scholarly journals Balamuthia mandrillaris, Free-Living Ameba and Opportunistic Agent of Encephalitis, Is a Potential Host for Legionella pneumophila Bacteria

2005 ◽  
Vol 71 (5) ◽  
pp. 2244-2249 ◽  
Author(s):  
Winlet Sheba Shadrach ◽  
Kerstin Rydzewski ◽  
Ulrike Laube ◽  
Gudrun Holland ◽  
Muhsin Özel ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Mammalian Cells ◽  
Mammalian Species ◽  
Acanthamoeba Castellanii ◽  
Electron Microscopic ◽  
Free Living ◽  
Balamuthia Mandrillaris ◽  
Microscopic Studies ◽  
Legionnaires Disease ◽  
Free Living Ameba

ABSTRACT Balamuthia mandrillaris is a free-living ameba and an opportunistic agent of granulomatous encephalitis in humans and other mammalian species. Other free-living amebas, such as Acanthamoeba and Hartmannella, can provide a niche for intracellular survival of bacteria, including the causative agent of Legionnaires' disease, Legionella pneumophila. Infection of amebas by L. pneumophila enhances the bacterial infectivity for mammalian cells and lung tissues. Likewise, the pathogenicity of amebas may be enhanced when they host bacteria. So far, the colonization of B. mandrillaris by bacteria has not been convincingly shown. In this study, we investigated whether this ameba could host L. pneumophila bacteria. Our experiments showed that L. pneumophila could initiate uptake by B. mandrillaris and could replicate within the ameba about 4 to 5 log cycles from 24 to 72 h after infection. On the other hand, a dotA mutant, known to be unable to propagate in Acanthamoeba castellanii, also did not replicate within B. mandrillaris. Approaching completion of the intracellular cycle, L. pneumophila wild-type bacteria were able to destroy their ameboid hosts. Observations by light microscopy paralleled our quantitative data and revealed the rounding, collapse, clumping, and complete destruction of the infected amebas. Electron microscopic studies unveiled the replication of the bacteria in a compartment surrounded by a structure resembling rough endoplasmic reticulum. The course of intracellular infection, the degree of bacterial multiplication, and the ultrastructural features of a L. pneumophila-infected B. mandrillaris ameba resembled those described for other amebas hosting Legionella bacteria. We hence speculate that B. mandrillaris might serve as a host for bacteria in its natural environment.

scholarly journals Highlighting the Potency of Biosurfactants Produced by Pseudomonas Strains as Anti-Legionella Agents

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Clémence Loiseau ◽  
Emilie Portier ◽  
Marie-Hélène Corre ◽  
Margot Schlusselhuber ◽  
Ségolène Depayras ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Close Association ◽  
Water Systems ◽  
Antagonistic Activity ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Free Living ◽  
Legionnaires Disease ◽  
Culture Supernatants ◽  
Multispecies Biofilms

Legionella pneumophila, the causative agent of Legionnaires’ disease, is a waterborne bacterium mainly found in man-made water systems in close association with free-living amoebae and multispecies biofilms. Pseudomonas strains, originating from various environments including freshwater systems or isolated from hospitalized patients, were tested for their antagonistic activity towards L. pneumophila. A high amount of tested strains was thus found to be active. This antibacterial activity was correlated to the presence of tensioactive agents in culture supernatants. As Pseudomonas strains were known to produce biosurfactants, these compounds were specifically extracted and purified from active strains and further characterized using reverse-phase HPLC and mass spectrometry methods. Finally, all biosurfactants tested (lipopeptides and rhamnolipids) were found active and this activity was shown to be higher towards Legionella strains compared to various other bacteria. Therefore, described biosurfactants are potent anti-Legionella agents that could be used in the water treatment industry although tests are needed to evaluate how effective they would be under field conditions.

scholarly journals Peptidyl-Prolyl-cis/trans-Isomerases Mip and PpiB ofLegionella pneumophilaContribute to Surface Translocation, Growth at Suboptimal Temperature, and Infection

2018 ◽  
Vol 87 (1) ◽  
Author(s):  
J. Rasch ◽  
C. M. Ünal ◽  
A. Klages ◽  
Ü. Karsli ◽  
N. Heinsohn ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Acanthamoeba Castellanii ◽  
Temperature Tolerance ◽  
Lung Damage ◽  
Atypical Pneumonia ◽  
Content Type ◽  
Wide Range ◽  
Legionnaires Disease ◽  
Environmental Fitness ◽  
Sliding Motility

ABSTRACTThe gammaproteobacteriumLegionella pneumophilais the causative agent of Legionnaires’ disease, an atypical pneumonia that manifests itself with severe lung damage.L. pneumophila, a common inhabitant of freshwater environments, replicates in free-living amoebae and persists in biofilms in natural and man-made water systems. Its environmental versatility is reflected in its ability to survive and grow within a broad temperature range as well as its capability to colonize and infect a wide range of hosts, including protozoa and humans. Peptidyl-prolyl-cis/trans-isomerases (PPIases) are multifunctional proteins that are mainly involved in protein folding and secretion in bacteria. InL. pneumophilathe surface-associated PPIase Mip was shown to facilitate the establishment of the intracellular infection cycle in its early stages. The cytoplasmic PpiB was shown to promote cold tolerance. Here, we set out to analyze the interrelationship of these two relevant PPIases in the context of environmental fitness and infection. We demonstrate that the PPIases Mip and PpiB are important for surfactant-dependent sliding motility and adaptation to suboptimal temperatures, features that contribute to the environmental fitness ofL. pneumophila. Furthermore, they contribute to infection of the natural hostAcanthamoeba castellaniias well as human macrophages and human explanted lung tissue. These effects were additive in the case of sliding motility or synergistic in the case of temperature tolerance and infection, as assessed by the behavior of the double mutant. Accordingly, we propose that Mip and PpiB are virulence modulators ofL. pneumophilawith compensatory action and pleiotropic effects.

scholarly journals Mitigation of Expression of Virulence Genes in Legionella pneumophila Internalized in the Free-Living Amoeba Willaertia magna C2c Maky

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 447 ◽  
Author(s):  
Rayane Mouh Mameri ◽  
Jacques Bodennec ◽  
Laurent Bezin ◽  
Sandrine Demanèche
Keyword(s):  
Gene Expression ◽  
Legionella Pneumophila ◽  
Virulence Genes ◽  
Natural Habitat ◽  
Acanthamoeba Castellanii ◽  
Severe Form ◽  
Aquatic Environments ◽  
Free Living ◽  
Intracellular Parasites ◽  
Free Living Amoeba

Legionella pneumophila is a human pathogen responsible for a severe form of pneumonia named Legionnaire disease. Its natural habitat is aquatic environments, being in a free state or intracellular parasites of free-living amoebae, such as Acanthamoeba castellanii. This pathogen is able to replicate within some amoebae. Willaertia magna C2c Maky, a non-pathogenic amoeba, was previously demonstrated to resist to L. pneumophila and even to be able to eliminate the L. pneumophila strains Philadelphia, Lens, and Paris. Here, we studied the induction of seven virulence genes of three L. pneumophila strains (Paris, Philadelphia, and Lens) within W. magna C2c Maky in comparison within A. castellanii and with the gene expression level of L. pneumophila strains alone used as controls. We defined a gene expression-based virulence index to compare easily and without bias the transcript levels in different conditions and demonstrated that W. magna C2c Maky did not increase the virulence of L. pneumophila strains in contrast to A. castellanii. These results confirmed the non-permissiveness of W. magna C2c Maky toward L. pneumophila strains.

scholarly journals Legionella pneumophila Contains a Type II General Secretion Pathway Required for Growth in Amoebae as Well as for Secretion of the Msp Protease

1999 ◽  
Vol 67 (7) ◽  
pp. 3662-3666 ◽  
Author(s):  
Laura M. Hales ◽  
Howard A. Shuman
Keyword(s):  
Legionella Pneumophila ◽  
Acanthamoeba Castellanii ◽  
Gram Negative Bacteria ◽  
Type Ii ◽  
Free Living ◽  
Gram Negative ◽  
Secretion Pathway ◽  
Free Living Amoeba ◽  
Substitution Mutation

ABSTRACT We report the identification of a set of Legionella pneumophila genes that encode products with homology to proteins of the type II general secretion pathway of gram-negative bacteria. A strain containing a deletion-substitution mutation of two of these genes was unable to secrete the Msp protease. This strain was unable to multiply within the free-living amoeba Acanthamoeba castellanii yet was able to kill HL-60-derived macrophages. Because Msp is not required for growth in amoebae, other proteins which are important for growth in amoebae are likely secreted by this pathway.

scholarly journals Cationic Porphyrins as Effective Agents in Photodynamic Inactivation of Opportunistic Plumbing Pathogen Legionella pneumophila

2020 ◽  
Vol 21 (15) ◽  
pp. 5367 ◽  
Author(s):  
Andrija Lesar ◽  
Martina Mušković ◽  
Gabrijela Begić ◽  
Martin Lončarić ◽  
Dijana Tomić Linšak ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Tap Water ◽  
Health Hazard ◽  
Acanthamoeba Castellanii ◽  
Water Disinfection ◽  
Cell Membrane Permeability ◽  
Photodynamic Inactivation ◽  
Cationic Porphyrins ◽  
Environmental Bacterium ◽  
Legionnaires Disease

Legionella pneumophila is an environmental bacterium, an opportunistic premise plumbing pathogen that causes the Legionnaires’ disease. L. pneumophila presents a serious health hazard in building water systems, due to its high resistance to standard water disinfection methods. Our aim was to study the use of photodynamic inactivation (PDI) against Legionella. We investigated and compared the photobactericidal potential of five cationic dyes. We tested toluidine blue (TBO) and methylene blue (MB), and three 3-N-methylpyridylporphyrins, one tetra-cationic and two tri-cationic, one with a short (CH3) and the other with a long (C17H35) alkyl chain, against L. pneumophila in tap water and after irradiation with violet light. All tested dyes demonstrated a certain dark toxicity against L. pneumophila; porphyrins with lower minimal effective concentration (MEC) values than TBO and MB. Nanomolar MEC values, significantly lower than with TBO and MB, were obtained with all three porphyrins in PDI experiments, with amphiphilic porphyrin demonstrating the highest PDI activity. All tested dyes showed increasing PDI with longer irradiation (0–108 J/cm2), especially the two hydrophilic porphyrins. All three porphyrins caused significant changes in cell membrane permeability after irradiation and L. pneumophila, co-cultivated with Acanthamoeba castellanii after treatment with all three porphyrins and irradiation, did not recover in amoeba. We believe our results indicate the considerable potential of cationic porphyrins as effective anti-Legionella agents.

scholarly journals Reduction of Legionella spp. in Water and in Soil by a Citrus Plant Extract Vapor

2014 ◽  
Vol 80 (19) ◽  
pp. 6031-6036 ◽  
Author(s):  
Katie Laird ◽  
Elena Kurzbach ◽  
Jodie Score ◽  
Jyoti Tejpal ◽  
George Chi Tangyie ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Water System ◽  
Severe Form ◽  
Gas Chromatography Mass Spectrometry ◽  
Free Living ◽  
Content Type ◽  
Soil Systems ◽  
Viable Cells ◽  
Legionnaires Disease ◽  
Soil And Water

ABSTRACTLegionnaires' disease is a severe form of pneumonia caused byLegionellaspp., organisms often isolated from environmental sources, including soil and water.Legionellaspp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred,Legionellais particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml−1on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor againstLegionellaspp. in water and in soil systems. Reductions of viable cells ofLegionella pneumophila,Legionella longbeachae,Legionella bozemanii, and an intra-amoebal culture ofLegionella pneumophila(water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml−1reduction inLegionellaspp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water wasL. pneumophila, with a 4-log cells ml−1reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controllingLegionellaspp. from environmental sources.

scholarly journals Temperature-Dependent Parasitic Relationship between Legionella pneumophila and a Free-Living Amoeba (Acanthamoeba castellanii)

2008 ◽  
Vol 74 (14) ◽  
pp. 4585-4588 ◽  
Author(s):  
Akira Ohno ◽  
Naoyuki Kato ◽  
Ryota Sakamoto ◽  
Soichiro Kimura ◽  
Keizo Yamaguchi
Keyword(s):  
Legionella Pneumophila ◽  
Low Temperatures ◽  
Acanthamoeba Castellanii ◽  
Temperature Dependent ◽  
Free Living ◽  
Free Living Amoeba ◽  
Effects Of Temperature ◽  
Number Of Bacteria

ABSTRACT We analyzed the effects of temperature on the interaction of Legionella pneumophila with Acanthamoeba castellanii. At <20°C, overexpression of type 1 metacaspase, a stimulator of A. castellanii encystation, was associated with a reduced number of bacteria within amoeba. At low temperatures, A. castellanii seems to eliminate L. pneumophila by encystation and digestion.

scholarly journals Environmental Mimics and the Lvh Type IVA Secretion System Contribute to Virulence-Related Phenotypes of Legionella pneumophila

2006 ◽  
Vol 75 (2) ◽  
pp. 723-735 ◽  
Author(s):  
Purnima Bandyopadhyay ◽  
Shuqing Liu ◽  
Carolina B. Gabbai ◽  
Zeah Venitelli ◽  
Howard M. Steinman
Keyword(s):  
Stationary Phase ◽  
Legionella Pneumophila ◽  
Acanthamoeba Castellanii ◽  
Secretion System ◽  
Resistant Bacteria ◽  
Causative Organism ◽  
Legionnaires Disease ◽  
Intracellular Multiplication ◽  
Type Ivb Secretion ◽  
Type Ivb Secretion System

ABSTRACT Legionella pneumophila, the causative organism of Legionnaires' disease, is a fresh-water bacterium and intracellular parasite of amoebae. This study examined the effects of incubation in water and amoeba encystment on L. pneumophila strain JR32 and null mutants in dot/icm genes encoding a type IVB secretion system required for entry, delayed acidification of L. pneumophila-containing phagosomes, and intracellular multiplication when stationary-phase bacteria infect amoebae and macrophages. Following incubation of stationary-phase cultures in water, mutants in dotA and dotB, essential for function of the type IVB secretion system, exhibited entry and delay of phagosome acidification comparable to that of strain JR32. Following encystment in Acanthamoeba castellanii and reversion of cysts to amoeba trophozoites, dotA and dotB mutants exhibited intracellular multiplication in amoebae. The L. pneumophila Lvh locus, encoding a type IVA secretion system homologous to that in Agrobacterium tumefaciens, was required for restoration of entry and intracellular multiplication in dot/icm mutants following incubation in water and amoeba encystment and was required for delay of phagosome acidification in strain JR32. These data support a model in which the Dot/Icm type IVB secretion system is conditionally rather than absolutely required for L. pneumophila virulence-related phenotypes. The data suggest that the Lvh type IVA secretion system, previously thought to be dispensable, is involved in virulence-related phenotypes under conditions mimicking the spread of Legionnaires' disease from environmental niches. Since environmental amoebae are implicated as reservoirs for an increasing number of environmental pathogens and for drug-resistant bacteria, the environmental mimics developed here may be useful in virulence studies of other pathogens.

scholarly journals ArgR-Regulated Genes Are Derepressed in the Legionella-Containing Vacuole

2010 ◽  
Vol 192 (17) ◽  
pp. 4504-4516 ◽  
Author(s):  
Galadriel Hovel-Miner ◽  
Sebastien P. Faucher ◽  
Xavier Charpentier ◽  
Howard A. Shuman
Keyword(s):  
Legionella Pneumophila ◽  
Acanthamoeba Castellanii ◽  
Transcriptional Response ◽  
Global Gene Expression ◽  
Host Cells ◽  
Intracellular Growth ◽  
Arginine Repressor ◽  
Legionnaires Disease ◽  
Global Gene Expression Analysis ◽  
Eukaryotic Organisms

ABSTRACT Legionella pneumophila is an intracellular pathogen that infects protozoa in aquatic environments and when inhaled by susceptible human hosts replicates in alveolar macrophages and can result in the often fatal pneumonia called Legionnaires' disease. The ability of L. pneumophila to replicate within host cells requires the establishment of a specialized compartment that evades normal phagolysosome fusion called the Legionella-containing vacuole (LCV). Elucidation of the biochemical composition of the LCV and the identification of the regulatory signals sensed during intracellular replication are inherently challenging. l-Arginine is a critical nutrient in the metabolism of both prokaryotic and eukaryotic organisms. We showed that the L. pneumophila arginine repressor homolog, ArgR, is required for maximal intracellular growth in the unicellular host Acanthamoeba castellanii. In this study, we present evidence that the concentration of l-arginine in the LCV is sensed by ArgR to produce an intracellular transcriptional response. We characterized the L. pneumophila ArgR regulon by global gene expression analysis, identified genes highly affected by ArgR, showed that ArgR repression is dependent upon the presence of l-arginine, and demonstrated that ArgR-regulated genes are derepressed during intracellular growth. Additional targets of ArgR that may account for the argR mutant's intracellular multiplication defect are discussed. These results suggest that l-arginine availability functions as a regulatory signal during Legionella intracellular growth.

scholarly journals First Draft Genome Sequence ofBalamuthia mandrillaris, the Causative Agent of Amoebic Encephalitis

2015 ◽  
Vol 3 (5) ◽  
Author(s):  
H. Detering ◽  
T. Aebischer ◽  
P. W. Dabrowski ◽  
A. Radonić ◽  
A. Nitsche ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Causative Agent ◽  
Mammalian Species ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Free Living ◽  
Balamuthia Mandrillaris ◽  
Free Living Amoeba ◽  
The Brain

The free-living amoebaBalamuthia mandrillarisis a rare but highly lethal agent of amoebic encephalitis in humans and many other mammalian species. Here, we announce the first draft genome sequence of the original 1990 isolate cultured from the brain of a deceased mandrill baboon.

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