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A Portable, Encapsulated Microbial Whole-Cell Biosensing System for the Detection of Bioavailable Copper (II) in Soil. Microchem J 2023; 193:109088. [PMID: 37982106 PMCID: PMC10655828 DOI: 10.1016/j.microc.2023.109088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
A portable, field deployable whole-cell biosensor was developed that can withstand the complex matrices of soil and requires minimal to no sample preparation to monitor bioavailable concentrations of the essential micronutrient copper (II). Conventional measurement of micronutrients is often complex, laboratory-based, and not suitable for monitoring their bioavailable concentration. To address this need, we developed a fluorescence based microbial whole-cell biosensing (MWCB) system encoding for a Cu2+-responsive protein capable of generating a signal upon binding to Cu2+. The sensing-reporting protein was designed by performing circular permutation on the green fluorescent protein (GFP) followed by insertion of a Cu2+ binding motif into the structure of GFP. The design included insertion of several binding motifs and creating plasmids that encoded the corresponding sensing proteins. The signal generated by the sensing-reporting protein is directly proportional to the concentration of Cu2+ in the sample. Evaluation of the resulting biosensing systems carrying these plasmids was performed prior to selection of the optimal fluorescence emitting Cu2+-binding protein. The resulting optimized biosensing system was encapsulated in polyacrylate-alginate beads and embedded in soil for detection of the analyte. Once exposed to the soil, the beads were interrogated to measure the fluorescence signal emitted by the sensing-reporting protein using a portable imaging device. The biosensor was optimized for detection of Cu2+ in terms of selectivity, sensitivity, matrix effects, detection limits, and reproducibility in both liquid and soil matrices. The limit of detection (LoD) of the optimized encapsulated biosensor was calculated as 0.27 mg/L and 1.26 mg/kg of Cu2+ for Cu2+ in solution and soil, respectively. Validation of the portable imaging tools as a potential biosensing device in the field was performed.
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Assessment of horizontal gene transfer-mediated destabilization of Synechococcus elongatus PCC 7942 biocontainment system. J Biosci Bioeng 2023; 135:190-195. [PMID: 36653270 DOI: 10.1016/j.jbiosc.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 01/18/2023]
Abstract
Biological containment is a biosafety strategy that prevents the dispersal of genetically modified organisms in natural ecosystems. We previously established a biocontainment system that makes bacterial growth dependent on the availability of phosphite (Pt), an ecologically rare form of phosphorus (P), by introducing Pt metabolic pathway genes and disrupting endogenous phosphate and organic phosphate transporter genes. Although this system proved highly effective, horizontal gene transfer (HGT) mediated recovery of a P transporter gene is considered as a potential pathway to abolish the Pt-dependent growth, resulting in escape from the containment. Here, we assessed the risk of HGT driven escape using the Pt-dependent cyanobacterium Synechococcus elongatus PCC 7942. Transformation experiments revealed that the Pt-dependent strain could regain phosphate transporter genes from the S. elongatus PCC 7942 wild-type genome and from the genome of the closely related strain, S. elongatus UTEX 2973. Transformed S. elongatus PCC 7942 became viable in a phosphate-containing medium. Meanwhile, transformation of the Synechocystis sp. PCC 6803 genome or environmental DNA did not yield escape strains, suggesting that only genetic material derived from phylogenetically-close species confer high risk to generate escape. Eliminating a single gene necessary for natural competence from the Pt-dependent strain reduced the escape occurrence rate. These results demonstrate that natural competence could be a potential risk to destabilize Pt-dependence, and therefore inhibiting exogenous DNA uptake would be effective for enhancing the robustness of the gene disruption-dependent biocontainment.
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Encapsulation of bacteria in bilayer Pluronic thin film hydrogels: A safe format for engineered living materials. BIOMATERIALS ADVANCES 2023; 145:213240. [PMID: 36577192 DOI: 10.1016/j.bioadv.2022.213240] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 12/04/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022]
Abstract
In engineered living materials (ELMs) non-living matrices encapsulate microorganisms to acquire capabilities like sensing or biosynthesis. The confinement of the organisms to the matrix and the prevention of overgrowth and escape during the lifetime of the material is necessary for the application of ELMs into real devices. In this study, a bilayer thin film hydrogel of Pluronic F127 and Pluronic F127 acrylate polymers supported on a solid substrate is introduced. The inner hydrogel layer contains genetically engineered bacteria and supports their growth, while the outer layer acts as an envelope and does not allow leakage of the living organisms outside of the film for at least 15 days. Due to the flat and transparent nature of the construct, the thin layer is suited for microscopy and spectroscopy-based analyses. The composition and properties of the inner and outer layer are adjusted independently to fulfil viability and confinement requirements. We demonstrate that bacterial growth and light-induced protein production are possible in the inner layer and their extent is influenced by the crosslinking degree of the used hydrogel. Bacteria inside the hydrogel are viable long term, they can act as lactate-sensors and remain active after storage in phosphate buffer at room temperature for at least 3 weeks. The versatility of bilayer bacteria thin-films is attractive for fundamental studies and for the development of application-oriented ELMs.
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Phosphite synthetic auxotrophy as an effective biocontainment strategy for the industrial chassis Pseudomonas putida. Microb Cell Fact 2022; 21:156. [PMID: 35934698 PMCID: PMC9358898 DOI: 10.1186/s12934-022-01883-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/26/2022] [Indexed: 11/12/2022] Open
Abstract
The inclusion of biosafety strategies into strain engineering pipelines is crucial for safe-by-design biobased processes. This in turn might enable a more rapid regulatory acceptance of bioengineered organisms in both industrial and environmental applications. For this reason, we equipped the industrially relevant microbial chassis Pseudomonas putida KT2440 with an effective biocontainment strategy based on a synthetic dependency on phosphite, which is generally not readily available in the environment. The produced PSAG-9 strain was first engineered to assimilate phosphite through the genome-integration of a phosphite dehydrogenase and a phosphite-specific transport complex. Subsequently, to deter the strain from growing on naturally assimilated phosphate, all native genes related to its transport were identified and deleted generating a strain unable to grow on media containing any phosphorous source other than phosphite. PSAG-9 exhibited fitness levels with phosphite similar to those of the wild type with phosphate, and low levels of escape frequency. Beyond biosafety, this strategy endowed P. putida with the capacity to be cultured under non-sterile conditions using phosphite as the sole phosphorous source with a reduced risk of contamination by other microbes, while displaying enhanced NADH regenerative capacity. These industrially beneficial features complement the metabolic advantages for which this species is known for, thereby strengthening it as a synthetic biology chassis with potential uses in industry, with suitability towards environmental release.
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Creating a Safety Officer Program to Enhance Staff Safety During the Care of COVID-19 Patients. Health Secur 2022; 20:S54-S59. [PMID: 35483094 DOI: 10.1089/hs.2021.0182] [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: 11/12/2022] Open
Abstract
Staff safety is paramount when managing an infectious disease event. However, early data from the COVID-19 pandemic suggested that staff compliance with personal protective equipment and other safety protocols was poor. In response to patient surges, many hospitals created dedicated "biomode" units to provide care for patients infected with SARS-CoV-2, the virus that causes COVID-19. To enhance staff safety on biomode units and during patient transports, our hospital created a safety officer/transport safety officer (SO/TSO) program. The first SOs/TSOs were nurses, clinical technicians, and other support staff who were redeployed from their home units when the units closed during the initial surge. During subsequent COVID-19 surges, dedicated SOs/TSOs were hired to maintain the program. SOs/TSOs provided just-in-time personal protective equipment training and helped staff safely enter and exit COVID-19 clinical units. SOs/TSOs participated in the transport of over 1,000 COVID-19 patients with no safety incidents reported. SOs/TSOs conducted safety audits throughout the hospital and observed 86% compliance with COVID-19 precautions across 32,500 activities. During contact tracing of frontline staff who became infected with SARS-CoV-2, potential deviations from COVID-19 precautions were identified in only 7.7% of cases. The SO/TSO program contributed to a culture of safety in the biomode units and helped to enhance infection prevention throughout the hospital. This program can serve as a model for other health systems during the response to the current pandemic and during future infectious disease threats.
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A pilot study of core body temperatures in healthcare workers wearing personal protective equipment in a high-level isolation unit. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2021; 18:430-435. [PMID: 34383620 DOI: 10.1080/15459624.2021.1949459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Personal protective equipment used by healthcare workers to mitigate disease transmission risks while caring for patients with high-consequence infectious diseases can impair normal body cooling mechanisms and exacerbate physiological strain. Symptoms of heat strain (e.g., cognitive impairment, confusion, muscle cramping) are especially harmful in the high-risk environment of high-consequence infectious disease care. In this pilot study, the core body temperatures of healthcare workers were assessed using an ingestible, wireless-transmission thermometer while performing patient care tasks common to a high-level isolation unit setting in powered air purifying respirator (PAPR)-level. The objective was to determine the potential for occupational health hazard due to heat stress in an environmentally controlled unit. Maximum core temperatures of the six participants ranged from 37.4 °C (99.3 °F) to 39.9 °C (103.8°F) during the 4-hr shift; core temperatures of half (n = 3) of the participants exceeded 38.5 °C (101.3 °F), the upper core temperature limit. Future investigations are needed to identify other heat stress risks both in and outside of controlled units. The ongoing COVID-19 pandemic offers unique opportunities for field-based research on risks of heat stress related to personal protective equipment in healthcare workers that can lead to both short- and long-term innovations in this field.
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Genomics in Patient Care and Workforce Decisions in High-Level Isolation Units: A Survey of Healthcare Workers. Health Secur 2021; 19:318-326. [PMID: 33826422 DOI: 10.1089/hs.2020.0182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The impact of host genomics on an individual's susceptibility, immune response, and risk of severe outcomes for a given infectious pathogen is increasingly recognized. As we uncover the links between host genomics and infectious disease, a number of ethical, legal, and social issues need to be considered when using that information in clinical practice or workforce decisions. We conducted a survey of the clinical staff at 10 federally funded Regional Ebola and Other Special Pathogen Treatment Centers to understand their views regarding the ethical, legal, and social issues related to host genomics and the administrative and clinical functions of high-level isolation units. Respondents overwhelmingly agreed that genomics could provide valuable information to identify patients and employees at higher risk for poor outcomes from highly infectious diseases. However, there was considerable disagreement about whether such data should inform the allocation of scarce resources or determine treatment decisions. While most respondents supported a confidential employer-based genomic testing system to inform individual employees about risk, respondents disagreed about whether such information should be used in staffing models. Respondents who thought genomic information would be valuable for patient treatment were more willing to undergo genetic testing for staffing purposes. Most respondents felt they would benefit from additional training to better interpret results from genetic testing. Although this study was completed before the COVID-19 pandemic, the responses provide a baseline assessment of provider attitudes that can inform policy during the current pandemic and in future infectious disease outbreaks.
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A Simple Technology for Generating Marker-Free Chloroplast Transformants of the Green Alga Chlamydomonas reinhardtii. Methods Mol Biol 2021; 2317:293-304. [PMID: 34028777 DOI: 10.1007/978-1-0716-1472-3_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The availability of routine methods for the genetic engineering of the chloroplast genome of Chlamydomonas reinhardtii is allowing researchers to explore the use of this microalga as a phototrophic cell platform for synthesis of high value recombinant proteins and metabolites. However, the established method for delivering transforming DNA into the algal chloroplast involves microparticle bombardment using an expensive "gene gun". Furthermore, selection of transformant lines most commonly involves the use of a bacterial antibiotic resistance gene. In this chapter, we describe a simple and cheap delivery method in which cell-DNA suspensions are agitated with glass beads: a method that is more commonly used for nuclear transformation of Chlamydomonas. We also describe the use of plasmid expression vectors that target transgenes to a neutral site within the chloroplast genome between psbH and trnE2, and employ psbH as the selectable marker-thereby avoiding issues of unwanted antibiotic resistance genes in the resulting transgenic lines. Finally, we highlight a feature in our latest vectors in which the presence of a novel tRNA gene on the plasmid results in recognition within the chloroplast of UGA stop codons in transgenes as tryptophan codons. This feature simplifies the cloning of transgenes that are normally toxic to E. coli, serves as a biocontainment strategy restricting the functional escape of transgenes from the algal chloroplast to environmental microorganisms, and offers a simple system of temperature-regulated translation of transgenes.
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The Risk of Not Being Ready: A Novel Approach to Managing Constant Readiness of a High-Level Isolation Unit During Times of Inactivity. Health Secur 2020; 18:212-218. [PMID: 32559152 DOI: 10.1089/hs.2019.0130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The biocontainment unit at Johns Hopkins Hospital is a specially designed, inactive high-level isolation unit designated to care for patients infected with high-consequence pathogens. The unit team designed a facility-specific readiness scale and checklist that focus on infrastructure, consumable supplies, and staffing to assess activation readiness of the biocontainment unit. Over a period of 50 days and 14 days, these tools were used as part of a routine risk assessment to first identify barriers and then tier the impact of these barriers into activation categories of "Ready," "Ready with Considerations," and "Not Ready." The assessment identified the greatest risks to activation readiness were staffing and waste management capabilities. Assessing threats to activation readiness and the risk of not being ready should be a priority for maintaining facility, regional, and national capacity to safely isolate and care for patients infected with high-consequence pathogens while maintaining healthcare worker safety.
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Guidance for building a dedicated health facility to contain the spread of the 2019 novel coronavirus outbreak. Indian J Med Res 2020; 151:177-183. [PMID: 32362643 PMCID: PMC7288764 DOI: 10.4103/ijmr.ijmr_518_20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Preparedness for the ongoing coronavirus disease 2019 (COVID-19) and its spread in India calls for setting up of adequately equipped and dedicated health facilities to manage sick patients while protecting healthcare workers and the environment. In the wake of other emerging dangerous pathogens in recent times, such as Ebola, Nipah and Zika, it is important that such facilities are kept ready during the inter-epidemic period for training of health professionals and for managing cases of multi-drug resistant and difficult-to-treat pathogens. While endemic potential of such critically ill patients is not yet known, the health system should have surge capacity for such critical care units and preferably each tertiary government hospital should have at least one such facility. This article describes elements of design of such unit (e.g., space, infection control, waste disposal, safety of healthcare workers, partners to be involved in design and plan) which can be adapted to the context of either a new construction or makeshift construction on top of an existing structure. In view of a potential epidemic of COVID-19, specific requirements to handle it are also given.
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Abstract
This article provides insights into the management of bovine respiratory disease in high-risk cattle populations. Biocontainment strategies, records, procurement, transport, arrival/receiving management, vaccination, and treatment protocols are discussed from practical and systems-thinking perspectives regarding their impact on health in high-risk cattle. Arrival management considerations, such as facilities, nutritional management, metaphylaxis, bovine viral diarrhea virus persistent infection testing, parasite control, and castration, are also addressed. Caretaker morale and job satisfaction are suggested as important factors to consider when managing high-risk cattle. The inter-relationships of variables within the system are explored as contributing causative factors to bovine respiratory disease in high-risk cattle.
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Biosafety and biosecurity requirements for Orientia spp. diagnosis and research: recommendations for risk-based biocontainment, work practices and the case for reclassification to risk group 2. BMC Infect Dis 2019; 19:1044. [PMID: 31822267 PMCID: PMC6902544 DOI: 10.1186/s12879-019-4653-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/22/2019] [Indexed: 11/22/2022] Open
Abstract
Scrub typhus is an important arthropod-borne disease causing significant acute febrile illness by infection with Orientia spp.Using a risk-based approach, this review examines current practice, the evidence base and regulatory requirements regarding matters of biosafety and biosecurity, and presents the case for reclassification from Risk Group 3 to Risk Group 2 along with recommendations for safe working practices of risk-based activities during the manipulation of Orientia spp. in the laboratory.We recommend to reclassify Orientia spp. to Risk Group 2 based on the classification for RG2 pathogens as being moderate individual risk, low community risk. We recommend that low risk activities, can be performed within a biological safety cabinet located in a Biosafety Level (BSL) 2 core laboratory using standard personal protective equipment. But when the risk assessment indicates, such as high concentration and volume, or aerosol generation, then a higher biocontainment level is warranted. For, the majority of animal activities involving Orientia spp., Animal BSL 2 (ABSL2) is recommended however where high risk activities are performed including necropsies, Animal BSL (ABSL3) is recommended.
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Perspectives on the Management of Children in a Biocontainment Unit: Report of the NETEC Pediatric Workgroup. Health Secur 2019; 17:11-17. [PMID: 30779612 DOI: 10.1089/hs.2018.0074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During the outbreak of Ebola virus disease that struck West Africa during 2014-2016, a small handful of expatriate patients were evacuated to specialized high-level containment care units, or biocontainment units, in the United States and Western Europe. Given the lower mortality rate (18% versus 40% for those treated in Africa) among these patients, it is likely that high-level containment care will be used in the future with increasing frequency. It is also likely that children infected with Ebola and other highly hazardous communicable diseases will someday require such care. The National Ebola Training and Education Center convened a pediatric workgroup to consider the unique and problematic issues posed by these potential child patients. We report here the results of those discussions.
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Abstract
The 2014 to 2016 Ebola outbreak response resulted in many lessons learned about biocontainment patient care, leading to enhanced domestic capabilities for highly infectious and hazardous communicable diseases. However, additional opportunities for improvement remain. The article identifies and describes key considerations and challenges for laboratory analysis, clinical management, transportation, and personnel management during the care of patients infected with Ebola or other special pathogens. Dedication to maintaining preparedness enables biocontainment patient care teams to perform at the highest levels of safety and confidence.
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Caring for patients with Ebola virus disease: Are U.S. biocontainment centers ready for the next outbreak? Semin Diagn Pathol 2019; 36:160-163. [PMID: 31010606 DOI: 10.1053/j.semdp.2019.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The 2014 West African Ebola virus disease (EVD) outbreak is the largest and deadliest EVD epidemic to date, resulting in fivefold more cases than all other outbreaks combined. This outbreak was particularly devastating to healthcare workers in West Africa and resulted in several EVD patients being medically evacuated for treatment in the U.S. and Europe. Governmental agencies provide recommendations for triaging and testing patients with EVD, however best laboratory practices are still unknown and are very resource dependent.
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Abstract
The Ebola epidemic of 2014 demonstrated that outbreaks of high-consequence infectious diseases, even in remote parts of the world, can affect communities anywhere in the developed world and that every healthcare facility must be prepared to identify, isolate, and provide care for infected patients. The Nebraska Biocontainment Unit (NBU), located at Nebraska Medicine in Omaha, Nebraska, cared for 3 American citizens exposed in West Africa and confirmed with Ebola virus disease (EVD). Symptom monitoring of healthcare workers caring for these patients was implemented, which included twice daily contact to document the absence or presence of signs of fever or illness. This article describes the symptom monitoring experience of the NBU and local and state public health agencies. Based on lessons learned from that experience, we sought a more efficient solution to meet the needs of both the healthcare facility and public health authorities. REDCap, an open-source application used commonly by academic health centers, was used to develop an inexpensive symptom monitoring application that could reduce the burden of managing these activities, thus freeing up valuable time. Our pilot activities demonstrated that this novel use of REDCap holds promise for minimizing costs and resource demands associated with symptom monitoring while offering a more user-friendly experience for people being monitored and the officials managing the response.
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Abstract
The concept and belief in the idea of "biocontainment" has undergone significant evolution during the past 20 years. The authors believe that the time is right to move to the next phase of this evolution to reassess establishment of formal standards for what constitutes a biocontainment unit and what diseases might be considered for admission to a biocontainment unit.
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The National Ebola Training and Education Center: Preparing the United States for Ebola and Other Special Pathogens. Health Secur 2018; 15:253-260. [PMID: 28636442 PMCID: PMC6532632 DOI: 10.1089/hs.2017.0005] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The National Ebola Training and Education Center (NETEC) was established in 2015 in response to the 2014-2016 Ebola virus disease outbreak in West Africa. The US Department of Health and Human Services office of the Assistant Secretary for Preparedness and Response and the US Centers for Disease Control and Prevention sought to increase the competency of healthcare and public health workers, as well as the capability of healthcare facilities in the United States, to deliver safe, efficient, and effective care to patients infected with Ebola and other special pathogens nationwide. NYC Health + Hospitals/Bellevue, Emory University, and the University of Nebraska Medical Center/Nebraska Medicine were awarded this cooperative agreement, based in part on their experience in safely and successfully evaluating and treating patients with Ebola virus disease in the United States. In 2016, NETEC received a supplemental award to expand on 3 initial primary tasks: (1) develop metrics and conduct peer review assessments; (2) develop and provide educational materials, resources, and tools, including exercise design templates; (3) provide expert training and technical assistance; and, to add a fourth task, create a special pathogens clinical research network.
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Synthetic alienation of microbial organisms by using genetic code engineering: Why and how? Biotechnol J 2017; 12. [PMID: 28671771 DOI: 10.1002/biot.201600097] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/19/2017] [Accepted: 05/31/2017] [Indexed: 12/31/2022]
Abstract
The main goal of synthetic biology (SB) is the creation of biodiversity applicable for biotechnological needs, while xenobiology (XB) aims to expand the framework of natural chemistries with the non-natural building blocks in living cells to accomplish artificial biodiversity. Protein and proteome engineering, which overcome limitation of the canonical amino acid repertoire of 20 (+2) prescribed by the genetic code by using non-canonic amino acids (ncAAs), is one of the main focuses of XB research. Ideally, estranging the genetic code from its current form via systematic introduction of ncAAs should enable the development of bio-containment mechanisms in synthetic cells potentially endowing them with a "genetic firewall" i.e. orthogonality which prevents genetic information transfer to natural systems. Despite rapid progress over the past two decades, it is not yet possible to completely alienate an organism that would use and maintain different genetic code associations permanently. In order to engineer robust bio-contained life forms, the chemical logic behind the amino acid repertoire establishment should be considered. Starting from recent proposal of Hartman and Smith about the genetic code establishment in the RNA world, here the authors mapped possible biotechnological invasion points for engineering of bio-contained synthetic cells equipped with non-canonical functionalities.
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Abstract
Synthetic biology is an emerging interdisciplinary field of biotechnology that involves applying the principles of engineering and chemical design to biological systems. Biosafety professionals have done an excellent job in addressing research laboratory safety as synthetic biology and gene editing have emerged from the larger field of biotechnology. Despite these efforts, risks posed by synthetic biology are of increasing concern as research procedures scale up to industrial processes in the larger bioeconomy. A greater number and variety of workers will be exposed to commercial synthetic biology risks in the future, including risks to a variety of workers from the use of lentiviral vectors as gene transfer devices. There is a need to review and enhance current protection measures in the field of synthetic biology, whether in experimental laboratories where new advances are being researched, in health care settings where treatments using viral vectors as gene delivery systems are increasingly being used, or in the industrial bioeconomy. Enhanced worker protection measures should include increased injury and illness surveillance of the synthetic biology workforce; proactive risk assessment and management of synthetic biology products; research on the relative effectiveness of extrinsic and intrinsic biocontainment methods; specific safety guidance for synthetic biology industrial processes; determination of appropriate medical mitigation measures for lentiviral vector exposure incidents; and greater awareness and involvement in synthetic biology safety by the general occupational safety and health community as well as by government occupational safety and health research and regulatory agencies.
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Abstract
The concept of clinical biocontainment, otherwise known as high-level containment care (HLCC), had its birth among a confluence of near-simultaneous events in 1969. The U.S. Army's Medical Research Institute of Infectious Diseases (USAMRIID) began construction of the first modern biocontainment unit that year, and opened the two-bed facility, often referred to as "the Slammer" in 1971. Over its 41-year existence, 21 persons exposed to highly hazardous infectious diseases were admitted to the Slammer, but none ever contracted the disease to which they had been exposed. Owing, in part, to this underutilization, some questioned the utility of HLCC units. This concern notwithstanding, Emory University and the University of Nebraska opened HLCC units in civilian academic medical centers in 2004 and 2005, respectively. These units, distinct from conventional infectious disease isolation wards found in most major medical centers, proved their worth during the West African Ebola Virus Disease (EVD) outbreak of 2014-2015. It is our opinion that such units, as well as the parallel high-level containment transport systems necessary to move patients to them, will continue to play an important role in the global response to emerging and highly hazardous contagious pathogens. Moreover, we feel that the lessons derived from their successful operation will lead to improvements in infection control procedures and practices throughout the healthcare system.
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Preparation of viral samples within biocontainment for ultrastructural analysis: Utilization of an innovative processing capsule for negative staining. J Virol Methods 2016; 238:70-76. [PMID: 27751950 DOI: 10.1016/j.jviromet.2016.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 01/22/2023]
Abstract
Transmission electron microscopy can be used to observe the ultrastructure of viruses and other microbial pathogens with nanometer resolution. In a transmission electron microscope (TEM), the image is created by passing an electron beam through a specimen with contrast generated by electron scattering from dense elements in the specimen. Viruses do not normally contain dense elements, so a negative stain that places dense heavy metal salts around the sample is added to create a dark border. To prepare a virus sample for a negative stain transmission electron microscopy, a virus suspension is applied to a TEM grid specimen support, which is a 3mm diameter fragile specimen screen coated with a few nanometers of plastic film. Then, deionized (dI) water rinses and a negative stain solution are applied to the grid. All infectious viruses must be handled in a biosafety cabinet (BSC) and many require a biocontainment laboratory environment. Staining viruses in biosafety levels (BSL) 3 and 4 is especially challenging because the support grids are small, fragile, and easily moved by air currents. In this study we evaluated a new device for negative staining viruses called mPrep/g capsule. It is a capsule that holds up to two TEM grids during all processing steps and for storage after staining is complete. This study reports that the mPrep/g capsule method is valid and effective to negative stain virus specimens, especially in high containment laboratory environments.
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Biosafety of biotechnologically important microalgae: intrinsic suicide switch implementation in cyanobacterium Synechocystis sp. PCC 6803. Biol Open 2016; 5:519-28. [PMID: 27029902 PMCID: PMC4890671 DOI: 10.1242/bio.017129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In recent years, photosynthetic autotrophic cyanobacteria have attracted interest for biotechnological applications for sustainable production of valuable metabolites. Although biosafety issues can have a great impact on public acceptance of cyanobacterial biotechnology, biosafety of genetically modified cyanobacteria has remained largely unexplored. We set out to incorporate biocontainment systems in the model cyanobacterium Synechocystis sp. PCC 6803. Plasmid-encoded safeguards were constructed using the nonspecific nuclease NucA from Anabaena combined with different metal-ion inducible promoters. In this manner, conditional lethality was dependent on intracellular DNA degradation for regulated autokilling as well as preclusion of horizontal gene transfer. In cells carrying the suicide switch comprising the nucA gene fused to a variant of the copM promoter, efficient inducible autokilling was elicited. Parallel to nuclease-based safeguards, cyanobacterial toxin/antitoxin (TA) modules were examined in biosafety switches. Rewiring of Synechocystis TA pairs ssr1114/slr0664 and slr6101/slr6100 for conditional lethality using metal-ion responsive promoters resulted in reduced growth, rather than cell killing, suggesting cells could cope with elevated toxin levels. Overall, promoter properties and translation efficiency influenced the efficacy of biocontainment systems. Several metal-ion promoters were tested in the context of safeguards, and selected promoters, including a nrsB variant, were characterized by beta-galactosidase reporter assay. Summary: Biosafety of biotechnologically important microalgae was addressed by suicide switch implementation in cyanobacterium Synechocystis sp. PCC 6803. This is the first report of biocontainment safeguards in cyanobacteria.
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Planning and response to Ebola virus disease: An integrated approach. Am J Infect Control 2015; 43:441-6. [PMID: 25952046 DOI: 10.1016/j.ajic.2015.01.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/16/2015] [Accepted: 01/20/2015] [Indexed: 10/23/2022]
Abstract
The care of patients with Ebola virus disease (EVD) requires the application of critical care medicine principles under conditions of stringent infection control precautions. The care of patients with EVD requires a number of elements in terms of physical layout, personal protective apparel, and other equipment. Provision of care is demanding in terms of depth of staff and training. The key to safely providing such care is a system that brings many valuable skills to the table, and allows communication between these individuals. We present our approach to leadership structure and function--a variation of incident command--in providing care to 3 patients with EVD.
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Abstract
Biosecurity on South American camelid operations involves both external and internal measures to prevent the introduction and spread of disease. External biosecurity involves practices and techniques directed at the prevention of entry of new diseases into a group of animals. Internal biosecurity or biocontainment, involves practices and techniques that are directed at the prevention or spread of disease within an existing group of animals. External biosecurity is particularly important in North America camelid operations due to the extensive movement of animals for breeding or show purposes. Internal biosecurity typically involves this the prevention and treatment of failure of passive transfer, maintenance of proper nutrition and housing, and the implementation of an appropriate vaccination program for endemic or relevant diseases. Attention to appropriate cleaning and disinfection procedures related to housing, feeding, and treatment equipment is important for the maintenance of both internal and external biosecurity practices. This paper discusses various risk factors associated with the control of infectious disease in the context of external and internal biosecurity measures in camelids operations.
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