Decontamination assessment of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surfaces using a hydrogen peroxide gas generator

AIMS: To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. METHODS AND RESULTS: Bacillus anthracis, B. subtilis, and G. stearothermophilus spores were dried on seven types of indoor surfaces and exposed to > or =1000 ppm hydrogen peroxide gas for 20 min. Hydrogen peroxide exposure significantly decreased viable B. anthracis, B. subtilis, and G. stearothermophilus spores on all test materials except G. stearothermophilus on industrial carpet. Significant differences were observed when comparing the reduction in viable spores of B. anthracis with both surrogates. The effectiveness of gaseous hydrogen peroxide on the growth of biological indicators and spore strips was evaluated in parallel as a qualitative assessment of decontamination. At 1 and 7 days postexposure, decontaminated biological indicators and spore strips exhibited no growth, while the nondecontaminated samples displayed growth. CONCLUSIONS: Significant differences in decontamination efficacy of hydrogen peroxide gas on porous and nonporous surfaces were observed when comparing the mean log reduction in B. anthracis spores with B. subtilis and G. stearothermophilus spores. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide comparative information for the decontamination of B. anthracis spores with surrogates on indoor surfaces using hydrogen peroxide gas.     

Evaluation of DNA extraction methods for Bacillus anthracis spores isolated from spiked food samples

Aims

Nine commercial DNA extraction kits were evaluated for the isolation of DNA from 10‐fold serial dilutions of Bacillus anthracis spores using quantitative real‐time PCR (qPCR). The three kits determined by qPCR to yield the most sensitive and consistent detection (Epicenter MasterPure Gram Positive; MoBio PowerFood; ABI PrepSeq) were subsequently tested for their ability to isolate DNA from trace amounts of B. anthracis spores (approx. 6·5 × 10¹ and 1·3 × 10² CFU in 25 ml or 50 g of food sample) spiked into complex food samples including apple juice, ham, whole milk and bagged salad and recovered with immunomagnetic separation (IMS).

Methods and Results

The MasterPure kit effectively and consistently isolated DNA from low amounts of B. anthracis spores captured from food samples. Detection was achieved from apple juice, ham, whole milk and bagged salad from as few as 65 ± 14, 68 ± 8, 66 ± 4 and 52 ± 16 CFU, respectively, and IMS samples were demonstrated to be free of PCR inhibitors.

Conclusions

Detection of B. anthracis spores isolated from food by IMS differs substantially between commercial DNA extraction kits; however, sensitive results can be obtained with the MasterPure Gram Positive kit.

Significance and Impact of the Study

The extraction protocol identified herein combined with IMS is novel for B. anthracis and allows detection of low levels of B. anthracis spores from contaminated food samples.     

Use of superabsorbent polymer gels for surface decontamination of Bacillus anthracis spores

Aims:  This study evaluated the inactivation of Bacillus anthracis Vollum spores dried on a nonporous surface using a superabsorbent polymer (SAP) gel containing commercially available liquid decontaminants.
Methods and Results:  The first phase determining the availability of the liquid decontaminant within the SAP showed that the SAP gel containing pH-adjusted sodium hypochlorite (NaOCl) inhibited B. anthracis growth while the water control SAP gel had no affect on growth. For testing surface decontamination, B. anthracis spores were dried onto steel coupons painted with chemical agent resistant coating and exposed to SAP containing either pH-adjusted NaOCl, chlorine dioxide (ClO₂) or hydrogen peroxide/peracetic acid (H₂O₂/PA) for 5 and 30 min. At contact times of both 5 and 30 min, all of the SAP gels containing pH-adjusted NaOCl, ClO₂ or H₂O₂/PA inactivated B. anthracis spores at levels ranging from 2·2 to ≥7·6 log reductions.
Conclusions:  Incorporation of three commercially available decontaminant technologies into a SAP gel promotes inactivation of B. anthracis spores without observable physical damage to the test surface.
Significance and Impact of the Study:  This work provides preliminary data for the feasibility of using SAP in inactivating B. anthracis spores on a nonporous surface, supporting the potential use of SAP in surface decontamination.     

A preliminary assessment of Bacillus anthracis spore inactivation using an electrochemically activated solution (ECASOL)

AIM: To evaluate the efficacy of electrochemically activated solution (ECASOL) in decontaminating Bacillus anthracis Ames and Vollum 1B spores, with and without changing the source water hardness and final ECASOL pH. METHODS AND RESULTS: Five different ECASOL formulations were generated, in which the source water hardness and final ECASOL pH were varied, resulting in cases where significant changes in free available chlorine (FAC) and oxidative-reduction potential (ORP) were observed. B. anthracis Ames and Vollum 1B spores were suspended in the various ECASOL formulations for 30 min, and decontamination efficacy was determined; calcium hypochlorite [5% high-test hypochlorite (HTH)] was used as a positive control. The five different ECASOL formulations yielded mean FAC levels ranging from 305 to 464 ppm, and mean ORP levels ranging from +826 to +1000 mV. Exposure to all the ECASOL formulations and 5% HTH resulted in >or=7.0 log reductions in both B. anthracis Ames and Vollum 1B spores. CONCLUSIONS: The present testing demonstrated that ECASOL with a minimum of c. 300-ppm FAC levels and +800-mV ORP inactivated the B. anthracis spores in suspension, similar to 5% HTH. Significance and Impact of the Study: These results provide information for decontaminating B. anthracis Ames and Vollum 1B spores in suspension using ECASOL.     

Terminal sterilization of medical devices using vaporized hydrogen peroxide: a review of current methods and emerging opportunities

Medical devices are an important and growing aspect of healthcare provision and are increasing in complexity to meet established and emerging patient needs. Terminal sterilization plays a vital role in the provision of safe medical devices. While terminal sterilization technologies for medical devices include multiple radiation options, ethylene oxide remains the predominant nonthermal gaseous option, sterilizing c. 50% of all manufactured devices. Vaporized hydrogen peroxide (abbreviated VH2O2 by the International Organization for Standardization) is currently deployed for clinical sterilization applications, where its performance characteristics appear aligned to requirements, constituting a viable alternative low-temperature process for terminal processing of medical devices. However, VH2O2 has operational limitations that create technical challenges for industrial-scale adoption. This timely review provides a succinct overview of VH2O2 in gaseous sterilization and addresses its applicability for terminal sterilization of medical devices. It also describes underappreciated factors such as the occurrence of nonlinear microbial inactivation kinetic plots that may dictate a need to develop a new standard approach to validate VH2O2 for terminal sterilization of medical devices.     

Hazard Group 3 agent decontamination using hydrogen peroxide vapour in a class III microbiological safety cabinet

Probiotics administration in aquafeed is known to increase feed consumption and absorption due to their capacity to release a wide range of digestive enzymes and nutrients which can participate in digestion process and feed utilization, along with the absorption of diet components led to an increase in host’s health and well-being. Furthermore, probiotics improve gut maturation, prevention of intestinal disorders, predigestion of antinutrient factors found in the feed ingredients, gut microbiota, disease resistance against pathogens and metabolism. The beneficial immune effects of probiotics are well established in finfish. However, in comparison, similar studies are less abundant in the shellfish. In this review, the discussions will mainly focus on studies reported the last 2 years. In recent studies, native probiotic bacteria were isolated and fed back to their hosts. Although beneficial effects were demonstrated, some studies showed adverse effects when treated with a high concentration. This adverse effect may be due to the imbalance of the gut microbiota caused by the replenished commensal probiotics. Probiotics revealed greatest effect on the shrimp digestive system particularly in the larval and early post-larval stages, and stimulate the production of endogenous enzymes in shrimp and contribute with improved the enzyme activities in the gut, as well as disease resistance.     

Evaluation of hydrogen peroxide vapour as a method for the decontamination of surfaces contaminated with Clostridium botulinum spores

The aim of this study was to evaluate the efficacy of hydrogen peroxide vapour (HPV) against spores of Clostridium botulinum, for use as a method for decontaminating environments where this pathogen has been handled. Spores were dried onto stainless steel slides and exposed to HPV in a sealed glovebox enclosure, transferred to a quenching agent at timed intervals during the exposure period, before survivors were cultured and enumerated. D-values were calculated from graphs of log₁₀ survivors plotted against time and were found to range from 1.41 to 4.38 min. HPV was found to be effective at deactivating spores of toxigenic Cl. botulinum, non-toxigenic Clostridium spp. and Geobacillus stearothermophilus dried onto stainless steel surfaces. HPV could be used to decontaminate cabinets and rooms where Cl. botulinum has been handled. The cycle parameters should be based on studies carried out with relevant spores of this organism, rather than based on inactivation data for G. stearothermophilus spores, which have been used in the past as a standard biological challenge for disinfection and sterilisation procedures. HPV could provide an attractive alternative to other decontamination methods, as it was rapid, residue-free and did not give rise to the health and safety concerns associated with other gaseous decontamination systems.