Applied Biosafety最新文献

Background: With increased rates of laboratory-acquired infections from clinical and research laboratories globally, efforts have been made to improve awareness of modern practices and pursue innovations in biosafety to manage risks and laboratory exposures arising from infectious agents and other hazards. Objectives: This article demonstrates a sustainable biosafety training model developed to enhance laboratory quality and support accreditation in health facilities in Kenya. Methods: A biosafety technical working group was formed, and sensitization meetings held with health managers. Trainings were then conducted for training of trainers (TOTs) who then cascaded trainings in health facilities. This was followed by mentorships and monitoring for implementation. Results: Five sensitization meetings were carried out for 264 health managers. TOTs was done for 48 trained trainers and 1044 laboratory workers in 216 facilities covering 44 counties. Site visits were done in 51 facilities, with biosafety achievements measured in 21 (41%), respectively. Achievements in 21 facilities included the following: improvised eye wash stations in 16 facilities (76%), biological spill kits in 17 (81%), buckets of sand in 15 (71%), fire extinguishers in 12 (57%), hepatitis B vaccination in 14 (66%), establishment of phlebotomy areas in 18 facilities (85%), material safety data sheets in 18 (85%), documentation of incidents and exposures in 16 (76%), and proper waste segregation in 17 (81%). Conclusion: This model ensured rapid scale-up to multiple counties and enabled learners to understand biosafety principles. Due to management buy-in, resources were availed to implement interventions, and this was demonstrated by remarkable achievements across all assessed facilities.

Introduction: Before 2016, there were no specific regulations or guidelines for the management of biological select agents and toxins (BSATs) in Taiwan. The Taiwan Centers for Disease Control responded to the global health security agenda in 2016 and made use of the Joint External Evaluation tool: International Health Regulations to evaluate Taiwan's epidemic prevention system capacities, including BSAT management. For technical areas that did not meet the highest requirements, the regulations and guidelines are now in place to strengthen the management of BSATs. Methods: In 2017, a survey on the BSAT entities management status in Taiwan was conducted to understand the gap between BSAT practice and international policies, and to improve BSAT management based on the findings. Results and Discussion: After 3 years of promotion, relevant management regulations and supervision mechanisms have been established. In 2021, the evaluation will be conducted again and it is expected that Taiwan's BSAT management capacity will reach the level of international biosafety and biosecurity.

Introduction: This study investigated formaldehyde decontamination efficacy against dried Bacillus spores on porous and non-porous test surfaces, under various environmental conditions. This knowledge will help responders determine effective formaldehyde exposure parameters to decontaminate affected spaces following a biological agent release.

Methods: Prescribed masses of paraformaldehyde or formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor within a bench-scale test chamber. Adsorbent cartridges were used to measure formaldehyde vapor concentrations in the chamber at pre-determined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. Spores of Bacillus globigii, Bacillus thuringiensis, and Bacillus anthracis were inoculated and dried onto porous bare pine wood and non-porous painted concrete material coupons. A series of tests was conducted where temperature, relative humidity, and formaldehyde concentration were varied, to determine treatment efficacy outside of conditions where this decontaminant is well-characterized (laboratory temperature and humidity and 12 mg/L theoretical formaldehyde vapor concentration) to predict decontamination efficacy in applications that may arise following a biological incident.

Results: Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations collected in the ambient temperature trials (approximately 22°C). Generally, decontamination efficacy on wood was lower for all three spore types compared with painted concrete. Also, higher recoveries resulted from painted concrete compared to wood, consistent with historical data on these materials. The highest decontamination efficacies were observed on the spores subjected to the longest exposures (48 hours) on both materials, with efficacies that gradually decreased with shorter exposures. Adsorption or absorption of the formaldehyde vapor may have been a factor, especially during the low temperature trials, resulting in less available formaldehyde in the air when measured.

Conclusion: Environmental conditions affect formaldehyde concentrations in the air and thereby affect decontamination efficacy. Efficacy is also impacted by the material with which the contaminants are in contact.

Introduction: Ionized hydrogen peroxide (iHP) is a new technology used for the decontamination of surfaces or laboratory areas. It utilizes a low concentration of hydrogen peroxide (H₂O₂) mixed with air and ionized through a cold plasma arc. This technology generates reactive oxygen species as a means of decontamination. Objectives: The purpose of this study is to review the effects of iHP on the structure of the spores of Bacillus atrophaeus by observing its effects using transmission electron microscopy (TEM) and also by evaluating the existence of DNA damage by fluorescence-based quantitative polymerase chain reaction (qPCR). Methods: Spore samples of B. atrophaeus decontaminated using iHP at different exposure times (Control, 1, 2, 6, and 12 h) were fixed for TEM. In addition, DNA was extracted for evaluation of DNA damages using fluorescence-based qPCR assays. Results: Damages to the spore structures of B. atrophaeus caused by the decontamination process with iHP at different exposure times (Control, 1, 2, 6, and 12 h) can be observed in micrographs. The effects of the decontamination to short DNA segment (132 base pairs [bp]) of the yaaH gene using qPCR present a linear degradation, and for the long DNA segment (680 bp), it presents a biphasic mode. Conclusion: The results of the qPCR analysis show two initial stages of damage to DNA with very noticeable damage at 12 h contact time, which confirms the observations of the TEM micrographs for the B. atrophaeus spores. The study demonstrates damage to the spore core DNA.

Introduction: During a pandemic, when the supply of N95 filtering facepiece respirators (FFRs) is limited, health care workers may reuse N95 FFRs. Room temperature storage of N95 FFRs-waiting before reuse-could be a simple low-cost method to reduce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) bioburden in such a situation. The U.S. Centers for Disease Control and Prevention specify this as a strategy for reducing self-contamination risk during a time of N95 FFR shortage. Objective: To review the literature on persistence of SARS-CoV-2 on surfaces to assess room temperature waiting times for bioburden reduction on N95 FFRs. Methods: The literature was searched for studies evaluating room temperature persistence of SARS-CoV-2. A 3-log decay time was extracted from published data for quantitative comparison between different studies. Studies using surgical masks and non-peer-reviewed studies that include N95 FFRs were used to draw conclusions. Key Findings: Experimental and analytical choices vary between studies and impact the estimated 3-log decay time. There is not a clear understanding of which material properties are significant. There are no peer-reviewed studies of virus persistence on an N95 FFR. Discussion and Conclusions: SARS-COV-2 inactivation occurs spontaneously at room temperature. The precise timing depends on factors including humidity, temperature, and surface material. In reviewed studies, a 7-day waiting period encompasses the 3-log reduction in infectious titer of SARS-COV-2 on specific N95 FFRs and surgical masks. Owing to variations between studies and among N95 FFR materials and room temperature conditions, it is impossible to extrapolate from these limited data to assign a precise 3-log decay time for all used N95 FFRs.

Introduction: During a pandemic, when the supply of N95 filtering facepiece respirators (FFRs) is limited, FFRs may be decontaminated by methods that inactivate pathogens as long as they do not damage FFR function. Hydrogen peroxide (H₂O₂) is widely used for decontamination in medical settings. Objective: To review the literature on the use of H₂O₂ to decontaminate N95 FFRs and identify methods that inactivate virus and preserve FFR filtration efficiency and fit. Methods: The literature was searched for studies evaluating H₂O₂ decontamination methods on inactivating SARS-CoV-2 and other viruses and microorganisms inoculated on N95 FFRs and the effects on respirator filtration efficiency and fit. Current U.S. Federal guidelines are also presented. Results: Findings from relevant laboratory studies (N = 24) are summarized in tables. Commercially available H₂O₂ decontamination systems differ on how H₂O₂ is delivered, the temperature, the duration of treatment, and other factors that can impact N95 FFR filtration efficiency and fit. Some methods inactivate SARS-CoV-2 virus-contaminated N95 FFRs with >3 log attenuation, whereas other methods are yet to be evaluated. Discussion and Conclusion: Most of the H₂O₂ methods reviewed effectively decontaminate N95 FFRs without damaging FFR function. However, some methods adversely impact N95 fit or filtration efficiency, which could go undetected by the end user and compromise their protection from pathogen inhalation. When making decisions about H₂O₂ decontamination of respirators, it is important to understand differences in methods, effects on different FFR models, and potential hazards to workers who manage the decontamination process.

Background: The SARS-CoV-2 pandemic put the entire healthcare sector under severe strain due to shortages of personal protection equipment. A large number of new filtering mask models were introduced on the market, claiming effectiveness that had undergone little or no objective and reliable verifications. Methods and Materials: Filter materials were tested against sodium chloride particles according to the EN149 §7.9.2 standard for particle penetration. Particle counters were used to measure the particle penetration of the filtering mask models, resolved over sizes in the range of 27-1000 nm. Results: We report on the results for 86 different filtering mask models. The majority of the tested models showed <3% penetration, whereas almost one third (i.e., 27 of 86) of the models performed poorly. Discussion: Interestingly, the poorest performing masks showed a tendency to have worse filtering effectiveness for larger particles than for smaller sized particles, following the opposite tendency of the best filtering masks. Conclusion: Almost one third of the filtering mask models tested failed the specified pass criteria as specified in the temporary EU COVID-19 standard. This fact, and the high health risks of COVID-19, highlights the need for independent testing.

Introduction: This effort investigated formaldehyde vapor characteristics under various environmental conditions by the analyses of air samples collected over a time-course. This knowledge will help responders achieve desired formaldehyde exposure parameters for decontamination of affected spaces after a biological contamination incident.

Methods: Prescribed masses of paraformaldehyde and formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor. Adsorbent cartridges were used to collect air samples from the test chamber at predetermined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. In addition, material demand for the formaldehyde was evaluated by inclusion of arrays of Plexiglas panels in the test chamber to determine the impact of varied surface areas within the test chamber. Temperature was controlled with a circulating water bath connected to a radiator and fan inside the chamber. Relative humidity was controlled with humidity fixed-point salt solutions and water vapor generated from evaporated water.

Results: Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations in the ambient temperature trials (approximately 22°C). The addition of clear Plexiglas panels to increase the surface area of the test chamber interior resulted in appreciable decreases of formaldehyde air concentration when compared to an empty test chamber.

Conclusion: This work has shown that environmental variables and surface-to-volume ratios in the decontaminated space may affect the availability of formaldehyde in the air and, therefore, may affect decontamination effectiveness.