According to Pharmacopoea Nordica, steam autoclaves should be regularly monitored by a specific Swedish preparation of Bacillus stearothermophilus spores. If another biological indicator (BI) is used for such a control, it should first be calibrated against the Swedish BI (SBI) and the two BIs should be equally thermoresistant. Attest No. 1262 BI (ABI) has previously been shown to be more thermoresistant than the SBI at 134 degrees C, saturated steam. The purpose of the present study was to compare the thermoresistance of the SBI and the ABI at 121 degrees C, saturated steam and prevacuum. Seven hundred and twenty units of each BI were heat-exposed in an Emmer 760 litre prevacuum, pressure-pulsing steam autoclave.
After prevacuum with steam injection (manual or automatic preconditioning), the following incremental heat exposure times were used in triplicate (20 simultaneously tested units of each BI in each cycle) according to a randomized scheme: 5, 6 1/2, 8, 9 1/2, 11, 12 1/2, 14 and 15 min. The intra-chamber pressure and temperature were continuously monitored throughout the test and equilibration cycles.
The heat-exposed BI units were cultivated and read as recommended by the manufacturers. SBI and ABI showed a survival-time of 8 min and 11 min respectively, and a kill-time between 14 min and 15 min for both BIs. Thus, the ABI had the narrower survival-kill window
. Probit analysis testing of the results showed that the difference in thermoresistance, at 121 degrees C, saturated steam and https://biodas.org/
prevacuum between Attest No. 1262 BI and the Swedish BI mentioned in Pharmacopea Nordica was not statistically significant.
Comparative thermoresistance of two biological indicators for monitoring steam autoclaves. 2. Comparison performed at 134 degrees C in a hospital prevacuum steam sterilizer
The thermoresistance of various lots of two biological indicators (BIs) for steam sterilization control, a Scandinavian BI (SBI) and the Attest BI (ABI), were compared during sterilization cycles in a hospital prevacuum (pressure-pulsing) steam autoclave at 134 degrees C, saturated steam. ABI No. 1242, ABI No. 1262 (its replacement) and incremental heat exposure times between 0 s and 180 s were used. The intrachamber temperature and pressure were continuously measured and monitored throughout the sterilization cycles.
The results showed that both of the ABIs were more thermoresistant than the SBI, giving 33.1% (ABI No. 1242), 18.9% (ABI No. 1262), and 0% (SBI) autoclave survivors. Because the time needed to reach 134 degrees C (preconditioning time) increased as the day progressed, and varied from day to day, correlation between individual incremental heat exposure times and the number of surviving BI units was not possible. Standardized test conditions are necessary for a true comparison of BIs.
Ozone: A Novel Sterilizer for Personal Protective Equipment
Objective: Personal protective equipment (PPE) is urgently sought during public health crises. It is necessary for the safety of both the patient and the healthcare professional. Yet during the recent COVID-19 pandemic, PPE scarcity in many countries, including the United States, has impacted the level of care for patients and the safety of healthcare personnel. Additionally, the implementation of mandatory mask mandates for the general public in many countries forced individuals to either reuse PPE, which can contribute to poor hygiene, or buy PPE in bulk and thereby contribute to the scarcity of PPE. In this study, we investigate the possibility of using a cost-effective ozone sterilization unit on contaminated N95 masks as an alternative to current sterilization methods.
Method: This protocol examined ozone’s ability to decontaminate N95 mask fabric that was exposed to a surrogate virus (Escherichia coli bacteriophage MS2). Once the sterilization unit achieves an ozone concentration of ~30 ppm, a 60-minute or 120-minute sterilization cycle commences. Following the sterilization cycle, we investigated the amount of viable virus on the slide using a viral plaque assay and compared it to a non-sterilized, control slide. Furthermore, we carried out trials to investigate the safety of an ozone sterilization device, by measuring the levels of ozone exposure that individuals may experience when operating the sterilization unit post-cycle.
Results: We showed that a 120-minute sterilization cycle at ~30 ppm achieves a 3-log reduction in viral activity, thereby complying with industry and U.S. Food and Drug Administration (FDA) standards. Further, we demonstrated that when following our protocol, the ozone exposure levels for a simple sterilization unit to be used at home complied with federal and industry standards.
Conclusion: Ozone may have the potential to decontaminate masks and other PPE.
Monitoring the Effective Sterilization of Low-Temperature Hydrogen Peroxide Gas Plasma Sterilizers in 58 Hospitals – 22 PLADs, China, June 2015-December 2019
What is already known on this topic?: Hydrogen peroxide sterilizeation is widely used for luminal devices. However, the low penetrability of the sterilant is of major concern.
What is added by this report?: This report investigated the effective sterilization of low-temperature hydrogen peroxide gas plasma sterilizers and compared the applicability of different biological monitoring methods based on medical luminal devices.
What are the implications for public health practice?: It is recommended to use a biological process challenge device for monitoring the sterilization of luminal devices with low-temperature hydrogen peroxide gas plasma sterilizers.
Portable sterilizer with microbe content detection device
- Background: Infectious diseases, such as the latest COVID pandemic, caused by microorganisms like bacteria and virus, wreak havoc shaking human civilization with its rapid infection rate, and high number of mortalities. In case of a contagious disease, the virus can survive on any surface over a period of time and can be transferred to the human host through touching those surfaces unknowingly. Cleaning those possible surfaces to which these microorganisms can cling onto is one of the major ways to curb the spread. The aim of this study was to design a sterilizer which can clean such surfaces of daily used items easily within a certain period of time and can assess the cleaning efficacy by estimating the presence of microbes before and after sanitization.
- Method development: To achieve this goal, we propose a portable sterilization unit that contains a sterilization chamber fitted with a microbe content detector. The sterilization chamber will cleanse the surfaces off the microbes using ultraviolet radiation. The chamber can be portable and at the same time big enough to accommodate items of daily use, like watch, wallet, clothes, utensils to even foods for single-house application. The microbe content detector will detect the success of the sterilization procedure by examining the time-lapse laser speckle images captured by a high-speed camera by mean of image processing algorithm, such that the user can determine whether further sterilization is required.
- Conclusions: Microbe content detection device associated with the conventional sterilization procedure will give an assessment of the effectiveness of the sterilization. Successful implementation of sterilization for a wide variety of items of everyday use aided with microbe content detection technique is first of its kind and should be an effective tool for use in large communities, offices and public places for effective sterilization to help fight against the spread of infectious diseases.