A gap exists between good laboratory practises with axenic animals and procedures applied. This work aimed at choosing the appropriate disinfectant between sodium dichloroisocyanurate (MB-10) and potassium peroxymonosulfate (Virkon<sup>™</sup>) disinfectants and to adjust the soaking time of the material used with ISOcage biosafety stations. Another aim was to compare the microbial load on cage systems hosting mice since two weeks in axenic (AR) rooms and typical specific-pathogen-free (SPF) non-axenic rooms (NAR) to identify resistant microorganisms targeted for longer soaking disinfection as well as evaluate microbial concentration reduction procedures in AR. <i>Staphylococcus</i> was the most frequently isolated genus (AR and NAR). An average of three spore-forming microorganisms per cage were counted from AR. The disinfection time to reach 1 log reduction for <i>Bacillus atrophaeus</i> spores varied from 138 (100 ppm MB-10) to 290 (Virkon<sup>™</sup>) seconds and below 20 seconds for <i>S. epidermidis</i> (100 ppm MB-10). AR management protocols lead to 1000 times lower microorganisms burden compared to NAR. Data comparing microbial load on SPF and axenic facilities can be used as comparison for facilities aiming at improving the effectiveness of their microbial control procedures.
The use of axenic animal models in experimental research has exponentially grown in the past few years and the most reliable way for confirming their axenic status remains unclear. It is especially the case when using individual ventilated positive-pressure cages such as the Isocage. This type of cage are at a greater risk of contamination and expose animals to a longer handling process leading to more potential stress when opened compared to isolators. The aim of this study was to propose simple ways to detect microbial contaminants with Isocages type isolator resulting by developing, validating and optimizing three different methods (culture, microscopy, and molecular). These three approaches were also tested in situ by spiking 21 axenic mice with different microorganisms. Our results suggest that the culture method can be used for feces and surface station (IBS) swabs exclusively (in Brain Heart Infusion for 7 days at 25°C and 37°C in aerobic conditions, and at 30°C in anaerobic conditions), while microscopy (wet mounts) and molecular method (quantitative PCR) were only suitable for fecal matter analyses. In situ results suggests that the culture and molecular methods can detect up to 100% of bacterial contamination events while the microscopy approach generates many erroneous results when not performed by a skilled microscopist. In situ results also suggest that when an axenic mouse is contaminated by a microbial agent, the microorganism will colonize the mouse to such an extent that detection is obvious in 4 days, in average. This report validates simple but complimentary tests that can be used for optimal detection of contaminants in axenic animal facilities using Isocage type isolators.
Objective
While facing personal protective equipment (PPE) shortages during the COVID-19 pandemic, several institutions looked to PPE decontamination and reuse options. This study documents the effect of two hydrogen peroxide treatments on filtration efficiency and fit tests as well as the side effects for volunteers after the decontamination of N95 filtering facepiece respirators (FFRs). We also propose an efficient and large-scale treatment protocol that allows for the traceability of this protective equipment in hospitals during PPE shortages.
Methods
The effects of low-temperature hydrogen peroxide sterilization and hydrogen peroxide vapor (HPV) on two FFR models (filtration, decontamination level, residual emanation) were evaluated. Ten volunteers reported comfort issues and side effects after wearing 1h FFRs worn and decontaminated up to five times.
Results
The decontamination process does not negatively affect FFR efficiency, but repeated use and handling tend to lead to damage, limiting the number of times FFRs can be reused. Moreover, the recommended 24-h post-treatment aeration does not sufficiently eliminate residual hydrogen peroxide. Prolonged aeration time increased user comfort when using decontaminated FFRs.
Conclusions
HPV and low-temperature hydrogen peroxide sterilization seem to be appropriate treatments for FFR decontamination when the PPE is reused by the same user. PPE decontamination and reuse methods should be carefully considered as they are critical for the comfort and safety of healthcare workers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.