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Price CTD, Hanford HE, Al-Quadan T, Santic M, Shin CJ, Da'as MSJ, Abu Kwaik Y. Amoebae as training grounds for microbial pathogens. mBio 2024:e0082724. [PMID: 38975782 DOI: 10.1128/mbio.00827-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024] Open
Abstract
Grazing of amoebae on microorganisms represents one of the oldest predator-prey dynamic relationships in nature. It represents a genetic "melting pot" for an ancient and continuous multi-directional inter- and intra-kingdom horizontal gene transfer between amoebae and its preys, intracellular microbial residents, endosymbionts, and giant viruses, which has shaped the evolution, selection, and adaptation of microbes that evade degradation by predatory amoeba. Unicellular phagocytic amoebae are thought to be the ancient ancestors of macrophages with highly conserved eukaryotic processes. Selection and evolution of microbes within amoeba through their evolution to target highly conserved eukaryotic processes have facilitated the expansion of their host range to mammals, causing various infectious diseases. Legionella and environmental Chlamydia harbor an immense number of eukaryotic-like proteins that are involved in ubiquitin-related processes or are tandem repeats-containing proteins involved in protein-protein and protein-chromatin interactions. Some of these eukaryotic-like proteins exhibit novel domain architecture and novel enzymatic functions absent in mammalian cells, such as ubiquitin ligases, likely acquired from amoebae. Mammalian cells and amoebae may respond similarly to microbial factors that target highly conserved eukaryotic processes, but mammalian cells may undergo an accidental response to amoeba-adapted microbial factors. We discuss specific examples of microbes that have evolved to evade amoeba predation, including the bacterial pathogens- Legionella, Chlamydia, Coxiella, Rickettssia, Francisella, Mycobacteria, Salmonella, Bartonella, Rhodococcus, Pseudomonas, Vibrio, Helicobacter, Campylobacter, and Aliarcobacter. We also discuss the fungi Cryptococcus, and Asperigillus, as well as amoebae mimiviruses/giant viruses. We propose that amoeba-microbe interactions will continue to be a major "training ground" for the evolution, selection, adaptation, and emergence of microbial pathogens equipped with unique pathogenic tools to infect mammalian hosts. However, our progress will continue to be highly dependent on additional genomic, biochemical, and cellular data of unicellular eukaryotes.
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Affiliation(s)
- Christopher T D Price
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Hannah E Hanford
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Tasneem Al-Quadan
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | | | - Cheon J Shin
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Manal S J Da'as
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
- Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, Kentucky, USA
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2
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Pustijanac E, Buršić M, Millotti G, Paliaga P, Iveša N, Cvek M. Tick-Borne Bacterial Diseases in Europe: Threats to public health. Eur J Clin Microbiol Infect Dis 2024; 43:1261-1295. [PMID: 38676855 DOI: 10.1007/s10096-024-04836-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024]
Abstract
BACKGROUND Tick-borne diseases, caused by bacterial pathogens, pose a growing threat to public health in Europe. This paper provides an overview of the historical context of the discovery of the most impactful pathogens transmitted by ticks, including Borrelia burgdorferi sensu lato, Rickettsia spp., Anaplasma spp., Francisella spp., Ehrlichia spp., and Neoehrlichia mikurensis. Understanding the historical context of their discovery provides insight into the evolution of our understanding of these pathogens. METHODS AND RESULTS Systematic investigation of the prevalence and transmission dynamics of these bacterial pathogens is provided, highlighting the intricate relationships among ticks, host organisms, and the environment. Epidemiology is explored, providing an in-depth analysis of clinical features associated with infections. Diagnostic methodologies undergo critical examination, with a spotlight on technological advancements that enhance detection capabilities. Additionally, the paper discusses available treatment options, addressing existing therapeutic strategies and considering future aspects. CONCLUSIONS By integrating various pieces of information on these bacterial species, the paper aims to provide a comprehensive resource for researchers and healthcare professionals addressing the impact of bacterial tick-borne diseases in Europe. This review underscores the importance of understanding the complex details influencing bacterial prevalence and transmission dynamics to better combat these emerging public health threats.
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Affiliation(s)
- Emina Pustijanac
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia.
| | - Moira Buršić
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Gioconda Millotti
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Paolo Paliaga
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Neven Iveša
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Maja Cvek
- Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000, Rijeka, Croatia
- Teaching Institute of Public Health of the Region of Istria, Nazorova 23, 52100, Pula, Croatia
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3
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Wu HJ, Bostic TD, Horiuchi K, Kugeler KJ, Mead PS, Nelson CA. Tularemia Clinical Manifestations, Antimicrobial Treatment, and Outcomes: An Analysis of US Surveillance Data, 2006-2021. Clin Infect Dis 2024; 78:S29-S37. [PMID: 38294115 DOI: 10.1093/cid/ciad689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND Tularemia, a potentially fatal zoonosis caused by Francisella tularensis, has been reported from nearly all US states. Information on relative effectiveness of various antimicrobials for treatment of tularemia is limited, particularly for newer classes such as fluoroquinolones. METHODS Data on clinical manifestations, antimicrobial treatment, and illness outcome of patients with tularemia are provided voluntarily through case report forms to the US Centers for Disease Control and Prevention by state and local health departments. We summarized available demographic and clinical information submitted during 2006-2021 and evaluated survival according to antimicrobial treatment. We grouped administered antimicrobials into those considered effective for treatment of tularemia (aminoglycosides, fluoroquinolones, and tetracyclines) and those with limited efficacy. Logistic regression models with a bias-reduced estimation method were used to evaluate associations between antimicrobial treatment and survival. RESULTS Case report forms were available for 1163 US patients with tularemia. Francisella tularensis was cultured from a clinical specimen (eg, blood, pleural fluid) in approximately half of patients (592; 50.9%). Nearly three-quarters (853; 73.3%) of patients were treated with a high-efficacy antimicrobial. A total of 27 patients (2.3%) died. After controlling for positive culture as a proxy for illness severity, use of aminoglycosides, fluoroquinolones, and tetracyclines was independently associated with increased odds of survival. CONCLUSIONS Most US patients with tularemia received high-efficacy antimicrobials; their use was associated with improved odds of survival regardless of antimicrobial class. Our findings provide supportive evidence that fluoroquinolones are an effective option for treatment of tularemia.
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Affiliation(s)
- Hung-Jen Wu
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Taylor D Bostic
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
- Oak Ridge Institute for Science and Education, Centers for Disease Control and Prevention Fellowship Program, Oak Ridge, Tennessee, USA
| | - Kalanthe Horiuchi
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
| | - Kiersten J Kugeler
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
| | - Paul S Mead
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
| | - Christina A Nelson
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
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Sharma R, Patil RD, Singh B, Chakraborty S, Chandran D, Dhama K, Gopinath D, Jairath G, Rialch A, Mal G, Singh P, Chaicumpa W, Saikumar G. Tularemia - a re-emerging disease with growing concern. Vet Q 2023; 43:1-16. [PMID: 37916743 PMCID: PMC10732219 DOI: 10.1080/01652176.2023.2277753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/25/2023] [Indexed: 11/03/2023] Open
Abstract
Tularemia caused by Gram-negative, coccobacillus bacterium, Francisella tularensis, is a highly infectious zoonotic disease. Human cases have been reported mainly from the United States, Nordic countries like Sweden and Finland, and some European and Asian countries. Naturally, the disease occurs in several vertebrates, particularly lagomorphs. Type A (subspecies tularensis) is more virulent and causes disease mainly in North America; type B (subspecies holarctica) is widespread, while subspecies mediasiatica is present in central Asia. F. tularensis is a possible bioweapon due to its lethality, low infectious dosage, and aerosol transmission. Small mammals like rabbits, hares, and muskrats are primary sources of human infections, but true reservoir of F. tularensis is unknown. Vector-borne tularemia primarily involves ticks and mosquitoes. The bacterial subspecies involved and mode of transmission determine the clinical picture. Early signs are flu-like illnesses that may evolve into different clinical forms of tularemia that may or may not include lymphadenopathy. Ulcero-glandular and glandular forms are acquired by arthropod bite or handling of infected animals, oculo-glandular form as a result of conjunctival infection, and oro-pharyngeal form by intake of contaminated food or water. Pulmonary form appears after inhalation of bacteria. Typhoidal form may occur after infection via different routes. Human-to-human transmission has not been known. Diagnosis can be achieved by serology, bacterial culture, and molecular methods. Treatment for tularemia typically entails use of quinolones, tetracyclines, or aminoglycosides. Preventive measures are necessary to avoid infection although difficult to implement. Research is underway for the development of effective live attenuated and subunit vaccines.
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Affiliation(s)
- Rinku Sharma
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Rajendra Damu Patil
- Department of Veterinary Pathology, DGCN College of Veterinary and Animal Sciences, CSK HPKV, Palampur, Himachal Pradesh, India
| | - Birbal Singh
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Sandip Chakraborty
- Department of Veterinary Microbiology, College of Veterinary Sciences and Animal Husbandry, R.K. Nagar, West Tripura, India
| | | | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India
| | - Devi Gopinath
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Gauri Jairath
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Ajayta Rialch
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Gorakh Mal
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Putan Singh
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Wanpen Chaicumpa
- Center of Research Excellence in Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - G. Saikumar
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India
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5
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Wang Y, Ledvina HE, Tower CA, Kambarev S, Liu E, Charity JC, Kreuk LSM, Tang Q, Chen Q, Gallagher LA, Radey MC, Rerolle GF, Li Y, Penewit KM, Turkarslan S, Skerrett SJ, Salipante SJ, Baliga NS, Woodward JJ, Dove SL, Peterson SB, Celli J, Mougous JD. Discovery of a glutathione utilization pathway in Francisella that shows functional divergence between environmental and pathogenic species. Cell Host Microbe 2023; 31:1359-1370.e7. [PMID: 37453420 PMCID: PMC10763578 DOI: 10.1016/j.chom.2023.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/19/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023]
Abstract
Glutathione (GSH) is an abundant metabolite within eukaryotic cells that can act as a signal, a nutrient source, or serve in a redox capacity for intracellular bacterial pathogens. For Francisella, GSH is thought to be a critical in vivo source of cysteine; however, the cellular pathways permitting GSH utilization by Francisella differ between strains and have remained poorly understood. Using genetic screening, we discovered a unique pathway for GSH utilization in Francisella. Whereas prior work suggested GSH catabolism initiates in the periplasm, the pathway we define consists of a major facilitator superfamily (MFS) member that transports intact GSH and a previously unrecognized bacterial cytoplasmic enzyme that catalyzes the first step of GSH degradation. Interestingly, we find that the transporter gene for this pathway is pseudogenized in pathogenic Francisella, explaining phenotypic discrepancies in GSH utilization among Francisella spp. and revealing a critical role for GSH in the environmental niche of these bacteria.
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Affiliation(s)
- Yaxi Wang
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Hannah E Ledvina
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Catherine A Tower
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Stanimir Kambarev
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA 99164, USA
| | - Elizabeth Liu
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - James C Charity
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Qing Tang
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Qiwen Chen
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Larry A Gallagher
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Matthew C Radey
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Guilhem F Rerolle
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Yaqiao Li
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA; Institute for Systems Biology, Seattle, WA 98109, USA
| | - Kelsi M Penewit
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | | | - Shawn J Skerrett
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Stephen J Salipante
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | | | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Simon L Dove
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - S Brook Peterson
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Jean Celli
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA 99164, USA
| | - Joseph D Mougous
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA; Microbial Interactions and Microbiome Center, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98109, USA.
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6
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Jakielaszek C, Hilliard JJ, Mannino F, Hossain M, Qian L, Fishman C, Chou YL, Henning L, Novak J, Demons S, Hershfield J, O'Dwyer K. Efficacy of Intravenously Administered Gepotidacin in Cynomolgus Macaques following a Francisella tularensis Inhalational Challenge. Antimicrob Agents Chemother 2023; 67:e0138122. [PMID: 37097147 DOI: 10.1128/aac.01381-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Francisella tularensis (F. tularensis) is a Centers for Disease Control (CDC) category "A" Gram-negative biothreat pathogen. Inhalation of F. tularensis can cause pneumonia and respiratory failure and is associated with high mortality rates without early treatment. Gepotidacin is a novel, first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action. Gepotidacin selectively inhibits bacterial DNA replication via a unique binding mode, has activity against multidrug-resistant target pathogens, and has demonstrated in vitro activity against diverse collections of F. tularensis isolates (MIC90 of 0.5 to 1 μg/mL). Gepotidacin was evaluated in the cynomolgus macaque model of inhalational tularemia, using the SCHU S4 strain, with treatment initiated after exposure and sustained fever. Macaques were dosed via intravenous (i.v.) infusion with saline or gepotidacin at 72 mg/kg/day to support a human i.v. infusion dosing regimen of 1,000 mg three times daily. The primary study endpoint was survival, with survival duration and bacterial clearance as secondary endpoints. Gepotidacin treatment resulted in 100% survival compared to 12.5% in the saline-treated control group (P < 0.0001) at Day 43 postinhalational challenge. All gepotidacin-treated animals were blood and organ culture negative for F. tularensis at the end of the study. In contrast, none of the saline control animals were blood and organ culture negative. Gepotoidacin's novel mechanism of action and the efficacy data reported here (aligned with the Food and Drug Administration Animal Rule) support gepotidacin as a potential treatment for pneumonic tularemia in an emergency biothreat situation.
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Affiliation(s)
| | | | - Frank Mannino
- GSK Pharmaceuticals, Collegeville, Pennsylvania, USA
| | | | - Lian Qian
- GSK Pharmaceuticals, Collegeville, Pennsylvania, USA
| | - Cindy Fishman
- GSK Pharmaceuticals, Collegeville, Pennsylvania, USA
| | - Ying-Liang Chou
- Battelle Biomedical Research Center (BBRC), Columbus, Ohio, USA
| | - Lisa Henning
- Battelle Biomedical Research Center (BBRC), Columbus, Ohio, USA
| | - Joseph Novak
- Battelle Biomedical Research Center (BBRC), Columbus, Ohio, USA
| | - Samandra Demons
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Jeremy Hershfield
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Karen O'Dwyer
- GSK Pharmaceuticals, Collegeville, Pennsylvania, USA
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7
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Porges E, Jenner D, Taylor AW, Harrison JS, De Grazia A, Hailes AR, Wright KM, Whelan AO, Norville IH, Prior JL, Mahajan S, Rowland CA, Newman TA, Evans ND. Antibiotic-Loaded Polymersomes for Clearance of Intracellular Burkholderia thailandensis. ACS NANO 2021; 15:19284-19297. [PMID: 34739227 PMCID: PMC7612142 DOI: 10.1021/acsnano.1c05309] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Melioidosis caused by the facultative intracellular pathogen Burkholderia pseudomallei is difficult to treat due to poor intracellular bioavailability of antibiotics and antibiotic resistance. In the absence of novel compounds, polymersome (PM) encapsulation may increase the efficacy of existing antibiotics and reduce antibiotic resistance by promoting targeted, infection-specific intracellular uptake. In this study, we developed PMs composed of widely available poly(ethylene oxide)-polycaprolactone block copolymers and demonstrated their delivery to intracellular B. thailandensis infection using multispectral imaging flow cytometry (IFC) and coherent anti-Stokes Raman scattering microscopy. Antibiotics were tightly sequestered in PMs and did not inhibit the growth of free-living B. thailandensis. However, on uptake of antibiotic-loaded PMs by infected macrophages, IFC demonstrated PM colocalization with intracellular B. thailandensis and a significant inhibition of their growth. We conclude that PMs are a viable approach for the targeted antibiotic treatment of persistent intracellular Burkholderia infection.
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Affiliation(s)
- Eleanor Porges
- Bioengineering Sciences Group, Faculty of Engineering and the Environment, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
- Centre for Human Development, Stem Cells and Regeneration, Bone and Joint Research Group, University of Southampton Faculty of Medicine, Southampton, SO16 6YD,United Kingdom
- Clinical and Experimental Sciences, Faculty of Medicine, Institute for Life Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Dominic Jenner
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, SP4 0JQ, United Kingdom
| | - Adam W. Taylor
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, SP4 0JQ, United Kingdom
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
| | - James S.P. Harrison
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
- School of Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Antonio De Grazia
- Bioengineering Sciences Group, Faculty of Engineering and the Environment, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
- Clinical and Experimental Sciences, Faculty of Medicine, Institute for Life Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
| | - Alethia R. Hailes
- Bioengineering Sciences Group, Faculty of Engineering and the Environment, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
- Centre for Human Development, Stem Cells and Regeneration, Bone and Joint Research Group, University of Southampton Faculty of Medicine, Southampton, SO16 6YD,United Kingdom
- Clinical and Experimental Sciences, Faculty of Medicine, Institute for Life Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Kimberley M. Wright
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, SP4 0JQ, United Kingdom
| | - Adam O. Whelan
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, SP4 0JQ, United Kingdom
| | - Isobel H. Norville
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, SP4 0JQ, United Kingdom
| | - Joann L. Prior
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, SP4 0JQ, United Kingdom
| | - Sumeet Mahajan
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
- School of Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Caroline A. Rowland
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, SP4 0JQ, United Kingdom
| | - Tracey A. Newman
- Clinical and Experimental Sciences, Faculty of Medicine, Institute for Life Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Nicholas D. Evans
- Bioengineering Sciences Group, Faculty of Engineering and the Environment, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom
- Centre for Human Development, Stem Cells and Regeneration, Bone and Joint Research Group, University of Southampton Faculty of Medicine, Southampton, SO16 6YD,United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom
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8
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Pavkova I, Klimentova J, Bavlovic J, Horcickova L, Kubelkova K, Vlcak E, Raabova H, Filimonenko V, Ballek O, Stulik J. Francisella tularensis Outer Membrane Vesicles Participate in the Early Phase of Interaction With Macrophages. Front Microbiol 2021; 12:748706. [PMID: 34721352 PMCID: PMC8554293 DOI: 10.3389/fmicb.2021.748706] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/21/2021] [Indexed: 01/18/2023] Open
Abstract
Francisella tularensis is known to release unusually shaped tubular outer membrane vesicles (OMV) containing a number of previously identified virulence factors and immunomodulatory proteins. In this study, we present that OMV isolated from the F. tularensis subsp. holarctica strain FSC200 enter readily into primary bone marrow-derived macrophages (BMDM) and seem to reside in structures resembling late endosomes in the later intervals. The isolated OMV enter BMDM generally via macropinocytosis and clathrin-dependent endocytosis, with a minor role played by lipid raft-dependent endocytosis. OMVs proved to be non-toxic and had no negative impact on the viability of BMDM. Unlike the parent bacterium itself, isolated OMV induced massive and dose-dependent proinflammatory responses in BMDM. Using transmission electron microscopy, we also evaluated OMV release from the bacterial surface during several stages of the interaction of Francisella with BMDM. During adherence and the early phase of the uptake of bacteria, we observed numerous tubular OMV-like protrusions bulging from the bacteria in close proximity to the macrophage plasma membrane. This suggests a possible role of OMV in the entry of bacteria into host cells. On the contrary, the OMV release from the bacterial surface during its cytosolic phase was negligible. We propose that OMV play some role in the extracellular phase of the interaction of Francisella with the host and that they are involved in the entry mechanism of the bacteria into macrophages.
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Affiliation(s)
- Ivona Pavkova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Jana Klimentova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Jan Bavlovic
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Lenka Horcickova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Klara Kubelkova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Erik Vlcak
- Electron Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Helena Raabova
- Electron Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Vlada Filimonenko
- Electron Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia.,Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Ondrej Ballek
- Laboratory of Immunobiology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Jiri Stulik
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
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9
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Type VI Secretion System and Its Effectors PdpC, PdpD, and OpiA Contribute to Francisella Virulence in Galleria mellonella Larvae. Infect Immun 2021; 89:e0057920. [PMID: 33875476 PMCID: PMC8208517 DOI: 10.1128/iai.00579-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis causes the deadly zoonotic disease tularemia in humans and is able to infect a broad range of organisms including arthropods, which are thought to play a major role in Francisella transmission. However, while mammalian in vitro and in vivo infection models are widely used to investigate Francisella pathogenicity, a detailed characterization of the major Francisella virulence factor, a noncanonical type VI secretion system (T6SS), in an arthropod in vivo infection model is missing. Here, we use Galleria mellonella larvae to analyze the role of the Francisella T6SS and its corresponding effectors in F. tularensis subsp. novicida virulence. We report that G. mellonella larvae killing depends on the functional T6SS and infectious dose. In contrast to other mammalian in vivo infection models, even one of the T6SS effectors PdpC, PdpD, or OpiA is sufficient to kill G. mellonella larvae, while sheath recycling by ClpB is dispensable. We further demonstrate that treatment by polyethylene glycol (PEG) activates Francisella T6SS in liquid culture and that this is independent of the response regulator PmrA. PEG-activated IglC secretion is dependent on T6SS structural component PdpB but independent of putative effectors PdpC, PdpD, AnmK, OpiB1, OpiB2, and OpiB3. The results of larvae infection and secretion assay suggest that AnmK, a putative T6SS component with unknown function, interferes with OpiA-mediated toxicity but not with general T6SS activity. We establish that the easy-to-use G. mellonella larvae infection model provides new insights into the function of T6SS and pathogenesis of Francisella.
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Nakamura T, Shimizu T, Inagaki F, Okazaki S, Saha SS, Uda A, Watanabe K, Watarai M. Identification of Membrane-Bound Lytic Murein Transglycosylase A (MltA) as a Growth Factor for Francisella novicida in a Silkworm Infection Model. Front Cell Infect Microbiol 2021; 10:581864. [PMID: 33553001 PMCID: PMC7862118 DOI: 10.3389/fcimb.2020.581864] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 12/04/2020] [Indexed: 12/22/2022] Open
Abstract
Francisella tularensis, the causative agent of tularemia, is transmitted by arthropod vectors within mammalian hosts. The detailed mechanisms contributing to growth and survival of Francisella within arthropod remain poorly understood. To identify novel factors supporting growth and survival of Francisella within arthropods, a transposon mutant library of F. tularensis subsp. novicida (F. novicida) was screened using an F. novicida-silkworm infection model. Among 750 transposon mutants screened, the mltA-encoding membrane-bound lytic murein transglycosylase A (MltA) was identified as a novel growth factor of F. novicida in silkworms. Silkworms infection with an mltA deletion mutant (ΔmltA) resulted in a reduction in the number of bacteria and prolonged survival. The ΔmltA strain exhibited limited intracellular growth and cytotoxicity in BmN4 silkworm ovary cells. Moreover, the ΔmltA strain induced higher expression of the antimicrobial peptide in silkworms compared to the wild-type strain. These results suggest that F. novicida MltA contributes to the survival of F. novicida in silkworms via immune suppression-related mechanisms. Intracellular growth of the ΔmltA strain was also reduced in human monocyte THP-1 cells. These results also suggest the contribution of MltA to pathogenicity in humans and utility of the F. novicida-silkworm infection model to explore Francisella infection.
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Affiliation(s)
- Takemasa Nakamura
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Takashi Shimizu
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Fumiya Inagaki
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Shoma Okazaki
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Shib Shankar Saha
- Department of Pathology and Parasitology, Patuakhali Science and Technology University, Barisal, Bangladesh
| | - Akihiko Uda
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kenta Watanabe
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Masahisa Watarai
- Laboratory of Veterinary Public Health, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
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11
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Springer A, Glass A, Probst J, Strube C. Tick-borne zoonoses and commonly used diagnostic methods in human and veterinary medicine. Parasitol Res 2021; 120:4075-4090. [PMID: 33459849 PMCID: PMC8599405 DOI: 10.1007/s00436-020-07033-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/21/2020] [Indexed: 12/20/2022]
Abstract
Around the world, human health and animal health are closely linked in terms of the One Health concept by ticks acting as vectors for zoonotic pathogens. Animals do not only maintain tick cycles but can either be clinically affected by the same tick-borne pathogens as humans and/or play a role as reservoirs or sentinel pathogen hosts. However, the relevance of different tick-borne diseases (TBDs) may vary in human vs. veterinary medicine, which is consequently reflected by the availability of human vs. veterinary diagnostic tests. Yet, as TBDs gain importance in both fields and rare zoonotic pathogens, such as Babesia spp., are increasingly identified as causes of human disease, a One Health approach regarding development of new diagnostic tools may lead to synergistic benefits. This review gives an overview on zoonotic protozoan, bacterial and viral tick-borne pathogens worldwide, discusses commonly used diagnostic techniques for TBDs, and compares commercial availability of diagnostic tests for humans vs. domestic animals, using Germany as an example, with the aim of highlighting existing gaps and opportunities for collaboration in a One Health framework.
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Affiliation(s)
- Andrea Springer
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Buenteweg 17, 30559, Hanover, Germany
| | - Antje Glass
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Buenteweg 17, 30559, Hanover, Germany
| | - Julia Probst
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Buenteweg 17, 30559, Hanover, Germany
| | - Christina Strube
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Buenteweg 17, 30559, Hanover, Germany.
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12
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Rivera I, Linz B, Harvill ET. Evolution and Conservation of Bordetella Intracellular Survival in Eukaryotic Host Cells. Front Microbiol 2020; 11:557819. [PMID: 33178148 PMCID: PMC7593398 DOI: 10.3389/fmicb.2020.557819] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/28/2020] [Indexed: 11/25/2022] Open
Abstract
The classical bordetellae possess several partially characterized virulence mechanisms that are studied in the context of a complete extracellular life cycle in their mammalian hosts. Yet, classical bordetellae have repeatedly been reported within dendritic cells (DCs) and alveolar macrophages in clinical samples, and in vitro experiments convincingly demonstrate that the bacteria can survive intracellularly within mammalian phagocytic cells, an ability that appears to have descended from ancestral progenitor species that lived in the environment and acquired the mechanisms to resist unicellular phagocytic predators. Many pathogens, including Mycobacterium tuberculosis, Salmonella enterica, Francisella tularensis, and Legionella pneumophila, are known to parasitize and multiply inside eukaryotic host cells. This strategy provides protection, nutrients, and the ability to disseminate systemically. While some work has been dedicated at characterizing intracellular survival of Bordetella pertussis, there is limited understanding of how this strategy has evolved within the genus Bordetella and the contributions of this ability to bacterial pathogenicity, evasion of host immunity as well as within and between-host dissemination. Here, we explore the mechanisms that control the metabolic changes accompanying intracellular survival and how these have been acquired and conserved throughout the evolutionary history of the Bordetella genus and discuss the possible implications of this strategy in the persistence and reemergence of B. pertussis in recent years.
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Affiliation(s)
- Israel Rivera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Bodo Linz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States.,Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Eric T Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
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13
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The D-alanyl-d-alanine carboxypeptidase enzyme is essential for virulence in the Schu S4 strain of Francisella tularensis and a dacD mutant is able to provide protection against a pneumonic challenge. Microb Pathog 2019; 137:103742. [PMID: 31513897 DOI: 10.1016/j.micpath.2019.103742] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/22/2019] [Accepted: 09/09/2019] [Indexed: 01/04/2023]
Abstract
Low molecular mass penicillin binding proteins (LMM PBP) are bacterial enzymes involved in the final steps of peptidoglycan biosynthesis. In Escherichia coli, most LMM PBP exhibit dd-carboxypeptidase activity, are not essential for growth in routine laboratory media, and contributions to virulent phenotypes remain largely unknown. The Francisella tularensis Schu S4 genome harbors the dacD gene (FTT_1029), which encodes a LMM PBP with homology to PBP6b of E. coli. Disruption of this locus in the fully virulent Schu S4 strain resulted in a mutant that could not grow in Chamberlain's Defined Medium and exhibited severe morphological defects. Further characterization studies demonstrated that the growth defects of the dacD mutant were pH-dependent, and could be partially restored by growth at neutral pH or fully restored by genetic complementation. Infection of murine macrophage-like cells showed that the Schu S4 dacD mutant is capable of intracellular replication. However, this mutant was attenuated in BALB/c mice following intranasal challenge (LD50 = 603 CFU) as compared to mice challenged with the parent (LD50 = 1 CFU) or complemented strain (LD50 = 1 CFU). Additionally, mice that survived infection with the dacD mutant showed significant protection against subsequent challenge with the parent strain. Collectively, these results indicate that the DacD protein of F. tularensis is essential for growth in low pH environments and virulence in vivo. These results also suggest that a PBP mutant could serve as the basis of a novel, live attenuated vaccine strain.
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Francisella tularensis Periprosthetic Joint Infections Diagnosed with Growth in Cultures. J Clin Microbiol 2019; 57:JCM.00339-19. [PMID: 31189580 DOI: 10.1128/jcm.00339-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 05/27/2019] [Indexed: 01/02/2023] Open
Abstract
Tularemia caused by Francisella tularensis is a zoonotic infection of the Northern Hemisphere that mainly affects the skin, lymph nodes, bloodstream, and lungs. Other manifestations of tularemia are very rare, especially those with musculoskeletal involvement. Presenting in 2016, we diagnosed two cases of periprosthetic knee joint infections (PJI) caused by Francisella tularensis in Europe (one in Switzerland and one in the Czech Republic). We found only two other PJI cases in the literature, another knee PJI diagnosed 1999 in Ontario, Canada, and one hip PJI in Illinois, USA, in 2017. Diagnosis was made in all cases by positive microbiological cultures after 3, 4, 7, and 12 days. All were successfully treated, two cases by exchange of the prosthesis, one with debridement and retention, and one with repeated aspiration of the synovial fluid only. Antibiotic treatment was given between 3 weeks and 12 months with either ciprofloxacin-rifampin or with doxycycline alone or doxycycline in combination with gentamicin. Zoonotic infections should be considered in periprosthetic infections in particular in culture-negative PJIs with a positive histology or highly elevated leukocyte levels in synovial aspiration. Here, we recommend prolonging cultivation time up to 14 days, performing specific PCR tests, and/or conducting epidemiologically appropriate serological tests for zoonotic infections, including that for F. tularensis.
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White RC, Cianciotto NP. Assessing the impact, genomics and evolution of type II secretion across a large, medically important genus: the Legionella type II secretion paradigm. Microb Genom 2019; 5. [PMID: 31166887 PMCID: PMC6617341 DOI: 10.1099/mgen.0.000273] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The type II secretion system (T2SS) plays a major role in promoting bacterial survival in the environment and in human hosts. One of the best characterized T2SS is that of Legionella pneumophila, the agent of Legionnaires’ disease. Secreting at least 25 proteins, including degradative enzymes, eukaryotic-like proteins and novel effectors, this T2SS contributes to the ability of L. pneumophila to grow at low temperatures, infect amoebal and macrophage hosts, damage lung tissue, evade the immune system, and undergo sliding motility. The genes encoding the T2SS are conserved across the genus Legionella, which includes 62 species and >30 pathogens in addition to L. pneumophila. The vast majority of effectors associated with L. pneumophila are shared by a large number of Legionella species, hinting at a critical role for them in the ecology of Legionella as a whole. However, no other species has the same repertoire as L. pneumophila, with, as a general rule, phylogenetically more closely related species sharing similar sets of effectors. T2SS effectors that are involved in infection of a eukaryotic host(s) are more prevalent throughout Legionella, indicating that they are under stronger selective pressure. The Legionella T2SS apparatus is closest to that of Aquicella (another parasite of amoebae), and a significant number of L. pneumophila effectors have their closest homologues in Aquicella. Thus, the T2SS of L. pneumophila probably originated within the order Legionellales, with some of its effectors having arisen within that Aquicella-like progenitor, while other effectors derived from the amoebal host, mimiviruses, fungi and less closely related bacteria.
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Affiliation(s)
- Richard C White
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Nicholas P Cianciotto
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
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Barnes KB, Hamblin KA, Richards MI, Laws TR, Vente A, Atkins HS, Harding SV. The Fluoroquinolone Finafloxacin Protects BALB/c Mice Against an Intranasal Infection With Francisella tularensis Strain SchuS4. Front Microbiol 2019; 10:904. [PMID: 31118924 PMCID: PMC6504792 DOI: 10.3389/fmicb.2019.00904] [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: 02/14/2019] [Accepted: 04/09/2019] [Indexed: 01/07/2023] Open
Abstract
The efficacy of the novel fluoroquinolone finafloxacin was evaluated as a potential therapeutic in vitro and in vivo, following an intranasal infection of Francisella tularensis strain SchuS4 in BALB/c mice. We demonstrated that short treatment courses of finafloxacin provide high levels of protection, with a single dose resulting in a significant increase in time to death when compared to ciprofloxacin. In addition, following investigation into the window of opportunity for treatment, we have shown that finafloxacin can provided protection when administered up to 96 h post-challenge. This is particularly encouraging since mice displayed severe signs of disease at this time point. In summary, finafloxacin may be a promising therapy for use in the event of exposure to F. tularensis, perhaps enabling the treatment regimen to be shortened or if therapy is delayed. The efficacy of finafloxacin against other biological threat agents also warrants investigation.
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Affiliation(s)
- Kay B Barnes
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | | | - Mark I Richards
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Thomas R Laws
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | | | - Helen S Atkins
- Defence Science and Technology Laboratory, Salisbury, United Kingdom.,University of Exeter, Exeter, United Kingdom.,London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sarah V Harding
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
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17
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Kim BR, Kim BJ, Kook YH, Kim BJ. Phagosome Escape of Rough Mycobacterium abscessus Strains in Murine Macrophage via Phagosomal Rupture Can Lead to Type I Interferon Production and Their Cell-To-Cell Spread. Front Immunol 2019; 10:125. [PMID: 30766538 PMCID: PMC6365470 DOI: 10.3389/fimmu.2019.00125] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/15/2019] [Indexed: 12/27/2022] Open
Abstract
Mycobacterium abscessus complex (MAB) is a rapidly growing mycobacterium(RGM) whose clinical significance as an emerging human pathogen has been increasing worldwide. It has two types of colony morphology, a smooth (S) type, producing high glycopeptidolipid (GPL) content, and a rough (R) type, which produces low levels of GPLs and is associated with increased virulence. However, the mechanism responsible for their difference in virulence is poorly known. By ultrastructural examination of murine macrophages infected, we found that MAB-R strains could replicate more actively in the macrophage phagosome than the S variants and that they could escape into cytosol via phagosomal rupture. The cytosolic access of MAB-R strains via phagosomal rupture led to enhanced Type I interferon (IFN) production and cell death, which resulted in their cell-to-cell spreading. This behavior can provide an additional niche for the survival of MAB-R strains. In addition, we found that their enhancement of cell death mediated cell spreading are dependent on Type I IFN signaling via comparison of wild-type and IFNAR1 knockout mice. In conclusion, our data indicated that a transition of MAB-S strains into MAB-R variants increased their virulence via enhanced Type I IFN production, which led to enhanced survival in infected macrophage via cell death mediated cell-to-cell spreading. This result provides not only a novel insight into the difference in virulence between MAB-R and -S variants but also hints to their treatment strategy.
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Affiliation(s)
- Bo-Ram Kim
- Department of Microbiology and Immunology, Biomedical Sciences, Liver Research Institute and Cancer Research Institute, College of Medicine, Seoul National University, Seoul, South Korea
| | - Byoung-Jun Kim
- Department of Microbiology and Immunology, Biomedical Sciences, Liver Research Institute and Cancer Research Institute, College of Medicine, Seoul National University, Seoul, South Korea
| | - Yoon-Hoh Kook
- Department of Microbiology and Immunology, Biomedical Sciences, Liver Research Institute and Cancer Research Institute, College of Medicine, Seoul National University, Seoul, South Korea
| | - Bum-Joon Kim
- Department of Microbiology and Immunology, Biomedical Sciences, Liver Research Institute and Cancer Research Institute, College of Medicine, Seoul National University, Seoul, South Korea
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18
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van Elsland D, Neefjes J. Bacterial infections and cancer. EMBO Rep 2018; 19:embr.201846632. [PMID: 30348892 PMCID: PMC6216254 DOI: 10.15252/embr.201846632] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/10/2018] [Accepted: 09/24/2018] [Indexed: 12/30/2022] Open
Abstract
Infections are estimated to contribute to 20% of all human tumours. These are mainly caused by viruses, which explains why a direct bacterial contribution to cancer formation has been largely ignored. While epidemiological data link bacterial infections to particular cancers, tumour formation is generally assumed to be solely caused by the ensuing inflammation responses. Yet, many bacteria directly manipulate their host cell in various phases of their infection cycle. Such manipulations can affect host cell integrity and can contribute to cancer formation. We here describe how bacterial surface moieties, bacterial protein toxins and bacterial effector proteins can induce host cell DNA damage, and thereby can interfere with essential host cell signalling pathways involved in cell proliferation, apoptosis, differentiation and immune signalling.
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Affiliation(s)
- Daphne van Elsland
- Oncode Institute and Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Leiden, The Netherlands
| | - Jacques Neefjes
- Oncode Institute and Department of Cell and Chemical Biology, Leiden University Medical Center LUMC, Leiden, The Netherlands
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19
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Thelaus J, Lundmark E, Lindgren P, Sjödin A, Forsman M. Galleria mellonella Reveals Niche Differences Between Highly Pathogenic and Closely Related Strains of Francisella spp. Front Cell Infect Microbiol 2018; 8:188. [PMID: 29922601 PMCID: PMC5996057 DOI: 10.3389/fcimb.2018.00188] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/15/2018] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis, a highly virulent bacteria that causes the zoonotic disease tularemia, is considered a potential agent of biological warfare and bioterrorism. Although the host range for several species within the Francisella is known, little is known about the natural reservoirs of various Francisella species. The lack of knowledge regarding the environmental fates of these pathogens greatly reduces the possibilities for microbial risk assessments. The greater wax moth (Galleria mellonella) is an insect of the order Lepidoptera that has been used as an alternative model to study microbial infection during recent years. The aim of this study was to evaluate G. mellonella as a model system for studies of human pathogenic and closely related opportunistic and non-pathogenic strains within the Francisella genus. The employed G. mellonella larvae model demonstrated differences in lethality between human pathogenic and human non-pathogenic or opportunistic Francisella species. The F. novicida, F. hispaniensis and F. philomiragia strains were significantly more virulent in the G. mellonella model than the strains of human pathogens F. t. holarctica and F. t. tularensis. Our data show that G. mellonella is a possible in vivo model of insect immunity for studies of both opportunistic and virulent lineages of Francisella spp., that produces inverse results regarding lethality in G. mellonella and incapacitating disease in humans. The results provide insight into the potential host specificity of F. tularensis and closely related members of the same genus, thus increasing our present understanding of Francisella spp. ecology.
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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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Busch A, Thomas P, Zuchantke E, Brendebach H, Neubert K, Gruetzke J, Al Dahouk S, Peters M, Hotzel H, Neubauer H, Tomaso H. Revisiting Francisella tularensis subsp. holarctica, Causative Agent of Tularemia in Germany With Bioinformatics: New Insights in Genome Structure, DNA Methylation and Comparative Phylogenetic Analysis. Front Microbiol 2018; 9:344. [PMID: 29593661 PMCID: PMC5859110 DOI: 10.3389/fmicb.2018.00344] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/12/2018] [Indexed: 12/30/2022] Open
Abstract
Francisella (F.) tularensis is a highly virulent, Gram-negative bacterial pathogen and the causative agent of the zoonotic disease tularemia. Here, we generated, analyzed and characterized a high quality circular genome sequence of the F. tularensis subsp. holarctica strain 12T0050 that caused fatal tularemia in a hare. Besides the genomic structure, we focused on the analysis of oriC, unique to the Francisella genus and regulating replication in and outside hosts and the first report on genomic DNA methylation of a Francisella strain. The high quality genome was used to establish and evaluate a diagnostic whole genome sequencing pipeline. A genotyping strategy for F. tularensis was developed using various bioinformatics tools for genotyping. Additionally, whole genome sequences of F. tularensis subsp. holarctica isolates isolated in the years 2008–2015 in Germany were generated. A phylogenetic analysis allowed to determine the genetic relatedness of these isolates and confirmed the highly conserved nature of F. tularensis subsp. holarctica.
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Affiliation(s)
- Anne Busch
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Prasad Thomas
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Eric Zuchantke
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Holger Brendebach
- Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Kerstin Neubert
- Algorithmic Bioinformatics, Department of Mathematics and Computer Science, Institute of Computer Science, Freie Universität Berlin, Berlin, Germany
| | - Josephine Gruetzke
- Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Sascha Al Dahouk
- Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Martin Peters
- Standort Arnsberg, Chemisches und Veterinäruntersuchungsamt Westfalen, Arnsberg, Germany
| | - Helmut Hotzel
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Heinrich Neubauer
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
| | - Herbert Tomaso
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Jena, Germany
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22
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Mass spectrometry analysis of intact Francisella bacteria identifies lipid A structure remodeling in response to acidic pH stress. Biochimie 2017; 141:16-20. [DOI: 10.1016/j.biochi.2017.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/09/2017] [Indexed: 11/18/2022]
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Brenz Y, Winther-Larsen HC, Hagedorn M. Expanding Francisella models: Pairing up the soil amoeba Dictyostelium with aquatic Francisella. Int J Med Microbiol 2017; 308:32-40. [PMID: 28843671 DOI: 10.1016/j.ijmm.2017.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/31/2017] [Accepted: 08/04/2017] [Indexed: 12/19/2022] Open
Abstract
The bacterial genus Francisella comprises highly pathogenic species that infect mammals, arthropods, fish and protists. Understanding virulence and host defense mechanisms of Francisella infection relies on multiple animal and cellular model systems. In this review, we want to summarize the most commonly used Francisella host model platforms and highlight novel, alternative model systems using aquatic Francisella species. Established mouse and macrophage models contributed extensively to our understanding of Francisella infection. However, murine and human cells display significant differences in their response to Francisella infection. The zebrafish and the amoeba Dictyostelium are well-established model systems for host-pathogen interactions and open up opportunities to investigate bacterial virulence and host defense. Comparisons between model systems using human and fish pathogenic Francisella species revealed shared virulence strategies and pathology between them. Hence, zebrafish and Dictyostelium might complement current model systems to find new vaccine candidates and contribute to our understanding of Francisella infection.
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Affiliation(s)
- Yannick Brenz
- Department of Parasitology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany.
| | - Hanne C Winther-Larsen
- Centre for Integrative Microbial Evolution (CIME) and Department of Pharmaceutical Biosciences, University of Oslo, Sem Sælands vei 3, 0371 Oslo, Norway.
| | - Monica Hagedorn
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany.
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24
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Marecic V, Shevchuk O, Ozanic M, Mihelcic M, Steinert M, Jurak Begonja A, Abu Kwaik Y, Santic M. Isolation of F. novicida-Containing Phagosome from Infected Human Monocyte Derived Macrophages. Front Cell Infect Microbiol 2017; 7:303. [PMID: 28725638 PMCID: PMC5496951 DOI: 10.3389/fcimb.2017.00303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/20/2017] [Indexed: 11/28/2022] Open
Abstract
Francisella is a gram-negative bacterial pathogen, which causes tularemia in humans and animals. A crucial step of Francisella infection is its invasion of macrophage cells. Biogenesis of the Francisella-containing phagosome (FCP) is arrested for ~15 min at the endosomal stage, followed by gradual bacterial escape into the cytosol, where the microbe proliferates. The crucial step in pathogenesis of tularemia is short and transient presence of the bacterium within phagosome. Isolation of FCPs for further studies has been challenging due to the short period of time of bacterial residence in it and the characteristics of the FCP. Here, we will for the first time present the method for isolation of the FCPs from infected human monocytes-derived macrophages (hMDMs). For elimination of lysosomal compartment these organelles were pre-loaded with dextran coated colloidal iron particles prior infection and eliminated by magnetic separation of the post-nuclear supernatant (PNS). We encountered the challenge that mitochondria has similar density to the FCP. To separate the FCP in the PNS from mitochondria, we utilized iodophenylnitrophenyltetrazolium, which is converted by the mitochondrial succinate dehydrogenase into formazan, leading to increased density of the mitochondria and allowing separation by the discontinuous sucrose density gradient ultracentrifugation. The purity of the FCP preparation and its acquisition of early endosomal markers was confirmed by Western blots, confocal and transmission electron microscopy. Our strategy to isolate highly pure FCPs from macrophages should facilitate studies on the FCP and its biogenesis.
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Affiliation(s)
- Valentina Marecic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Olga Shevchuk
- Department of Microbiology, Institut für Mikrobiologie, Technische Universität Braunschweig and Helmholtz Center for Infection ResearchBraunschweig, Germany.,Department of Biotechnology, University of RijekaRijeka, Croatia
| | - Mateja Ozanic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Mirna Mihelcic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Michael Steinert
- Department of Microbiology, Institut für Mikrobiologie, Technische Universität Braunschweig and Helmholtz Center for Infection ResearchBraunschweig, Germany
| | | | - Yousef Abu Kwaik
- Department of Microbiology and Immunology and Center for Predictive MedicineLouisville, KY, United States
| | - Marina Santic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
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25
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Holland KM, Rosa SJ, Kristjansdottir K, Wolfgeher D, Franz BJ, Zarrella TM, Kumar S, Sunagar R, Singh A, Bakshi CS, Namjoshi P, Barry EM, Sellati TJ, Kron SJ, Gosselin EJ, Reed DS, Hazlett KRO. Differential Growth of Francisella tularensis, Which Alters Expression of Virulence Factors, Dominant Antigens, and Surface-Carbohydrate Synthases, Governs the Apparent Virulence of Ft SchuS4 to Immunized Animals. Front Microbiol 2017; 8:1158. [PMID: 28690600 PMCID: PMC5479911 DOI: 10.3389/fmicb.2017.01158] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/07/2017] [Indexed: 12/29/2022] Open
Abstract
The gram-negative bacterium Francisella tularensis (Ft) is both a potential biological weapon and a naturally occurring microbe that survives in arthropods, fresh water amoeba, and mammals with distinct phenotypes in various environments. Previously, we used a number of measurements to characterize Ft grown in Brain-Heart Infusion (BHI) broth as (1) more similar to infection-derived bacteria, and (2) slightly more virulent in naïve animals, compared to Ft grown in Mueller Hinton Broth (MHB). In these studies we observed that the free amino acids in MHB repress expression of select Ft virulence factors by an unknown mechanism. Here, we tested the hypotheses that Ft grown in BHI (BHI-Ft) accurately displays a full protein composition more similar to that reported for infection-derived Ft and that this similarity would make BHI-Ft more susceptible to pre-existing, vaccine-induced immunity than MHB-Ft. We performed comprehensive proteomic analysis of Ft grown in MHB, BHI, and BHI supplemented with casamino acids (BCA) and compared our findings to published “omics” data derived from Ft grown in vivo. Based on the abundance of ~1,000 proteins, the fingerprint of BHI-Ft is one of nutrient-deprived bacteria that—through induction of a stringent-starvation-like response—have induced the FevR regulon for expression of the bacterium's virulence factors, immuno-dominant antigens, and surface-carbohydrate synthases. To test the notion that increased abundance of dominant antigens expressed by BHI-Ft would render these bacteria more susceptible to pre-existing, vaccine-induced immunity, we employed a battery of LVS-vaccination and S4-challenge protocols using MHB- and BHI-grown Ft S4. Contrary to our hypothesis, these experiments reveal that LVS-immunization provides a barrier to infection that is significantly more effective against an MHB-S4 challenge than a BHI-S4 challenge. The differences in apparent virulence to immunized mice are profoundly greater than those observed with primary infection of naïve mice. Our findings suggest that tularemia vaccination studies should be critically evaluated in regard to the growth conditions of the challenge agent.
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Affiliation(s)
- Kristen M Holland
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | - Sarah J Rosa
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | | | - Donald Wolfgeher
- Department of Molecular Genetics and Cell Biology, University of ChicagoChicago, IL, United States
| | - Brian J Franz
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | - Tiffany M Zarrella
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | - Sudeep Kumar
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | - Raju Sunagar
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | - Anju Singh
- Trudeau InstituteSaranac Lake, NY, United States
| | - Chandra S Bakshi
- Department of Microbiology and Immunology, New York Medical CollegeValhalla, NY, United States
| | - Prachi Namjoshi
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | - Eileen M Barry
- School of Medicine, University of MarylandBaltimore, MD, United States
| | | | - Stephen J Kron
- Department of Molecular Genetics and Cell Biology, University of ChicagoChicago, IL, United States
| | - Edmund J Gosselin
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
| | - Douglas S Reed
- Center for Vaccine Research, University of PittsburghPittsburgh, PA, United States
| | - Karsten R O Hazlett
- Department of Immunology and Microbial Disease, Albany Medical CollegeAlbany, NY, United States
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26
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Ghoneim NH, Abdel-Moein KA, Zaher HM. Molecular Detection of Francisella spp. Among Ticks Attached to Camels in Egypt. Vector Borne Zoonotic Dis 2017; 17:384-387. [PMID: 28402703 DOI: 10.1089/vbz.2016.2100] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study was conducted to investigate the possible role of camels and attached ticks in the epidemiology of Francisella spp. including Francisella tularensis. For this purpose, a total of 319 ticks (248 Hyalomma dromedarii and 71 Amblyomma spp.) as well as 100 blood and 50 fecal samples collected from camels were screened for the presence of Francisella spp. by PCR through amplification of Francisella 16S rRNA gene. Positive samples were then tested for F. tularensis by PCR. In addition, serum samples from 75 camel abattoir workers were examined for the presence of IgG antibodies against F. tularensis using enzyme-linked immunosorbent assay (ELISA). Of the examined ticks, 15 were positive for Francisella spp. with prevalence of 4.7%, all positive results were recorded in Hyalomma dromedarii (6%). Neither blood nor fecal samples from camels yielded Francisella spp. even camels which carried Francisella spp. positive ticks. Moreover, F. tularensis could not be detected among Francisella-positive ticks. Phylogenetic analysis of some Francisella 16S rRNA gene sequences obtained in this study points out that these sequences are closely related to Francisella-like endosymbionts. In contrast, seroprevalence of F. tularensis antibodies among examined abattoir workers was 9.3% with significantly high prevalence among workers frequently exposed to tick bites (20.7%) rather than occasionally exposed workers (2.2%). In conclusion, however, F. tularensis could not be detected in this study; the high seroprevalence among camel abattoir workers especially those frequently exposed to tick bites underlines the possible role of ticks attached to camels in transmission of tularemia to humans.
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Affiliation(s)
- Nahed H Ghoneim
- Department of Zoonoses, Faculty of Veterinary Medicine, Cairo University , Cairo, Egypt
| | - Khaled A Abdel-Moein
- Department of Zoonoses, Faculty of Veterinary Medicine, Cairo University , Cairo, Egypt
| | - Hala M Zaher
- Department of Zoonoses, Faculty of Veterinary Medicine, Cairo University , Cairo, Egypt
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27
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Ramakrishnan G. Iron and Virulence in Francisella tularensis. Front Cell Infect Microbiol 2017; 7:107. [PMID: 28421167 PMCID: PMC5378763 DOI: 10.3389/fcimb.2017.00107] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/16/2017] [Indexed: 12/12/2022] Open
Abstract
Francisella tularensis, the causative agent of tularemia, is a Gram-negative bacterium that infects a variety of cell types including macrophages, and propagates with great efficiency in the cytoplasm. Iron, essential for key enzymatic and redox reactions, is among the nutrients required to support this pathogenic lifestyle and the bacterium relies on specialized mechanisms to acquire iron within the host environment. Two distinct pathways for iron acquisition are encoded by the F. tularensis genome- a siderophore-dependent ferric iron uptake system and a ferrous iron transport system. Genes of the Fur-regulated fslABCDEF operon direct the production and transport of the siderophore rhizoferrin. Siderophore biosynthesis involves enzymes FslA and FslC, while export across the inner membrane is mediated by FslB. Uptake of the rhizoferrin- ferric iron complex is effected by the siderophore receptor FslE in the outer membrane in a TonB-independent process, and FslD is responsible for uptake across the inner membrane. Ferrous iron uptake relies largely on high affinity transport by FupA in the outer membrane, while the Fur-regulated FeoB protein mediates transport across the inner membrane. FslE and FupA are paralogous proteins, sharing sequence similarity and possibly sharing structural features as well. This review summarizes current knowledge of iron acquisition in this organism and the critical role of these uptake systems in bacterial pathogenicity.
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Affiliation(s)
- Girija Ramakrishnan
- Department of Medicine/Division of Infectious Diseases, University of VirginiaCharlottesville, VA, USA
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28
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A spontaneous mutation in kdsD, a biosynthesis gene for 3 Deoxy-D-manno-Octulosonic Acid, occurred in a ciprofloxacin resistant strain of Francisella tularensis and caused a high level of attenuation in murine models of tularemia. PLoS One 2017; 12:e0174106. [PMID: 28328947 PMCID: PMC5362203 DOI: 10.1371/journal.pone.0174106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/03/2017] [Indexed: 12/26/2022] Open
Abstract
Francisella tularensis, a gram-negative facultative intracellular bacterial pathogen, is the causative agent of tularemia and able to infect many mammalian species, including humans. Because of its ability to cause a lethal infection, low infectious dose, and aerosolizable nature, F. tularensis subspecies tularensis is considered a potential biowarfare agent. Due to its in vitro efficacy, ciprofloxacin is one of the antibiotics recommended for post-exposure prophylaxis of tularemia. In order to identify therapeutics that will be efficacious against infections caused by drug resistant select-agents and to better understand the threat, we sought to characterize an existing ciprofloxacin resistant (CipR) mutant in the Schu S4 strain of F. tularensis by determining its phenotypic characteristics and sequencing the chromosome to identify additional genetic alterations that may have occurred during the selection process. In addition to the previously described genetic alterations, the sequence of the CipR mutant strain revealed several additional mutations. Of particular interest was a frameshift mutation within kdsD which encodes for an enzyme necessary for the production of 3-Deoxy-D-manno-Octulosonic Acid (KDO), an integral component of the lipopolysaccharide (LPS). A kdsD mutant was constructed in the Schu S4 strain. Although it was not resistant to ciprofloxacin, the kdsD mutant shared many phenotypic characteristics with the CipR mutant, including growth defects under different conditions, sensitivity to hydrophobic agents, altered LPS profiles, and attenuation in multiple models of murine tularemia. This study demonstrates that the KdsD enzyme is essential for Francisella virulence and may be an attractive therapeutic target for developing novel medical countermeasures.
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29
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Phenotypic characterization of the Francisella tularensis ΔpdpC and ΔiglG mutants. Microbes Infect 2016; 18:768-776. [PMID: 27477000 DOI: 10.1016/j.micinf.2016.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/18/2016] [Accepted: 07/22/2016] [Indexed: 01/01/2023]
Abstract
Several bacterial pathogens interact with their host through protein secretion effectuated by a type VI secretion system (T6SS). Francisella tularensis is a highly pathogenic intracellular bacterium that causes the disease tularemia. Proteins encoded by the Francisella pathogenicity island (FPI), which constitute a type VI secretion system, are essential for the virulence of the bacterium and a key mechanism behind this is the escape from the phagosome followed by productive cytosolic replication. It has been shown that T6SS in Francisella is distinct since all putative substrates of F. tularensis T6SS, except for VgrG, are unique to the species. Many of the FPI proteins are secreted into the macrophage cytosol and this is dependent on the functional components of DotU, VgrG, IglC and IglG. In addition, PdpC seems to have a regulatory role for the expression of iglABCD. Since previous results showed peculiar phenotypes of the ΔpdpC and ΔiglG mutants in mouse macrophages, their unique behavior was characterized in human monocyte-derived macrophages (HMDM) in this study. Our results show that both ΔpdpC and ΔiglG mutants of the live vaccine strain (LVS) of F. tularensis did not replicate within HMDMs. The ΔpdpC mutant did not escape from the Francisella containing phagosome (FCP), neither caused cytopathogenicity in primary macrophages and was attenuated in a mouse model. Interestingly, the ΔiglG mutant escaped from the HMDMs FCP and also caused pathological changes in the spleen and liver tissues of intradermally infected C57BL/6 mice. The ΔiglG mutant, with its unique phenotype, is a potential vaccine candidate.
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30
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Loughman K, Hall J, Knowlton S, Sindeldecker D, Gilson T, Schmitt DM, Birch JWM, Gajtka T, Kobe BN, Florjanczyk A, Ingram J, Bakshi CS, Horzempa J. Temperature-Dependent Gentamicin Resistance of Francisella tularensis is Mediated by Uptake Modulation. Front Microbiol 2016; 7:37. [PMID: 26858709 PMCID: PMC4729955 DOI: 10.3389/fmicb.2016.00037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 01/11/2016] [Indexed: 11/13/2022] Open
Abstract
Gentamicin (Gm) is an aminoglycoside commonly used to treat bacterial infections such as tularemia – the disease caused by Francisella tularensis. In addition to being pathogenic, F. tularensis is found in environmental niches such as soil where this bacterium likely encounters Gm producers (Micromonospora sp.). Here we show that F. tularensis exhibits increased resistance to Gm at ambient temperature (26°C) compared to mammalian body temperature (37°C). To evaluate whether F. tularensis was less permeable to Gm at 26°C, a fluorescent marker [Texas Red (Tr)] was conjugated with Gm, yielding Tr-Gm. Bacteria incubated at 26°C showed reduced fluorescence compared to those at 37°C when exposed to Tr-Gm suggesting that uptake of Gm was reduced at 26°C. Unconjugated Gm competitively inhibited uptake of Tr-Gm, demonstrating that this fluorescent compound was taken up similarly to unconjugated Gm. Lysates of F. tularensis bacteria incubated with Gm at 37°C inhibited the growth of Escherichia coli significantly more than lysates from bacteria incubated at 26°C, further indicating reduced uptake at this lower temperature. Other facultative pathogens (Listeria monocytogenes and Klebsiella pneumoniae) exhibited increased resistance to Gm at 26°C suggesting that the results generated using F. tularensis may be generalizable to diverse bacteria. Regulation of the uptake of antibiotics provides a mechanism by which facultative pathogens survive alongside antibiotic-producing microbes in nature.
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Affiliation(s)
- Kathleen Loughman
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Jesse Hall
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Samantha Knowlton
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Devin Sindeldecker
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Tricia Gilson
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Deanna M Schmitt
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - James W-M Birch
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Tara Gajtka
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Brianna N Kobe
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Aleksandr Florjanczyk
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Jenna Ingram
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
| | - Chandra S Bakshi
- Department of Microbiology and Immunology, New York Medical College Valhalla, NY, USA
| | - Joseph Horzempa
- Department of Natural Sciences and Mathematics, West Liberty University West Liberty, WV, USA
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