Applied Biosafety最新文献

Introduction: Bacillus anthracis, the etiological agent of anthrax, produces long-lived spores, which are resistant to heat, cold, pH, desiccation, and chemical agents. The spores maintain their ability to produce viable bacteria even after decades, and when inhaled can cause fatal disease in over half of the clinical cases. Owing to these characteristics, anthrax has been repeatedly selected for both bioweapon and bioterrorism use. In the event of a bioterrorism attack, surfaces in the vicinity of the attack will be contaminated, and recovering from such an event requires rapid and effective decontamination. Previous decontamination method development has focused mainly on temperatures >0°C, and have shown poor efficacy at subzero temperatures. Methods: In this study, we demonstrate the use of calcium chloride (CaCl₂) as a freezing point depression agent for pH-adjusted sodium hypochlorite (NaOCl) for the effective and rapid decontamination of B. anthracis Sterne strain spores at subzero temperatures. Results: We show the complete decontamination of 10⁶ B. anthracis Sterne strain spores at temperatures as low as -20°C within 2.5 min by submersion in solution containing 25% (w/v) CaCl₂, 0.50% NaOCl, and 0.40% (v/v) acetic acid. We also demonstrate significant reduction in number of spores at -28°C. Conclusions: The results show promise for rapidly decontaminating equipment and materials used in the response to bioterrorism events using readily available consumer chemicals. Future study should examine the efficacy of these results on complex surfaces.

Introduction: Failure of an existing effluent decontamination system (EDS) prompted the consideration of commercial off-the-shelf solutions for decontamination of containment laboratory waste. A bleach-based chemical EDS was purchased to serve as an interim solution. Methods: Studies were conducted in the laboratory to validate inactivation of Bacillus spores with bleach in complex matrices containing organic simulants including fetal bovine serum, humic acid, and animal room sanitation effluent. Results: These studies demonstrated effective decontamination of >10⁶ spores at a free chlorine concentration of ≥5700 parts per million with a 2-hour contact time. Translation of these results to biological validation of the bleach-based chemical EDS required some modifications to the system and its operation. Discussion: The chemical EDS was validated for the treatment of biosafety levels 3 and 4 waste effluent using laboratory-prepared spore packets along with commercial biological indicators; however, several issues and lessons learned identified during the process of onboarding are also discussed, including bleach product source, method of validation, dechlorination, and treated waste disposal.

Introduction: Part 1 of this two-part series describes the use of hydrogen peroxide as a fumigant and compares it with other fumigants on the market. Technical requirements are outlined while considering physical and biological limitations of the system. This second part focuses primarily on the use of process controls to verify and validate hydrogen peroxide fumigations. Finally, a model encompassing the entire fumigation process is presented. Methods: Part 2 of the series focuses on the authors' long-time personal experiences in room and filter fumigation using various fumigation systems and is supplemented with relevant literature searches. Results: The reader is introduced to the planning and implementation of fumigation process validations. Biological indicators help users develop safe and efficient processes. Chemical indicators can be used as process controls, while measuring physical parameters will help avoid condensation of hydrogen peroxide. How many biological and chemical indicators and what type should be applied for cycle development are additionally explained. Discussion: It is important to consider numerous technical requirements when planning to implement hydrogen peroxide fumigation at an institution. Also, considerable thought needs to go into the verification and validation of the fumigation process. Conclusions: Part 1 of this series presents an overview of different fumigation systems based on hydrogen peroxide on the market and their technical requirements. Part 2 focuses on validation and verification of hydrogen peroxide fumigation while considering the entire fumigation process. The two parts together will serve users as a guide to establishing hydrogen peroxide fumigations at their facilities.

Introduction: The complete inactivation of infectious tissues of large animal carcasses is one of the most challenging tasks in high-containment facilities. Steam sterilization is a method frequently in use to achieve biological inactivation of liquid and solid waste. Objective: This study aims to highlight parameters most effective in creating reproducible cycles for steam sterilization of pig and calf carcasses. Methods: Two pigs or 1 calf were sterilized by running a liquid cycle (n = 3) at 121°C for at least 120 minutes in a pass-through autoclave. To assess the physical and biological parameters, temperature data loggers and biological indicators (BIs) with spores of Geobacillus stearothermophilus (ATCC 7953) were placed at defined positions within animal carcasses. After completion of each cycle, data loggers were analyzed and BIs were incubated for 7 days at 60°C. Results: Initial testing with an undissected pig carcass resulted in suboptimal temperatures at the tissue level with growth on 1 BI. After modifications of the used stainless-steel boxes and by placing the reference probe of the autoclave in the animal carcass, reproducible cycles could be created. A complete inactivation of BIs and a temperature profile of >121°C for at least 20 minutes could be achieved in almost all probed tissues. Conclusion: Only minor modifications in carcass preparation and the used sterilization equipment resulted in effective and reproducible cycles to inactivate large animal carcasses by using a steam autoclave.

Background: The implementation of "no-touch" technologies such as ultraviolet (UV)-based sanitizers to effectively disinfect the air and high-touch surfaces may be important to keeping working environments and indoor public gathering places, where there may be a higher risk of infection from specific agents, safe for all occupants, particularly with the emergence of highly communicable diseases. UV technologies have been used for many years and are being revisited as one of disinfecting technology to address the SARS-CoV-2 virus that causes COVID-19. Methods: We selected over 20 relevant source documents from approximately 80 papers dating between 1985 and the present (2020) to evaluate the applicability, safety and relative contribution of ultraviolet to disinfect air and surfaces in the built environment. UV-based sanitizers have the potential for effective application when used in conjunction with other disinfecting means. Results: The efficacy of UV-based sanitizer technologies are promising but are dependent on numerous environmental, physical and technical factors. Conclusions: We believe that UV technologies should not be utilized in isolation and should be considered as an adjunct to protocol-driven standard operating procedures for cleaning and disinfection, had hygiene practices, and appropriate use of personal protective equipment (PPE).

Introduction: Use of sea water as a diluent for disinfectants has been of practical interest for control of aquaculture disease outbreaks in sea where fresh water is limited. This study evaluated the use of natural sea water (NSW), artificial sea water (ASW), or standard hard water (SHW) as a diluent for preparation of accelerated hydrogen peroxide (AHP) solutions against an avian influenza virus, a surrogate for the infectious salmon anemia virus. Methods: AHP solutions containing 0.18%, 0.35%, or 0.44% (w/w) of hydrogen peroxide (H₂O₂), corresponding to 1/40, 1/20, and 1/16 dilutions of the disinfectant concentrate, were evaluated at -20°C, 4°C, and 21°C. Results: When NSW was used as the diluent, a 0.35% H₂O₂ concentration was required to inactivate ∼6 log₁₀ virus at 21°C in a 5-min contact time. When temperature dropped to 4°C, 0.44% H₂O₂ in NSW was required to obtain a similar inactivation within a 5-min contact time. At -20°C, supplemented with antifreeze agents, the 0.44% H₂O₂ in NSW solutions produced complete inactivation of 5.4 log₁₀ virus within a 10-min contact time. In comparison, lower H₂O₂ concentrations and/or shorter contact times were needed to inactivate equal amounts of the virus at the same temperature when using SHW or ASW as a diluent to prepare disinfection solutions. Conclusion: The results suggested that NSW could be used as a diluent in disinfection solutions for virus inactivation as long as disinfectant concentrations and/or contact times are properly increased.

Introduction: Because of the nature of work conducted in veterinary laboratories and potential exposures to pathogenic microorganisms, good laboratory practices, risk assessments, biosafety, and biosecurity capacity is becoming vital. In this study, the Food and Agriculture Organization Laboratory Mapping Tool-Safety Module was applied to demonstrate its practical implementation in the assessment of biosafety and biosecurity statuses of veterinary laboratories in Nigeria.

Methods: The Laboratory Mapping Tool-Safety Module, a standardized questionnaire, systematically and semiquantitatively gathered data on 98 subcategories covering 4 areas of biosafety and biosecurity capabilities: administrative, operational, engineering, and personal protective equipment.

Results: Overall, the various areas and categories covered by the Laboratory Mapping Tool-Safety Module were weak across the board, with a mean performance of 19.5% (95% confidence interval, 14.0%-25.1%; range, 0.8%-29.6%). The weakest functionality was in emergency preparedness (0.8%; ie, emergency responses and exercises such as fire drills, spill cleanup, and biological spill kit availability). Also, many laboratories were deficient in metrology procedures, biosafety cabinets, chemical hazard containment, regular maintenance and external calibration procedures for laboratory equipment, and personnel health and safety. However, a few functionalities within individual laboratories scored above average (50%), for example, a university microbiology laboratory animal facility (100%). Interlaboratory comparison indicated that biosafety and biosecurity performance was similar across laboratories (P = .07) and did not vary by location (P = .37).

Conclusions: Significant biosafety and biosecurity improvements are needed to guarantee the health and safety of workers and the global community, efficient responses to infectious disease containment, and compliance with the Global Health Security Agenda.

Introduction: During pandemic situations like the one caused by the emergent coronavirus SARS-CoV-2, healthcare systems face the challenge of limited personal protective equipment and impaired supply chains. This problem poses a threat to healthcare workers, first responders, and the public, which demands solutions that can span the gap between institutional shortages and resupplies.

Objectives: To examine the efficacy of autoclave-based decontamination for the reuse of single-use surgical masks and N95 filtering facepiece respirators (FFRs). This method is the most readily available form of decontamination in the hospital and laboratory settings.

Methods: Three models of N95 FFRs and two procedural masks were evaluated in this study. A moist heat autoclave using four different autoclave cycles: 115°C for one hour, 121.1°C for 30 minutes, 130°C for two minutes, and 130°C for four minutes was used. After the autoclave process, the FFRs were NIOSH fit tested and particle counting was performed for both coarse particles of 5 micrometers (µM) and fine particles from 0.1µM to 1.0µM.

Results: We observed negligible alterations in the functionality and integrity of 3M 1805 and 3M 1870/1870+ N95 FFRs after three autoclave cycles. Surgical masks also showed minimal changes in functionality and integrity. The 3M 1860 FFR failed fit test after a single autoclave decontamination cycle.

Discussion and conclusion: The study finds that specific surgical masks and N95 FFR models can withstand autoclave decontamination for up to three cycles. Additionally, the autoclave cycles tested were those that could be readily achieved by both clinical and research institutions.