); (M.D.W.); (N.C.)
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Abstract
Amoebae are protists that have complicated relationships with bacteria, covering the whole spectrum of symbiosis. Amoeba-bacterium interactions contribute to the study of predation, symbiosis, pathogenesis, and human health. Given the complexity of their relationships, it is necessary to understand the ecology and evolution of their interactions. In this paper, we provide an updated review of the current understanding of amoeba-bacterium interactions. We start by discussing the diversity of amoebae and their bacterial partners. We also define three types of ecological interactions between amoebae and bacteria and discuss their different outcomes. Finally, we focus on the implications of amoeba-bacterium interactions on human health, horizontal gene transfer, drinking water safety, and the evolution of symbiosis. In conclusion, amoeba-bacterium interactions are excellent model systems to investigate a wide range of scientific questions. Future studies should utilize advanced techniques to address research gaps, such as detecting hidden diversity, lack of amoeba genomes, and the impacts of amoeba predation on the microbiome.
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Quan FS, Kong HH, Lee HA, Chu KB, Moon EK. Identification of differentially expressed Legionella genes during its intracellular growth in Acanthamoeba. Heliyon 2020; 6:e05238. [PMID: 33088972 PMCID: PMC7566939 DOI: 10.1016/j.heliyon.2020.e05238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/01/2020] [Accepted: 10/08/2020] [Indexed: 11/28/2022] Open
Abstract
Legionella grows intracellularly in free-living amoeba as well as in mammalian macrophages. Until now, the overall gene expression pattern of intracellular Legionella in Acanthamoeba was not fully explained. Intracellular bacteria are capable of not only altering the gene expression of its host, but it can also regulate the expression of its own genes for survival. In this study, differentially expressed Legionella genes within Acanthamoeba during the 24 h intracellular growth period were investigated for comparative analysis. RNA sequencing analysis revealed 3,003 genes from the intracellular Legionella. Among them, 115 genes were upregulated and 1,676 genes were downregulated more than 2 fold compared to the free Legionella. Gene ontology (GO) analysis revealed the suppression of multiple genes within the intracellular Legionella, which were categorized under 'ATP binding' and 'DNA binding' in the molecular function domain. Gene expression of alkylhydroperoxidase, an enzyme involved in virulence and anti-oxidative stress response, was strongly enhanced 24 h post-intracellular growth. Amino acid ABC transporter substrate-binding protein that utilizes energy generation was also highly expressed. Genes associated with alkylhydroperoxidase, glucose pathway, and Dot/Icm type IV secretion system were shown to be differentially expressed. These results contribute to a better understanding of the survival strategies of intracellular Legionella within Acanthamoeba.
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Affiliation(s)
- Fu-Shi Quan
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul, Republic of Korea.,Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul, Republic of Korea
| | - Hyun-Hee Kong
- Department of Parasitology, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Hae-Ahm Lee
- Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul, Republic of Korea
| | - Ki-Back Chu
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Republic of Korea
| | - Eun-Kyung Moon
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul, Republic of Korea
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14
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Genotypic and phenotypic adaptation of pathogens: lesson from the genus Bordetella. Curr Opin Infect Dis 2020; 32:223-230. [PMID: 30921085 DOI: 10.1097/qco.0000000000000549] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE OF REVIEW To relate genomic changes to phenotypic adaptation and evolution from environmental bacteria to obligate human pathogens, focusing on the examples within Bordetella species. RECENT FINDINGS Recent studies showed that animal-pathogenic and human-pathogenic Bordetella species evolved from environmental ancestors in soil. The animal-pathogenic Bordetella bronchiseptica can hijack the life cycle of the soil-living amoeba Dictyostelium discoideum, surviving inside single-celled trophozoites, translocating to the fruiting bodies and disseminating along with amoeba spores. The association with amoeba may have been a 'training ground' for bacteria during the evolution to pathogens. Adaptation to an animal-associated life style was characterized by decreasing metabolic versatility and genome size and by acquisition of 'virulence factors' mediating the interaction with the new animal hosts. Subsequent emergence of human-specific pathogens, such as Bordetella pertussis from zoonoses of broader host range progenitors, was accompanied by a dramatic reduction in genome size, marked by the loss of hundreds of genes. SUMMARY The evolution of Bordetella from environmental microbes to animal-adapted and obligate human pathogens was accompanied by significant genome reduction with large-scale gene loss during divergence.
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15
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Lim WG, Tong T, Chew J. Chryseobacterium indologenes and Chryseobacterium gleum interact and multiply intracellularly in Acanthamoeba castellanii. Exp Parasitol 2020; 211:107862. [PMID: 32087220 DOI: 10.1016/j.exppara.2020.107862] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/02/2020] [Accepted: 02/17/2020] [Indexed: 01/11/2023]
Abstract
Chryseobacterium indologenes and Chryseobacterium gleum are Gram negative environmental bacteria that have been frequently reported to implicate in fatal nosocomial infections, such as bacteraemia and ventilator-associated pneumonia in immunocompromised individuals in the past decades. The interaction between Chryseobacterium spp. and Acanthamoeba castellanii, a free-living amoeba ubiquitous in the environment, has not been explored previously. In this study, C. indologenes and C. gleum were co-cultured with A. castellanii trophozoites and their interactions were evaluated. Our results showed that when co-cultured with A. castellanii, bacterial numbers of C. indologenes and C. gleum increased significantly (p < 0.05), indicating growth-supporting role of A. castellanii. Specifically, our findings showed that C. indologenes and C. gleum were able to associate, invade and/or taken up by A. castellani trophozoites, and multiply intracellularly at similar rates (p > 0.05). Interestingly, the two Chryseobacterium spp. associated, invaded and/or taken up by A. castellanii at significantly higher rates than Escherichia coli K1, a neuropathogenic bacterial strain known to interact and replicate intracellularly in A. castellanii (p < 0.05). However, the ability of both Chryseobacterium spp. to multiply in A. castellanii was significantly weaker than E. coli K1 (p < 0.001). This is the first time that Chryseobacterium spp. and A. castellanii were shown to interact with each other. The ability to survive intracellularly in A. castellanii may confer protection to C. indologenes and C. gleum and assist in the survival and transmission of Chryseobacterium spp. to susceptible hosts within a hospital setting. Future studies will determine the ability of C. indologenes and C. gleum survival in A. castellanii cysts and the possible molecular mechanisms involved in such interactions.
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Affiliation(s)
- Wei-Gene Lim
- Department of Biological Sciences, Sunway University, Bandar Sunway, Selangor, 47500, Malaysia
| | - Tommy Tong
- Department of Biological Sciences, Sunway University, Bandar Sunway, Selangor, 47500, Malaysia
| | - Jactty Chew
- Department of Biological Sciences, Sunway University, Bandar Sunway, Selangor, 47500, Malaysia.
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16
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Suleiman AKA, Harkes P, van den Elsen S, Holterman M, Korthals GW, Helder J, Kuramae EE. Organic amendment strengthens interkingdom associations in the soil and rhizosphere of barley (Hordeum vulgare). THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 695:133885. [PMID: 31756853 DOI: 10.1016/j.scitotenv.2019.133885] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/25/2019] [Accepted: 08/10/2019] [Indexed: 06/10/2023]
Abstract
Anthropogenic modification of soil systems has diverse impacts on food web interactions and ecosystem functioning. To understand the positive, neutral or adverse effects of agricultural practices on the associations of community members of soil microbes and microfaunal biomes, we characterized the effects of different fertilization types (organic, inorganic and a combination of organic and inorganic) on the food web active communities in the bulk soil and rhizosphere compartments in field conditions. We examined the influence of fertilization on (i) individual groups (bacteria, protozoa and fungi as microbe representatives and metazoans as microfauna representatives) and (ii) inter-kingdom interactions (focusing on the interactions between bacteria and eukaryotic groups) both neglecting and considering environmental factors in our analysis in combination with the microbial compositional data. Our results revealed different patterns of biota communities under organic versus inorganic fertilization, which shaped food web associations in both the bulk and rhizosphere compartments. Overall, organic fertilization increased the complexity of microbial-microfaunal ecological associations with inter- and intra- connections among categories of primary decomposers (bacteria and fungi) and predators (protozoa and microfauna) and differences in potential function in the soil food web in both the bulk and rhizosphere compartments. Furthermore, the inter-connections between primary decomposers and predators in bulk soil were more pronounced when environmental factors were considered. We suggest that organic fertilization selects bacterial orders with different potential ecological functions and interactions as survival, predation and cooperation due to more complex environment than those of inorganic or combined fertilization. Our findings support the importance of a comprehensive understanding of trophic food web patterns for soil management systems.
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Affiliation(s)
- Afnan K A Suleiman
- Netherlands Institute of Ecology (NIOO-KNAW), Department of Microbial Ecology, Wageningen, the Netherlands.
| | - Paula Harkes
- Wageningen University and Research Centre (WUR), Laboratory of Nematology, Wageningen, the Netherlands.
| | - Sven van den Elsen
- Wageningen University and Research Centre (WUR), Laboratory of Nematology, Wageningen, the Netherlands.
| | - Martijn Holterman
- Wageningen University and Research Centre (WUR), Laboratory of Nematology, Wageningen, the Netherlands.
| | - Gerard W Korthals
- Netherlands Institute of Ecology (NIOO-KNAW), Department of Microbial Ecology, Wageningen, the Netherlands; Wageningen University and Research Centre (WUR), Laboratory of Nematology, Wageningen, the Netherlands.
| | - Johannes Helder
- Wageningen University and Research Centre (WUR), Laboratory of Nematology, Wageningen, the Netherlands
| | - Eiko E Kuramae
- Netherlands Institute of Ecology (NIOO-KNAW), Department of Microbial Ecology, Wageningen, the Netherlands.
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17
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Tavakolian A, Heydari S, Siavoshi F, Brojeni GN, Sarrafnejad A, Eftekhar F, Khormali M. Localization of Staphylococcus inside the vacuole of Candida albicans by immunodetection and FISH. INFECTION GENETICS AND EVOLUTION 2019; 75:104014. [PMID: 31446135 DOI: 10.1016/j.meegid.2019.104014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 08/18/2019] [Accepted: 08/19/2019] [Indexed: 01/04/2023]
Abstract
In our previous study, two bacteria B1 and B2 were excised from two amphotericin B-treated Candida albicans Y1 and Y2, respectively. Bacteria were identified as B1: Staphylococcus hominis and B2: Staphylococcus haemolyticus according to their biochemical characteristics and detection and sequencing of Staphylococcus-specific genes. In this study the intracellular origin of staphylococci inside the vacuole of yeast was examined. Polyclonal antibodies against S. hominis and S. haemolyticus were raised in rabbit and used for detection of staphylococcal proteins in protein pool of yeasts by western blotting (WB). Fluorescein-isothiocyanate (FITC)-conjugated antibodies were used for bacterial localization inside yeast's vacuole by direct immunofluorescence (DIF). Fluorescent in situ hybridization (FISH) with Staphylococcaceae -specific probe was performed for validation of immunodetection results. WB results showed occurrence of several proteins in protein pool of yeasts that were similar to staphylococcal proteins such as those with molecular weight of 57.5 and 66 kDa. Fluorescent microscopy showed interactions of FITC-antibodies with intracellular staphylococci which appeared as green spots. Hybridization of staphylococcal- specific probe with bacteria inside yeasts' vacuole confirmed immunodetection results. Detection of staphylococcal proteins and genes inside Candida albicans yeast indicates existence of intracellular bacteria inside the vacuole of yeast. These results suggest C. albicans as the potential reservoir of medically important bacteria.
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Affiliation(s)
- Atefeh Tavakolian
- Department of Microbiology, Faculty of Biological Sciences and Technology, Shahid Beheshti University, Tehran, Iran
| | - Samira Heydari
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran
| | - Farideh Siavoshi
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran.
| | - Gholamreza Nikbakht Brojeni
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Abdolfatah Sarrafnejad
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fereshteh Eftekhar
- Department of Microbiology, Faculty of Biological Sciences and Technology, Shahid Beheshti University, Tehran, Iran
| | - Mahmood Khormali
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
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18
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Christensen LM, Sule P, Strain M, Cirillo JD. Legionella pneumophila p45 element influences host cell entry and sensitivity to sodium. PLoS One 2019; 14:e0218941. [PMID: 31246988 PMCID: PMC6597080 DOI: 10.1371/journal.pone.0218941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/12/2019] [Indexed: 11/19/2022] Open
Abstract
Legionella pneumophila are environmental bacteria found ubiquitously in both natural and man-made water reservoirs, sometimes as constituents of biofilm communities, but mostly intracellularly within protozoal hosts. In the event that Legionella become aerosolized in water droplets and inhaled by humans, they can cause a potentially fatal form of pneumonia called Legionnaires' disease. Strains of L. pneumophila have highly plastic genomes that harbor numerous inter- and intra-genomic elements, enhancing their ability to live under diverse environmental conditions. One such mobile genomic element, p45 carries ~45 kbp of genes, including the Lvh (Legionella Vir homolog) type IVa secretion system. This element was evaluated for its contribution to L. pneumophila environmental resilience and virulence-related characteristics by comparing clinically isolated strain Philadelphia-1 that carries p45, Lp01 that lacks p45, and Lp01 with p45 reintroduced, Lp01+p45. We found that the p45 element impacts host cell entry and resistance to sodium, both virulence-related characteristics in Legionella species.
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Affiliation(s)
- Lanette M. Christensen
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas, United States of America
| | - Preeti Sule
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas, United States of America
| | - Madison Strain
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas, United States of America
| | - Jeffrey D. Cirillo
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas, United States of America
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19
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Abstract
Within the human host, Legionella pneumophila replicates within alveolar macrophages, leading to pneumonia. However, L. pneumophila is an aquatic generalist pathogen that replicates within a wide variety of protist hosts, including amoebozoa, percolozoa, and ciliophora. The intracellular lifestyles of L. pneumophila within the two evolutionarily distant hosts macrophages and protists are remarkably similar. Coevolution with numerous protist hosts has shaped plasticity of the genome of L. pneumophila, which harbors numerous proteins encoded by genes acquired from primitive eukaryotic hosts through interkingdom horizontal gene transfer. The Dot/Icm type IVb translocation system translocates ∼6,000 effectors among Legionella species and >320 effector proteins in L. pneumophila into host cells to modulate a plethora of cellular processes to create proliferative niches. Since many of the effectors have likely evolved to modulate cellular processes of primitive eukaryotic hosts, it is not surprising that most of the effectors do not contribute to intracellular growth within human macrophages. Some of the effectors may modulate highly conserved eukaryotic processes, while others may target protist-specific processes that are absent in mammals. The lack of studies to determine the role of the effectors in adaptation of L. pneumophila to various protists has hampered the progress to determine the function of most of these effectors, which are routinely studied in mouse or human macrophages. Since many protists restrict L. pneumophila, utilization of such hosts can also be instrumental in deciphering the mechanisms of failure of L. pneumophila to overcome restriction of certain protist hosts. Here, we review the interaction of L. pneumophila with its permissive and restrictive protist environmental hosts and outline the accomplishments as well as gaps in our knowledge of L. pneumophila-protist host interaction and L. pneumophila's evolution to become a human pathogen.
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Affiliation(s)
- Ashley Best
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, Kentucky, USA
- Center for Predictive Medicine, University of Louisville, Louisville, Kentucky, USA
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20
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Matamala-Valdés L, Sánchez-Alonzo K, Parra C, Sáez K, Aguayo-Reyes A, García A. Detection of intracellular Helicobacter pylori in Candida. SPP from neonate oral swabs. Rev Assoc Med Bras (1992) 2018; 64:928-935. [DOI: 10.1590/1806-9282.64.10.928] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 02/16/2018] [Indexed: 01/26/2023] Open
Abstract
SUMMARY BACKGROUND: There is evidence of detection of Helicobacter pylori (H. pylori) in the stool of newborns and in the yeast that colonizes the oral cavity of this age group. However, there is a lack of research to confirm it. This study proposes to determine the existence of the bacteria at an early age, specifically in newborns. OBJECTIVE: To identify intracellular H. pylori in oral yeasts and to detect antigens of the bacteria in newborn stools. METHODOLOGY: Cross-sectional and descriptive study. Samples were obtained from infants (oral swab and meconium). Identification of yeast species was performed using the following techniques: CHROMagar Candida, Germinal Tube Test and API Candida Identification System, then the yeasts were observed by light microscopy and fluorescence. Detection of H. pylori antigen in meconium and PCR were performed to amplify specific genes of the bacterium (rRNA16S, cagA, vacA s1a, vacA s1b, vacA s2, vacA m1, vacA m2 and dupA). RESULTS: Intracellular H. pylori was detected in yeast of the species Candida glabrata (C. glabrata) isolated from an oral swab of a newborn. CONCLUSION: The results of this study evidenced the existence of intracellular H. pylori in newborns.
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21
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Knowledge to Predict Pathogens: Legionella pneumophila Lifecycle Critical Review Part I Uptake into Host Cells. WATER 2018. [DOI: 10.3390/w10020132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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22
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Oliva G, Sahr T, Buchrieser C. The Life Cycle of L. pneumophila: Cellular Differentiation Is Linked to Virulence and Metabolism. Front Cell Infect Microbiol 2018; 8:3. [PMID: 29404281 PMCID: PMC5780407 DOI: 10.3389/fcimb.2018.00003] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 01/05/2018] [Indexed: 12/20/2022] Open
Abstract
Legionella pneumophila is a gram-negative bacterium that inhabits freshwater ecosystems, where it is present in biofilm or as planktonic form. L. pneumophila is mainly found associated with protozoa, which serve as protection from hostile environments and as replication niche. If inhaled within aerosols, L. pneumophila is also able to infect and replicate in human alveolar macrophages, eventually causing the Legionnaires' disease. The transition between intracellular and extracellular environments triggers a differentiation program in which metabolic as well as morphogenetic changes occur. We here describe the current knowledge on how the different developmental states of this bacterium are regulated, with a particular emphasis on the stringent response activated during the transition from the replicative phase to the infectious phase and the metabolic features going in hand. We propose that the cellular differentiation of this intracellular pathogen is closely associated to key metabolic changes in the bacterium and the host cell, which together have a crucial role in the regulation of L. pneumophila virulence.
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Affiliation(s)
- Giulia Oliva
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,Centre National de la Recherche Scientifique, UMR 3525, Paris, France
| | - Tobias Sahr
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,Centre National de la Recherche Scientifique, UMR 3525, Paris, France
| | - Carmen Buchrieser
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,Centre National de la Recherche Scientifique, UMR 3525, Paris, France
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23
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Kuhn P, Thiem S, Steinert M, Purvis D, Lugmayr V, Treutlein U, Plobner L, Leiser RM, Hust M, Dübel S. Human Anti-Lipopolysaccharid (LPS) antibodies against Legionella with high species specificity. Hum Antibodies 2017; 26:29-38. [PMID: 28582852 DOI: 10.3233/hab-170318] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Legionella are Gram-negative bacteria that are ubiquitously present in natural and man-made water reservoirs. When humans inhale aerosolized water contaminated with Legionella, alveolar macrophages can be infected, which may lead to a life-threatening pneumonia called Legionnaires' disease. Due to the universal distribution of Legionella in water and their potential threat to human health, the Legionella concentration in water for human use must be strictly monitored, which is difficult since the standard detection still relies on lengthy cultivation and analysis of bacterial morphology. In this study, an antibody against L. pneumophila has been generated from the naïve human HAL antibody libraries by phage-display for the first time. The panning was performed on whole bacterial cells in order to select antibodies that bind specifically to the cell surface of untreated Legionella. The bacterial cell wall component lipopolysaccharide (LPS) was identified as the target structure. Specific binding to the important pathogenic L. pneumophila strains Corby, Philadelphia-1 and Knoxville was observed, while no binding was detected to seven members of the families Enterobacteriaceae, Pseudomonadaceae or Clostridiaceae. Production of this antibody in the recombinant scFv-Fc format using either a murine or a human Fc part allowed the set-up of a sandwich-ELISA for detection of Legionella cells. The scFv-Fc construct proved to be very stable, even when stored for several weeks at elevated temperatures. A sensitivity limit of 4,000 cells was achieved. The scFv-Fc antibody pair was integrated on a biosensor, demonstrating the specific and fast detection of L. pneumophila on a portable device. With this system, 10,000 Legionella cells were detected within 35 min. Combined with a water filtration/concentration system, this antibody may be developed into a promising reagent for rapid on-site Legionella monitoring.
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Affiliation(s)
- Philipp Kuhn
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany
- YUMAB GmbH, Rebenring, Braunschweig, Germany
| | - Stefanie Thiem
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Department of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Michael Steinert
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Helmholtz Center for Infection Research, Braunschweig, Germany
| | | | | | | | | | | | - Michael Hust
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stefan Dübel
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany
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24
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Yersinia pestis Resists Predation by Acanthamoeba castellanii and Exhibits Prolonged Intracellular Survival. Appl Environ Microbiol 2017; 83:AEM.00593-17. [PMID: 28455335 DOI: 10.1128/aem.00593-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 04/10/2017] [Indexed: 12/13/2022] Open
Abstract
Plague is a flea-borne rodent-associated zoonotic disease caused by Yersinia pestis The disease is characterized by epizootics with high rodent mortalities, punctuated by interepizootic periods when the bacterium persists in an unknown reservoir. This study investigates the interaction between Y. pestis and the ubiquitous soil free-living amoeba (FLA) Acanthamoeba castellanii to assess if the bacterium can survive within soil amoebae and whether intracellular mechanisms are conserved between infection of mammalian macrophages and soil amoebae. The results demonstrate that during coculture with amoebae, representative Y. pestis strains of epidemic biovars Medievalis, Orientalis, and Antiqua are phagocytized and able to survive within amoebae for at least 5 days. Key Y. pestis determinants of the intracellular interaction of Y. pestis and phagocytic macrophages, PhoP and the type three secretion system (T3SS), were then tested for their roles in the Y. pestis-amoeba interaction. Consistent with a requirement for the PhoP transcriptional activator in the intracellular survival of Y. pestis in macrophages, a PhoP mutant is unable to survive when cocultured with amoebae. Additionally, induction of the T3SS blocks phagocytic uptake of Y. pestis by amoebae, similar to that which occurs during macrophage infection. Electron microscopy revealed that in A. castellanii, Y. pestis resides intact within spacious vacuoles which were characterized using lysosomal trackers as being separated from the lysosomal compartment. This evidence for prolonged survival and subversion of intracellular digestion of Y. pestis within FLA suggests that protozoa may serve as a protective soil reservoir for Y. pestisIMPORTANCEYersinia pestis is a reemerging flea-borne zoonotic disease. Sylvatic plague cycles are characterized by an epizootic period during which the disease spreads rapidly, causing high rodent mortality, and an interepizootic period when the bacterium quiescently persists in an unknown reservoir. An understanding of the ecology of Y. pestis in the context of its persistence in the environment and its reactivation to initiate a new epizootic cycle is key to implementing novel surveillance strategies to more effectively predict and prevent new disease outbreaks. Here, we demonstrate prolonged survival and subversion of intracellular digestion of Y. pestis within a soil free-living amoeba. This suggests the potential role for protozoa as a protective soil reservoir for Y. pestis, which may help explain the recrudescence of plague epizootics.
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25
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Campodonico EM, Roy CR, Ninio S. Legionella pneumophila Type IV Effectors YlfA and YlfB Are SNARE-Like Proteins that Form Homo- and Heteromeric Complexes and Enhance the Efficiency of Vacuole Remodeling. PLoS One 2016; 11:e0159698. [PMID: 27459495 PMCID: PMC4961411 DOI: 10.1371/journal.pone.0159698] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 06/13/2016] [Indexed: 11/28/2022] Open
Abstract
Legionella pneumophila is a Gram-negative bacterium that can colonize both freshwater protozoa and human alveolar macrophages, the latter infection resulting in Legionnaires’ disease. The intracellular lifecycle of L. pneumophila requires extensive manipulation of its host cell, which is carried out by effector proteins that are translocated into the host cell through the Dot/Icm type IV secretion system. This study focuses on a pair of highly similar type IV substrates called YlfA/LegC7 and YlfB/LegC2 that were initially identified in a screen for proteins that cause growth inhibition in yeast. Analysis of truncation mutants revealed that the hydrophobic residues in the Ylf amino termini were required for localization of each protein to the membranes of host cells. Central and carboxy terminal coiled coil domains were found to mediate binding of YlfA and YlfB to themselves and to each other. In vivo, a ΔylfA ΔylfB double mutant strain of L. pneumophila was shown to be defective in establishing a vacuole that supports bacterial replication. This phenotype was subsequently correlated with a decrease in the association of endoplasmic reticulum (ER)-derived vesicles with vacuoles containing ΔylfA ΔylfB mutant bacteria. These data suggest that the Ylf proteins are membrane-associated effectors that enhance remodeling of the L. pneumophila -containing vacuole by promoting association and possibly fusion of ER-derived membrane vesicles with the bacterial compartment.
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Affiliation(s)
- Eva M. Campodonico
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Craig R. Roy
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Shira Ninio
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
- The Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, Israel
- * E-mail:
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Alipour N, Gaeini N, Taner A, Yıldız F, Masseret S, Malfertheiner P. Retracted: Vacuoles ofAcanthamoeba castellaniiBehave as a Specialized Shelter (host) forHelicobacter pylori. Helicobacter 2015. [DOI: 10.1111/hel.12233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
Affiliation(s)
- Nader Alipour
- Department of Biotechnology; METU; Ankara Turkey
- Department of Medical Microbiology; Faculty of Medicine; Giresun university; Giresun Turkey
| | - Nasrin Gaeini
- Department of Radiology; Trakya University; Edirne Turkey
| | - Abbas Taner
- Department of Medical Microbiology; Yuksek ihtisas university; Ankara Turkey
| | - Fatih Yıldız
- Department of Biotechnology; METU; Ankara Turkey
| | - Sadegh Masseret
- Digestive Disease Research Center of Tehran Medical Science university; Shariati hospital; Tehran IRAN
| | - Peter Malfertheiner
- Digestive Disease Department; Otto von Guarig Clinical University; Magdeburg Germany
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Saniee P, Siavoshi F. Endocytotic uptake of FITC-labeled anti-H. pylori egg yolk immunoglobulin Y in Candida yeast for detection of intracellular H. pylori. Front Microbiol 2015; 6:113. [PMID: 25852651 PMCID: PMC4362214 DOI: 10.3389/fmicb.2015.00113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 01/29/2015] [Indexed: 01/24/2023] Open
Abstract
Intracellular life of Helicobacter pylori inside Candida yeast vacuole describes the establishment of H. pylori in yeast as a pre-adaptation to life in human epithelial cells. IgY-Hp conjugated with fluorescein isothiocyanate (FITC) has been previously used for identification and localization of H. pylori inside the yeast vacuole. Here we examined whether FITC-IgY-Hp internalization into yeast follows the endocytosis pathway in yeast. Fluorescent microscopy was used to examine the entry of FITC-IgY-Hp into Candida yeast cells at different time intervals. The effect of low temperature, H2O2 or acetic acid on the internalization of labeled antibody was also examined. FITC-IgY-Hp internalization initiated within 0-5 min in 5-10% of yeast cells, increased to 20-40% after 30 min-1 h and reached >70% before 2 h. FITC-IgY-Hp traversed the pores of Candida yeast cell wall and reached the vacuole where it bound with H. pylori antigens. Internalization of FITC-IgY-Hp was inhibited by low temperature, H2O2 or acetic acid. It was concluded that internalization of FITC-IgY-Hp into yeast cell is a vital phenomenon and follows the endocytosis pathway. Furthermore, it was proposed that FITC-IgY-Hp internalization could be recruited for localization and identification of H. pylori inside the vacuole of Candida yeast.
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Affiliation(s)
| | - Farideh Siavoshi
- Department of Microbiology, School of Biology, College of Sciences, University of Tehran, Tehran, Iran
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28
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Wheat WH, Casali AL, Thomas V, Spencer JS, Lahiri R, Williams DL, McDonnell GE, Gonzalez-Juarrero M, Brennan PJ, Jackson M. Long-term survival and virulence of Mycobacterium leprae in amoebal cysts. PLoS Negl Trop Dis 2014; 8:e3405. [PMID: 25521850 PMCID: PMC4270725 DOI: 10.1371/journal.pntd.0003405] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 11/07/2014] [Indexed: 11/18/2022] Open
Abstract
Leprosy is a curable neglected disease of humans caused by Mycobacterium leprae that affects the skin and peripheral nerves and manifests clinically in various forms ranging from self-resolving, tuberculoid leprosy to lepromatous leprosy having significant pathology with ensuing disfiguration disability and social stigma. Despite the global success of multi-drug therapy (MDT), incidences of clinical leprosy have been observed in individuals with no apparent exposure to other cases, suggestive of possible non-human sources of the bacteria. In this study we show that common free-living amoebae (FLA) can phagocytose M. leprae, and allow the bacillus to remain viable for up to 8 months within amoebic cysts. Viable bacilli were extracted from separate encysted cocultures comprising three common Acanthamoeba spp.: A. lenticulata, A. castellanii, and A. polyphaga and two strains of Hartmannella vermiformis. Trophozoites of these common FLA take up M. leprae by phagocytosis. M. leprae from infected trophozoites induced to encyst for long-term storage of the bacilli emerged viable by assessment of membrane integrity. The majority (80%) of mice that were injected with bacilli extracted from 35 day cocultures of encysted/excysted A. castellanii and A. polyphaga showed lesion development that was similar to mice challenged with fresh M. leprae from passage mice albeit at a slower initial rate. Mice challenged with coculture-extracted bacilli showed evidence of acid-fast bacteria and positive PCR signal for M. leprae. These data support the conclusion that M. leprae can remain viable long-term in environmentally ubiquitous FLA and retain virulence as assessed in the nu/nu mouse model. Additionally, this work supports the idea that M. leprae might be sustained in the environment between hosts in FLA and such residence in FLA may provide a macrophage-like niche contributing to the higher-than-expected rate of leprosy transmission despite a significant decrease in human reservoirs due to MDT.
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Affiliation(s)
- William H. Wheat
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Amy L. Casali
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | | | - John S. Spencer
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ramanuj Lahiri
- Department of Health & Human Services, HRSA, HSB, National Hansen's Disease Programs, Laboratory Research Branch, Baton Rouge, Louisiana, United States of America
- School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Diana L. Williams
- Department of Health & Human Services, HRSA, HSB, National Hansen's Disease Programs, Laboratory Research Branch, Baton Rouge, Louisiana, United States of America
- School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Gerald E. McDonnell
- Department of Research and Development, STERIS Corporation, Mentor, Ohio, United States of America
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Patrick J. Brennan
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
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29
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Zeybek Z, Binay AR. Growth ability of Gram negative bacteria in free-living amoebae. Exp Parasitol 2014; 145 Suppl:S121-6. [DOI: 10.1016/j.exppara.2014.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 06/04/2014] [Accepted: 06/12/2014] [Indexed: 11/30/2022]
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Polyketide synthase (PKS) reduces fusion of Legionella pneumophila-containing vacuoles with lysosomes and contributes to bacterial competitiveness during infection. Int J Med Microbiol 2014; 304:1169-81. [PMID: 25218702 DOI: 10.1016/j.ijmm.2014.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/14/2014] [Accepted: 08/18/2014] [Indexed: 11/22/2022] Open
Abstract
L. pneumophila-containing vacuoles (LCVs) exclude endocytic and lysosomal markers in human macrophages and protozoa. We screened a L. pneumophila mini-Tn10 transposon library for mutants, which fail to inhibit the fusion of LCVs with lysosomes by loading of the lysosomal compartment with colloidal iron dextran, mechanical lysis of infected host cells, and magnetic isolation of LCVs that have fused with lysosomes. In silico analysis of the mutated genes, D. discoideum plaque assays and infection assays in protozoa and U937 macrophage-like cells identified well established as well as novel putative L. pneumophila virulence factors. Promising candidates were further analyzed for their co-localization with lysosomes in host cells using fluorescence microscopy. This approach corroborated that the O-methyltransferase, PilY1, TPR-containing protein and polyketide synthase (PKS) of L. pneumophila interfere with lysosomal degradation. Competitive infections in protozoa and macrophages revealed that the identified PKS contributes to the biological fitness of pneumophila strains and may explain their prevalence in the epidemiology of Legionnaires' disease.
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31
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Medina G, Flores-Martin S, Fonseca B, Otth C, Fernandez H. Mechanisms associated with phagocytosis of Arcobacter butzleri by Acanthamoeba castellanii. Parasitol Res 2014; 113:1933-42. [PMID: 24652445 DOI: 10.1007/s00436-014-3842-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 02/24/2014] [Indexed: 11/28/2022]
Abstract
Acanthamoeba castellanii is a free-living amoeba widely found in environmental matrices such as soil and water. Arcobacter butzleri is an emerging potential zoonotic pathogen that can be isolated from environmental water sources, where they can establish endosymbiotic relationships with amoebas. The aim of this study was to describe the implication of mannose-binding proteins and membrane-associated receptors of glucose and galactose present in the amoebic membrane, during the attachment of Arcobacter butzleri by blocking with different saccharides. Another objective was to describe the signaling pathways involved in phagocytosis of these bacteria using specific inhibitors and analyze the implication of phagolysosome formation on the survival of Arcobacter butzleri inside the amoeba. We infer that the attachment of Arcobacter butzleri to the amoeba is a process which involves the participation of mannose-binding proteins and membrane-associated receptors of glucose and galactose present in the amoeba. We also demonstrated an active role of protozoan actin polymerization in the phagocytosis of Arcobacter butzleri and a critical involvement of PI3K and RhoA pathways. Further, we demonstrated that the tyrosine kinase-induced actin polymerization signal is essential in Acanthamoeba-mediated bacterial uptake. Through phagolysosomal formation analysis, we conclude that the survival of Arcobacter butzleri inside the amoeba could be related with the ability to remain inside vacuoles not fused with lysosomes, or with the ability to retard the fusion between these structures. All these results help the understanding of the bacterial uptake mechanisms used by Acanthamoeba castellanii and contribute to evidence of the survival mechanisms of Arcobacter butzleri.
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32
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Schuppler M. How the interaction of Listeria monocytogenes and Acanthamoeba spp. affects growth and distribution of the food borne pathogen. Appl Microbiol Biotechnol 2014; 98:2907-16. [PMID: 24557567 DOI: 10.1007/s00253-014-5546-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
Listeria monocytogenes is a foodborne opportunistic pathogen capable to switch from an environmental saprophyte to a potentially fatal human pathogen. The fact that the pathogen maintains the genes suitable for an elaborate infectious process indicates that these genes are required to survive in the environment. However, no environmental host reservoir for L. monocytogenes has been identified so far. The similarity of free-living, bacteria-scavenging amoebae to macrophages led to the hypothesis that protozoa may represent the missing link in the ecology and pathology of L. monocytogenes. Consequently, numerous studies have been published reporting on the potential of Acanthamoeba spp. to serve as host for a variety of pathogenic bacteria. However, the data on the interaction of L. monocytogenes with Acanthamoeba spp. are inconsistent and relatively little information on the impact of this interaction on growth and distribution of the foodborne pathogen is currently available. Hence, this review focuses on the interaction of L. monocytogenes and Acanthamoeba spp. affecting survival and growth of the foodborne pathogen in natural and man-made environments, in order to highlight the potential impact of this interplay on food safety and human health.
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Affiliation(s)
- Markus Schuppler
- Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092, Zurich, Switzerland,
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33
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Lutz C, Erken M, Noorian P, Sun S, McDougald D. Environmental reservoirs and mechanisms of persistence of Vibrio cholerae. Front Microbiol 2013; 4:375. [PMID: 24379807 PMCID: PMC3863721 DOI: 10.3389/fmicb.2013.00375] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 11/21/2013] [Indexed: 12/23/2022] Open
Abstract
It is now well accepted that Vibrio cholerae, the causative agent of the water-borne disease cholera, is acquired from environmental sources where it persists between outbreaks of the disease. Recent advances in molecular technology have demonstrated that this bacterium can be detected in areas where it has not previously been isolated, indicating a much broader, global distribution of this bacterium outside of endemic regions. The environmental persistence of V. cholerae in the aquatic environment can be attributed to multiple intra- and interspecific strategies such as responsive gene regulation and biofilm formation on biotic and abiotic surfaces, as well as interactions with a multitude of other organisms. This review will discuss some of the mechanisms that enable the persistence of this bacterium in the environment. In particular, we will discuss how V. cholerae can survive stressors such as starvation, temperature, and salinity fluctuations as well as how the organism persists under constant predation by heterotrophic protists.
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Affiliation(s)
- Carla Lutz
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Science, University of New South Wales Sydney, NSW, Australia
| | - Martina Erken
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Science, University of New South Wales Sydney, NSW, Australia ; Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, School of Biological Sciences, Nanyang Technological University Singapore, Singapore
| | - Parisa Noorian
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Science, University of New South Wales Sydney, NSW, Australia
| | - Shuyang Sun
- The Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University Singapore, Singapore
| | - Diane McDougald
- Centre for Marine Bio-Innovation, School of Biotechnology and Biomolecular Science, University of New South Wales Sydney, NSW, Australia ; Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, School of Biological Sciences, Nanyang Technological University Singapore, Singapore
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34
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Olofsson J, Axelsson-Olsson D, Brudin L, Olsen B, Ellström P. Campylobacter jejuni actively invades the amoeba Acanthamoeba polyphaga and survives within non digestive vacuoles. PLoS One 2013; 8:e78873. [PMID: 24223169 PMCID: PMC3819376 DOI: 10.1371/journal.pone.0078873] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 09/16/2013] [Indexed: 11/18/2022] Open
Abstract
The Gram-negative bacterium Campylobacter jejuni is able to enter, survive and multiply within the free living amoeba Acanthamoeba polyphaga, but the molecular mechanisms behind these events are still unclear. We have studied the uptake and intracellular trafficking of viable and heat killed bacterial cells of the C. jejuni strain 81–176 in A. polyphaga. We found that viable bacteria associated with a substantially higher proportion of Acanthamoeba trophozoites than heat killed bacteria. Furthermore, the kinetics of internalization, the total number of internalized bacteria as well as the intracellular localization of internalized C. jejuni were dramatically influenced by bacterial viability. Viable bacteria were internalized at a high rate already after 1 h of co-incubation and were observed in small vacuoles tightly surrounding the bacteria. In contrast, internalization of heat killed C. jejuni was low at early time points and did not peak until 96 h. These cells were gathered in large spacious vacuoles that were part of the degradative pathway as determined by the uptake of fluorescently labeled dextran. The amount of heat killed bacteria internalized by A. polyphaga did never reach the maximal amount of internalized viable bacteria. These results suggest that the uptake and intracellular survival of C. jejuni in A. polyphaga is bacterially induced.
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Affiliation(s)
- Jenny Olofsson
- Department of Medical Sciences, Infectious Diseases, Uppsala University, Uppsala, Sweden
- Section for Zoonotic Ecology and Epidemiology, School of Natural Sciences, Linnaeus University, Kalmar, Sweden
- * E-mail:
| | - Diana Axelsson-Olsson
- Marine Microbiology, School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | - Lars Brudin
- Department of Clinical Physiology, Kalmar County Hospital, Kalmar, Sweden
- Department of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Björn Olsen
- Department of Medical Sciences, Infectious Diseases, Uppsala University, Uppsala, Sweden
- Section for Zoonotic Ecology and Epidemiology, School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | - Patrik Ellström
- Department of Medical Sciences, Clinical Bacteriology, Uppsala University, Uppsala, Sweden
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Sánchez-Busó L, Coscollá M, Pinto-Carbó M, Catalán V, González-Candelas F. Genetic Characterization of Legionella pneumophila Isolated from a Common Watershed in Comunidad Valenciana, Spain. PLoS One 2013; 8:e61564. [PMID: 23634210 PMCID: PMC3636276 DOI: 10.1371/journal.pone.0061564] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/11/2013] [Indexed: 11/19/2022] Open
Abstract
Legionella pneumophila infects humans to produce legionellosis and Pontiac fever only from environmental sources. In order to establish control measures and study the sources of outbreaks it is essential to know extent and distribution of strain variants of this bacterium in the environment. Sporadic and outbreak-related cases of legionellosis have been historically frequent in the Comunidad Valenciana region (CV, Spain), with a high prevalence in its Southeastern-most part (BV). Environmental investigations for the detection of Legionella pneumophila are performed in this area routinely. We present a population genetics study of 87 L. pneumophila strains isolated in 13 different localities of the BV area irrigated from the same watershed and compare them to a dataset of 46 strains isolated in different points of the whole CV. Our goal was to compare environmental genetic variation at two different geographic scales, at county and regional levels. Genetic diversity, recombination and population structure were analyzed with Sequence-Based Typing data and three intergenic regions. The results obtained reveal a low, but detectable, level of genetic differentiation between both datasets, mainly, but not only, attributed to the occurrence of unusual variants of the neuA locus present in the BV populations. This differentiation is still detectable when the 10 loci considered are analyzed independently, despite the relatively high incidence of the most common genetic variant in this species, sequence type 1 (ST-1). However, when the genetic data are considered without their associated geographic information, four major groups could be inferred at the genetic level which did not show any correlation with sampling locations. The overall results indicate that the population structure of these environmental samples results from the joint action of a global, widespread ST-1 along with genetic differentiation at shorter geographic distances, which in this case are related to the common watershed for the BV localities.
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Affiliation(s)
- Leonor Sánchez-Busó
- Genomics and Health Joint Unit CSISP (FISABIO)-University of Valencia/Cavanilles Institute, Valencia, Spain
- CIBER Epidemiology and Public Health, Valencia, Spain
| | - Mireia Coscollá
- Tuberculosis Research Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Marta Pinto-Carbó
- Genomics and Health Joint Unit CSISP (FISABIO)-University of Valencia/Cavanilles Institute, Valencia, Spain
| | | | - Fernando González-Candelas
- Genomics and Health Joint Unit CSISP (FISABIO)-University of Valencia/Cavanilles Institute, Valencia, Spain
- CIBER Epidemiology and Public Health, Valencia, Spain
- * E-mail:
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36
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Escoll P, Rolando M, Gomez-Valero L, Buchrieser C. From amoeba to macrophages: exploring the molecular mechanisms of Legionella pneumophila infection in both hosts. Curr Top Microbiol Immunol 2013; 376:1-34. [PMID: 23949285 DOI: 10.1007/82_2013_351] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Legionella pneumophila is a Gram-negative bacterium and the causative agent of Legionnaires' disease. It replicates within amoeba and infects accidentally human macrophages. Several similarities are seen in the L. pneumophila-infection cycle in both hosts, suggesting that the tools necessary for macrophage infection may have evolved during co-evolution of L. pneumophila and amoeba. The establishment of the Legionella-containing vacuole (LCV) within the host cytoplasm requires the remodeling of the LCV surface and the hijacking of vesicles and organelles. Then L. pneumophila replicates in a safe intracellular niche in amoeba and macrophages. In this review we will summarize the existing knowledge of the L. pneumophila infection cycle in both hosts at the molecular level and compare the factors involved within amoeba and macrophages. This knowledge will be discussed in the light of recent findings from the Acanthamoeba castellanii genome analyses suggesting the existence of a primitive immune-like system in amoeba.
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Affiliation(s)
- Pedro Escoll
- Institut Pasteur, Biologie des Bactéries Intracellulaires and CNRS UMR, 3525, Paris, France
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37
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Doyscher D, Fieseler L, Dons L, Loessner MJ, Schuppler M. Acanthamoebafeature a unique backpacking strategy to trap and feed onListeria monocytogenesand other motile bacteria. Environ Microbiol 2012; 15:433-46. [DOI: 10.1111/j.1462-2920.2012.02858.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 07/05/2012] [Accepted: 07/24/2012] [Indexed: 12/28/2022]
Affiliation(s)
- Dominik Doyscher
- Institute of Food, Nutrition and Health; ETH Zurich; Schmelzbergstrasse 7; 8092; Zurich; Switzerland
| | | | - Lone Dons
- Department of Food Science; University of Copenhagen; Rolighedsvej 30; DK-1958; Frederiksberg C; Denmark
| | - Martin J. Loessner
- Institute of Food, Nutrition and Health; ETH Zurich; Schmelzbergstrasse 7; 8092; Zurich; Switzerland
| | - Markus Schuppler
- Institute of Food, Nutrition and Health; ETH Zurich; Schmelzbergstrasse 7; 8092; Zurich; Switzerland
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38
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Functional expression and characterization of an iron-containing superoxide dismutase of Acanthamoeba castellanii. Parasitol Res 2012; 111:1673-82. [PMID: 22752747 DOI: 10.1007/s00436-012-3006-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 06/08/2012] [Indexed: 10/28/2022]
Abstract
Acanthamoeba spp. are free-living amoebae, but opportunistic infections of some strains of the organisms cause severe diseases such as acanthamoebic keratitis, pneumonitis, and granulomatous amoebic encephalitis in human. In this study, we identified a gene encoding iron superoxide dismutase of Acanthamoeba castellanii (AcFe-SOD) and characterized biochemical and functional properties of the recombinant enzyme. Multiple sequence alignment of the deduced amino acid sequence of AcFe-SOD with those of previously reported iron-containing SODs (Fe-SODs) from other protozoan parasites showed that AcFe-SOD shared common metal-binding residues and motifs that are conserved in Fe-SODs. The genomic length of the AcFe-SOD gene was 926 bp consisting of five exons interrupted by four introns. The recombinant AcFe-SOD showed similar biochemical characteristics with its native enzyme and shared typical biochemical properties with other characterized Fe-SODs, including molecular structure, broad pH optimum, and sensitivity to hydrogen peroxide. Immunolocalization analysis revealed that the enzyme localized in the cytosol of the trophozoites. Activity and expression level of the enzyme were significantly increased under oxidative stressed conditions. These results collectively suggest that AcFe-SOD may play essential roles in the survival of the parasite not only by protecting itself from endogenous oxidative stress but also by detoxifying oxidative killing of the parasite by host immune effector cells.
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39
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Iwashkiw JA, Seper A, Weber BS, Scott NE, Vinogradov E, Stratilo C, Reiz B, Cordwell SJ, Whittal R, Schild S, Feldman MF. Identification of a general O-linked protein glycosylation system in Acinetobacter baumannii and its role in virulence and biofilm formation. PLoS Pathog 2012; 8:e1002758. [PMID: 22685409 PMCID: PMC3369928 DOI: 10.1371/journal.ppat.1002758] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/01/2012] [Indexed: 01/12/2023] Open
Abstract
Acinetobacter baumannii is an emerging cause of nosocomial infections. The isolation of strains resistant to multiple antibiotics is increasing at alarming rates. Although A. baumannii is considered as one of the more threatening “superbugs” for our healthcare system, little is known about the factors contributing to its pathogenesis. In this work we show that A. baumannii ATCC 17978 possesses an O-glycosylation system responsible for the glycosylation of multiple proteins. 2D-DIGE and mass spectrometry methods identified seven A. baumannii glycoproteins, of yet unknown function. The glycan structure was determined using a combination of MS and NMR techniques and consists of a branched pentasaccharide containing N-acetylgalactosamine, glucose, galactose, N-acetylglucosamine, and a derivative of glucuronic acid. A glycosylation deficient strain was generated by homologous recombination. This strain did not show any growth defects, but exhibited a severely diminished capacity to generate biofilms. Disruption of the glycosylation machinery also resulted in reduced virulence in two infection models, the amoebae Dictyostelium discoideum and the larvae of the insect Galleria mellonella, and reduced in vivo fitness in a mouse model of peritoneal sepsis. Despite A. baumannii genome plasticity, the O-glycosylation machinery appears to be present in all clinical isolates tested as well as in all of the genomes sequenced. This suggests the existence of a strong evolutionary pressure to retain this system. These results together indicate that O-glycosylation in A. baumannii is required for full virulence and therefore represents a novel target for the development of new antibiotics. Multidrug resistant (MDR) Acinetobacter baumannii strains are an increasing cause of nosocomial infections worldwide. Due to the remarkable ability of A. baumannii to gain resistance to antibiotics, this bacterium is now considered to be a “superbug”. A. baumannii strains resistant to all clinically relevant antibiotics known have also been isolated. Although MDR A. baumannii continues to disseminate globally, very little is known about its pathogenesis mechanisms. Our experiments revealed that A. baumannii ATCC 17978 has a functional O-linked protein glycosylation system, which seems to be present in all strains of A. baumannii sequenced to date and several clinical isolates. We identified seven glycoproteins and elucidated the structure of the glycan moiety. A glycosylation-deficient strain was generated. This strain produced severely reduced biofilms, and exhibited attenuated virulence in amoeba, insect, and murine models. These experiments suggest that glycosylation may play an important role in virulence and may lay the foundation for new drug discovery strategies that could stop the dissemination of this emerging human pathogen, which has become a major threat for healthcare systems.
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Affiliation(s)
- Jeremy A. Iwashkiw
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Andrea Seper
- Institut fuer Molekulare Biowissenschaften, Karl-Franzens-Universitaet Graz, Graz, Austria
| | - Brent S. Weber
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Nichollas E. Scott
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, New South Wales, Australia
| | - Evgeny Vinogradov
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada
| | - Chad Stratilo
- Defence Research and Development Canada Suffield, Medicine Hat, Alberta, Canada
| | - Bela Reiz
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Stuart J. Cordwell
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, New South Wales, Australia
| | - Randy Whittal
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Stefan Schild
- Institut fuer Molekulare Biowissenschaften, Karl-Franzens-Universitaet Graz, Graz, Austria
| | - Mario F. Feldman
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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Qin T, Iida KI, Piao Z, Shiota S, Ren H, Shao Z, Yoshida SI. Importance of the icmN gene in the growth of Legionella pneumophila in amoebic cells at low temperature. Can J Microbiol 2012; 58:490-501. [PMID: 22435730 DOI: 10.1139/w2012-011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Legionella pneumophila grows in amoebae and has achieved the ability to grow at various temperatures, although the mechanisms controlling this ability remain poorly understood. The Icm/Dot type IVB secretion system is composed of more than 25 proteins and is known to be essential for intracellular growth. The role of the icmN gene in intracellular multiplication and the effects of culture temperatures on it are not precisely understood. We conducted our investigation using an icmN mutant made by gene replacement mutagenesis. Intracellular growth of the mutant was impaired both in mammalian macrophages and amoeba at 37 °C. In particular, intracellular growth in amoebae was completely impaired at 25 °C. It was found that genes from icmN to icmC formed an operon, i.e., icmN, -M, -L, -E, -G, -C,, and the promoter activity of the icmN operon was stronger at 25 than at 37 °C. It was suggested that icmM and its downstream genes had a secondary promoter that enables icmN mutant grow in amoebae at lower temperatures and macrophages at 37 °C. These results show that the icmN promoter has a low temperature inducible nature, and gene products of the icmN operon require high expression for bacterial proliferation at low temperatures within amoeba.
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Affiliation(s)
- Tian Qin
- Department of Bacteriology, Division of Oral Infectious Diseases and Immunology, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan.
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Bui XT, Winding A, Qvortrup K, Wolff A, Bang DD, Creuzenet C. Survival of Campylobacter jejuni in co-culture with Acanthamoeba castellanii: role of amoeba-mediated depletion of dissolved oxygen. Environ Microbiol 2011; 14:2034-47. [PMID: 22176643 DOI: 10.1111/j.1462-2920.2011.02655.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Campylobacter jejuni is a major cause of infectious diarrhoea worldwide but relatively little is known about its ecology. In this study, we examined its interactions with Acanthamoeba castellanii, a protozoan suspected to serve as a reservoir for bacterial pathogens. We observed rapid degradation of intracellular C.jejuni in A.castellanii 5 h post gentamicin treatment at 25°C. Conversely, we found that A.castellanii promoted the extracellular growth of C.jejuni in co-cultures at 37°C in aerobic conditions. This growth-promoting effect did not require amoebae - bacteria contact. The growth rates observed with or without contact with amoeba were similar to those observed when C.jejuni was grown in microaerophilic conditions. Preconditioned media prepared with live or dead amoebae cultivated with or without C.jejuni did not promote the growth of C.jejuni in aerobic conditions. Interestingly, the dissolved oxygen levels of co-cultures with or without amoebae - bacteria contact were much lower than those observed with culture media or with C.jejuni alone incubated in aerobic conditions, and were comparable with levels obtained after 24 h of growth of C.jejuni under microaerophilic conditions. Our studies identified the depletion of dissolved oxygen by A.castellanii as the major contributor for the observed amoeba-mediated growth enhancement.
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Affiliation(s)
- Xuan Thanh Bui
- Laboratory of Applied Micro and Nanotechnology (LAMINATE), National Veterinary Institute (VET), Technical University of Denmark (DTU), Hangøvej 2, DK-8200 Aarhus N, Denmark
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Matin A, Jung SY. Interaction of Escherichia coli K1 and K5 with Acanthamoeba castellanii trophozoites and cysts. THE KOREAN JOURNAL OF PARASITOLOGY 2011; 49:349-56. [PMID: 22355201 PMCID: PMC3279672 DOI: 10.3347/kjp.2011.49.4.349] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 09/22/2011] [Accepted: 09/22/2011] [Indexed: 11/23/2022]
Abstract
The existence of symbiotic relationships between Acanthamoeba and a variety of bacteria is well-documented. However, the ability of Acanthamoeba interacting with host bacterial pathogens has gained particular attention. Here, to understand the interactions of Escherichia coli K1 and E. coli K5 strains with Acanthamoeba castellanii trophozoites and cysts, association assay, invasion assay, survival assay, and the measurement of bacterial numbers from cysts were performed, and nonpathogenic E. coli K12 was also applied. The association ratio of E. coli K1 with A. castellanii was 4.3 cfu per amoeba for 1 hr but E. coli K5 with A. castellanii was 1 cfu per amoeba for 1 hr. By invasion and survival assays, E. coli K5 was recovered less than E. coli K1 but still alive inside A. castellanii. E. coli K1 and K5 survived and multiplied intracellularly in A. castellanii. The survival assay was performed under a favourable condition for 22 hr and 43 hr with the encystment of A. castellanii. Under the favourable condition for the transformation of trophozoites into cysts, E. coli K5 multiplied significantly. Moreover, the pathogenic potential of E. coli K1 from A. castellanii cysts exhibited no changes as compared with E. coli K1 from A. castellanii trophozoites. E. coli K5 was multiplied in A. castellanii trophozoites and survived in A. castellanii cysts. Therefore, this study suggests that E. coli K5 can use A. castellanii as a reservoir host or a vector for the bacterial transmission.
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Affiliation(s)
- Abdul Matin
- Institute of Biomedical & Genetic Engineering, PO Box 2891, Islamabad, Pakistan
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RpkA, a highly conserved GPCR with a lipid kinase domain, has a role in phagocytosis and anti-bacterial defense. PLoS One 2011; 6:e27311. [PMID: 22073313 PMCID: PMC3206951 DOI: 10.1371/journal.pone.0027311] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 10/13/2011] [Indexed: 12/03/2022] Open
Abstract
RpkA (Receptor phosphatidylinositol kinase A) is an unusual seven-helix transmembrane protein of Dictyostelium discoideum with a G protein coupled receptor (GPCR) signature and a C-terminal lipid kinase domain (GPCR-PIPK) predicted as a phosphatidylinositol-4-phosphate 5-kinase. RpkA-homologs are present in all so far sequenced Dictyostelidae as well as in several other lower eukaryotes like the oomycete Phytophthora, and in the Legionella host Acanthamoeba castellani. Here we show by immunofluorescence that RpkA localizes to endosomal membranes and is specifically recruited to phagosomes. RpkA interacts with the phagosomal protein complex V-ATPase as proteins of this complex co-precipitate with RpkA-GFP as well as with the GST-tagged PIPK domain of RpkA. Loss of RpkA leads to a defect in phagocytosis as measured by yeast particle uptake. The uptake of the pathogenic bacterium Legionella pneumophila was however unaltered whereas its intra-cellular replication was significantly enhanced in rpkA-. The difference between wild type and rpkA- was even more prominent when L. hackeliae was used. When we investigated the reason for the enhanced susceptibility for L. pneumophila of rpkA- we could not detect a difference in endosomal pH but rpkA- showed depletion of phosphoinositides (PIP and PIP2) when we compared metabolically labeled phosphoinositides from wild type and rpkA-. Furthermore rpkA- exhibited reduced nitrogen starvation tolerance, an indicator for a reduced autophagy rate. Our results indicate that RpkA is a component of the defense system of D. discoideum as well as other lower eukaryotes.
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Thomas JM, Ashbolt NJ. Do free-living amoebae in treated drinking water systems present an emerging health risk? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:860-9. [PMID: 21194220 DOI: 10.1021/es102876y] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
There is an expanding body of evidence that free-living amoebae (FLA) increase both the numbers and virulence of water-based, human-pathogenic, amoeba-resisting microorganisms (ARM). Legionella spp., Mycobacterium spp., and other opportunistic human pathogens are known to be both ARM and also the etiologic agents of potentially fatal human lung infections. However, comparatively little is known about the FLA that may facilitate ARM growth in drinking water. This review examines the available literature on FLA in treated drinking water systems; in total 26 studies from 18 different countries. FLA were reported to breakthrough the water treatment barrier and enter distribution systems, in addition to the expected post-treatment system ingress. Once in the distribution system there is evidence of FLA colonization and regrowth especially in reservoirs and in-premise plumbing storage tanks. At the point of use the average FLA detection rate was 45% but highly variable (n = 16, σ = 31) due to both differences in both assay methods and the type of water systems examined. This review reveals that FLA are consistently detected in treated drinking water systems around the world and present a yet unquantified emerging health risk. However, more research is urgently required before accurate risks assessments can be undertaken to assess the impacts on human health, in households and institutions, due to exposure to FLA facilitated pathogenic ARM.
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Affiliation(s)
- Jacqueline M Thomas
- Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, NSW 2052 Australia.
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Khweek AA, Amer A. Replication of Legionella Pneumophila in Human Cells: Why are We Susceptible? Front Microbiol 2010; 1:133. [PMID: 21687775 PMCID: PMC3109522 DOI: 10.3389/fmicb.2010.00133] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 11/16/2010] [Indexed: 11/13/2022] Open
Abstract
Legionella pneumophila is the causative agent of Legionnaires’ disease, a serious and often fatal form of pneumonia. The susceptibility to L. pneumophila arises from the ability of this intracellular pathogen to multiply in human alveolar macrophages and monocytes. L. pneumophila also replicates in several professional and non-professional phagocytic human-derived cell lines. With the exception of the A/J mouse strain, most mice strains are restrictive, thus they do not support L. pneumophila replication. Mice lacking the NOD-like receptor Nlrc4 or caspase-1 are also susceptible to L. pneumophila. On the other hand, in the susceptible human hosts, L. pneumophila utilizes several strategies to ensure intracellular replication and protect itself against the host immune system. Most of these strategies converge to prevent the fusion of the L. pneumophila phagosome with the lysosome, inhibiting host cell apoptosis, activating survival pathways, and sequestering essential nutrients for replication and pathogenesis. In this review, we summarize survival mechanisms employed by L. pneumophila to maintain its replication in human cells. In addition, we highlight different human-derived cell lines that support the multiplication of this intracellular bacterium. Therefore, these in vitro models can be applicable and are reproducible when investigating L. pneumophila/phagocyte interactions at the molecular and cellular levels in the human host.
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Affiliation(s)
- Arwa Abu Khweek
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Center for Microbial Interface Biology and the Department of Internal Medicine, Ohio State University Columbus, OH, USA
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Proteomic analysis of growth phase-dependent expression of Legionella pneumophila proteins which involves regulation of bacterial virulence traits. PLoS One 2010; 5:e11718. [PMID: 20661449 PMCID: PMC2908689 DOI: 10.1371/journal.pone.0011718] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 06/17/2010] [Indexed: 01/05/2023] Open
Abstract
Legionella pneumophila, which is a causative pathogen of Legionnaires' disease, expresses its virulent traits in response to growth conditions. In particular, it is known to become virulent at a post-exponential phase in vitro culture. In this study, we performed a proteomic analysis of differences in expression between the exponential phase and post-exponential phase to identify candidates associated with L. pneumophila virulence using 2-Dimentional Fluorescence Difference Gel Electrophoresis (2D-DIGE) combined with Matrix-Assisted Laser Desorption/Ionization–Mass Spectrometry (MALDI-TOF-MS). Of 68 identified proteins that significantly differed in expression between the two growth phases, 64 were up-regulated at a post-exponential phase. The up-regulated proteins included enzymes related to glycolysis, ketone body biogenesis and poly-3-hydroxybutyrate (PHB) biogenesis, suggesting that L. pneumophila may utilize sugars and lipids as energy sources, when amino acids become scarce. Proteins related to motility (flagella components and twitching motility-associated proteins) were also up-regulated, predicting that they enhance infectivity of the bacteria in host cells under certain conditions. Furthermore, 9 up-regulated proteins of unknown function were found. Two of them were identified as novel bacterial factors associated with hemolysis of sheep red blood cells (SRBCs). Another 2 were found to be translocated into macrophages via the Icm/Dot type IV secretion apparatus as effector candidates in a reporter assay with Bordetella pertussis adenylate cyclase. The study will be helpful for virulent analysis of L. pneumophila from the viewpoint of physiological or metabolic modulation dependent on growth phase.
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Abstract
The genus Legionella contains more than 50 species, of which at least 24 have been associated with human infection. The best-characterized member of the genus, Legionella pneumophila, is the major causative agent of Legionnaires' disease, a severe form of acute pneumonia. L. pneumophila is an intracellular pathogen, and as part of its pathogenesis, the bacteria avoid phagolysosome fusion and replicate within alveolar macrophages and epithelial cells in a vacuole that exhibits many characteristics of the endoplasmic reticulum (ER). The formation of the unusual L. pneumophila vacuole is a feature of its interaction with the host, yet the mechanisms by which the bacteria avoid classical endosome fusion and recruit markers of the ER are incompletely understood. Here we review the factors that contribute to the ability of L. pneumophila to infect and replicate in human cells and amoebae with an emphasis on proteins that are secreted by the bacteria into the Legionella vacuole and/or the host cell. Many of these factors undermine eukaryotic trafficking and signaling pathways by acting as functional and, in some cases, structural mimics of eukaryotic proteins. We discuss the consequences of this mimicry for the biology of the infected cell and also for immune responses to L. pneumophila infection.
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Singer M. Pathogen-pathogen interaction: a syndemic model of complex biosocial processes in disease. Virulence 2010; 1:10-8. [PMID: 21178409 PMCID: PMC3080196 DOI: 10.4161/viru.1.1.9933] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 08/24/2009] [Accepted: 08/27/2009] [Indexed: 11/19/2022] Open
Abstract
There is growing awareness of the health implications of fact that infectious agents often do not act independently; rather their disease potential is mediated in diverse and significant ways by their relationships with other pathogens. Pathogen-pathogen interaction (PPI), for example, impacts various virulence factors in human infection. Although still in its infancy, the study of PPI, a form of epidemiological synergism, is emerging as an important arena of new research and new understanding in health and clinical care. The aims of this paper are to: 1) draw attention to the role of PPI in human disease patterns; 2) present the syndemics model as a biosocial approach for examining the nature, pathways, contexts, and health implications of PPI; and 3) suggest the utility of this approach to PPI. Toward these ends, this paper (a) reviews three of case examples of alternative PPIs, (b) describes the development and key concepts and components of the syndemics model with specific reference to interacting infectious agents, (c) contextualizes this discussion with a brief review of broader syndemics disease processes (not necessarily involving infections disease), and (d) comments on the research, treatment and prevention implications of syndemic interaction among pathogens.
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Affiliation(s)
- Merrill Singer
- University of Connecticut, Center for Health, Intervention and Prevention, Storrs, CT, USA.
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Molmeret M, Jones S, Santic M, Habyarimana F, Esteban MTG, Kwaik YA. Temporal and spatial trigger of post-exponential virulence-associated regulatory cascades by Legionella pneumophila after bacterial escape into the host cell cytosol. Environ Microbiol 2009; 12:704-15. [PMID: 19958381 DOI: 10.1111/j.1462-2920.2009.02114.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During late stages of infection and prior to lysis of the infected macrophages or amoeba, the Legionella pneumophila-containing phagosome becomes disrupted, followed by bacterial escape into the host cell cytosol, where the last few rounds of bacterial proliferation occur prior to lysis of the plasma membrane. This coincides with growth transition into the post-exponential (PE) phase, which is controlled by regulatory cascades including RpoS and the LetA/S two-component regulator. Whether the temporal expression of flagella by the regulatory cascades at the PE phase is exhibited within the phagosome or after bacterial escape into the host cell cytosol is not known. We have utilized fluorescence microscopy-based phagosome integrity assay to differentiate between vacuolar and cytosolic bacteria/or bacteria within disrupted phagosomes. Our data show that during late stages of infection, expression of FlaA is triggered after bacterial escape into the macrophage cytosol and the peak of FlaA expression is delayed for few hours after cytosolic residence of the bacteria. Importantly, bacterial escape into the host cell cytosol is independent of flagella, RpoS and the two-component regulator LetA/S, which are all triggered by L. pneumophila upon growth transition into the PE phase. Disruption of the phagosome and bacterial escape into the cytosol of macrophages is independent of the bacterial pore-forming activity, and occurs prior to the induction of apoptosis during late stages of infection. We conclude that the temporal and spatial engagement of virulence-associated regulatory cascades by L. pneumophila at the PE phase is temporally and spatially triggered after phagosomal escape and bacterial residence in the host cell cytosol.
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Affiliation(s)
- Maëlle Molmeret
- Department of Microbiology and Immunology, Room MS-410, University of Louisville College of Medicine, Louisville, KY 40292, USA
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Akya A, Pointon A, Thomas C. Listeria monocytogenes does not survive ingestion by Acanthamoeba polyphaga. MICROBIOLOGY-SGM 2009; 156:809-818. [PMID: 19892759 DOI: 10.1099/mic.0.031146-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Listeria monocytogenes is a ubiquitous bacterium capable of infecting humans, particularly pregnant women and immunocompromised individuals. Although the intracellular invasion and pathogenesis of listeriosis in mammalian tissues has been well studied, little is known about the ecology of L. monocytogenes , and in particular the environmental reservoir for this bacterium has not been identified. This study used short-term co-culture at 15, 22 and 37 degrees C to examine the interaction of L. monocytogenes strains with Acanthamoeba polyphaga ACO12. Survival of L. monocytogenes cells phagocytosed by monolayers of trophozoites was assessed by culture techniques and microscopy. A. polyphaga trophozoites eliminated bacterial cells within a few hours post-phagocytosis, irrespective of the incubation temperature used. Wild-type L. monocytogenes and a phenotypic listeriolysin O mutant were unable to either multiply or survive within trophozoites. By contrast, Salmonella enterica serovar Typhimurium C5 cells used as controls were able to survive and multiply within A. polyphaga trophozoites. The data presented indicate that A. polyphaga ACO12 is unlikely to harbour L. monocytogenes, or act as an environmental reservoir for this bacterium.
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Affiliation(s)
- Alisha Akya
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide 5005, Australia
| | - Andrew Pointon
- South Australian Research and Development Institute, Glenside, South Australia
| | - Connor Thomas
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide 5005, Australia
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