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 Human Lung Tissue Explants Reveal Novel Interactions during Legionella pneumophila Infections

2013 ◽  
Vol 82 (1) ◽  
pp. 275-285 ◽  
Author(s):  
Jens Jäger ◽  
Sebastian Marwitz ◽  
Jana Tiefenau ◽  
Janine Rasch ◽  
Olga Shevchuk ◽  
...  
Keyword(s):  
Lung Tissue ◽  
Legionella Pneumophila ◽  
Human Lung ◽  
Transcriptional Response ◽  
Human Infection ◽  
Bacterial Invasion ◽  
Human Lung Tissue ◽  
Content Type ◽  
Tissue Explants ◽  
Legionnaires Disease

ABSTRACTHistological and clinical investigations describe late stages of Legionnaires' disease but cannot characterize early events of human infection. Cellular or rodent infection models lack the complexity of tissue or have nonhuman backgrounds. Therefore, we developed and applied a novel model forLegionella pneumophilainfection comprising living human lung tissue. We stimulated lung explants withL. pneumophilastrains and outer membrane vesicles (OMVs) to analyze tissue damage, bacterial replication, and localization as well as the transcriptional response of infected tissue. Interestingly, we found that extracellular adhesion ofL. pneumophilato the entire alveolar lining precedes bacterial invasion and replication in recruited macrophages. In contrast, OMVs predominantly bound to alveolar macrophages. Specific damage to septa and epithelia increased over 48 h and was stronger in wild-type-infected and OMV-treated samples than in samples infected with the replication-deficient, type IVB secretion-deficient DotA−strain. Transcriptome analysis of lung tissue explants revealed a differential regulation of 2,499 genes after infection. The transcriptional response included the upregulation of uteroglobin and the downregulation of the macrophage receptor with collagenous structure (MARCO). Immunohistochemistry confirmed the downregulation of MARCO at sites of pathogen-induced tissue destruction. Neither host factor has ever been described in the context ofL. pneumophilainfections. This work demonstrates that the tissue explant model reproduces realistic features of Legionnaires' disease and reveals new functions for bacterial OMVs during infection. Our model allows us to characterize early steps of human infection which otherwise are not feasible for investigations.

scholarly journals The Legionella pneumophila Metaeffector Lpg2505 (MesI) Regulates SidI-Mediated Translation Inhibition and Novel Glycosyl Hydrolase Activity

2020 ◽  
Vol 88 (5) ◽  
Author(s):  
Ashley M. Joseph ◽  
Adrienne E. Pohl ◽  
Theodore J. Ball ◽  
Troy G. Abram ◽  
David K. Johnson ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Glycosyl Hydrolase ◽  
Protein Translation ◽  
Effector Proteins ◽  
Hydrolase Activity ◽  
Intracellular Replication ◽  
Content Type ◽  
Translation Inhibition ◽  
Legionnaires Disease ◽  
The Impact

ABSTRACT Legionella pneumophila, the etiological agent of Legionnaires’ disease, employs an arsenal of hundreds of Dot/Icm-translocated effector proteins to facilitate replication within eukaryotic phagocytes. Several effectors, called metaeffectors, function to regulate the activity of other Dot/Icm-translocated effectors during infection. The metaeffector Lpg2505 is essential for L. pneumophila intracellular replication only when its cognate effector, SidI, is present. SidI is a cytotoxic effector that interacts with the host translation factor eEF1A and potently inhibits eukaryotic protein translation by an unknown mechanism. Here, we evaluated the impact of Lpg2505 on SidI-mediated phenotypes and investigated the mechanism of SidI function. We determined that Lpg2505 binds with nanomolar affinity to SidI and suppresses SidI-mediated inhibition of protein translation. SidI binding to eEF1A and Lpg2505 is not mutually exclusive, and the proteins bind distinct regions of SidI. We also discovered that SidI possesses GDP-dependent glycosyl hydrolase activity and that this activity is regulated by Lpg2505. We have therefore renamed Lpg2505 MesI (metaeffector of SidI). This work reveals novel enzymatic activity for SidI and provides insight into how intracellular replication of L. pneumophila is regulated by a metaeffector.

scholarly journals Development of a DNA Microarray Method for Detection and Identification of All 15 Distinct O-Antigen Forms of Legionella pneumophila

2013 ◽  
Vol 79 (21) ◽  
pp. 6647-6654 ◽  
Author(s):  
Boyang Cao ◽  
Fangfang Yao ◽  
Xiangqian Liu ◽  
Lu Feng ◽  
Lei Wang
Keyword(s):  
Dna Microarray ◽  
Legionella Pneumophila ◽  
Detection Sensitivity ◽  
Immunological Methods ◽  
Clinical Samples ◽  
Content Type ◽  
O Antigen ◽  
Detection And Identification ◽  
Legionnaires Disease ◽  
Reference Strains

ABSTRACTLegionellais ubiquitous in many environments. At least 50 species and 70 serogroups of the Gram-negative bacterium have been identified. Of the 50 species, 20 are pathogenic, andLegionella pneumophilais responsible for the great majority (approximately 90%) of the Legionnaires' disease cases that occur. Furthermore, of the 15L. pneumophilaserogroups identified, O1 alone causes more than 84% of the Legionnaires' disease cases that occur worldwide. Rapid and reliable assays for the detection and identification ofL. pneumophilain water, environmental, and clinical samples are in great demand.L. pneumophilabacteria are traditionally identified by their O antigens by immunological methods. We have recently developed an O serogroup-specific DNA microarray for the detection of all 15 distinct O-antigen forms ofL. pneumophila, including serogroups O1 to O15. A total of 35 strains were used to verify the specificity of the microarray, including 15L. pneumophilaO-antigen standard reference strains and sevenL. pneumophilaclinical isolates as target strains, seven reference strains of other non-pneumophila Legionellaspecies as closely related strains, and six non-Legionellabacterial species as nonrelated strains. The detection sensitivity was 1 ng of genomic DNA or 0.4 CFU/ml in water samples with filter enrichment and plate culturing. This study demonstrated that the microarray allows specific, sensitive, and reproducible detection ofL. pneumophilaserogroups. To the best of our knowledge, this is the first report of a microarray serotyping method for all 15 distinct O-antigen forms ofL. pneumophila.

scholarly journals Aerosol infection of animals with strains ofLegionella pneumophilaof different virulence: comparison with intraperitoneal and intranasal routes of infection

1983 ◽  
Vol 90 (1) ◽  
pp. 81-89 ◽  
Author(s):  
R. B. Fitzgeorge ◽  
A. Baskerville ◽  
M. Broster ◽  
P. Hambleton ◽  
P. J. Dennis
Keyword(s):  
Legionella Pneumophila ◽  
Small Particle ◽  
Guinea Pigs ◽  
Rhesus Monkeys ◽  
Type Strain ◽  
Wide Range ◽  
Strain Nctc ◽  
Legionnaires Disease ◽  
Aerosol Infection ◽  
Intranasal Instillation

SUMMARYInfection of guinea-pigs by intranasal (i.n.) instillation of 109viable organisms of two newly isolated strains ofLegionella pneumophila(74/81, serogroup 1; 166/81, serogroup 3) did not induce disease, but 104organisms administered as a small particle aerosol (< 5 μm diameter) produced a fatal widespread bronchopneumonia within 3 days. Milder illness and less extensive bronchopneumonia were also produced in rhesus monkeys and marmosets by one of these two strains (74/81). Mice were resistant to induction of disease by aerosols of both these two strains, though organisms did persist in the lungs for at least 4 days. Both of theseL. pneumophilastrains were pathogenic for guinea-pigs by aerosol infection over a wide range of doses but the serogroup 1 type strain (NCTC 11192) was not. There was no mortality after infection of guinea-pigs by intranasal instillation of any of these strains but all proved to be fatal after intraperitoneal (i.p.) injection of large doses. Guinea-pigs, rhesus monkeys and marmosets exposed to aerosol infection withL. pneumophilaprovide relevant models for studying the pathogenesis of Legionnaires' disease.

scholarly journals Lab Diagnosis of Legionnaires’ Disease

JMS SKIMS ◽  
2014 ◽  
Vol 17 (2) ◽  
pp. 50-54
Author(s):  
Nayeem U-Din Wani ◽  
Aamir Ali
Keyword(s):  
Legionella Pneumophila ◽  
Water System ◽  
Laboratory Diagnosis ◽  
Significant Rise ◽  
Control Measures ◽  
Causative Organism ◽  
Common Source ◽  
Contaminated Water ◽  
Atypical Pneumonia ◽  
Legionnaires Disease

Legionnaires’ disease is a multi-system disease which causes atypical pneumonia due to Legionella bacteria, most commonly of the species Legionella pneumophila. About one out of every 10 people who get sick from Legionnaires’ disease will die. Most common source of infection-contaminated water supply through inhalation of contaminated water droplets (aerosols). A laboratory diagnosis of Legionnaires’ disease can be made using a variety of laboratory tests including: culture/isolation of the causative organism, antigen detection in urine, a significant rise in antibody titres or PCR methods. Determination of the monoclonal subtype and molecular sequence typing can support linking between strains from the sampled environment and from patients. The control measures available to reduce the amount of Legionella in a water system include structural adaptations to the water system, temperature control, disinfection using chemicals or other oxidizing materials, and use of biocides or installation of filters. JMS 2014;17(2):50-54

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 Utility of PCR, Culture, and Antigen Detection Methods for Diagnosis of Legionellosis

2015 ◽  
Vol 53 (11) ◽  
pp. 3474-3477 ◽  
Author(s):  
Derrick J. Chen ◽  
Gary W. Procop ◽  
Sherilynn Vogel ◽  
Belinda Yen-Lieberman ◽  
Sandra S. Richter
Keyword(s):  
Electronic Medical Records ◽  
Legionella Pneumophila ◽  
Medical Records ◽  
Cleveland Clinic ◽  
Test Methods ◽  
Detection Methods ◽  
Content Type ◽  
Epidemiologic Factors ◽  
Legionnaires Disease ◽  
Positive Results

The goal of this retrospective study was to evaluate the performance of different diagnostic tests for Legionnaires' disease in a clinical setting whereLegionella pneumophilaPCR had been introduced. Electronic medical records at the Cleveland Clinic were searched forLegionellaurinary antigen (UAG), culture, and PCR tests ordered from March 2010 through December 2013. For cases where two or more test methods were performed and at least one was positive, the medical record was reviewed for relevant clinical and epidemiologic factors. Excluding repeat testing on a given patient, 19,912 tests were ordered (12,569 UAG, 3,747 cultures, and 3,596 PCR) with 378 positive results. The positivity rate for each method was 0.4% for culture, 0.8% for PCR, and 2.7% for UAG. For 37 patients, at least two test methods were performed with at least one positive result: 10 (27%) cases were positive by all three methods, 16 (43%) were positive by two methods, and 11 (30%) were positive by one method only. For the 32 patients with medical records available, clinical presentation was consistent with proven or probableLegionellainfection in 84% of the cases. For those cases, the sensitivities of culture, PCR, and UAG were 50%, 92%, and 96%, respectively. The specificities were 100% for culture and 99.9% for PCR and UAG.

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 Invasion of Eukaryotic Cells byLegionella Pneumophila: A Common Strategy for all Hosts?

1997 ◽  
Vol 8 (3) ◽  
pp. 139-146 ◽  
Author(s):  
Paul S Hoffman
Keyword(s):  
Legionella Pneumophila ◽  
Human Infection ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Mature Form ◽  
Cellular Processes ◽  
Wide Range ◽  
Common Strategy ◽  
Legionnaires Disease ◽  
Host Parasite

Legionella pneumophilais an environmental micro-organism capable of producing an acute lobar pneumonia, commonly referred to as Legionnaires’ disease, in susceptible humans. Legionellae are ubiquitous in aquatic environments, where they survive in biofilms or intracellularly in various protozoans. Susceptible humans become infected by breathing aerosols laden with the bacteria. The target cell for human infection is the alveolar macrophage, in which the bacteria abrogate phagolysosomal fusion. The remarkable ability ofL pneumophilato infect a wide range of eukaryotic cells suggests a common strategy that exploits very fundamental cellular processes. The bacteria enter host cells via coiling phagocytosis and quickly subvert organelle trafficking events, leading to formation of a replicative phagosome in which the bacteria multiply. Vegetative growth continues for 8 to 10 h, after which the bacteria develop into a short, highly motile form called the ‘mature form’. The mature form exhibits a thickening of the cell wall, stains red with the Gimenez stain, and is between 10 and 100 times more infectious than agar-grown bacteria. Following host cell lysis, the released bacteria infect other host cells, in which the mature form differentiates into a Gimenez-negative vegetative form, and the cycle begins anew. Virulence ofL pneumophilais considered to be multifactorial, and there is growing evidence for both stage specific and sequential gene expression. Thus,L pneumophilamay be a good model system for dissecting events associated with the host-parasite interactions.

scholarly journals KKL-35 Exhibits Potent Antibiotic Activity against Legionella Species Independently of trans-Translation Inhibition

2017 ◽  
Vol 62 (2) ◽  
Author(s):  
Romain Brunel ◽  
Ghislaine Descours ◽  
Isabelle Durieux ◽  
Patricia Doublet ◽  
Sophie Jarraud ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Messenger Rna ◽  
Antibiotic Activity ◽  
Resistance Development ◽  
Content Type ◽  
Translation Inhibition ◽  
New Family ◽  
Rescue System ◽  
Legionella Species ◽  
Legionnaires Disease

ABSTRACTtrans-Translation is a ribosome-rescue system that is ubiquitous in bacteria. Small molecules defining a new family of oxadiazole compounds that inhibittrans-translation have been found to have broad-spectrum antibiotic activity. We sought to determine the activity of KKL-35, a potent member of the oxadiazole family, against the human pathogenLegionella pneumophilaand other related species that can also cause Legionnaires' disease (LD). Consistent with the essential nature oftrans-translation inL. pneumophila, KKL-35 inhibited the growth of all tested strains at submicromolar concentrations. KKL-35 was also active against other LD-causingLegionellaspecies. KKL-35 remained equally active againstL. pneumophilamutants that have evolved resistance to macrolides. KKL-35 inhibited the multiplication ofL. pneumophilain human macrophages at several stages of infection. No resistant mutants could be obtained, even during extended and chronic exposure. Surprisingly, KKL-35 was not synergistic with other ribosome-targeting antibiotics and did not induce the filamentation phenotype observed in cells defective fortrans-translation. Importantly, KKL-35 remained active againstL. pneumophilamutants expressing an alternate ribosome-rescue system and lacking transfer-messenger RNA, the essential component oftrans-translation. These results indicate that the antibiotic activity of KKL-35 is not related to the specific inhibition oftrans-translation and its mode of action remains to be identified. In conclusion, KKL-35 is an effective antibacterial agent against the intracellular pathogenL. pneumophilawith no detectable resistance development. However, further studies are needed to better understand its mechanism of action and to assess further the potential of oxadiazoles in treatment.

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