Scalable in-hospital decontamination of N95 filtering face-piece respirator with a peracetic acid room disinfection system.

BACKGROUND: Critical shortages of personal protective equipment, especially N95 respirators, during the coronavirus disease 2019 (COVID-19) pandemic continues to be a source of concern. Novel methods of N95 filtering face-piece respirator decontamination that can be scaled-up for in-hospital use can help address this concern and keep healthcare workers (HCWs) safe. METHODS: A multidisciplinary pragmatic study was conducted to evaluate the use of an ultrasonic room high-level disinfection system (HLDS) that generates aerosolized peracetic acid (PAA) and hydrogen peroxide for decontamination of large numbers of N95 respirators. A cycle duration that consistently achieved disinfection of N95 respirators (defined as ≥6 log10 reductions in bacteriophage MS2 and Geobacillus stearothermophilus spores inoculated onto respirators) was identified. The treated masks were assessed for changes to their hydrophobicity, material structure, strap elasticity, and filtration efficiency. PAA and hydrogen peroxide off-gassing from treated masks were also assessed. RESULTS: The PAA room HLDS was effective for disinfection of bacteriophage MS2 and G. stearothermophilus spores on respirators in a 2,447 cubic-foot (69.6 cubic-meter) room with an aerosol deployment time of 16 minutes and a dwell time of 32 minutes. The total cycle time was 1 hour and 16 minutes. After 5 treatment cycles, no adverse effects were detected on filtration efficiency, structural integrity, or strap elasticity. There was no detectable off-gassing of PAA and hydrogen peroxide from the treated masks at 20 and 60 minutes after the disinfection cycle, respectively. CONCLUSION: The PAA room disinfection system provides a rapidly scalable solution for in-hospital decontamination of large numbers of N95 respirators during the COVID-19 pandemic.

Evaluation of Low-Temperature Sterilization using Hydrogen Peroxide Gas Containing Peracetic Acid.

In low-temperature sterilization for the medical field, hydrogen peroxide sterilization is widely used for its safety. However, its low penetrability and residual amount of sterilant are major concerns. Recently, the combination of hydrogen peroxide and peracetic acid has been found to enforce sporicidal effect, with low concentration in hydrogen peroxide. The application of this finding in medical sterilization is still very limited. To elucidate the combination effect, we compare peracetic acid containing hydrogen peroxide gas sterilizer and conventional hydrogen peroxide gas (plasma) sterilizers. The sterilant penetrability was examined in hollow load process challenge devices with inner diameters of 1 and 2 mm and lengths of 1, 2, and 3 m. As a result, peracetic acid containing hydrogen peroxide gas sterilizer demonstrated total inactivation with all diameters and lengths and achieved the highest sterilant penetrability in this study. The amount of residual sterilant on the surface of the sterilized object was 4.2 µg/cm2, which corresponds to half amount of those of conventional hydrogen peroxide gas sterilizers. These results suggest that the addition of peracetic acid to hydrogen peroxide gas sterilizer can enhance sterilization efficiency and safety.

Decellularization of submillimeter-diameter vascular scaffolds using peracetic acid.

Various decellularization methods for allogenic and xenogenic bioscaffolds have been previously reported; however, decellularization methods for very thin (submillimeter-diameter) vascular tissues have not been discussed well. In this study, rat tail arteries (inner diameter, 0.6 mm) were decellularized with peracetic acid (PAA) and DNase I. PAA treatment is expected not only to disrupt cell membranes which improves the decellularization efficiency in the subsequent DNase treatment, but also to sterilize vascular scaffolds. We succeeded in adequate cell removal by immersing in 0.3% isotonic PAA solution and subsequent washing with DNase solution. For the DNase washing process, the perfusion method was superior in terms of cell removal to the static immersion method. Graft lumen was modified with a peptide composed of a collagen binding sequence and endothelial progenitor cell-binding sequence, (Pro-Hyp-Gly)7-Gly-Gly-Gly-Arg-Glu-Asp-Val, as previously reported. They were patent in rat allogeneic transplantation model for 2 weeks, but unexpectedly resulted in graft rupture or tear formation, thereafter, suggesting reduced mechanical strength of the decellularized scaffolds. Histology showed that the thickness of the extracellular matrix (ECM) was decreased by the perfusion of the DNase solution. The method of combination of PAA and DNase was not necessarily optimal for the decellularization of very thin vascular tissues. The decellularization method is a compromise between effective cell removal and maintenance of the ECM nature. Since the acceptability of ECM denaturation by the host tissue highly depends on individual cases, decellularization methods should be carefully selected according to the type of target tissue and its intended use.

Ação de diferentes sanitizantes em biofilmes de Salmonella Minnesota / Action of different sanitizers in biofilmes of Salmonella Minnesota

Objetivou-se avaliar a eficiência do contato por 15 minutos do hipoclorito de sódio 1%, e ácido peracético 0,8% na inibição de biofilmes formad os por três cepas distintas de Salmonella Minnesota em aço, poliuretano e polipropileno e determinar a recuperação das células remanescentes. Qualitativamente houve influência na classificação dos biofilmes de acordo com a superfície, que foram diferentes dependendo do tipo de cepa e de material, porém a quantidade de células sésseis permanece constante, pois independente da cepa e da superfície, os biofilmes mantiveram uma contagem de 5,18 Log UFC, indicando que as diferenças referem-se à matriz polimérica. O uso do hipoclorito foi capaz de destruir as células, que não foram recuperadas após reincubação. Já o ácido peracético não promoveu redução significativa. O uso do hipoclorito de sódio 1% é eficiente na sua remoção.

Microbiological surveillance of flexible bronchoscopes after a high-level disinfection with peracetic acid: preliminary results from an Italian teaching hospital.

BACKGROUND: Flexible bronchoscopes are heat labile, complex and difficult to clean, and some nosocomial outbreaks related to bronchoscopy have been reported in literature. The aim of our study was to determine, through a systematic monitoring, whether bronchoscopes' cleaning and disinfection procedures have been correctly adopted by health operators. METHODS: We conducted a 19 months-long prospective study in the Unit of Pulmonology at Careggi Teaching Hospital (Florence, Italy), analyzing endoscopes that were reprocessed through a high-level disinfection procedure. Samples collection was performed weekly by two trained operators. Results were organized in a database and then exported for descriptive and inferential statistical analysis. RESULTS: From February 2016 to September 2017 we collected 218 samples from bronchoscopes' valves (N=109) and from their inner channels (N=109). Staphylococci were found in 34 samples (15.69% of all samples). Pseudomonas was found in 11 samples (5.04% of all samples). Pseudomonas aeruginosa wasn't found in any sample. CONCLUSIONS: Our results came out to be better than similar studies in literature and demonstrated that a correct endoscopes' hygiene should be part of a more complex strategy of surveillance and control of healthcare-associated infections. However, a continuous monitoring of endoscopes could provide a wider view about this problem, and more reliable results.

Cytotoxicity assessment of 1% peracetic acid, 2.5% sodium hypochlorite and 17% EDTA on FG11 and FG15 human fibroblasts.

The aim of this study was to evaluate the cytotoxic effects of 2. 5% sodium hypochlorite (NaOCl), 17% ethylenediamine tetraacetic acid (EDTA), and 1% peracetic acid (PAA) on human fibroblasts. FG11 and FG15 cell lines were cultured in 24-well cell culture plates for cell proliferation assessment and 96-well cell culture plates for the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay; Dulbecco's modified Eagle's medium (DMEM) was used as control data. The experimental solutions were used at 0. 01%, 0. 05%, and 0. 1% dilutions and assessed at 1-, 2-, and 4-hour intervals. Data were subjected to statistical analysis by two-way analysis of variance (ANOVA), followed by the Bonferroni test at a significance level of p <0. 05. The assessment of cell proliferation in this study showed cytotoxicity to the fibroblasts with 2. 5% NaOCl for all three dilutions at all time intervals, 17% EDTA for the 0. 05% and 0. 1% dilutions at the 2- and 4-hour intervals, and 1% PAA for all three dilutions at the 4-hour interval. The cell viability assay (MTT assay) for fibroblasts showed 2. 5% NaOCl to be cytotoxic at the 0. 05% and 0. 1% dilutions at all time intervals, 17% EDTA to be cytotoxic at the 0. 1% dilution at the 2- and 4-hour intervals, and 1% PAA to be cytotoxic at the 0. 1% dilution at the 2- and 4-hour intervals. In conclusion, 1% PAA was less cytotoxic than 2. 5% NaOCl and 17% EDTA.

O objetivo do presente estudo foi o de avaliar os efeitos citotóxicos de hipoclorito de sódio (NaOCl) a 2,5%, ácido etilenodiaminotetracético (EDTA) a 17% e ácido peracético (PAA) a 1% em fibroblastos humanos. As linhagens celulares FG11 e FG15 foram colonizadas em 24-well cell plates para avaliaçâo da proliferaçâo celularr e em 96-well cell plates para o ensaio de MTT; O médio modificado Dulbecco's Eagle's (DMEM) foi usado como controle. As soluções experimentais foram usadas com diluições de 0,01%, 0. 05%, e 0,1% e avaliadas com 1, 2 e 4 horas de intervalo. Os dados foram submetidos à análise estatística pelo two-way ANOVA, seguido do teste de Bonferroni com nivel de significância dep <0. 05. A avaliaçâo da proliferação celular neste estudo mostrou o NaOCL a 2,5% como citotóxico nas 3 diluições e 3 intervalos de tempo, o EDTA a 17% nas diluições de 0,05% e 0,1% nos intervalos de 2 e 4 horas, e o PAA a 1% em todas as diluições no intervalo de 4 horas. O teste de viabilidade cellular (MTT) mostrou o NaOCl a 2,5% citotóxico a 0,05% e 0,1% em todos os intervalos, o EDTA a 17% citotóxico nas diluições de 0,1% nos intervalos de 2 e 4 horas e o PAA a 1% citotóxico na diluição de 0,1% nos intervalos de 2 e 4 horas. Como conclusão o PAA a 1% mostrou-se menos citotóxico que o NaOCl a 2,5%> e o EDTA a 17%>.

[Treatment of chronic endometritis in cattle by intrauterine application of peroxyethan acid]. / Intrauterine Therapie der chronischen Endometritis des Rindes mit Peressigsäure.

OBJECTIVE: Peroxyethane acid (POA) is capable of disrupting the ring of bacterial catalase and has a broad microbiocidal spectrum. Following application, POA degrades to acetic acid and peroxide. There are no residues and no resistance development. Because POA administration for bladder and wound lavage in human medicine produced positive results, the substance was tested for the treatment of cows with endometritis. MATERIAL AND METHODS: After successful preliminary trials under clinical conditions, a comparative analysis using standard uterine treatments, focusing particularly on antibiotics, followed. A total of 3557 cows from large herds with chronic endometritis catarrhalis of varying degrees were included. A 0.2% POA solution was used. The effect was evaluated based on the reproductive data for each substance used. RESULTS: After POA use, equivalent or better results were achieved compared to antibiotic-treated cows. Histological and cytological examinations demonstrated a rapid and high regenerative ability of the endometrium after intrauterine POA instillation. POA induced an intensive phagocytosis beyond the 6th day of instillation. CONCLUSION: According to the results, POA may be used as an alternative to antibiotics to treat endometritis catarrhalis chronica in cows. Currently, no licensed product is available, which significantly restricts POA use. In view of the increasing problems associated with antibiotic resistance, the new approval of a corresponding POA pre - paration is justified.

Assessment of Chicken Carcass Microbiome Responses During Processing in the Presence of Commercial Antimicrobials Using a Next Generation Sequencing Approach.

The purpose of this study was to 1) identify microbial compositional changes on chicken carcasses during processing, 2) determine the antimicrobial efficacy of peracetic acid (PAA) and Amplon (blend of sulfuric acid and sodium sulfate) at a poultry processing pilot plant scale, and 3) compare microbial communities between chicken carcass rinsates and recovered bacteria from media. Birds were collected from each processing step and rinsates were applied to estimate aerobic plate count (APC) and Campylobacter as well as Salmonella prevalence. Microbiome sequencing was utilized to identify microbial population changes over processing and antimicrobial treatments. Only the PAA treatment exhibited significant reduction of APC at the post chilling step while both Amplon and PAA yielded detectable Campylobacter reductions at all steps. Based on microbiome sequencing, Firmicutes were the predominant bacterial group at the phyla level with over 50% frequency in all steps while the relative abundance of Proteobacteria decreased as processing progressed. Overall microbiota between rinsate and APC plate microbial populations revealed generally similar patterns at the phyla level but they were different at the genus level. Both antimicrobials appeared to be effective on reducing problematic bacteria and microbiome can be utilized to identify optimal indicator microorganisms for enhancing product quality.

Evaluation of an automated room decontamination device using aerosolized peracetic acid.

Because manual cleaning is often suboptimal, there is increasing interest in use of automated devices for room decontamination. We demonstrated that an ultrasonic room fogging system that generates submicron droplets of peracetic acid and hydrogen peroxide eliminated Clostridium difficile spores and vegetative pathogens from exposed carriers in hospital rooms and adjacent bathrooms.

A pilot study to assess the effectiveness and cost of routine universal use of peracetic acid sporicidal wipes in a real clinical environment.

BACKGROUND: Peracetic acid sporicidal wipes have been shown to be an effective disinfectant, but in controlled test environments. Their high cost may restrict use. AIMS: This pilot study investigated the efficacy and compared the costs of routine universal use of peracetic acid sporicidal wipes versus sporicidal quaternary ammonium compound and alcohol wipes in the disinfection of a hospital environment. METHODS: The routine universal use of peracetic acid wipes (Clinell Sporicidal; GAMA Healthcare Ltd, London, UK) was allocated to a study ward, whereas the control ward continued with the use of quaternary ammonium compound wipes (Tuffie 5; Vernacare, Bolton, UK) and alcohol wipes (PDI Sani-Cloth 70; PDI, Flint, UK). Twenty high-touch areas in the 2 wards were sampled for the presence of indicator organisms. The weekly detection rates of indicator organisms and weekly healthcare associated infection (HCAI) rates in the 2 wards were compared and examined for decreasing trends over the trial period. RESULTS: The detection rates of indicator organisms and HCAI rates were not significantly different in the 2 wards, and did not decrease significantly over the trial period. However, the peracetic acid wipes seem to be more effective against gram-negative organisms but at a significantly higher cost. CONCLUSIONS: Further prospective studies are needed to assess the cost-effectiveness of peracetic acid wipes.

Evaluation of the effectiveness of manual and automated dialyzers reprocessing after multiple reuses.

A cross-sectional study was conducted to evaluate the effectiveness of manual and automated dialyzer reprocessing. Dialyzers were filled with fluid thioglycollate medium from blood and dialysate chambers after being reprocessed and chemically sterilized with 0.2% peracetic acid. They were incubated for 14 days at 35°C ± 2°C, and microbiologic analysis was performed. Microorganisms were identified in 3 of the 11 samples (27.3%) from the blood chambers: Sphingomonas paucimobilis (2/3) and Penicillium spp (1/3) and in 11 of the 11 samples (100%) from the dialysate chambers: S paucimobilis (7/11), Stenotrophomonas maltophilia (4/11), Pseudomonas aeruginosa (3/11), Candida spp (1/11), and Acinetobacter baumannii (1/11). Of the 4 manually reprocessed dialyzers, gram-positive bacillus were identified in 1 sample (25%) from the blood chamber, and Bacillus spp and Burkholderia spp were identified in 1 sample (25%) from the dialysate chamber. The dialyzers reprocessing can pose risks safety because of exposure patient to microorganisms.

Antimicrobial interventions for O157:H7 and non-O157 Shiga toxin-producing Escherichia coli on beef subprimal and mechanically tenderized steaks.

Non-O157 Shiga toxin-producing Escherichia coli (STEC) is an emerging risk for food safety. Although numerous postharvest antimicrobial interventions have been effectively used to control E. coli O157:H7 during beef harvesting, research regarding their effectiveness against non-O157 STEC is scarce. The objectives of this study were (i) to evaluate effects of the spray treatments-ambient water, 5% lactic acid (LA), 200 ppm of hypobromous acid (HA), and 200 ppm of peroxyacetic acid (PA)-on the reduction of O157:H7 or non-O157 STEC (O26, O103, O111, and O145) with high (10(6) log CFU/50 cm(2)) or low (10(2) log CFU/50 cm(2)) levels on beef subprimals after vacuum storage for 14 days and (ii) to evaluate the association of the antimicrobial treatments and cooking (50 or 70°C) on the reduction of the pathogens in blade-tenderized steaks. The treatment effects were only observed (P = 0.012) on samples taken immediately after spray intervention treatment following inoculation with a high level of O157:H7. The LA and PA treatments significantly reduced low-inoculated non-O157 STEC after spray intervention; further, the LA and HA treatments resulted in significant reductions of non-O157 STEC on the low-inoculated samples after storage. Although cooking effectively reduced the detection of pathogens in internal steak samples, internalized E. coli O157:H7 and non-O157 STEC were able to survive in steaks cooked to a medium degree of doneness (70°C). This study indicated that the reduction on surface populations was not sufficient enough to eliminate the pathogen's detection following vacuum storage, mechanical tenderization, and cooking. Nevertheless, the findings of this study emphasize the necessity for a multihurdle approach and further investigations of factors that may influence thermal tolerance of internalized pathogenic STEC.

Estabilidade do ácido peracético no processo de desinfecção prévia à lavagem / Peracetic acid stability in disinfection process prior to wash

Objetivo: Avaliar a efetividade antimicrobiana e a estabilidade de formulações de ácido peracético com (Apc) e sem inibidor (Aps) de corrosão. Materiais e Métodos: Corpos de prova em aço inoxidável foram contaminados com Staphylococcus aureus, Escherichia coli, Candida albicans, sangue e saliva e imersos em ácido peracético (Aps e Apc) por dez, quinze e trinta minutos. Após estes períodos, Apc e Aps foram neutralizados, agitados durante um minuto e a suspenção obtida foi semeada (ágar sangue), incubada (24h/37 °C) e as unidades formadoras de colônia (UFC) contadas. Este procedimento foi realizado seis vezes ao dia por 18 dias não consecutivos por um período de trinta dias. Corpos de prova contaminados e não submetidos à desinfecção foram utilizados como grupo controle. Resultados: Houve redução significativa das médias diárias de crescimento dos microrganismos para os dois grupos teste (Aps e Apc) quando comparados ao grupo controle (p= 0,0000) sem diferença estatística significativa entre eles (p= 0,7517). Conclusão: As duas soluções de ácido peracético mostraram-se eficientes no processo de desinfecção, sendo a solução sem inibidor de corrosão estável por um período maior...

Objective: To evaluate the stability of formulations of peracetic acid with (Apc) and without inhibitor (Aps) of corrosion in the disinfection process prior to washing. Materials and Methods: Specimens of stainless steel were contaminated with Staphylococcus aureus, Escherichia coli, Candida albicans, blood and saliva and immersed in peracetic acid (Aps and Apc) for ten, fifteen and thirty minutes. After these periods, Aps and Apc were neutralized, stirred and the suspension obtained was seeded (blood agar) incubated (24h/37°C) and colony forming units counted. This procedure was carried out six times a day for 18 consecutive days for a period of thirty days. Contaminated specimens and not disinfected were used as control group. Results: There was significant reduction in the daily growth average of microorganisms for the two test groups (Aps and Apc) when compared to control group (p = 0.0000) with no significant statistical difference between them (p = 0.7517). Conclusion: The two solutions of peracetic acid were effective in the disinfection process, with the solution without corrosion inhibitor stable for a longer period...

Erratum to: the acaricidal efficacy of peracetic acid and deltamethrin against the fowl tick, Argas persicus, infesting laying hens.

The fowl tick, Argas persicus (Oken), is of veterinary importance as a parasite of poultry and wild birds. The antitick efficacy, in vitro and in vivo, of peracetic acid (PAA) and deltamethrin (DMT) was tested separately against A. persicus through the dipping technique. PAA (0.5%) was highly efficient against soft tick larvae (A. persicus), resulting in 100 % mortality after 2 min. The lethal concentrations LC50 and LC95 were 0.310 and 0.503 %, respectively. The lethal time values LT50 and LT95 were 5.34 and 40.00 min, respectively, after treatment with PAA (0.25%). Two minutes after exposure to DMT, LC50 and LC95 values were 0.0033 and 0.0052% (33.204 and 51.527 mg/L), respectively. The LT50 and LT95 values were 27.03 and 305.46 min, respectively, after treatment with 0.0025% DMT (25 mg/L). After dipping in PAA (0.5%), the chickens did not show respiratory signs or inflammation on the eyes and/or skin. By contrast, temporary coughing, sneezing, and ocular inflammations without dermatitis were observed in chickens dipped in DMT (0.005 % or 50 mg /L). Seven days posttreatment (PT), the reduction in the percentages of A. persicus infesting laying hens were 99.15 and 63.42% after dipping in PAA and DMT, respectively. However, complete elimination of the number of ticks occurred after 28 days PT with DMT. PAA inhibits molting effectively (28%) when compared with that of DMT (52%). Results indicated that PAA is a more potent and promising acaricide against A. persicus (in vitro and in vivo) than DMT.

Uso de ácido peracético e dióxido de cloro como agentes antimicrobianos em carne de frango / Use of peracetic acid and chlorine dioxide as antimicrobials in chicken

A qualidade microbiológica e a segurança alimentar são assuntos que têm ganhado cada vez mais importância na área de alimentos. Várias tecnologias para a descontaminação de micro-organismos em produtos cárneos têm sido investigadas. A adição de interventores químicos, como dióxido de cloro e ácido peracético também tem sido fonte para a realização de diversos estudos. Este trabalho objetivou determinar a eficiência do ácido peracético e dióxido de cloro no tratamento para a conservação de sobrecoxas de frango.

[Study on cytotoxicity of microdoses peracetic acid in vitro].

OBJECTIVE: To evaluate the cytotoxicity of microdoses peracetic acid (PAA) so as to provide the evidence for making residual limit of PAA sterilization. METHODS: Mouse fibroblasts (L929 cell line) cultured in vitro were observed to evaluate the influence of microdoses PAA including 1 x 10(-6), 2 x 10(-6), 3 x 10(-6), 4 x 10(-6), 5 x 10(-6), and 10 x 10(-6) (V/V). The proliferation of cells was determined by MTT assay at 2, 4, and 7 days of culture. The growth curve and the relative growth rate (RGR) were obtained. The cytotoxicity of PAA at different concentrations was evaluated according to RGR. RESULTS: At 2, 4, and 7 days after culture, fibroblasts of 1 x 10(-6) group grew with normal morphology analogous to control group, while the cell growth of other groups were poor. With the increase of PAA concentration, the absorbance (A) values decreased, which suggested that there was a significant negative correlation between cell proliferation and PAA concentration. And the correlation coefficient was -1.000 at 2 and 4 days, - 0.964 at 7 days. There was no significant difference in A value between 1 x 10(-6) group and the control group (P > 0.05), while there were significant differences in A value between the control group and other concentration groups (P < 0.05). The growth curve of 1 x 10(-6) group was similar to that of the control group, both had obvious phase of exponential growth. The growth curves of other groups had no obvious phase of exponential growth. The cytotoxicity of 1 x 10(-6) group was classified as level 1, 2 x 10(-6) group as level 2, 3 x 10(-6) group as level 3, 4 x 10(-6) group as level 3-4, 5 x 10(-6) group and 10 x 10(-6) group as level 4. CONCLUSION: PAA of 1 x 10(-6) had no obvious cytotoxicity. The residual limit of PAA less than 1 x 10(-6) was recommended.

Desinfecção de alginato / Alginate disinfection

A presente dissertação, composta de dois manuscritos, buscou preencher lacunas do conhecimento no que diz respeito à desinfecção de impressões de alginato. O primeiro trabalho foi realizado com o intuito de avaliar a eficácia antimicrobiana da solução de glutaraldeído 2% através do seu comportamento bactericida e bacteriostático quando utilizada para desinfecção de impressões de alginato dos pacientes de uma clínica de ensino odontológico de uma instituição federal, durante 28 dias. Logo após a ativação de 3L da solução desinfetante e sempre após a desinfecção de 10 impressões, foram coletadas amostras de 05 mL da solução para a análise microbiológica. No período avaliado, foram imersas 70 impressões de alginato na solução desinfetante. Nenhuma amostra apresentou bactérias viáveis, caracterizando o perfil bacteriostático da solução. Todas as amostras foram capazes de inibir o crescimento de Escherichia coli, Pseudomonas aeruginosa, e Staphylococcus aureus, confirmando o poder bactericida da solução, mostrando que um volume de 3L de glutaraldeído 2% é eficaz como desinfetante de até 70 impressões de alginato ao longo do período de 28 dias. O segundo estudo preocupou-se em avaliar a eficácia do glutaraldeído 2% e do ácido peracético 0,2% em eliminar o microrganismo Staphylococcus aureus, sabidamente presente nos corpos de prova de alginato. Os corpos de prova de alginato foram contaminados com caldo de cultura contendo S. aureus. Estes foram...

This research made an effort to amplify the knowledge about disinfection of alginate dental impression. The aim of the first study was to evaluate the efficacy of 2% glutaraldehyde solution after successive immersions of contaminated alginate impressions of dental patients from a Dental School by analyzing its bacteriostatic and bactericidal activity through 28 days. After the disinfection of every 10 alginate impressions a 10mL sample of the disinfectant solution (05mL) was collected to be microbiological analyzed. In this period, 70 alginate impressions were immersed in the solution. No viable bacterial grouth was observed at any of the microbiology analyses. All the samples tested were able to inhibit the bacterial growth of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The bacteriostatic and bactericidal activity of 2% glutaraldehyde solution was confirmed and 3L of the solution can be safetely used for the disinfection of at least 70 impression during 28 days. The aim of the second study was to evaluate the efficacy of 2% glutaraldehyde and 0.2% peracetic acid against Staphylococcus aureus. Alginate specimens were contaminated at S. aureus culture media. Specimens were divided into six groups: control, washed in sterile water, immersed...

Moderate and high doses of sodium hypochlorite, neutral electrolyzed oxidizing water, peroxyacetic acid, and gaseous chlorine dioxide did not affect the nutritional and sensory qualities of fresh-cut Iceberg lettuce (Lactuca sativa Var. capitata L.) after washing.

Besides the traditionally used sodium hypochlorite (20 and 200 mg L(-1)), alternative sanitizers such as peroxyacetic acid (80 and 250 mg L(-1)) and neutral electrolyzed oxidizing water (4.5 and 30 mg L(-1) free chlorine) as well as chlorine dioxide gas (1.54 mg L(-1)) were evaluated for their efficiency in reducing the microbial load of fresh-cut iceberg lettuce. An additional rinsing step with tap water and cooling of the sanitizing solutions, which are obvious for the fresh-cut industry, were not performed within the current study. The high doses of sodium hypochlorite and peroxyacetic acid tested within this study do not conform to the normally used concentrations within the fresh-cut industry. Neutral electrolyzed oxidizing water (30 mg L(-1)), peroxyacetic acid (250 mg L(-1)), and gaseous chlorine dioxide significantly reduced the total aerobic plate count of cut lettuce in comparison with water wash treatments alone. None of the treatments significantly affected the sensory quality of the lettuce, although small color changes were observed after colorimetric measurements. From a nutritional point of view water rinsing significantly decreased the vitamin C (maximum 35%) and phenol (maximum 17%) contents, but did not affect the carotenoid and α-tocopherol contents. Additional effects caused by adding a sanitizer to the wash water were not observed for vitamin C and phenols. Conversely, washing with 250 mg L(-1) peroxyacetic acid reduced the ß-carotene content by about 30%, whereas using 200 mg L(-1) sodium hypochlorite reduced both the lactucaxanthin and the lutein contents by about 60%. Use of gaseous chlorine dioxide also had an impact on the lutein content (-18%). Furthermore, the α-tocopherol content was reduced by 19.7 and 15.4% when the two concentrations of neutral electrolyzed oxidizing water were used, respectively. These data represent the situation on day 0. In a next phase, shelf-life studies considering microbial and sensory quality and nutrient content should be conducted.

A influência da imersão em ácido peracético sobre a reprodução de detalhes e compatibilidade dos elastômeros com gesso / The influence of peracetic acid immersion on detail reproduction and compatibility of elastomers with gypsum

O objetivo deste trabalho foi verificar a influência da imersão no desinfetante à base de ácido peracético 0,2% sobre a reprodução de detalhes e compatibilidade com gesso dos elastômeros: Silicona de Adição, Silicona de Condensação e Poliéter. Para a reprodução de detalhes foram confeccionados 10 corpos de prova de cada material utilizando-se a matriz determinada pela especificação n. 19 para Materiais de Impressão Elastoméricos Não-Aquosos da A.D.A., sendo que 5 corpos de prova foram imersos no desinfetante por 10 minutos e os outros 5, utilizados como controle. A reprodução de detalhes foi analisada pela visualização de uma linha de 30 mm de comprimento e 20 μm de espessura de forma completa e contínua em pelo menos duas de três impressões, segundo a especificação. Para compatibilidade com gesso avaliou-se a reprodução dos mesmos detalhes nos modelos vazados com gesso tipo IV sobre as referidas impressões. Todos os materiais utilizados apresentaram reprodução de detalhes e compatibilidade com gesso em 100% dos corpos de prova. Concluiu-se que a imersão no desinfetante à base de ácido peracético não alterou as propriedades avaliadas destes materiais.

[Efficient killing of anthrax spores using aqueous and alcoholic peracetic acid solutions]. / Effiziente Abtötung von Milzbrandsporen durch wässrige und alkoholische Peressigsäure-Lösungen.

We analysed the sporicidal effect of different concentrations of aqueous and alcoholic peracetic acid (PAA) solutions on anthrax spores in suspension and germ carrier tests. In activation of anthrax spores in suspension assays was achieved in less than 2 min using 1% PAA solution and in less than 3 min using 0.5% PAA solution, respectively. In contrast, in germ carrier as says, a test under practical conditions, spores on 38% of the germ carriers survived treatment with 1% PAA solution for 15 min. The use of PAA in 80% ethyl alcohol outclassed the sporicidal effect of aqueous PAA solutions in both suspension and germ carrier assays. Anthrax spores on 14% of germ carriers tested survived 30 min of treatment with a 1% aqueous PAA solution. In contrast anthrax spores were reliably inactivated under the same test procedure using a 1% alcoholic PAA solution for 30 min. The proven enhancement of the sporicidal effect of alcoholic PAA solutions should be kept in mind when using disinfectants in practice. In further surveys we will optimise the test conditions.