Inactivation of murine norovirus by chemical biocides on stainless steel

<p>Abstract</p> <p>Background</p> <p>Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces.</p> <p>Methods</p> <p>The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells.</p> <p>Results</p> <p>PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by ≥ 4 log₁₀within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes).</p> <p>Conclusion</p> <p>Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces.</p

Exploring the Function of Alcohol Dehydrogenases During the Endophytic Life of Azoarcus Sp Strain BH72

International audienceThe endophytic bacterium Azoarcus sp. strain BH72 is capable of colonizing the interior of rice roots, where it finds suitable physicochemical properties for multiplying and fixing nitrogen. Because these properties are poorly understood, a microtiter-plate-based screening of a transcriptional gfp (green fluorescent protein) fusion library of Azoarcus sp. grown under different conditions was performed. Monitoring of the GFP activity allowed the identification of a gene highly expressed in medium supplemented with ethanol. Sequence analysis revealed that this gene encodes a pyrrolo-quinoline quinone-dependent alcohol dehydrogenase (ADH). Inspection of the complete genome sequence of the Azoarcus sp. strain BH72 identified seven additional genes encoding putative ADH, indicating that BH72 is well equipped to survive in different environmental conditions offering various alcohols as carbon source. Analyses of these eight putative ADH showed that expression of three was induced by ethanol, of which two were also expressed inside rice roots. The fact that waterlogged plants such as rice accumulate ethanol suggests that ethanol occurs in sufficiently high concentration within the root to induce expression of bacterial ADH. Disruption of these two ADH evoked a reduced competitiveness to the wild type in colonizing rice roots internally. Thus, it is likely that ethanol is an important carbon source for the endophytic life of Azoarcus sp

Virucidal efficacy of a sonicated hydrogen peroxide system (trophon EPR) following European and German test methods.

The virucidal efficacy of an automated ultrasound probe disinfector (trophon® EPR) was evaluated in a three step procedure according to European and German test methods. This system uses sonicated hydrogen peroxide mist (35%) at elevated temperature (50°C) in a closed chamber with control of all parameters within a 7 minute cycle. Methods: In the first step of examination, the peroxide solution was tested in a quantitative suspension assay according to the Guideline of Deutsche Vereinigung zur Bekämpfung der Viruskrankheiten (DVV) e.V. and Robert Koch-Institute (RKI) and in parallel with the European Norm EN 14476 with all test viruses creating a virucidal claim. In the second step, the virucidal efficacy of the hydrogen peroxide solution was evaluated in a hard surface carrier test according to the Guideline of DVV with adenovirus, murine norovirus and parvovirus simulating practical conditions. Finally, the efficacy was evaluated by the automated system using stainless steel carriers inoculated with test virus and positioned at different levels inside the chamber

Virucidal efficacy of peracetic acid for instrument disinfection

Abstract Background Various peracetic-acid (PAA)-based products for processing flexible endoscopes on the market are often based on a two-component system including a cleaning step before the addition of PAA as disinfectant. The peracetic acid concentrations in these formulations from different manufacturers are ranging from 400 to 1500 ppm (part per million). These products are used at temperatures between 20 °C and 37 °C. Since information on the virus-inactivating properties of peracetic acid at different concentrations and temperature is missing, it was the aim of the study to evaluate peracetic acid solutions against test viruses using the quantitative suspension test, EN 14476. In addition, further studies were performed with the recently established European pre norm (prEN 17111:2017) describing a carrier assay for simulating practical conditions using frosted glass. Methods In the first step of examination, different PAA solutions between 400 and 1500 ppm were tested at 20 °C, 25 °C, and 35 °C with three test viruses (adenovirus, murine norovirus and poliovirus) necessary for creating a virucidal action according to the European Norm, EN 14476. A second step for simulating practical conditions based on prEN 17111:2017 followed by spreading a test virus together with soil load onto a glass carrier which was immerged into a peracetic acid solution. A fixed exposure time of five minutes was used in all experiments. Results In the quantitative suspension test 1500 ppm PAA solution was needed at 35 °C for five minutes for the inactivation of poliovirus, whereas only 400 ppm at 20 °C for adeno- and murine norovirus were necessary. In the carrier assay 400 ppm peracetic acid at 20 °C were sufficient for adenovirus inactivation, whereas 600 ppm PAA were needed at 25 °C and 35 °C and 1000 ppm at 20 °C for murine norovirus. A PAA solution with 1000 ppm at 35 °C was required for complete inactivation of poliovirus. However, a dramatically decrease of titer after the drying and immerging could be observed. In consequence, a four log reduction of poliovirus titer could not be achieved in the carrier test. Conclusion In summary, 1500 ppm PAA at 35 °C was necessary for a virucidal action in the quantitative suspension test. After passing the requirements of the suspension test, additional examinations with adeno- and murine norovirus on glass carriers based on prEN 17111:2017 will not additionally contribute to the final claim of an instrument disinfectant for virucidal efficacy. This is due to the great stability of poliovirus in the preceded quantitative suspension test and the fact that poliovirus could not serve as test virus in the following carrier assay

Development and virucidal activity of a novel alcohol-based hand disinfectant supplemented with urea and citric acid.

Hand disinfectants are important for the prevention of virus transmission in the health care system and environment. The development of broad antiviral spectrum hand disinfectants with activity against enveloped and non-enveloped viruses is limited due to a small number of permissible active ingredients able to inactivate viruses