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Abstract
Biofilms form when bacteria adhere to a surface and secrete an extracellular polymeric substance. Bacteria embedded within a biofilm benefit from increased resistance to antibiotics, host immune responses, and harsh environmental factors. Nitric oxide (NO) is a signaling molecule that can modulate communal behavior, including biofilm formation, in many bacteria. In many cases, NO-induced biofilm dispersal is accomplished through signal transduction pathways that ultimately lead to a decrease in intracellular cyclic-di-GMP levels. H-NOX (heme nitric oxide/oxygen binding domain) proteins are the best characterized bacterial NO sensors and have been implicated in NO-mediated cyclic-di-GMP signaling, but we have recently discovered a second family of NO-sensitive proteins in bacteria named NosP (NO sensing protein); to date, a clear link between NosP signaling and cyclic-di-GMP metabolism has not been established. Here we present evidence that NosP (Lpg0279) binds to NO and directly affects cyclic-di-GMP production from two-component signaling proteins Lpg0278 and Lpg0277 encoded within the NosP operon. Lpg0278 and Lpg0277 are a histidine kinase and cyclic-di-GMP synthase/phosphodiesterase, respectively, that have already been established as being important in regulating Legionella pneumophila cyclic-di-GMP levels; NosP is thus implicated in regulating cyclic-di-GMP in L. pneumophila.
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Affiliation(s)
- Jonathan T Fischer
- Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794, United States
| | - Sajjad Hossain
- Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794, United States
| | - Elizabeth M Boon
- Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794, United States
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Moosavian M, Moradzadeh M, Ghadiri A, Saki M. Isolation and Identification of Legionella spp. in environmental water sources based on macrophage infectivity potentiator ( mip) gene sequencing in southwest Iran. AIMS Microbiol 2019; 5:223-231. [PMID: 31663058 PMCID: PMC6787354 DOI: 10.3934/microbiol.2019.3.223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/13/2019] [Indexed: 12/11/2022] Open
Abstract
Legionella species are widespread in natural water sources and man-made aqueous environments, as well as fresh-water. The present study was conducted owing to the lack of research regarding the prevalence of Legionella spp in the water sources of Ahvaz city in southwest Iran. In this study the macrophage infectivity potentiator (mip) gene sequencing was used for identification of various Legionella species isolated from different water sources. In this study, 144 water samples were collected and inoculated on the buffered charcoal-yeast extract (BCYE) agar and modified Wadowsky-Yee (MWY) medium. The DNA was extracted from positive cultures. The Legionella species were confirmed by amplifying a 654 bp fragment of the 16S rRNA gene. The mip gene of all isolates were amplified by PCR and purified for sequencing. The mip gene sequences were analyzed by jPHYDIT software version 1. The results showed a 13.9% (20/144) prevalence of Legionella spp. in water sources of Ahvaz city, southwest Iran. Analyzing of the mip gene sequences showed, out of 20 Legionella isolates, 13 isolates (54.1%) were positive for L. pneumophila, 5 isolates (20.8%) were positive for L. worsleinsis, one isolates for each one of L. dumoffi and L. fairfieldensis, (4.1%). According to our research, the occurrence of Legionella spp in water sources could be a hazard for the health systems especially in the hospitals. The regular monitoring of these water sources by health planners may therefore be useful for decreasing the risk for Legionella spp. infections.
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Affiliation(s)
- Mojtaba Moosavian
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mina Moradzadeh
- Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Ataollah Ghadiri
- Department of Immunology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Cellular and Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Morteza Saki
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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53
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Fuochi V, Coniglio MA, Laghi L, Rescifina A, Caruso M, Stivala A, Furneri PM. Metabolic Characterization of Supernatants Produced by Lactobacillus spp. With in vitro Anti- Legionella Activity. Front Microbiol 2019; 10:1403. [PMID: 31293545 PMCID: PMC6606692 DOI: 10.3389/fmicb.2019.01403] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/04/2019] [Indexed: 12/28/2022] Open
Abstract
Legionella pneumophila is an organism of public health interest for its presence in water supply systems and other humid thermal habitats. In this study, ten cell-free supernatants produced by Lactobacillus strains were evaluated for their ability to inhibit L. pneumophila strains isolated from hot tap water. Production of antimicrobial substances by Lactobacillus strains were assessed by agar well diffusion test on BCYE agar plates pre-inoculated with L. pneumophila. Cell-free supernatants (CFS) showed antimicrobial activity against all Legionella strains tested: L. rhamnosus and L. salivarius showed the highest activity. By means of a proton-based nuclear magnetic resonance (1H-NMR) spectroscopy, we detected and quantified the Lactobacillus metabolites of these CFSs, so to gain information about which metabolic pathway was likely to be connected to the observed inhibition activity. A panel of metabolites with variations in concentration were revealed, but considerable differences among inter-species were not showed as reported in a similar work by Foschi et al. (2018). More than fifty molecules belonging mainly to the groups of amino acids, organic acids, monosaccharides, ketones, and alcohols were identified in the metabolome. Significant differences were recorded comparing the metabolites found in the supernatants of strains grown in MRS with glycerol and the same strains grown in MRS without supplements. Indeed, pathway analysis revealed that glycine, serine and threonine, pyruvate, and sulfur metabolic pathways had a higher impact when strains were grown in MRS medium with a supplement such as glycerol. Among the metabolites identified, many were amino acids, suggesting the possible presence of bacteriocins which could be linked to the anti-Legionella activity shown by cell-free supernatants.
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Affiliation(s)
- Virginia Fuochi
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), University of Catania, Catania, Italy
| | - Maria Anna Coniglio
- Department of Medical and Surgical Sciences and Advanced Technologies "GF Ingrassia", University of Catania, Catania, Italy
| | - Luca Laghi
- Centre of Foodomics, Department of Agro-Food Science and Technology, University of Bologna, Bologna, Italy
| | | | - Massimo Caruso
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), University of Catania, Catania, Italy.,Department of Clinical and Experimental Medicine (MEDCLIN), University of Catania, Catania, Italy
| | - Aldo Stivala
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), University of Catania, Catania, Italy
| | - Pio Maria Furneri
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), University of Catania, Catania, Italy
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54
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Abdel-Nour M, Su H, Duncan C, Li S, Raju D, Shamoun F, Valton M, Ginevra C, Jarraud S, Guyard C, Kerman K, Terebiznik MR. Polymorphisms of a Collagen-Like Adhesin Contributes to Legionella pneumophila Adhesion, Biofilm Formation Capacity and Clinical Prevalence. Front Microbiol 2019; 10:604. [PMID: 31024468 PMCID: PMC6460258 DOI: 10.3389/fmicb.2019.00604] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/11/2019] [Indexed: 11/22/2022] Open
Abstract
Legionellosis is a severe respiratory illness caused by the inhalation of aerosolized water droplets contaminated with the opportunistic pathogen Legionella pneumophila. The ability of L. pneumophila to produce biofilms has been associated with its capacity to colonize and persist in human-made water reservoirs and distribution systems, which are the source of legionellosis outbreaks. Nevertheless, the factors that mediate L. pneumophila biofilm formation are largely unknown. In previous studies we reported that the adhesin Legionella collagen-like protein (Lcl), is required for auto-aggregation, attachment to multiple surfaces and the formation of biofilms. Lcl structure contains three distinguishable regions: An N-terminal region with a predicted signal sequence, a central region containing tandem collagen-like repeats (R-domain) and a C-terminal region (C-domain) with no significant homology to other known proteins. Lcl R-domain encodes tandem repeats of the collagenous tripeptide Gly-Xaa-Yaa (GXY), a motif that is key for the molecular organization of mammalian collagen and mediates the binding of collagenous proteins to different cellular and environmental ligands. Interestingly, Lcl is polymorphic in the number of GXY tandem repeats. In this study, we combined diverse biochemical, genetic, and cellular approaches to determine the role of Lcl domains and GXY repeats polymorphisms on the structural and functional properties of Lcl, as well as on bacterial attachment, aggregation and biofilm formation. Our results indicate that the R-domain is key for assembling Lcl collagenous triple-helices and has a more preponderate role over the C-domain in Lcl adhesin binding properties. We show that Lcl molecules oligomerize to form large supramolecular complexes to which both, R and C-domains are required. Furthermore, we found that the number of GXY tandem repeats encoded in Lcl R-domain correlates positively with the binding capabilities of Lcl and with the attachment and biofilm production capacity of L. pneumophila strains. Accordingly, the number of GXY tandem repeats in Lcl influences the clinical prevalence of L. pneumophila strains. Therefore, the number of Lcl tandem repeats could be considered as a potential predictor for virulence in L. pneumophila isolates.
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Affiliation(s)
- Mena Abdel-Nour
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,The Mount Sinai Hospital, Toronto, ON, Canada
| | - Han Su
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Carla Duncan
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada
| | - Shaopei Li
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Deepa Raju
- Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto at Scarborough, Toronto, ON, Canada
| | - Feras Shamoun
- Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto at Scarborough, Toronto, ON, Canada
| | - Marine Valton
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,Polytech Clermont-Ferrand, Aubière, France
| | - Christophe Ginevra
- CIRI-International Center for Infectiology Research, Legionella Pathogenesis Team, Université de Lyon, Lyon, France.,INSERM U1111, Lyon, France.,Centre International de Recherche en Infectiologie, Claude Bernard University Lyon 1, Lyon, France.,National Center for Legionella, Hospices Civils de Lyon, Lyon, France
| | - Sophie Jarraud
- CIRI-International Center for Infectiology Research, Legionella Pathogenesis Team, Université de Lyon, Lyon, France.,INSERM U1111, Lyon, France.,Centre International de Recherche en Infectiologie, Claude Bernard University Lyon 1, Lyon, France.,National Center for Legionella, Hospices Civils de Lyon, Lyon, France
| | - Cyril Guyard
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,The Mount Sinai Hospital, Toronto, ON, Canada.,BIOASTER Microbiology Technology Institute, Lyon, France
| | - Kagan Kerman
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Mauricio R Terebiznik
- Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto at Scarborough, Toronto, ON, Canada
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55
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Di Pippo F, Di Gregorio L, Congestri R, Tandoi V, Rossetti S. Biofilm growth and control in cooling water industrial systems. FEMS Microbiol Ecol 2019; 94:4935158. [PMID: 29596620 DOI: 10.1093/femsec/fiy044] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/13/2018] [Indexed: 12/18/2022] Open
Abstract
Matrix-embedded, surface-attached microbial communities, known as biofilms, profusely colonise industrial cooling water systems, where the availability of nutrients and organic matter favours rapid microbial proliferation and their adhesion to surfaces in the evaporative fill material, heat exchangers, water reservoir and cooling water sections and pipelines. The extensive growth of biofilms can promote micro-biofouling and microbially induced corrosion (MIC) as well as pose health problems associated with the presence of pathogens like Legionella pneumophila. This review examines critically biofilm occurrence in cooling water systems and the main factors potentially affecting biofilm growth, biodiversity and structure. A broad evaluation of the most relevant biofilm monitoring and control strategies currently used or potentially useful in cooling water systems is also provided.
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Affiliation(s)
- F Di Pippo
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy.,CNR-IAMC, National Research Council, Institute for Coastal Marine Environment, Località Sa Mardini, Torregrande, 09170 Oristano, Italy
| | - L Di Gregorio
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy.,University of Rome Tor Vergata, Department of Biology, Via Cracovia 1, 00133 Rome, Italy
| | - R Congestri
- University of Rome Tor Vergata, Department of Biology, Via Cracovia 1, 00133 Rome, Italy
| | - V Tandoi
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy
| | - S Rossetti
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy
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56
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Ahmed S, Liwak-Muir U, Walker D, Zoldowski A, Mears A, Golovan S, Mohr S, Lem P, Harder C. Validation and in-field testing of a new on-site qPCR system for quantification of Legionella pneumophila according to ISO/TS 12869:2012 in HVAC cooling towers. JOURNAL OF WATER AND HEALTH 2019; 17:237-253. [PMID: 30942774 DOI: 10.2166/wh.2019.252] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Legionella pneumophila, found in engineered water systems such as HVAC cooling towers, poses a significant public health risk. Culture, though routinely used to quantify L. pneumophila, has several disadvantages including long turnaround time, low sensitivity, and inter-laboratory variability. In this study, we validated the performance of an on-site quantitative polymerase chain reaction (qPCR) detection system for L. pneumophila in accordance with International Standards Organization Technical Specification 12869:2012. We evaluated specificity, limit of detection and quantification, and calibration curve linearity. Additionally, we evaluated whole system recovery and robustness using samples taken from taps and evaporative cooling towers. We then compared the system's performance against laboratory culture and laboratory qPCR across 53 cooling towers in a 12-week in-field study. We found that concordance between on-site qPCR and culture was both laboratory- and site/sample-dependent. Comparison of laboratory qPCR with on-site qPCR revealed that laboratory results were highly variable and showed little concordance. Some discordance may be explained by time delay between sample collection and testing ('shipping effect') which may lead to inaccurate reporting. Overall, our study highlights the value of on-site qPCR detection of L. pneumophila, demonstrates that laboratories are prone to misreporting results due to shipping effects, and reveals significant discordance between laboratory qPCR and culture.
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Affiliation(s)
- Shaimaa Ahmed
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Urszula Liwak-Muir
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Danielle Walker
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Agnes Zoldowski
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Alan Mears
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Sergey Golovan
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Steve Mohr
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Paul Lem
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Chris Harder
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
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57
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Donohue MJ, King D, Pfaller S, Mistry JH. The sporadic nature of Legionella pneumophila, Legionella pneumophila Sg1 and Mycobacterium avium occurrence within residences and office buildings across 36 states in the United States. J Appl Microbiol 2019; 126:1568-1579. [PMID: 30891905 PMCID: PMC6850209 DOI: 10.1111/jam.14196] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 12/20/2022]
Abstract
Aim Premise plumbing may disseminate the bacteria Legionella pneumophila and Mycobacterium avium, the causative agents for legionellosis and pulmonary nontuberculous mycobacterium disease respectively. Methods and Results Using quantitative PCR, the occurrence and persistence of L. pneumophila, L. pneumophila serogroup (Sg)1 and M. avium were evaluated in drinking water samples from 108 cold water taps (residences: n = 43) and (office buildings: n = 65). Mycobacterium avium, L. pneumophila and L. pneumophila Sg1 were detected 45, 41 and 25% of all structures respectively. Two occurrence patterns were evaluated: sporadic (a single detection from the three samplings) and persistent (detections in two or more of the three samples). Conclusions The micro‐organism's occurrence was largely sporadic. Office buildings were prone to microbial persistence independent of building age and square footage. Microbial persistence at residences was observed in those older than 40 years for L. pneumophila and was rarely observed for M. avium. The microbial occurrence was evenly distributed between structure types but there were differences in density and persistence. Significance of and Impact of the Study The study is important because residences are often suspected to be the source when a case of disease is reported. These data demonstrate that this may not be the case for a sporadic incidence.
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Affiliation(s)
- M J Donohue
- National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH, USA
| | - D King
- National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH, USA
| | - S Pfaller
- National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH, USA
| | - J H Mistry
- Region 6, United States Environmental Protection Agency, Dallas, TX, USA
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58
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Hochstrasser R, Kessler A, Sahr T, Simon S, Schell U, Gomez-Valero L, Buchrieser C, Hilbi H. The pleiotropic Legionella transcription factor LvbR links the Lqs and c-di-GMP regulatory networks to control biofilm architecture and virulence. Environ Microbiol 2019; 21:1035-1053. [PMID: 30623561 DOI: 10.1111/1462-2920.14523] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 01/05/2019] [Indexed: 11/29/2022]
Abstract
The causative agent of Legionnaires' disease, Legionella pneumophila, colonizes amoebae and biofilms in the environment. The opportunistic pathogen employs the Lqs (Legionella quorum sensing) system and the signalling molecule LAI-1 (Legionella autoinducer-1) to regulate virulence, motility, natural competence and expression of a 133 kb genomic "fitness island", including a putative novel regulator. Here, we show that the regulator termed LvbR is an LqsS-regulated transcription factor that binds to the promoter of lpg1056/hnox1 (encoding an inhibitor of the diguanylate cyclase Lpg1057), and thus, regulates proteins involved in c-di-GMP metabolism. LvbR determines biofilm architecture, since L. pneumophila lacking lvbR accumulates less sessile biomass and forms homogeneous mat-like structures, while the parental strain develops more compact bacterial aggregates. Comparative transcriptomics of sessile and planktonic ΔlvbR or ΔlqsR mutant strains revealed concerted (virulence, fitness island, metabolism) and reciprocally (motility) regulated genes in biofilm and broth respectively. Moreover, ΔlvbR is hyper-competent for DNA uptake, defective for phagocyte infection, outcompeted by the parental strain in amoebae co-infections and impaired for cell migration inhibition. Taken together, our results indicate that L. pneumophila LvbR is a novel pleiotropic transcription factor, which links the Lqs and c-di-GMP regulatory networks to control biofilm architecture and pathogen-host cell interactions.
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Affiliation(s)
- Ramon Hochstrasser
- Institute of Medical Microbiology, Faculty of Medicine, University of Zürich, Gloriastrasse 30, 8006 Zürich, Switzerland
| | - Aline Kessler
- Max von Pettenkofer Institute, Faculty of Medicine, Ludwig-Maximilians University, Pettenkoferstrasse 9a, 80336 Munich, Germany
| | - Tobias Sahr
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, 28 Rue du Dr Roux, 75724 Paris, France.,CNRS UMR 3525, 28 Rue du Dr Roux, 75724 Paris, France
| | - Sylvia Simon
- Institute of Medical Microbiology, Faculty of Medicine, University of Zürich, Gloriastrasse 30, 8006 Zürich, Switzerland
| | - Ursula Schell
- Max von Pettenkofer Institute, Faculty of Medicine, Ludwig-Maximilians University, Pettenkoferstrasse 9a, 80336 Munich, Germany
| | - Laura Gomez-Valero
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, 28 Rue du Dr Roux, 75724 Paris, France.,CNRS UMR 3525, 28 Rue du Dr Roux, 75724 Paris, France
| | - Carmen Buchrieser
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, 28 Rue du Dr Roux, 75724 Paris, France.,CNRS UMR 3525, 28 Rue du Dr Roux, 75724 Paris, France
| | - Hubert Hilbi
- Institute of Medical Microbiology, Faculty of Medicine, University of Zürich, Gloriastrasse 30, 8006 Zürich, Switzerland
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59
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Birteksoz-Tan AS, Zeybek Z, Hacioglu M, Savage PB, Bozkurt-Guzel C. In vitro activities of antimicrobial peptides and ceragenins against Legionella pneumophila. J Antibiot (Tokyo) 2019; 72:291-297. [DOI: 10.1038/s41429-019-0148-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/03/2019] [Accepted: 01/22/2019] [Indexed: 12/18/2022]
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60
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Corre MH, Delafont V, Legrand A, Berjeaud JM, Verdon J. Exploiting the Richness of Environmental Waterborne Bacterial Species to Find Natural Legionella pneumophila Competitors. Front Microbiol 2019; 9:3360. [PMID: 30697209 PMCID: PMC6340971 DOI: 10.3389/fmicb.2018.03360] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/31/2018] [Indexed: 11/17/2022] Open
Abstract
Legionella pneumophila is one of the most tracked waterborne pathogens and remains an important threat to human health. Despite the use of biocides, L. pneumophila is able to persist in engineered water systems with the help of multispecies biofilms and phagocytic protists. For few years now, high-throughput sequencing methods have enabled a better understanding of microbial communities in freshwater environments. Those unexplored and complex communities compete for nutrients using antagonistic molecules as war weapons. Up to now, few of these molecules were characterized in regards of L. pneumophila sensitivity. In this context, we established, from five freshwater environments, a vast collection of culturable bacteria and investigated their ability to inhibit the growth of L. pneumophila. All bacterial isolates were classified within 4 phyla, namely Proteobacteria (179/273), Bacteroidetes (48/273), Firmicutes (43/273), and Actinobacteria (3/273) according to 16S rRNA coding sequences. Aeromonas, Bacillus, Flavobacterium, and Pseudomonas were the most abundant genera (154/273). Among the 273 isolates, 178 (65.2%) were shown to be active against L. pneumophila including 137 isolates of the four previously cited main genera. Additionally, other less represented genera depicted anti-Legionella activity such as Acinetobacter, Kluyvera, Rahnella, or Sphingobacterium. Furthermore, various inhibition diameters were observed among active isolates, ranging from 0.4 to 9 cm. Such variability suggests the presence of numerous and diverse natural compounds in the microenvironment of L. pneumophila. These molecules include both diffusible secreted compounds and volatile organic compounds, the latter being mainly produced by Pseudomonas strains. Altogether, this work sheds light on unexplored freshwater bacterial communities that could be relevant for the biological control of L. pneumophila in manmade water systems.
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Affiliation(s)
- Marie-Hélène Corre
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, Poitiers, France
| | - Vincent Delafont
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, Poitiers, France
| | - Anasthasia Legrand
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, Poitiers, France
| | - Jean-Marc Berjeaud
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, Poitiers, France
| | - Julien Verdon
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, Poitiers, France
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Mobarez AM, Rajabi RA, Salmanian AH, Khoramabadi N, Hosseini Doust SR. Induction of protective immunity by recombinant peptidoglycan associated lipoprotein (rPAL) protein of Legionella pneumophila in a BALB/c mouse model. Microb Pathog 2018; 128:100-105. [PMID: 30550844 DOI: 10.1016/j.micpath.2018.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 11/05/2018] [Accepted: 12/10/2018] [Indexed: 12/15/2022]
Abstract
Legionella pneumophila causes a severe form of pneumonia known as Legionnaires' disease especially in patients with impaired cellular immune response. In order to prevent the disease, immunogenicity and the level of the induction of protective immunity from the recombinant peptidoglycan-associated lipoprotein (rPAL) against Legionella pneumophila in BALB/c mice was examined. Mice immunized with (rPAL) rapidly increased an antibody response in serum and also displayed a strong activation of both innate and adaptive cell-mediated immunity as determined by antigen-specific splenocyte proliferation, an early production of pro-inflammatory cytokines in the serum and in the splenocyte cultures. Infection with a primary sublethal does of Legionella pneumophila serogroup 1, strain paris, caused resistance to a lethal challenge infection in the animals with 100% survival rate. However, mice treated with rPAL survived with 60% rate in 10 days after a lethal i.v challenge with L. pneumophila. All of the control animals receiving PBS died within 24 h. The present study indicates that recombinant protein PAL of Legionella pneumophila is strongly immunogenic and capable to elicit early innate and adaptive immune responses and lasting immunity against a lethal dose of Legionella pneumophila challenge. Antigenic characterization and immune protection of recombinant protein PAL would be of considerable value in comprehension the immune-pathogenesis of the disease and in development possible vaccine against the Legionella.
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Affiliation(s)
- Ashraf Mohabati Mobarez
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Roya Ahamad Rajabi
- Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Ali Hatef Salmanian
- Department of Plant Biotechnology, National Institutes for Genetic Engineering and Biotechnology, Tehran, Iran
| | - Nima Khoramabadi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Seyed Reza Hosseini Doust
- Department of Microbiology, Faculty of Advanced Sciences, Medical Sciences University Islamic Azad, Tehran, Iran
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Highlighting the Potency of Biosurfactants Produced by Pseudomonas Strains as Anti- Legionella Agents. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8194368. [PMID: 30426015 PMCID: PMC6217892 DOI: 10.1155/2018/8194368] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/12/2018] [Accepted: 09/27/2018] [Indexed: 12/18/2022]
Abstract
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.
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63
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Jing H, Sahle-Demessie E, Sorial GA. Inhibition of biofilm growth on polymer-MWCNTs composites and metal surfaces. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 633:167-178. [PMID: 29573683 DOI: 10.1016/j.scitotenv.2018.03.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
There is an increased interest in incorporating multi-wall carbon nanotubes (MWCNTs) into polymer matrices to control the adhesion of bacteria to surfaces and the subsequent formation of biofilm growth on the surface of water pipes, food packages, and medical devices. Microbial interactions with carbon nanotube-polymer composites in the environment are not well understood. The growth of Pseudomonas fluorescens (gram-negative) and Mycobacterium smegmatis (gram-positive) biofilms on copper, polyethylene (PE), polyvinyl chloride, and stainless steel was compared with growth on MWCNT-PE composites in order to gain insight into the effect of the surface properties of nanomaterials on the attachment and proliferation of microorganism which could result in the engineering of better, non-fouling materials. A statistical analysis of the biofilm growth showed a significant impact of materials for both P. fluorescens (p < 0.0001) and M. smegmatis (p = 0.00426). Biofilm growth after 56 days on PE compared to biofilm growth on copper surfaces decreased by 46.4% and 34.9% for P. fluorescens and M. smegmatis, respectively. Biofilm growth on PE-multiwall-carbon-nanotubes (MWCNTs)-composites surface compared to PE decreased by 89.3% and 29% for P. fluorescens and M. smegmatis, respectively. Bacterial species (p < 0.0006) and surface roughness (p < 0.0001) were important factors in determining the attachment and initial biofilm growth rate. The interactions between cells and material surface could be attributed to the complicated and collective effect of electrostatic forces, hydrophobic interactions, and hydrogen/covalent bonding. Further study is needed to determine whether or not there is a difference between the cell attachment in the exponential growth phase and the stationary, or decay, phase cells.
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Affiliation(s)
- Hengye Jing
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
| | | | - George A Sorial
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
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64
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Biosensors for the Detection of Interaction between Legionella pneumophila Collagen-Like Protein and Glycosaminoglycans. SENSORS 2018; 18:s18082668. [PMID: 30110899 PMCID: PMC6111780 DOI: 10.3390/s18082668] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/08/2018] [Accepted: 08/10/2018] [Indexed: 01/18/2023]
Abstract
The adhesin Legionella collagen-like (Lcl) protein can bind to extracellular matrix components and mediate the binding of Legionella pneumophila to host cells. In this study, electrochemical impedance spectroscopy (EIS) and surface plasmon resonance (SPR)-based biosensors were employed to characterize these interactions between glycosaminoglycans (GAGs) and the adhesin Lcl protein. Fucoidan displayed a high affinity (KD 18 nM) for Lcl protein. Chondroitin sulfate A and dermatan sulfate differ in the position of a carboxyl group replacing D-glucuronate with D-iduronate. Our results indicated that the presence of D-iduronate in dermatan sulfate strongly hindered its interaction with Lcl. These biophysical studies provided valuable information in our understanding of adhesin-ligand interactions related to Legionella pneumophila infections.
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65
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Coniglio MA, Ferrante M, Yassin MH. Preventing Healthcare-Associated Legionellosis: Results after 3 Years of Continuous Disinfection of Hot Water with Monochloramine and an Effective Water Safety Plan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15081594. [PMID: 30060459 PMCID: PMC6121960 DOI: 10.3390/ijerph15081594] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 07/22/2018] [Accepted: 07/26/2018] [Indexed: 12/13/2022]
Abstract
The purpose of this study is to report the experience of the implementation and application of a 3-year Water Safety Plan (WSP) together with the secondary disinfection of water by monochloramine to control and prevent healthcare-associated legionellosis in an Italian hospital strongly colonized by Legionella. Risk assessment was carried out by the WSP team. The main critical control points focused on in developing the WSP for the control of Legionella was the water distribution system. A sampling plan for the detection of Legionella was implemented. A widespread contamination of the hot water distribution system by L. pneumophila sg5 was found. Results after 3 years of the continuous disinfection of hot water with monochloramine indicate the eradication of Legionella. The implementation and application of a WSP in a hospital, together with the disinfection of the water distribution system with monochloramine, can be effective in controlling the growth of Legionella and in preventing nosocomial legionellosis.
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Affiliation(s)
- Maria Anna Coniglio
- Legionella Reference Laboratory, Department of Medical, Surgical Sciences and Advanced Technologies "G.F. Ingrassia", University of Catania, via Santa Sofia 87, 95123 Catania, Italy.
- Hygiene Complex Operative Unit, A.O.U. Policlinico-Vittorio Emanuele, via S. Sofia 87, 95123 Catania, Italy.
| | - Margherita Ferrante
- Hygiene Complex Operative Unit, A.O.U. Policlinico-Vittorio Emanuele, via S. Sofia 87, 95123 Catania, Italy.
| | - Mohamed H Yassin
- Infection Control Department, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA 15213, USA.
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66
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Sun S, Noorian P, McDougald D. Dual Role of Mechanisms Involved in Resistance to Predation by Protozoa and Virulence to Humans. Front Microbiol 2018; 9:1017. [PMID: 29867902 PMCID: PMC5967200 DOI: 10.3389/fmicb.2018.01017] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/30/2018] [Indexed: 12/12/2022] Open
Abstract
Most opportunistic pathogens transit in the environment between hosts and the environment plays a significant role in the evolution of protective traits. The coincidental evolution hypothesis suggests that virulence factors arose as a response to other selective pressures rather for virulence per se. This idea is strongly supported by the elucidation of bacterial-protozoal interactions. In response to protozoan predation, bacteria have evolved various defensive mechanisms which may also function as virulence factors. In this review, we summarize the dual role of factors involved in both grazing resistance and human pathogenesis, and compare the traits using model intracellular and extracellular pathogens. Intracellular pathogens rely on active invasion, blocking of the phagosome and lysosome fusion and resistance to phagocytic digestion to successfully invade host cells. In contrast, extracellular pathogens utilize toxin secretion and biofilm formation to avoid internalization by phagocytes. The complexity and diversity of bacterial virulence factors whose evolution is driven by protozoan predation, highlights the importance of protozoa in evolution of opportunistic pathogens.
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Affiliation(s)
- Shuyang Sun
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia
| | - Parisa Noorian
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia.,School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Diane McDougald
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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67
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Sousa PS, Silva IN, Moreira LM, Veríssimo A, Costa J. Differences in Virulence Between Legionella pneumophila Isolates From Human and Non-human Sources Determined in Galleria mellonella Infection Model. Front Cell Infect Microbiol 2018; 8:97. [PMID: 29670859 PMCID: PMC5893783 DOI: 10.3389/fcimb.2018.00097] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/16/2018] [Indexed: 01/13/2023] Open
Abstract
Legionella pneumophila is a ubiquitous bacterium in freshwater environments and in many man-made water systems capable of inducing pneumonia in humans. Despite its ubiquitous character most studies on L. pneumophila virulence focused on clinical strains and isolates from man-made environments, so little is known about the nature and extent of virulence variation in strains isolated from natural environments. It has been established that clinical isolates are less diverse than man-made and natural environmental strains, suggesting that only a subset of environmental isolates is specially adapted to infect humans. In this work we intended to determine if unrelated L. pneumophila strains, isolated from different environments and with distinct virulence-related genetic backgrounds, displayed differences in virulence, using the Wax Moth Galleria mellonella infection model. We found that all tested strains were pathogenic in G. mellonella, regardless of their origin. Indeed, a panoply of virulence-related phenotypes was observed sustaining the existence of significant differences on the ability of L. pneumophila strains to induce disease. Taken together our results suggest that the occurrence of human infection is not related with the increased capability of some strains to induce disease since we also found a concentration threshold above which L. pneumophila strains are equally able to cause disease. In addition, no link could be established between the sequence-type (ST) and L. pneumophila pathogenicity. We envision that in man-made water distribution systems environmental filtering selection and biotic competition acts structuring L. pneumophila populations by selecting more resilient and adapted strains that can rise to high concentration if no control measures are implemented. Therefore, public health strategies based on the sequence based typing (STB) scheme analysis should take into account that the major disease-associated clones of L. pneumophila were not related with higher virulence in G. mellonella infection model, and that potential variability of virulence-related phenotypes was found within the same ST.
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Affiliation(s)
- Patrícia S Sousa
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Inês N Silva
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Leonilde M Moreira
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal.,Department of Bioengineering, IST, University of Lisbon, Lisbon, Portugal
| | - António Veríssimo
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal.,Centre for Functional Ecology - Science for People & the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Joana Costa
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal.,Centre for Functional Ecology - Science for People & the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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68
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Assaidi A, Ellouali M, Latrache H, Mabrouki M, Timinouni M, Zahir H, Tankiouine S, Barguigua A, Mliji EM. Adhesion of Legionella pneumophila on glass and plumbing materials commonly used in domestic water systems. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2018; 28:125-133. [PMID: 29376417 DOI: 10.1080/09603123.2018.1429580] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 12/20/2017] [Indexed: 06/07/2023]
Abstract
We aimed to investigate the adhesion of Legionella pneumophila serogroup1 and L. pneumophila serogroup2-15 on glass, galvanized steel, stainless steel, copper, Polyvinyl chloride(PVC), Cross-linked polyethylene(PEX-c) and Polypropylene Random Copolymer(PPR). The surface physicochemical properties of both bacterial cells and materials were estimated through contact angle measurements. The roughness and surface topography of the materials were evaluated by Atomic Force Microscopy. The two L. pneumophila serogroups and plumbing materials showed a hydrophobic character, while glass surface was hydrophilic. All strains were adhered to all materials with the exception of copper. The result showed that the adhesion of both L. pneumophila sg1 and sg2-15 was systematically expressed with high intensity on galvanized steel followed by PVC, PEX-c, PPR, stainless steel and the low intensity on glass. The extent of adhesion is in correlation with the surface roughness and acid-bases interactions, while hydrophobicity seems to have no effect in adhesion intensity.
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Affiliation(s)
- Abdelwahid Assaidi
- a Laboratory of Bioprocess and Biointerfaces, Faculty of Sciences and Techniques , Sultan Moulay Slimane University , Beni Mellal , Morocco
- b Laboratory of Water Microbiology and Environmental Hygiene , Institut Pasteur du Maroc , Casablanca , Morocco
| | - Mostafa Ellouali
- a Laboratory of Bioprocess and Biointerfaces, Faculty of Sciences and Techniques , Sultan Moulay Slimane University , Beni Mellal , Morocco
| | - Hassan Latrache
- a Laboratory of Bioprocess and Biointerfaces, Faculty of Sciences and Techniques , Sultan Moulay Slimane University , Beni Mellal , Morocco
| | - Mustapha Mabrouki
- c Laboratory of Industrial Engineering, Faculty of Sciences and Techniques , Sultan Moulay Slimane University , Beni Mellal , Morocco
| | - Mohammed Timinouni
- b Laboratory of Water Microbiology and Environmental Hygiene , Institut Pasteur du Maroc , Casablanca , Morocco
| | - Hafida Zahir
- a Laboratory of Bioprocess and Biointerfaces, Faculty of Sciences and Techniques , Sultan Moulay Slimane University , Beni Mellal , Morocco
| | - Safae Tankiouine
- a Laboratory of Bioprocess and Biointerfaces, Faculty of Sciences and Techniques , Sultan Moulay Slimane University , Beni Mellal , Morocco
| | - Abouddihaj Barguigua
- d Polyvalent Laboratory of Research and Development, Polydisciplinary Faculty , Sultan Moulay Slimane University , Beni Mellal , Morocco
| | - El Mostafa Mliji
- b Laboratory of Water Microbiology and Environmental Hygiene , Institut Pasteur du Maroc , Casablanca , Morocco
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69
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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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70
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Boamah DK, Zhou G, Ensminger AW, O'Connor TJ. From Many Hosts, One Accidental Pathogen: The Diverse Protozoan Hosts of Legionella. Front Cell Infect Microbiol 2017; 7:477. [PMID: 29250488 PMCID: PMC5714891 DOI: 10.3389/fcimb.2017.00477] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/31/2017] [Indexed: 01/03/2023] Open
Abstract
The 1976 outbreak of Legionnaires' disease led to the discovery of the intracellular bacterial pathogen Legionella pneumophila. Given their impact on human health, Legionella species and the mechanisms responsible for their replication within host cells are often studied in alveolar macrophages, the primary human cell type associated with disease. Despite the potential severity of individual cases of disease, Legionella are not spread from person-to-person. Thus, from the pathogen's perspective, interactions with human cells are accidents of time and space—evolutionary dead ends with no impact on Legionella's long-term survival or pathogenic trajectory. To understand Legionella as a pathogen is to understand its interaction with its natural hosts: the polyphyletic protozoa, a group of unicellular eukaryotes with a staggering amount of evolutionary diversity. While much remains to be understood about these enigmatic hosts, we summarize the current state of knowledge concerning Legionella's natural host range, the diversity of Legionella-protozoa interactions, the factors influencing these interactions, the importance of avoiding the generalization of protozoan-bacterial interactions based on a limited number of model hosts and the central role of protozoa to the biology, evolution, and persistence of Legionella in the environment.
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Affiliation(s)
- David K Boamah
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Guangqi Zhou
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Alexander W Ensminger
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Public Health Ontario, Toronto, ON, Canada
| | - Tamara J O'Connor
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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71
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Wang J, Nong XH, Amin M, Qi SH. Hygrocin C from marine-derived Streptomyces sp. SCSGAA 0027 inhibits biofilm formation in Bacillus amyloliquefaciens SCSGAB0082 isolated from South China Sea gorgonian. Appl Microbiol Biotechnol 2017; 102:1417-1427. [PMID: 29189900 DOI: 10.1007/s00253-017-8672-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/19/2017] [Accepted: 11/22/2017] [Indexed: 11/25/2022]
Abstract
Several ansamycins have been reported to inhibit bacterial biofilm formation and accelerate the eradication of developed biofilms, but little is known about the effect of hygrocin C, an ansamycin, on bacterial biofilm formation. Here, hygrocin C was isolated from the marine-derived Streptomyces sp. SCSGAA 0027 and reported for the first time to be capable of inhibiting the biofilm formation of Staphylococcus aureus and Bacillus amyloliquefaciens SCSGAB0082 with the production of anti-microbial lipopeptides from South China Sea gorgonian Subergorgia suberosa at concentrations of less than minimum inhibitory concentrations. Moreover, hygrocin C also promoted the eradication of developed biofilms, affected the biofilm architecture, and lowered the extracellular polymeric matrix formation, cell motility, and surface hydrophobicity in B. amyloliquefaciens, which was in accordance with the inhibition of biofilm formation. Furthermore, transcriptome analysis revealed that hygrocin C altered the transcripts of several genes associated with bacterial chemotaxis and flagellar, two-component system and the synthesis of arginine and histidine, which are important for bacterial biofilm formation. In conclusion, hygrocin C could be used as a potential biofilm inhibitor against S. aureus and B. amyloliquefaciens. But further genetic investigations are needed to provide more details for elucidation of the molecular mechanisms responsible for the effects of hygrocin C on B. amyloliquefaciens biofilm formation.
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Affiliation(s)
- Jie Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Material Medical, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou, 510301, China
- College of Food Science, South China Agricultural University, Guangzhou, 510642, China
| | - Xu-Hua Nong
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Material Medical, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou, 510301, China
| | - Muhammad Amin
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Material Medical, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou, 510301, China
| | - Shu-Hua Qi
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Material Medical, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou, 510301, China.
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72
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Appelt S, Heuner K. The Flagellar Regulon of Legionella-A Review. Front Cell Infect Microbiol 2017; 7:454. [PMID: 29104863 PMCID: PMC5655016 DOI: 10.3389/fcimb.2017.00454] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 10/06/2017] [Indexed: 12/15/2022] Open
Abstract
The Legionella genus comprises more than 60 species. In particular, Legionella pneumophila is known to cause severe illnesses in humans. Legionellaceae are ubiquitous inhabitants of aquatic environments. Some Legionellaceae are motile and their motility is important to move around in habitats. Motility can be considered as a potential virulence factor as already shown for various human pathogens. The genes of the flagellar system, regulator and structural genes, are structured in hierarchical levels described as the flagellar regulon. Their expression is modulated by various environmental factors. For L. pneumophila it was shown that the expression of genes of the flagellar regulon is modulated by the actual growth phase and temperature. Especially, flagellated Legionella are known to express genes during the transmissive phase of growth that are involved in the expression of virulence traits. It has been demonstrated that the alternative sigma-28 factor is part of the link between virulence expression and motility. In the following review, the structure of the flagellar regulon of L. pneumophila is discussed and compared to other flagellar systems of different Legionella species. Recently, it has been described that Legionella micdadei and Legionella fallonii contain a second putative partial flagellar system. Hence, the report will focus on flagellated and non-flagellated Legionella strains, phylogenetic relationships, the role and function of the alternative sigma factor (FliA) and its anti-sigma-28 factor (FlgM).
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Affiliation(s)
- Sandra Appelt
- Highly Pathogenic Microorganisms, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Klaus Heuner
- Cellular Interactions of Bacterial Pathogens, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
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73
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Messi P, de Niederhäusern S, Anacarso I, Iseppi R, Sabia C, Bondi M. Legionella pneumophila in healthcare settings: sensitivity to biocidal treatments in mono- and multi-species biofilms. J Hosp Infect 2017; 97:200-201. [DOI: 10.1016/j.jhin.2017.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/02/2017] [Indexed: 10/19/2022]
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74
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Prussin AJ, Schwake DO, Marr LC. Ten Questions Concerning the Aerosolization and Transmission of Legionella in the Built Environment. BUILDING AND ENVIRONMENT 2017; 123:684-695. [PMID: 29104349 PMCID: PMC5665586 DOI: 10.1016/j.buildenv.2017.06.024] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Legionella is a genus of pathogenic Gram-negative bacteria responsible for a serious disease known as legionellosis, which is transmitted via inhalation of this pathogen in aerosol form. There are two forms of legionellosis: Legionnaires' disease, which causes pneumonia-like symptoms, and Pontiac fever, which causes influenza-like symptoms. Legionella can be aerosolized from various water sources in the built environment including showers, faucets, hot tubs/swimming pools, cooling towers, and fountains. Incidence of the disease is higher in the summertime, possibly because of increased use of cooling towers for air conditioning systems and differences in water chemistry when outdoor temperatures are higher. Although there have been decades of research related to Legionella transmission, many knowledge gaps remain. While conventional wisdom suggests that showering is an important source of exposure in buildings, existing measurements do not provide strong support for this idea. There has been limited research on the potential for Legionella transmission through heating, ventilation, and air conditioning (HVAC) systems. Epidemiological data suggest a large proportion of legionellosis cases go unreported, as most people who are infected do not seek medical attention. Additionally, controlled laboratory studies examining water-to-air transfer and source tracking are still needed. Herein, we discuss ten questions that spotlight current knowledge about Legionella transmission in the built environment, engineering controls that might prevent future disease outbreaks, and future research that is needed to advance understanding of transmission and control of legionellosis.
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Affiliation(s)
- Aaron J. Prussin
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
- Corresponding Author:
| | - David Otto Schwake
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Linsey C. Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
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75
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Phylogenetic Analysis and Antimicrobial Profiles of Cultured Emerging Opportunistic Pathogens (Phyla Actinobacteria and Proteobacteria) Identified in Hot Springs. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14091070. [PMID: 28914802 PMCID: PMC5615607 DOI: 10.3390/ijerph14091070] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/07/2017] [Accepted: 09/07/2017] [Indexed: 02/08/2023]
Abstract
Hot spring water may harbour emerging waterborne opportunistic pathogens that can cause infections in humans. We have investigated the diversity and antimicrobial resistance of culturable emerging and opportunistic bacterial pathogens, in water and sediment of hot springs located in Limpopo, South Africa. Aerobic bacteria were cultured and identified using 16S ribosomal DNA (rDNA) gene sequencing. The presence of Legionella spp. was investigated using real-time polymerase chain reaction. Isolates were tested for resistance to ten antibiotics representing six different classes: β-lactam (carbenicillin), aminoglycosides (gentamycin, kanamycin, streptomycin), tetracycline, amphenicols (chloramphenicol, ceftriaxone), sulphonamides (co-trimoxazole) and quinolones (nalidixic acid, norfloxacin). Gram-positive Kocuria sp. and Arthrobacter sp. and gram-negative Cupriavidus sp., Ralstonia sp., Cronobacter sp., Tepidimonas sp., Hafnia sp. and Sphingomonas sp. were isolated, all recognised as emerging food-borne pathogens. Legionella spp. was not detected throughout the study. Isolates of Kocuria, Arthrobacter and Hafnia and an unknown species of the class Gammaproteobacteria were resistant to two antibiotics in different combinations of carbenicillin, ceftriaxone, nalidixic acid and chloramphenicol. Cronobacter sp. was sensitive to all ten antibiotics. This study suggests that hot springs are potential reservoirs for emerging opportunistic pathogens, including multiple antibiotic resistant strains, and highlights the presence of unknown populations of emerging and potential waterborne opportunistic pathogens in the environment.
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Abstract
Type II secretion (T2S) is one means by which Gram-negative pathogens secrete proteins into the extracellular milieu and/or host organisms. Based upon recent genome sequencing, it is clear that T2S is largely restricted to the Proteobacteria, occurring in many, but not all, genera in the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria classes. Prominent human and/or animal pathogens that express a T2S system(s) include Acinetobacter baumannii, Burkholderia pseudomallei, Chlamydia trachomatis, Escherichia coli, Klebsiella pneumoniae, Legionella pneumophila, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Vibrio cholerae, and Yersinia enterocolitica T2S-expressing plant pathogens include Dickeya dadantii, Erwinia amylovora, Pectobacterium carotovorum, Ralstonia solanacearum, Xanthomonas campestris, Xanthomonas oryzae, and Xylella fastidiosa T2S also occurs in nonpathogenic bacteria, facilitating symbioses, among other things. The output of a T2S system can range from only one to dozens of secreted proteins, encompassing a diverse array of toxins, degradative enzymes, and other effectors, including novel proteins. Pathogenic processes mediated by T2S include the death of host cells, degradation of tissue, suppression of innate immunity, adherence to host surfaces, biofilm formation, invasion into and growth within host cells, nutrient assimilation, and alterations in host ion flux. The reach of T2S is perhaps best illustrated by those bacteria that clearly use it for both environmental survival and virulence; e.g., L. pneumophila employs T2S for infection of amoebae, growth within lung cells, dampening of cytokines, and tissue destruction. This minireview provides an update on the types of bacteria that have T2S, the kinds of proteins that are secreted via T2S, and how T2S substrates promote infection.
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Brouse L, Brouse R, Brouse D. Natural Pathogen Control Chemistry to Replace Toxic Treatment of Microbes and Biofilm in Cooling Towers. Pathogens 2017; 6:pathogens6020014. [PMID: 28420074 PMCID: PMC5488648 DOI: 10.3390/pathogens6020014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/15/2017] [Accepted: 03/28/2017] [Indexed: 11/16/2022] Open
Abstract
Application of toxic antibacterial agents is considered necessary to control prevalent fresh water microorganisms that grow in evaporative cooling water systems, but can adversely affect the environment and human health. However, natural antibacterial water chemistry has been applied in industrial cooling water systems for over 10 years to inhibit microorganisms with excellent results. The water chemistry method concentrates natural minerals in highly-softened water to produce elevated pH and dissolved solids, while maintaining low calcium and magnesium content. The method provides further benefits in water conservation, and generates a small volume of non-toxic natural salt concentrate for cost efficient separation and disposal if required. This report describes the antimicrobial effects of these chemistry modifications in the cooling water environment and the resultant collective inhibition of microbes, biofilm, and pathogen growth. This article also presents a novel perspective of parasitic microbiome functional relationships, including "Trojan Protozoans" and biofilms, and the function of polyvalent metal ions in the formation and inhibition of biofilms. Reducing global dependence on toxic antibacterial agents discharged to the environment is an emerging concern due to their impact on the natural microbiome, plants, animals and humans. Concurrently, scientists have concluded that discharge of antibacterial agents plays a key role in development of pathogen resistance to antimicrobials as well as antibiotics. Use of natural antibacterial chemistry can play a key role in managing the cooling water environment in a more ecologically sustainable manner.
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Affiliation(s)
- Lon Brouse
- Chemistry Consultant, 2200 Mead Ln., Montrose, CO 81401, USA.
| | - Richard Brouse
- Sunnyside Health Center, 17396 S. Rory Ct., Oregon City, OR 97045, USA.
| | - Daniel Brouse
- Southwestern Oregon Community College, 1448 Evergreen Dr., Mail Stop 2070, Coos Bay, OR 97420, USA,.
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Legionella pneumophila OxyR Is a Redundant Transcriptional Regulator That Contributes to Expression Control of the Two-Component CpxRA System. J Bacteriol 2017; 199:JB.00690-16. [PMID: 27994017 DOI: 10.1128/jb.00690-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/13/2016] [Indexed: 12/27/2022] Open
Abstract
Nominally an environmental organism, Legionella pneumophila is an intracellular parasite of protozoa but is also the causative agent of the pneumonia termed Legionnaires' disease, which results from inhalation of aerosolized bacteria by susceptible humans. Coordination of gene expression by a number of identified regulatory factors, including OxyR, assists L. pneumophila in adapting to the stresses of changing environments. L. pneumophila OxyR (OxyRLp) is an ortholog of Escherichia coli OxyR; however, OxyRLp was shown elsewhere to be functionally divergent, such that it acts as a transcription regulator independently of the oxidative stress response. In this study, the use of improved gene deletion methods has enabled us to generate an unmarked in-frame deletion of oxyR in L. pneumophila Lack of OxyRLp did not affect in vitro growth or intracellular growth in Acanthamoeba castellanii protozoa and U937-derived macrophages. The expression of OxyRLp does not appear to be regulated by CpxR, even though purified recombinant CpxR bound a DNA sequence similar to that reported for CpxR elsewhere. Surprisingly, a lack of OxyRLp resulted in elevated activity of the promoters located upstream of icmR and the lpg1441-cpxA operon, and OxyRLp directly bound to these promoter regions, suggesting that OxyRLp is a direct repressor. Interestingly, a strain overexpressing OxyRLp demonstrated reduced intracellular growth in A. castellanii but not in U937-derived macrophages, suggesting that balanced expression control of the two-component CpxRA system is necessary for survival in protozoa. Taken together, this study suggests that OxyRLp is a functionally redundant transcriptional regulator in L. pneumophila under the conditions evaluated herein.IMPORTANCELegionella pneumophila is an environmental pathogen, with its transmission to the human host dependent upon its ability to replicate in protozoa and survive within its aquatic niche. Understanding the genetic factors that contribute to L. pneumophila survival within each of these unique environments will be key to limiting future point-source outbreaks of Legionnaires' disease. The transcriptional regulator L. pneumophila OxyR (OxyRLp) has been previously identified as a potential regulator of virulence traits warranting further investigation. This study demonstrated that oxyR is nonessential for L. pneumophila survival in vitro and in vivo via mutational analysis. While the mechanisms of how OxyRLp expression is regulated remain elusive, this study shows that OxyRLp negatively regulates the expression of the cpxRA two-component system necessary for intracellular survival in protozoa.
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Schmölders J, Manske C, Otto A, Hoffmann C, Steiner B, Welin A, Becher D, Hilbi H. Comparative Proteomics of Purified Pathogen Vacuoles Correlates Intracellular Replication of Legionella pneumophila with the Small GTPase Ras-related protein 1 (Rap1). Mol Cell Proteomics 2017; 16:622-641. [PMID: 28183814 DOI: 10.1074/mcp.m116.063453] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/24/2017] [Indexed: 12/19/2022] Open
Abstract
Legionella pneumophila is an opportunistic bacterial pathogen that causes a severe lung infection termed "Legionnaires' disease." The pathogen replicates in environmental protozoa as well as in macrophages within a unique membrane-bound compartment, the Legionella-containing-vacuole (LCV). LCV formation requires the bacterial Icm/Dot type IV secretion system, which translocates ca. 300 "effector proteins" into host cells, where they target distinct host factors. The L. pneumophila "pentuple" mutant (Δpentuple) lacks 5 gene clusters (31% of the effector proteins) and replicates in macrophages but not in Dictyostelium discoideum amoeba. To elucidate the host factors defining a replication-permissive compartment, we compare here the proteomes of intact LCVs isolated from D. discoideum or macrophages infected with Δpentuple or the parental strain Lp02. This analysis revealed that the majority of host proteins are shared in D. discoideum or macrophage LCVs containing the mutant or the parental strain, respectively, whereas some proteins preferentially localize to distinct LCVs. The small GTPase Rap1 was identified on D. discoideum LCVs containing strain Lp02 but not the Δpentuple mutant and on macrophage LCVs containing either strain. The localization pattern of active Rap1 on D. discoideum or macrophage LCVs was confirmed by fluorescence microscopy and imaging flow cytometry, and the depletion of Rap1 by RNA interference significantly reduced the intracellular growth of L. pneumophila Thus, comparative proteomics identified Rap1 as a novel LCV host component implicated in intracellular replication of L. pneumophila.
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Affiliation(s)
- Johanna Schmölders
- From the ‡Max von Pettenkofer Institute, Ludwig-Maximilians University, Munich, Germany
| | - Christian Manske
- From the ‡Max von Pettenkofer Institute, Ludwig-Maximilians University, Munich, Germany
| | - Andreas Otto
- §Institute for Microbiology, Ernst Moritz Arndt University, Greifswald, Germany
| | - Christine Hoffmann
- From the ‡Max von Pettenkofer Institute, Ludwig-Maximilians University, Munich, Germany
| | - Bernhard Steiner
- ¶Institute of Medical Microbiology, University of Zürich, Switzerland
| | - Amanda Welin
- ¶Institute of Medical Microbiology, University of Zürich, Switzerland
| | - Dörte Becher
- §Institute for Microbiology, Ernst Moritz Arndt University, Greifswald, Germany;
| | - Hubert Hilbi
- From the ‡Max von Pettenkofer Institute, Ludwig-Maximilians University, Munich, Germany; .,¶Institute of Medical Microbiology, University of Zürich, Switzerland
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Hochstrasser R, Hilbi H. Intra-Species and Inter-Kingdom Signaling of Legionella pneumophila. Front Microbiol 2017; 8:79. [PMID: 28217110 PMCID: PMC5289986 DOI: 10.3389/fmicb.2017.00079] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/11/2017] [Indexed: 12/24/2022] Open
Abstract
The ubiquitous Gram-negative bacterium Legionella pneumophila parasitizes environ mental amoebae and, upon inhalation, replicates in alveolar macrophages, thus causing a life-threatening pneumonia called “Legionnaires’ disease.” The opportunistic pathogen employs a bi-phasic life cycle, alternating between a replicative, non-virulent phase and a stationary, transmissive/virulent phase. L. pneumophila employs the Lqs (Legionella quorum sensing) system as a major regulator of the growth phase switch. The Lqs system comprises the autoinducer synthase LqsA, the homologous sensor kinases LqsS and LqsT, as well as a prototypic response regulator termed LqsR. These components produce, detect, and respond to the α-hydroxyketone signaling molecule LAI-1 (Legionella autoinducer-1, 3-hydroxypentadecane-4-one). LAI-1-mediated signal transduction through the sensor kinases converges on LqsR, which dimerizes upon phosphorylation. The Lqs system regulates the bacterial growth phase switch, pathogen-host cell interactions, motility, natural competence, filament production, and expression of a chromosomal “fitness island.” Yet, LAI-1 not only mediates bacterial intra-species signaling, but also modulates the motility of eukaryotic cells through the small GTPase Cdc42 and thus promotes inter-kingdom signaling. Taken together, the low molecular weight compound LAI-1 produced by L. pneumophila and sensed by the bacteria as well as by eukaryotic cells plays a major role in pathogen-host cell interactions.
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Affiliation(s)
- Ramon Hochstrasser
- Department of Medicine, Institute of Medical Microbiology, University of Zürich Zürich, Switzerland
| | - Hubert Hilbi
- Department of Medicine, Institute of Medical Microbiology, University of Zürich Zürich, Switzerland
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Springston JP, Yocavitch L. Existence and control of Legionella bacteria in building water systems: A review. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2017; 14:124-134. [PMID: 27624495 DOI: 10.1080/15459624.2016.1229481] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Legionellae are waterborne bacteria which are capable of causing potentially fatal Legionnaires' disease (LD), as well as Pontiac Fever. Public concern about Legionella exploded following the 1976 outbreak at the American Legion conference in Philadelphia, where 221 attendees contracted pneumonia and 34 died. Since that time, a variety of different control methods and strategies have been developed and implemented in an effort to eradicate Legionella from building water systems. Despite these efforts, the incidence of LD has been steadily increasing in the U.S. for more than a decade. Public health and occupational hygiene professionals have maintained an active debate regarding best practices for management and control of Legionella. Professional opinion remains divided with respect to the relative merits of performing routine sampling for Legionella, vs. the passive, reactive approach that has been largely embraced by public health officials and facility owners. Given the potential risks and ramifications associated with waiting to assess systems for Legionella until after disease has been identified and confirmed, a proactive approach of periodic testing for Legionella, along with proper water treatment, is the best approach to avoiding large-scale disease outbreaks.
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Millares L, Bermudo G, Pérez-Brocal V, Domingo C, Garcia-Nuñez M, Pomares X, Moya A, Monsó E. The respiratory microbiome in bronchial mucosa and secretions from severe IgE-mediated asthma patients. BMC Microbiol 2017; 17:20. [PMID: 28103814 PMCID: PMC5248442 DOI: 10.1186/s12866-017-0933-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/13/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The bronchial microbiome in chronic lung diseases presents an abnormal pattern, but its microbial composition and regional differences in severe asthma have not been sufficiently addressed. The aim of the study was to describe the bacterial community in bronchial mucosa and secretions of patients with severe chronic asthma chronically treated with corticosteroids in addition to usual care according to Global Initiative for Asthma. Bacterial community composition was obtained by 16S rRNA gene amplification and sequencing, and functional capabilities through PICRUSt. RESULTS Thirteen patients with severe asthma were included and provided 11 bronchial biopsies (BB) and 12 bronchial aspirates (BA) suitable for sequence analyses. Bacteroidetes, Firmicutes, Proteobacteria and Actinobacteria showed relative abundances (RAs) over 5% in BB, a cutoff that was reached by Streptococcus and Prevotella at genus level. Legionella genus attained a median RA of 2.7 (interquartile range 1.1-4.7) in BB samples. In BA a higher RA of Fusobacteria was found, when compared with BB [8.7 (5.9-11.4) vs 4.2 (0.8-7.5), p = 0.037], while the RA of Proteobacteria was lower in BA [4.3 (3.7-6.5) vs 17.1 (11.2-33.4), p = 0.005]. RA of the Legionella genus was also significantly lower in BA [0.004 (0.001-0.02) vs. 2.7 (1.1-4.7), p = 0.005]. Beta-diversity analysis confirmed the differences between the microbial communities in BA and BB (R2 = 0.20, p = 0.001, Adonis test), and functional analysis revealed also statistically significant differences between both types of sample on Metabolism, Cellular processes, Human diseases, Organismal systems and Genetic information processing pathways. CONCLUSIONS The microbiota in the bronchial mucosa of severe asthma has a specific pattern that is not accurately represented in bronchial secretions, which must be considered a different niche of bacteria growth.
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Affiliation(s)
- Laura Millares
- Fundació Parc Taulí, Parc Taulí 1, Edificio Santa Fe, planta baja, 08208, Sabadell, Barcelona, Spain.
- CIBER de Enfermedades Respiratorias, CIBERES, Madrid, Spain.
- Universitat Autònoma de Barcelona, Esfera UAB, Barcelona, Spain.
- Fundació Insitut d'Investigació Germans Trias i Pujol, Badalona, Spain.
| | - Guadalupe Bermudo
- Department of Respiratory Medicine, Hospital Universitari Parc Taulí, Sabadell, Spain
| | - Vicente Pérez-Brocal
- Genomics and Health Area, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO-Public Health), Valencia, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Evolutionary Genetics Unit, Institut Cavanilles de Biodiversitat i Biologia Evolutiva (ICBiBE), Universitat de València, Valencia, Spain
| | - Christian Domingo
- Department of Respiratory Medicine, Hospital Universitari Parc Taulí, Sabadell, Spain
- Department of Medicine, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Marian Garcia-Nuñez
- Fundació Parc Taulí, Parc Taulí 1, Edificio Santa Fe, planta baja, 08208, Sabadell, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, CIBERES, Madrid, Spain
- Universitat Autònoma de Barcelona, Esfera UAB, Barcelona, Spain
- Fundació Insitut d'Investigació Germans Trias i Pujol, Badalona, Spain
| | - Xavier Pomares
- Department of Respiratory Medicine, Hospital Universitari Parc Taulí, Sabadell, Spain
| | - Andrés Moya
- Genomics and Health Area, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO-Public Health), Valencia, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Evolutionary Genetics Unit, Institut Cavanilles de Biodiversitat i Biologia Evolutiva (ICBiBE), Universitat de València, Valencia, Spain
| | - Eduard Monsó
- CIBER de Enfermedades Respiratorias, CIBERES, Madrid, Spain
- Universitat Autònoma de Barcelona, Esfera UAB, Barcelona, Spain
- Department of Medicine, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
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Xiong L, Yan H, Shi L, Mo Z. Antibiotic susceptibility of Legionella strains isolated from public water sources in Macau and Guangzhou. JOURNAL OF WATER AND HEALTH 2016; 14:1041-1046. [PMID: 27959883 DOI: 10.2166/wh.2016.056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The purpose of this study was to investigate the susceptibility of waterborne strains of Legionella to eight antimicrobials commonly used in legionellosis therapy. The minimum inhibitory concentrations (MICs) of 66 environmental Legionella strains, isolated from fountains and cooling towers of public facilities (hotels, schools, and shopping malls) in Macau and Guangzhou, were tested using the microdilution method in buffered yeast extract broth. The MIC50/MIC90 values for erythromycin, cefotaxime (CTX), doxycycline (DOC), minocycline (MIN), azithromycin, ciprofloxacin, levofloxacin (LEV), and moxifloxacin were 0.125/0.5 mg/L, 4/8 mg/L, 8/16 mg/L, 4/8 mg/L, 0.125/0.5 mg/L, 0.031/0.031 mg/L, 0.031/0.031 mg/L, and 0.031/0.062 mg/L, respectively. Legionella isolates were inhibited by either low concentrations of macrolides and fluoroquinolones, or high concentrations of CTX and tetracycline drugs. LEV was the most effective drug against different Legionella species and serogroups of L. pneumophila isolates. The latter were inhibited in decreasing order by MIN > CTX >DOC, while non-L. pneumophila isolates were inhibited by CTX> MIN >DOC. In this study, we evaluated drug resistance of pathogenic bacteria from the environment. This may help predict the emergence of drug resistance, improve patient outcomes, and reduce hospitalization costs.
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Affiliation(s)
- Lina Xiong
- School of Food Science and Technology, South China University of Technology, No. 381, Wushan Road, TianHe District, Guangzhou, Guangdong 510641, China
| | - He Yan
- School of Food Science and Technology, South China University of Technology, No. 381, Wushan Road, TianHe District, Guangzhou, Guangdong 510641, China
| | - Lei Shi
- School of Food Science and Technology, South China University of Technology, No. 381, Wushan Road, TianHe District, Guangzhou, Guangdong 510641, China
| | - Ziyao Mo
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Institute of Respiratory Disease, No. 151, YanJiang Xi Road, YueXiu District, Guangzhou, Guangdong 510120, China E-mail:
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Characterization of aerosols containing Legionella generated upon nebulization. Sci Rep 2016; 6:33998. [PMID: 27671446 PMCID: PMC5037422 DOI: 10.1038/srep33998] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/01/2016] [Indexed: 01/01/2023] Open
Abstract
Legionella pneumophila is, by far, the species most frequently associated with Legionnaires' disease (LD). Human infection occurs almost exclusively by aerosol inhalation which places the bacteria in juxtaposition with alveolar macrophages. LD risk management is based on controlling water quality by applying standardized procedures. However, to gain a better understanding of the real risk of exposure, there is a need (i) to investigate under which conditions Legionella may be aerosolized and (ii) to quantify bacterial deposition into the respiratory tract upon nebulization. In this study, we used an original experimental set-up that enables the generation of aerosol particles containing L. pneumophila under various conditions. Using flow cytometry in combination with qPCR and culture, we determined (i) the size of the aerosols and (ii) the concentration of viable Legionella forms that may reach the thoracic region. We determined that the 0.26-2.5 μm aerosol size range represents 7% of initial bacterial suspension. Among the viable forms, 0.7% of initial viable bacterial suspension may reach the pulmonary alveoli. In conclusion, these deposition profiles can be used to standardize the size of inoculum injected in any type of respiratory tract model to obtain new insights into the dose response for LD.
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Pécastaings S, Allombert J, Lajoie B, Doublet P, Roques C, Vianney A. New insights into Legionella pneumophila biofilm regulation by c-di-GMP signaling. BIOFOULING 2016; 32:935-948. [PMID: 27494738 DOI: 10.1080/08927014.2016.1212988] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 07/07/2016] [Indexed: 06/06/2023]
Abstract
The waterborne pathogen Legionella pneumophila grows as a biofilm, freely or inside amoebae. Cyclic-di-GMP (c-di-GMP), a bacterial second messenger frequently implicated in biofilm formation, is synthesized and degraded by diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), respectively. To characterize the c-di-GMP-metabolizing enzymes involved in L. pneumophila biofilm regulation, the consequences on biofilm formation and the c-di-GMP concentration of each corresponding gene inactivation were assessed in the Lens strain. The results showed that one DGC and two PDEs enhance different aspects of biofilm formation, while two proteins with dual activity (DGC/PDE) inhibit biofilm growth. Surprisingly, only two mutants exhibited a change in global c-di-GMP concentration. This study highlights that specific c-di-GMP pathways control L. pneumophila biofilm formation, most likely via temporary and/or local modulation of c-di-GMP concentration. Furthermore, Lpl1054 DGC is required to enable the formation a dense biofilm in response to nitric oxide, a signal for biofilm dispersion in many other species.
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Affiliation(s)
- Sophie Pécastaings
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Julie Allombert
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
| | - Barbora Lajoie
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Patricia Doublet
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
| | - Christine Roques
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Anne Vianney
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
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Eisenreich W, Heuner K. The life stage-specific pathometabolism of Legionella pneumophila. FEBS Lett 2016; 590:3868-3886. [PMID: 27455397 DOI: 10.1002/1873-3468.12326] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 07/08/2016] [Accepted: 07/21/2016] [Indexed: 12/17/2022]
Abstract
The genus Legionella belongs to Gram-negative bacteria found ubiquitously in aquatic habitats, where it grows in natural biofilms and replicates intracellularly in various protozoa (amoebae, ciliates). L. pneumophila is known as the causative agent of Legionnaires' disease, since it is also able to replicate in human alveolar macrophages, finally leading to inflammation of the lung and pneumonia. To withstand the degradation by its host cells, a Legionella-containing vacuole (LCV) is established for intracellular replication, and numerous effector proteins are secreted into the host cytosol using a type four B secretion system (T4BSS). During intracellular replication, Legionella has a biphasic developmental cycle that alternates between a replicative and a transmissive form. New knowledge about the host-adapted and life stage-dependent metabolism of intracellular L. pneumophila revealed a bipartite metabolic network with life stage-specific usages of amino acids (e.g. serine), carbohydrates (e.g. glucose) and glycerol as major substrates. These metabolic features are associated with the differentiation of the intracellular bacteria, and thus have an important impact on the virulence of L. pneumophila.
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Affiliation(s)
| | - Klaus Heuner
- Cellular Interactions of Bacterial Pathogens, ZBS 2, Robert Koch Institute, Berlin, Germany
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Metabolism of myo-Inositol by Legionella pneumophila Promotes Infection of Amoebae and Macrophages. Appl Environ Microbiol 2016; 82:5000-14. [PMID: 27287324 DOI: 10.1128/aem.01018-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/06/2016] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED Legionella pneumophila is a natural parasite of environmental amoebae and the causative agent of a severe pneumonia termed Legionnaires' disease. The facultative intracellular pathogen employs a bipartite metabolism, where the amino acid serine serves as the major energy supply, while glycerol and glucose are mainly utilized for anabolic processes. The L. pneumophila genome harbors the cluster lpg1653 to lpg1649 putatively involved in the metabolism of the abundant carbohydrate myo-inositol (here termed inositol). To assess inositol metabolism by L. pneumophila, we constructed defined mutant strains lacking lpg1653 or lpg1652, which are predicted to encode the inositol transporter IolT or the inositol-2-dehydrogenase IolG, respectively. The mutant strains were not impaired for growth in complex or defined minimal media, and inositol did not promote extracellular growth. However, upon coinfection of Acanthamoeba castellanii, the mutants were outcompeted by the parental strain, indicating that the intracellular inositol metabolism confers a fitness advantage to the pathogen. Indeed, inositol added to L. pneumophila-infected amoebae or macrophages promoted intracellular growth of the parental strain, but not of the ΔiolT or ΔiolG mutant, and growth stimulation by inositol was restored by complementation of the mutant strains. The expression of the Piol promoter and bacterial uptake of inositol required the alternative sigma factor RpoS, a key virulence regulator of L. pneumophila Finally, the parental strain and ΔiolG mutant bacteria but not the ΔiolT mutant strain accumulated [U-(14)C6]inositol, indicating that IolT indeed functions as an inositol transporter. Taken together, intracellular L. pneumophila metabolizes inositol through the iol gene products, thus promoting the growth and virulence of the pathogen. IMPORTANCE The environmental bacterium Legionella pneumophila is the causative agent of a severe pneumonia termed Legionnaires' disease. The opportunistic pathogen replicates in protozoan and mammalian phagocytes in a unique vacuole. Amino acids are thought to represent the prime source of carbon and energy for L. pneumophila However, genome, transcriptome, and proteome studies indicate that the pathogen not only utilizes amino acids as carbon sources but possesses broader metabolic capacities. In this study, we analyzed the metabolism of inositol by extra- and intracellularly growing L. pneumophila By using genetic, biochemical, and cell biological approaches, we found that L. pneumophila accumulates and metabolizes inositol through the iol gene products, thus promoting the intracellular growth, virulence, and fitness of the pathogen. Our study significantly contributes to an understanding of the intracellular niche of a human pathogen.
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88
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Lesnik R, Brettar I, Höfle MG. Legionella species diversity and dynamics from surface reservoir to tap water: from cold adaptation to thermophily. THE ISME JOURNAL 2016; 10:1064-80. [PMID: 26528838 PMCID: PMC5029207 DOI: 10.1038/ismej.2015.199] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 08/12/2015] [Accepted: 09/22/2015] [Indexed: 12/20/2022]
Abstract
Water samples of the Drinking Water Supply System (DWSS) of the city of Braunschweig were analysed for its Legionella species composition using genus-specific PCR amplicons and single-strand conformation polymorphism (SSCP) fingerprint analyses based on 16S rRNA genes. These analyses comprised the whole supply chain including raw water, treatment process and large-scale storage, and a seasonal study of finished drinking water sampled monthly from cold and hot tap water. Treatment of raw water had a major impact on Legionella species by reducing their diversity and abundances. The Legionella species composition of the tap water was highly distinct from that of both source waters. In cold water, 8-14 different phylotypes of Legionella (PTLs) were observed per sample with relative abundances ranging from >1% to 53%. In hot water, L. pneumophila was present during all seasons at high relative abundances (8-40%) accompanied by 5-14 other PTLs of which 6 PTLs were in common with cold water. This thermophilic Legionella community, including L. pneumophila, was able to grow in the hot water above 50 °C. Such thermophilic Legionella populations are of general relevance for drinking water management and public health, but also for the ecology and evolution of the genus Legionella.
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Affiliation(s)
- René Lesnik
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ingrid Brettar
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Manfred G Höfle
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
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89
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Tanner JR, Li L, Faucher SP, Brassinga AKC. The CpxRA two-component system contributes to Legionella pneumophila virulence. Mol Microbiol 2016; 100:1017-38. [PMID: 26934669 DOI: 10.1111/mmi.13365] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2016] [Indexed: 12/11/2022]
Abstract
The bacterium Legionella pneumophila is capable of intracellular replication within freshwater protozoa as well as human macrophages, the latter of which results in the serious pneumonia Legionnaires' disease. A primary factor involved in these host cell interactions is the Dot/Icm Type IV secretion system responsible for translocating effector proteins needed to establish and maintain the bacterial replicative niche. Several regulatory factors have been identified to control the expression of the Dot/Icm system and effectors, one of which is the CpxRA two-component system, suggesting essentiality for virulence. In this study, we generated cpxR, cpxA and cpxRA in-frame null mutant strains to further delineate the role of the CpxRA system in bacterial survival and virulence. We found that cpxR is essential for intracellular replication within Acanthamoeba castellanii, but not in U937-derived macrophages. Transcriptome analysis revealed that CpxRA regulates a large number of virulence-associated proteins including Dot/Icm effectors as well as Type II secreted substrates. Furthermore, the cpxR and cpxRA mutant strains were more sodium resistant than the parental strain Lp02, and cpxRA expression reaches maximal levels during postexponential phase. Taken together, our findings suggest the CpxRA system is a key contributor to L. pneumophila virulence in protozoa via virulence factor regulation.
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Affiliation(s)
- Jennifer R Tanner
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Laam Li
- Faculty of Agricultural and Environmental Sciences, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Sébastien P Faucher
- Faculty of Agricultural and Environmental Sciences, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Ann Karen C Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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90
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Berjeaud JM, Chevalier S, Schlusselhuber M, Portier E, Loiseau C, Aucher W, Lesouhaitier O, Verdon J. Legionella pneumophila: The Paradox of a Highly Sensitive Opportunistic Waterborne Pathogen Able to Persist in the Environment. Front Microbiol 2016; 7:486. [PMID: 27092135 PMCID: PMC4824771 DOI: 10.3389/fmicb.2016.00486] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/23/2016] [Indexed: 01/28/2023] Open
Abstract
Legionella pneumophila, the major causative agent of Legionnaires’ disease, is found in freshwater environments in close association with free-living amoebae and multispecies biofilms, leading to persistence, spread, biocide resistance, and elevated virulence of the bacterium. Indeed, legionellosis outbreaks are mainly due to the ability of this bacterium to colonize and persist in water facilities, despite harsh physical and chemical treatments. However, these treatments are not totally efficient and, after a lag period, L. pneumophila may be able to quickly re-colonize these systems. Several natural compounds (biosurfactants, antimicrobial peptides…) with anti-Legionella properties have recently been described in the literature, highlighting their specific activities against this pathogen. In this review, we first consider this hallmark of Legionella to resist killing, in regard to its biofilm or host-associated life style. Then, we focus more accurately on natural anti-Legionella molecules described so far, which could provide new eco-friendly and alternative ways to struggle against this important pathogen in plumbing.
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Affiliation(s)
- Jean-Marc Berjeaud
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Sylvie Chevalier
- Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Université de Rouen Evreux, France
| | - Margot Schlusselhuber
- Laboratoire Aliments Bioprocédés Toxicologie Environnements, EA 4651, Université de Caen Caen, France
| | - Emilie Portier
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Clémence Loiseau
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Willy Aucher
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Olivier Lesouhaitier
- Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Université de Rouen Evreux, France
| | - Julien Verdon
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
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91
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Kruse EB, Wehner A, Wisplinghoff H. Prevalence and distribution of Legionella spp in potable water systems in Germany, risk factors associated with contamination, and effectiveness of thermal disinfection. Am J Infect Control 2016; 44:470-4. [PMID: 26775932 DOI: 10.1016/j.ajic.2015.10.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/20/2015] [Accepted: 10/28/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Worldwide, Legionella spp are a common cause of community-acquired pneumonia. Potable water systems are a main reservoir; however, exposure in the community is unknown. METHODS Water samples from 718 buildings in Germany were collected. Possible risk factors were prospectively recorded. All samples were tested for Legionella spp using cultural microbiologic methods. Samples were assigned to 1 of 5 levels of contamination. Statistical analysis was performed to determine the influence of risk factors for contamination and, in a subgroup of buildings, for unsuccessful thermal disinfection. RESULTS In total, 4,482 water samples from 718 different water supply systems were analyzed. In 233 buildings (32.7%), Legionella spp were identified, 148 (63.5%) of which had a medium or higher level of contamination. The most common species was Legionella pneumophila (94%). Contamination was strongly associated with temperature in the circulation, but not with the size of the building, time of the year, or transport time to the laboratory. Thermal disinfection was successful in fewer than half of the buildings. CONCLUSIONS There is relevant exposure to Legionella spp in the community. Water systems are not always up to current technical standards. Although microbiological risk assessment remains a challenge, there is a case for monitoring for Legionella spp outside of hospitals.
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Affiliation(s)
| | | | - Hilmar Wisplinghoff
- Wisplinghoff Laboratories, Cologne, Germany; Institute for Medical Microbiology, Immunology, and Hygiene, University of Cologne, Cologne, Germany
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92
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Porteous N, Dang S, Schoolfield J, Sun Y. Evaluation of the Antimicrobial Functions of N-halamine Dental Unit Waterline Tubing for One Year. THE JOURNAL OF CLINICAL DENTISTRY 2016; 27:19-22. [PMID: 28390212 PMCID: PMC5831062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
OBJECTIVES The objective of this study was to test the biofilm-controlling properties of N-halamine antimicrobial dental unit waterline (DUWL) tubing (T) tubing, without recharging over one year, compared to a control line (C). METHODS A simulated clinical model was used to pump ultrapure water through T and C lines at a rate of 1.4 mL/min, five minutes on, 15 minutes off, eight hours/day, five days a week. Samples of source water, effluent from T and C, and from the stagnant water in the carboy (liquid container) after bench work was completed (S2), were collected aseptically, serially diluted, and cultured on R2A agar for seven days every six weeks. SEM images of the inside surfaces of detached tubing sections were also taken. The carboy was rinsed with a 1:10 dilution of sodium hypochlorite after six months. Means of log transformed CFU values obtained in triplicate were paired by T and C lines across months for comparison by paired Student's t-tests. RESULTS An increase in effluent and carboy bacterial counts were noted after six months, but decreased after bleach rinse of the carboy. No significant difference (p > 0.25) between T and C lines were observed; similarly, T and carboy were not significantly different (p > 0.30). SEM images showed biofilm attachment on the inside surface of C after two months, but not on T. Organisms identified in the effluent reflected those in the source carboy. CONCLUSIONS No biofilm attachment was detected on the N-halamine test line after 12 months, indicating its antimicrobial properties were retained. Further evaluation is recommended to determine the optimal recharge interval for N-halamine DUWL tubing when ultrapure source water is used.
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Affiliation(s)
- N Porteous
- Department of Comprehensive Dentistry, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - S Dang
- Department of Comprehensive Dentistry, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - J Schoolfield
- Department of Comprehensive Dentistry, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Y Sun
- Department of Chemistry, The University of Massachusetts, Lowell, MA, USA
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93
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Wunderlich A, Torggler C, Elsässer D, Lück C, Niessner R, Seidel M. Rapid quantification method for Legionella pneumophila in surface water. Anal Bioanal Chem 2016; 408:2203-13. [DOI: 10.1007/s00216-016-9362-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/15/2016] [Accepted: 01/25/2016] [Indexed: 01/08/2023]
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94
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Berebichez-Fridman R, Blachman-Braun R, Azrad-Daniel S, Vázquez-Campuzano R, Vázquez-López R. Atypical pneumonias caused by Legionella pneumophila, Chlamydophila pneumoniae and Mycoplasma pneumonia. REVISTA MÉDICA DEL HOSPITAL GENERAL DE MÉXICO 2015. [DOI: 10.1016/j.hgmx.2015.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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95
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McCoy WF, Rosenblatt AA. HACCP-Based Programs for Preventing Disease and Injury from Premise Plumbing: A Building Consensus. Pathogens 2015; 4:513-28. [PMID: 26184325 PMCID: PMC4584270 DOI: 10.3390/pathogens4030513] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/04/2015] [Accepted: 07/06/2015] [Indexed: 12/22/2022] Open
Abstract
Thousands of preventable injuries and deaths are annually caused by microbial, chemical and physical hazards from building water systems. Water is processed in buildings before use; this can degrade the quality of the water. Processing steps undertaken on-site in buildings often include conditioning, filtering, storing, heating, cooling, pressure regulation and distribution through fixtures that restrict flow and temperature. Therefore, prevention of disease and injury requires process management. A process management framework for buildings is the hazard analysis and critical control point (HACCP) adaptation of failure mode effects analysis (FMEA). It has been proven effective for building water system management. Validation is proof that hazards have been controlled under operating conditions and may include many kinds of evidence including cultures of building water samples to detect and enumerate potentially pathogenic microorganisms. However, results from culture tests are often inappropriately used because the accuracy and precision are not sufficient to support specifications for control limit or action triggers. A reliable negative screen is based on genus-level Polymerase Chain Reaction (PCR) for Legionella in building water systems; however, building water samples with positive results from this test require further analysis by culture methods.
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Affiliation(s)
- William F McCoy
- Phigenics, LLC, 1701 Quincy Ave., Suite 32, Naperville, IL 60540, USA.
| | - Aaron A Rosenblatt
- Gordon & Rosenblatt, LLC, 45 Rockefeller Plaza, 20th Floor, New York, NY 10111, USA.
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96
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Kell D, Potgieter M, Pretorius E. Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology. F1000Res 2015; 4:179. [PMID: 26629334 PMCID: PMC4642849 DOI: 10.12688/f1000research.6709.2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/04/2015] [Indexed: 01/28/2023] Open
Abstract
For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.
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Affiliation(s)
- Douglas Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester, Manchester, Lancashire, M1 7DN, UK
| | - Marnie Potgieter
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
| | - Etheresia Pretorius
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
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97
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Jjemba PK, Johnson W, Bukhari Z, LeChevallier MW. Occurrence and Control of Legionella in Recycled Water Systems. Pathogens 2015; 4:470-502. [PMID: 26140674 PMCID: PMC4584268 DOI: 10.3390/pathogens4030470] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 06/24/2015] [Indexed: 01/11/2023] Open
Abstract
Legionella pneumophila is on the United States Environmental Protection Agency (USEPA) Candidate Contaminant list (CCL) as an important pathogen. It is commonly encountered in recycled water and is typically associated with amoeba, notably Naegleria fowleri (also on the CCL) and Acanthamoeba sp. No legionellosis outbreak has been linked to recycled water and it is important for the industry to proactively keep things that way. A review was conducted examine the occurrence of Legionella and its protozoa symbionts in recycled water with the aim of developing a risk management strategy. The review considered the intricate ecological relationships between Legionella and protozoa, methods for detecting both symbionts, and the efficacy of various disinfectants.
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Affiliation(s)
- Patrick K Jjemba
- American Water Research Laboratory, 213 Carriage Lane, Delran, NJ 08075, USA.
| | - William Johnson
- American Water Research Laboratory, 213 Carriage Lane, Delran, NJ 08075, USA.
| | - Zia Bukhari
- American Water, 1025 Laurel Oak Road, Voorhees, NJ 08043, USA.
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98
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Kell D, Potgieter M, Pretorius E. Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology. F1000Res 2015; 4:179. [PMID: 26629334 DOI: 10.12688/f1000research.6709.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/29/2015] [Indexed: 01/28/2023] Open
Abstract
For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.
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Affiliation(s)
- Douglas Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester, Manchester, Lancashire, M1 7DN, UK
| | - Marnie Potgieter
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
| | - Etheresia Pretorius
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
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99
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Ning Y, Cheng L, Ling M, Feng X, Chen L, Wu M, Deng L. Efficient suppression of biofilm formation by a nucleic acid aptamer. Pathog Dis 2015; 73:ftv034. [PMID: 26025307 DOI: 10.1093/femspd/ftv034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2015] [Indexed: 11/13/2022] Open
Abstract
Biofilms are microbial communities that are attached to a solid surface using extracellular polymeric substances. Motility and initial attachment mediated by flagella are required for biofilm formation. Therefore, blocking the motility of flagella is a potential strategy to inhibit biofilm formation. In this study, single-stranded DNA aptamers specific to the Salmonella choleraesuis were selected after 14 cycles of the systematic evolution of ligands by exponential enrichment. Among the selected aptamers, the aptamer 3 showed the highest affinity for S. choleraesuis with a dissociation constant (Kd) of 41 ± 2 nM. Aptamer 3, conjugated with magnetic beads, was then used to capture its binding target on the bacteria. After mass spectrometry and specific binding analysis, the flagellin was identified as the target captured by aptamer 3. Furthermore, inhibition experiments, inverted microscopy and atomic force microscopy demonstrated that aptamer 3 was able to control the biofilm formation and promote the inhibitory effect of an antibiotic on bacterial biofilms. Single-stranded DNA aptamers therefore have great potential as inhibitors of biofilm formation.
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Affiliation(s)
- Yi Ning
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China The Medicine School of Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China
| | - Lijuan Cheng
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China The Medicine School of Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China
| | - Min Ling
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
| | - Xinru Feng
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
| | - Lingli Chen
- The Medicine School of Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China
| | - Minxi Wu
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
| | - Le Deng
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
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100
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So EC, Mattheis C, Tate EW, Frankel G, Schroeder GN. Creating a customized intracellular niche: subversion of host cell signaling by Legionella type IV secretion system effectors. Can J Microbiol 2015; 61:617-35. [PMID: 26059316 DOI: 10.1139/cjm-2015-0166] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The Gram-negative facultative intracellular pathogen Legionella pneumophila infects a wide range of different protozoa in the environment and also human alveolar macrophages upon inhalation of contaminated aerosols. Inside its hosts, it creates a defined and unique compartment, termed the Legionella-containing vacuole (LCV), for survival and replication. To establish the LCV, L. pneumophila uses its Dot/Icm type IV secretion system (T4SS) to translocate more than 300 effector proteins into the host cell. Although it has become apparent in the past years that these effectors subvert a multitude of cellular processes and allow Legionella to take control of host cell vesicle trafficking, transcription, and translation, the exact function of the vast majority of effectors still remains unknown. This is partly due to high functional redundancy among the effectors, which renders conventional genetic approaches to elucidate their role ineffective. Here, we review the current knowledge about Legionella T4SS effectors, highlight open questions, and discuss new methods that promise to facilitate the characterization of T4SS effector functions in the future.
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Affiliation(s)
- Ernest C So
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK.,b Department of Chemistry, South Kensington Campus, Imperial College, London, SW7 2AZ, UK
| | - Corinna Mattheis
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Edward W Tate
- b Department of Chemistry, South Kensington Campus, Imperial College, London, SW7 2AZ, UK
| | - Gad Frankel
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gunnar N Schroeder
- a MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
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