Disinfection efficiency of positive pressure respiratory protective hood using fumigation sterilization cabinet

Concerns have been raised about both the disinfection and the reusability of respiratory protective equipment following a disinfection process.Currently,there is little data available on the effects of disinfection and decontamination on positive pressure respiratory protective hoods(PPRPH).In this study,we evaluated the effect of vaporized hydrogen peroxide(VHP)on the disinfection of PPRPH to determine applicability of this method for disinfection of protective equipment,especially protective equipment with an electric supply system.A hydrogen peroxide-based fumigation sterilization cabinet was developed particularly for disinfection of protective equipment,and the disinfection experiments were conducted using four PPRPHs hung in the fumigation chamber.The pathogenic microorganism Geobacillus stearothermophilus ATCC 7953 was used as a biological indicator in this study and the relationship between air flow(the amount of VHP)and disinfection was investigated.Both function and the material physical properties of the PPRPH were assessed following the disinfection procedure.No surviving Geobacillus stearothermophilus ATCC 7953,both inside and outside of these disinfected PPRPHs,could be observed after a 60 min treatment with an air flow of 10.5–12.3 m^(3)/h.Both function and material physical properties of these PPRPHs met the working requirements after disinfection.This study indicates that air flow in the fumigation chamber directly influences the concentration of VHP.The protective equipment fumigation sterilization cabinet developed in this paper achieves the complete sterilization of the PPRPHs when the air flow is at 10.5–12.3 m^(3)/h,and provides a potential solution for the disinfection of various kind of protective equipment.

Development of a negative pressure hood for isolation and transportation of individual patient with respiratory infectious disease

The frequent and sudden occurrence of both known and unknown infectious diseases can cause global social panic.If the source of infection can be effectively controlled in the early stages of an outbreak,the spread of infectious diseases can be prevented.In view of this situation,this study developed for infectious or suspected infectious patients a negative pressure isolation hood which effectively achieves direct individual isolation during the early stages of disease outbreak,and facilitates long-distance transport.The hood body is made of flexible transparent polyvinyl chloride(PVC)material,and the combination of the hood material is airtight.The unique inflatable column support structure and the design of the inflatable neck sleeve effectively ensure both stiffness and air tightness of the hood body.The electrical exhaust system maintains a stable negative pressure environment inside the hood,and polluted air inside the hood can be purified by a high efficiency filter.Test results showed that the internal noise of the hood was 68±1 dB(A),the air exhaust volume of the electric exhaust system was not<200 L/min,and the filtration efficiency of the filter to 0.3μm particles was>99.99%,indicating that the hood achieved effective isolation protection for patients with respiration infectious diseases.

Research and development of airtight biosafety containment facility for stainless steel structures

Objective:Airtightness of containment structures of a high-level biosafety laboratory is a critical parameter for preventing leakage of harmful bioaerosols.The aim of this study is to investigate the sealing technology of stainless steel structural airtight biosafety containment facilities.Methods:An experimental study was conducted on a domestic high-level pathogenic microorganism model laboratory,considering the sealing process of the containment structure,including airtight doors,pass boxes,dunk tanks,through-wall pipeline sealing devices,and sealed floor drains.Results:The results indicate that the airtightness of the model laboratory containment structure meets the tightness requirements of a biosafety level-4(BSL-4)laboratory.They also indicate that the construction technology of stainless steel enclosure structures used by the laboratory and the tightness performance and installation process of the developed airtight protective equipment meet the technical requirements of a BSL-4 laboratory.Conclusions:This successful model laboratory indicates that China has the research and development capacity for stainless steel airtight containment structure manufacturing processes,airtight protective equipment,and technical capacity for independent construction of the highest-level pathogenic microorganism laboratories.

Rapid and accurate evaluation of vaporized hydrogen peroxide on the efficiency of disinfection, using a sensitive dual-channel laser scanning cytometer

Vaporized hydrogen peroxide(VHP)is a highly active disinfectant,and VHP decontamination systems have been widely applied in hospitals,microbiological laboratories,and pharmaceutical industries.However,the decomposition of VHP into non-toxic by-products is essential.Evaluation of the disinfection efficacy of VHP is crucial to ensuring the reliability of VHP disinfection and controlling microbial contamination.In this study,a rapid and sensitive strategy is proposed to evaluate the efficacy of VHP in surface disinfection by detecting the survived and killed bacteria from VHP-exposed biological indicators(BIs).A dual-channel solid-phase cytometer is designed,and fluorescent dyes are used as indicators to automatically and accurately distinguish live cells from dead cells in themixtures of bacteria.To verify the availability and effectiveness of the laser scanning cytometry,experiments on its application in estimating the efficacy of VHP disinfection practice have been carried out in this study,and its estimation effect compared with that of the traditional plate counting method.Results show that the proposed assay might distinctly identify live or killed cells labeled by green and red fluorescent dyes and examined the disinfection efficacy in 30 min by calculating the bactericidal rate.Compared with the plate counting method,the proposed approach is accurate and practical,with an average detection efficiency of 98.47%±1.55%.Moreover,an excellent correlation between the concentrations of B.subtilis var niger(ATCC 9372)measured by the proposed detection system and by the plate counting method is noticed(R2=0.9971),indicating that this approach had advantages in the detection of trace microorganisms.To summarize,the proposed strategy appears practical and significant in many fields in which microbial counting and identification are required.