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Tullius MV, Bowen RA, Back PS, Masleša-Galić S, Nava S, Horwitz MA. LVS Δ capB-vectored multiantigenic melioidosis vaccines protect against lethal respiratory Burkholderia pseudomallei challenge in highly sensitive BALB/c mice. mBio 2024; 15:e0018624. [PMID: 38511933 PMCID: PMC11005352 DOI: 10.1128/mbio.00186-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 02/05/2024] [Indexed: 03/22/2024] Open
Abstract
Melioidosis, caused by the intracellular bacterial pathogen and Tier 1 select agent Burkholderia pseudomallei (Bp), is a highly fatal disease endemic in tropical areas. No licensed vaccine against melioidosis exists. In preclinical vaccine studies, demonstrating protection against respiratory infection in the highly sensitive BALB/c mouse has been especially challenging. To address this challenge, we have used a safe yet potent live attenuated platform vector, LVS ΔcapB, previously used successfully to develop vaccines against the Tier 1 select agents of tularemia, anthrax, and plague, to develop a melioidosis vaccine. We have engineered melioidosis vaccines (rLVS ΔcapB/Bp) expressing multiple immunoprotective Bp antigens among type VI secretion system proteins Hcp1, Hcp2, and Hcp6, and membrane protein LolC. Administered intradermally, rLVS ΔcapB/Bp vaccines strongly protect highly sensitive BALB/c mice against lethal respiratory Bp challenge, but protection is overwhelmed at very high challenge doses. In contrast, administered intranasally, rLVS ΔcapB/Bp vaccines remain strongly protective against even very high challenge doses. Under some conditions, the LVS ΔcapB vector itself provides significant protection against Bp challenge, and consistent with this, both the vector and vaccines induce humoral immune responses to Bp antigens. Three-antigen vaccines expressing Hcp6-Hcp1-Hcp2 or Hcp6-Hcp1-LolC are among the most potent and provide long-term protection and protection even with a single intranasal immunization. Protection via the intranasal route was either comparable to or statistically significantly better than the single-deletional Bp mutant Bp82, which served as a positive control. Thus, rLVS ΔcapB/Bp vaccines are exceptionally promising safe and potent melioidosis vaccines. IMPORTANCE Melioidosis, a major neglected disease caused by the intracellular bacterial pathogen Burkholderia pseudomallei, is endemic in many tropical areas of the world and causes an estimated 165,000 cases and 89,000 deaths in humans annually. Moreover, B. pseudomallei is categorized as a Tier 1 select agent of bioterrorism, largely because inhalation of low doses can cause rapidly fatal pneumonia. No licensed vaccine is available to prevent melioidosis. Here, we describe a safe and potent melioidosis vaccine that protects against lethal respiratory challenge with B. pseudomallei in a highly sensitive small animal model-even a single immunization is highly protective, and the vaccine gives long-term protection. The vaccine utilizes a highly attenuated replicating intracellular bacterium as a vector to express multiple key proteins of B. pseudomallei; this vector platform has previously been used successfully to develop potent vaccines against other Tier 1 select agent diseases including tularemia, anthrax, and plague.
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Affiliation(s)
- Michael V. Tullius
- Division of Infectious Diseases, Department of Medicine, Center for Health Sciences, School of Medicine, University of California, Los Angeles, California, USA
| | - Richard A. Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Peter S. Back
- Division of Infectious Diseases, Department of Medicine, Center for Health Sciences, School of Medicine, University of California, Los Angeles, California, USA
| | - Saša Masleša-Galić
- Division of Infectious Diseases, Department of Medicine, Center for Health Sciences, School of Medicine, University of California, Los Angeles, California, USA
| | - Susana Nava
- Division of Infectious Diseases, Department of Medicine, Center for Health Sciences, School of Medicine, University of California, Los Angeles, California, USA
| | - Marcus A. Horwitz
- Division of Infectious Diseases, Department of Medicine, Center for Health Sciences, School of Medicine, University of California, Los Angeles, California, USA
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Streva VA, Weinstein J, Jankowski-Romano C, Osakwe N, Duong S, Juretschko S, Lemon JK. The Brief Case: Incidental finding of Brucella abortus bacteremia in a patient with urinary tract infection. J Clin Microbiol 2024; 62:e0138123. [PMID: 38597631 PMCID: PMC11005331 DOI: 10.1128/jcm.01381-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024] Open
Affiliation(s)
- Vincent A. Streva
- Department of Pathology and Laboratory Medicine, Northwell Health, New York, New York, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, New York, USA
| | - Jacqueline Weinstein
- Department of Pathology and Laboratory Medicine, Northwell Health, New York, New York, USA
| | | | - Nonso Osakwe
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, New York, USA
- Department of Medicine, Northern Westchester Hospital, Northwell Health, New York, New York, USA
| | - Scott Duong
- Department of Pathology and Laboratory Medicine, Northwell Health, New York, New York, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, New York, USA
| | - Stefan Juretschko
- Department of Pathology and Laboratory Medicine, Northwell Health, New York, New York, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, New York, USA
| | - Jamie K. Lemon
- Department of Pathology and Laboratory Medicine, Northwell Health, New York, New York, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, New York, USA
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Rangel MV, Bourguet FA, Hall CI, Weilhammer DR. Evaluation of Inactivation Methods for Rift Valley Fever Virus in Mouse Microglia. Pathogens 2024; 13:159. [PMID: 38392897 PMCID: PMC10892077 DOI: 10.3390/pathogens13020159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/30/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
Rift Valley fever phlebovirus (RVFV) is a highly pathogenic mosquito-borne virus with bioweapon potential due to its ability to be spread by aerosol transmission. Neurological symptoms are among the worst outcomes of infection, and understanding of pathogenesis mechanisms within the brain is limited. RVFV is classified as an overlap select agent by the CDC and USDA; therefore, experiments involving fully virulent strains of virus are tightly regulated. Here, we present two methods for inactivation of live virus within samples derived from mouse microglia cells using commercially available kits for the preparation of cells for flow cytometry and RNA extraction. Using the flow cytometry protocol, we demonstrate key differences in the response of primary murine microglia to infection with fully virulent versus attenuated RVFV.
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Affiliation(s)
- Margarita V. Rangel
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.V.R.); (F.A.B.)
| | - Feliza A. Bourguet
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.V.R.); (F.A.B.)
| | - Carolyn I. Hall
- Environment, Safety & Health, Biosafety & Biogovernance Functional Area, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA;
| | - Dina R. Weilhammer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.V.R.); (F.A.B.)
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Gavina K, Whitacre BE, Meyer TL, Van Benten K, Glazier M, Emery CL, Lavik JP, Relich RF. The Brief Case: Suspicious Gram-Negative Coccobacilli-Francisella tularensis subsp. novicida Isolated from an Immunocompromised Patient. J Clin Microbiol 2023; 61:e0078722. [PMID: 37338229 DOI: 10.1128/jcm.00787-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023] Open
Affiliation(s)
- Kenneth Gavina
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Brynne E Whitacre
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | | | | | - Mark Glazier
- Indiana Department of Health Laboratories, Indianapolis, Indiana, USA
| | - Christopher L Emery
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Indiana University Health, Indianapolis, Indiana, USA
| | - John-Paul Lavik
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Indiana University Health, Indianapolis, Indiana, USA
| | - Ryan F Relich
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Indiana University Health, Indianapolis, Indiana, USA
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Hayes MM, Dewberry RJ, Babujee L, Moritz R, Allen C. Validating Methods To Eradicate Plant-Pathogenic Ralstonia Strains Reveals that Growth In Planta Increases Bacterial Stress Tolerance. Microbiol Spectr 2022; 10:e0227022. [PMID: 36453936 PMCID: PMC9769772 DOI: 10.1128/spectrum.02270-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/14/2022] [Indexed: 12/03/2022] Open
Abstract
Plant-pathogenic bacteria in the Ralstonia solanacearum species complex (RSSC) cause highly destructive bacterial wilt disease of diverse crops. Wilt disease prevention and management is difficult because RSSC persists in soil, water, and plant material. Growers need practical methods to kill these pathogens in irrigation water, a common source of disease outbreaks. Additionally, the R. solanacearum race 3 biovar 2 (R3bv2) subgroup is a quarantine pest in many countries and a highly regulated select agent pathogen in the United States. Plant protection officials and researchers need validated protocols to eradicate R3bv2 for regulatory compliance. To meet these needs, we measured the survival of four R3bv2 and three phylotype I RSSC strains following treatment with hydrogen peroxide, stabilized hydrogen peroxide (Huwa-San), active chlorine, heat, UV radiation, and desiccation. No surviving RSSC cells were detected after cultured bacteria were exposed for 10 min to 400 ppm hydrogen peroxide, 50 ppm Huwa-San, 50 ppm active chlorine, or temperatures above 50°C. RSSC cells on agar plates were eradicated by 30 s of UV irradiation and killed by desiccation on most biotic and all abiotic surfaces tested. RSSC bacteria did not survive the cell lysis steps of four nucleic acid extraction protocols. However, bacteria in planta were more difficult to kill. Stems of infected tomato plants contained a subpopulation of bacteria with increased tolerance of heat and UV light, but not oxidative stress. This result has significant management implications. We demonstrate the utility of these protocols for compliance with select agent research regulations and for management of a bacterial wilt outbreak in the field. IMPORTANCE Bacteria in the Ralstonia solanacearum species complex (RSSC) are globally distributed and cause destructive vascular wilt diseases of many high-value crops. These aggressive pathogens spread in diseased plant material and via contaminated soil, tools, and irrigation water. A subgroup of the RSSC, race 3 biovar 2, is a European and Canadian quarantine pathogen and a U.S. select agent subject to stringent and constantly evolving regulations intended to prevent pathogen introduction or release. We validated eradication and inactivation methods that can be used by (i) growers seeking to disinfest water and manage bacterial wilt disease outbreaks, (ii) researchers who must remain in compliance with regulations, and (iii) regulators who are expected to define containment practices. Relevant to all these stakeholders, we show that while cultured RSSC cells are sensitive to relatively low levels of oxidative chemicals, desiccation, and heat, more aggressive treatment, such as autoclaving or incineration, is required to eradicate plant-pathogenic Ralstonia growing inside plant material.
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Affiliation(s)
- Madeline M. Hayes
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Ronnie J. Dewberry
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Lavanya Babujee
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Rebecca Moritz
- Select Agent Program, Environment, Health, and Safety, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
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Chow SK. Uncommon Things Being Common: Gram Variability of Brucella as a Cause of Laboratory Exposure. J Clin Microbiol 2022;:e0050722. [PMID: 35531666 DOI: 10.1128/jcm.00507-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Roman-Reyna V, Truchon A, Sharma P, Hand FP, Mazloom R, Vinatzer BA, Jacobs JM, Allen C. Genome Resource: Ralstonia solanacearum Phylotype II Sequevar 1 (Race 3 Biovar 2) Strain UW848 From the 2020 U.S. Geranium Introduction. Plant Dis 2021; 105:207-208. [PMID: 33175669 DOI: 10.1094/pdis-06-20-1269-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ralstonia solanacearum phylotype II sequevar 1 (RsII-1, formerly race 3 biovar 2) causes tomato bacterial wilt, potato brown rot, and Southern wilt of geranium. Strains in RsII-1 cause wilting in potato and tomato at cooler temperatures than tropical lowland R. solanacearum strains. Although periodically introduced, RsII-1 has not established in the United States. This pathogen is of quarantine concern and listed as a Federal Select Agent. We report a rapidly sequenced (<2 days) draft genome of UW848, a RsII-1 isolate introduced to the United States in geranium cuttings in spring 2020. UW848 belongs to the near-clonal cluster of RsII-1 global pandemic strains.
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Affiliation(s)
- Veronica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH
- Infectious Disease Institute, The Ohio State University, Columbus, OH
| | - Alicia Truchon
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI
| | - Parul Sharma
- Department of Computer Science, Virginia Tech, Blacksburg, VA
| | | | - Reza Mazloom
- Department of Computer Science, Virginia Tech, Blacksburg, VA
| | - Boris A Vinatzer
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH
- Infectious Disease Institute, The Ohio State University, Columbus, OH
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI
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Welkos S, Blanco I, Okaro U, Chua J, DeShazer D. A DUF4148 family protein produced inside RAW264.7 cells is a critical Burkholderia pseudomallei virulence factor. Virulence 2020; 11:1041-1058. [PMID: 32835600 PMCID: PMC7549894 DOI: 10.1080/21505594.2020.1806675] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 11/12/2022] Open
Abstract
Burkholderia pseudomallei: is the etiological agent of the disease melioidosis and is a Tier 1 select agent. It survives and replicates inside phagocytic cells by escaping from the endocytic vacuole, replicating in the cytosol, spreading to other cells via actin polymerization and promoting the fusion of infected and uninfected host cells to form multinucleated giant cells. In this study, we utilized a proteomics approach to identify bacterial proteins produced inside RAW264.7 murine macrophages and host proteins produced in response to B. pseudomallei infection. Cells infected with B. pseudomallei strain K96243 were lysed and the lysate proteins digested and analyzed using nanoflow reversed-phase liquid chromatography and tandem mass spectrometry. Approximately 160 bacterial proteins were identified in the infected macrophages, including BimA, TssA, TssB, Hcp1 and TssM. Several previously uncharacterized B. pseudomallei proteins were also identified, including BPSS1996 and BPSL2748. Mutations were constructed in the genes encoding these novel proteins and their relative virulence was assessed in BALB/c mice. The 50% lethal dose for the BPSS1996 mutant was approximately 55-fold higher than that of the wild type, suggesting that BPSS1996 is required for full virulence. Sera from B. pseudomallei-infected animals reacted with BPSS1996 and it was found to localize to the bacterial surface using indirect immunofluorescence. Finally, we identified 274 host proteins that were exclusively present or absent in infected RAW264.7 cells, including chemokines and cytokines involved in controlling the initial stages of infection.
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Affiliation(s)
- Susan Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Irma Blanco
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Udoka Okaro
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Jennifer Chua
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
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Hettiarachchi IT, Duckers J, Lau D, Dhillon R. The Brief Case: A Traveler's Tale-Burkholderia pseudomallei Infection in a Cystic Fibrosis Patient. J Clin Microbiol 2019; 57:e00106-19. [PMID: 31757885 DOI: 10.1128/JCM.00106-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Cote CK, Buhr T, Bernhards CB, Bohmke MD, Calm AM, Esteban-Trexler JS, Hunter M, Katoski SE, Kennihan N, Klimko CP, Miller JA, Minter ZA, Pfarr JW, Prugh AM, Quirk AV, Rivers BA, Shea AA, Shoe JL, Sickler TM, Young AA, Fetterer DP, Welkos SL, Bozue JA, McPherson D, Fountain AW 3rd, Gibbons HS. A Standard Method To Inactivate Bacillus anthracis Spores to Sterility via Gamma Irradiation. Appl Environ Microbiol 2018; 84:e00106-18. [PMID: 29654186 DOI: 10.1128/AEM.00106-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/05/2018] [Indexed: 12/19/2022] Open
Abstract
In 2015, a laboratory of the United States Department of Defense (DoD) inadvertently shipped preparations of gamma-irradiated spores of Bacillus anthracis that contained live spores. In response, a systematic evidence-based method for preparing, concentrating, irradiating, and verifying the inactivation of spore materials was developed. We demonstrate the consistency of spore preparations across multiple biological replicates and show that two different DoD institutions independently obtained comparable dose-inactivation curves for a monodisperse suspension of B. anthracis spores containing 3 × 1010 CFU. Spore preparations from three different institutions and three strain backgrounds yielded similar decimal reduction (D10) values and irradiation doses required to ensure sterility (DSAL) to the point at which the probability of detecting a viable spore is 10-6 Furthermore, spores of a genetically tagged strain of B. anthracis strain Sterne were used to show that high densities of dead spores suppress the recovery of viable spores. Together, we present an integrated method for preparing, irradiating, and verifying the inactivation of spores of B. anthracis for use as standard reagents for testing and evaluating detection and diagnostic devices and techniques.IMPORTANCE The inadvertent shipment by a U.S. Department of Defense (DoD) laboratory of live Bacillus anthracis (anthrax) spores to U.S. and international destinations revealed the need to standardize inactivation methods for materials derived from biological select agents and toxins (BSAT) and for the development of evidence-based methods to prevent the recurrence of such an event. Following a retrospective analysis of the procedures previously employed to generate inactivated B. anthracis spores, a study was commissioned by the DoD to provide data required to support the production of inactivated spores for the biodefense community. The results of this work are presented in this publication, which details the method by which spores can be prepared, irradiated, and tested, such that the chance of finding residual living spores in any given preparation is 1/1,000,000. These irradiated spores are used to test equipment and methods for the detection of agents of biological warfare and bioterrorism.
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Poonawala H, Marrs Conner T, Peaper DR. Closing the Brief Case: Misidentification of Brucella melitensis as Ochrobactrum anthropi by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). J Clin Microbiol 2018; 56:e00918-17. [PMID: 29802239 DOI: 10.1128/JCM.00918-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Poonawala H, Marrs Conner T, Peaper DR. The Brief Case: Misidentification of Brucella melitensis as Ochrobactrum anthropi by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). J Clin Microbiol 2018; 56:e00914-17. [PMID: 29802238 DOI: 10.1128/JCM.00914-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Turner MW, Cort JR, McDougal OM. α-Conotoxin Decontamination Protocol Evaluation: What Works and What Doesn't. Toxins (Basel) 2017; 9:E281. [PMID: 28906461 DOI: 10.3390/toxins9090281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/04/2017] [Accepted: 09/09/2017] [Indexed: 11/30/2022] Open
Abstract
Nine publically available biosafety protocols for safely handling conotoxin peptides were tested to evaluate their decontamination efficacy. Circular dichroism (CD) spectroscopy and mass spectrometry (MS) were used to assess the effect of each chemical treatment on the secondary and primary structure of α-CTx MII (L10V, E11A). Of the nine decontamination methods tested, treatment with 1% (m/v) solution of the enzymatic detergent Contrex™ EZ resulted in a 76.8% decrease in α-helical content as assessed by the mean residue ellipticity at 222 nm, and partial peptide digestion was demonstrated using high performance liquid chromatography mass spectrometry (HPLC-MS). Additionally, treatment with 6% sodium hypochlorite (m/v) resulted in 80.5% decrease in α-helical content and complete digestion of the peptide. The Contrex™ EZ treatment was repeated with three additional α-conotoxins (α-CTxs), α-CTxs LvIA, ImI and PeIA, which verified the decontamination method was reasonably robust. These results support the use of either 1% Contrex™ EZ solution or 6% sodium hypochlorite in biosafety protocols for the decontamination of α-CTxs in research laboratories.
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Emery FD, Stabenow JM, Miller MA. Efficient inactivation of Burkholderia pseudomallei or Francisella tularensis in infected cells for safe removal from biosafety level 3 containment laboratories. Pathog Dis 2014; 71:276-81. [PMID: 24449562 DOI: 10.1111/2049-632x.12138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/10/2013] [Accepted: 01/06/2014] [Indexed: 12/30/2022] Open
Abstract
Working with infectious agents that require BSL-3 level containment agents offers many challenges for researchers. BSL-3 containment laboratories are usually not equipped with expensive specialty equipment that is needed for studies such as flow cytometric analysis, microscopy, and proteomic analyses. Therefore, for most researchers that are working with BSL-3 level infectious agents, removal of samples from BSL-3 laboratories for these types of studies is necessary, and methods for complete and dependable inactivation of the samples are required. In this report, we have carried out a thorough characterization of the effectiveness of paraformaldehyde fixation for inactivation of cell samples infected with the intracellular bacterial agents Burkholderia pseudomallei (Bp) and Francisella tularensis (Ft), both of which are Tier 1 select agent pathogens that require BSL-3 containment. We have demonstrated that cells infected with these pathogens are completely inactivated via 5-min treatment with 4% paraformaldehyde. Moreover, a 15-min treatment with 2% paraformaldehyde completely sterilized both Bp- and Ft-infected cells. These studies also revealed that Bp is significantly more sensitive to paraformaldehyde treatment than Ft. Our findings have clearly demonstrated that a 15-min treatment of Bp- or Ft-infected cells with 4% paraformaldehyde solution will allow for safe removal of the cell samples from BSL-3 laboratories for downstream studies.
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Affiliation(s)
- Felicia D Emery
- The University of Tennessee Health Science Center, Memphis, TN, USA
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Abstract
Francisella tularensis is a facultative intracellular pathogen that causes the disease tularemia. F. tularensis subsp. tularensis causes the most severe disease in humans and has been classified as a Category A select agent and potential bioweapon. There is currently no vaccine approved for human use, making genetic manipulation of this organism critical to unraveling the genetic basis of pathogenesis and developing countermeasures against tularemia. The development of genetic techniques applicable to F. tularensis have lagged behind those routinely used for other bacteria, primarily due to lack of research and the restricted nature of the biocontainment required for studying this pathogen. However, in recent years, genetic techniques, such as transposon mutagenesis and targeted gene disruption, have been developed, that have had a dramatic impact on our understanding of the genetic basis of F. tularensis virulence. In this review, we describe some of the methods developed for genetic manipulation of F. tularensis.
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Affiliation(s)
- Xhavit Zogaj
- Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas San Antonio San Antonio, TX, USA
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