Structure properties change of ready-to-use nonwoven wiping materials over storage time

Healthcare-associated infections (HAIs) caused by the transfer of nosocomial pathogens from high-touch environmental surfaces and medical devices are responsible for significant patient morbidity, mortality and economic cost.[1] An effective cleaning and disinfection practice plays a key role in preventing cross-contaminations and spread of HAIs.[2] Traditionally, healthcare staff has used the “bucket method”, which consists of towels saturated with diluted disinfectant contained in a bucket. This method exhibits several limitations such as improper disinfectant dilution, inadequate saturation, uneven moisture distribution, unknown material compatibility and possible contamination from reusing.[3-4] Among the most effective surface disinfection methods, the nonwoven ready-to-use disinfectant wipes are increasingly accepted for decontamination of high-touch surfaces because of its convenience and reliable performance.[5] Though some research has been done on the effectiveness of commercial available disinfecting wipes in practical use.[6] Whereas their behaviour during storage remains unknown. In addition, a lower or even abolished disinfectant efficacy of the active ingredients due to their interaction with the textile materials has been also reported.[7] This project studied the ageing of the disinfecting wipes over storage time. Chloramine as a surface disinfectant and 3 commercial wiping materials of polyester, viscose, and their combination have been selected. The wipes before and after the contact with disinfectant solution were analysed by FTIR (Fourier-transform infrared spectroscopy) and DMA (Dynamic mechanical analysis).Xinyu Song acknowledges Fundação para a Ciência e Tecnologia (FCT), Portugal, for its PhD grant financial support (SFRH/BD/130028/2017). Andrea Zille also acknowledges FCT through the iFCT Research contract (IF/00071/2015) and the project POCI-01-0145-FEDER-007136 under the COMPETE and FCT/MCTES (PIDDAC) co-financed by European funds (FEDER) through the PT2020 program.info:eu-repo/semantics/publishedVersio

Storage time effects on the bactericidal activity of plasma treated quats disinfectant-impregnated wipes

Introduction: An efficient cleaning and disinfection practice plays a crucial role in preventing cross-contamination in nosocomial environment. The binding of quaternary ammonium compounds (QACs) on cellulosic material which may fail the disinfection process hinder the broad use of pre-impregnated disinfecting wipes (ready-to-use disinfectant wipes) in hospital. Moreover, ageing of disinfectant-impregnated wipes may affect the products’ disinfection performance later in practice but very little research was performed regarding this issue. Objectives: The purpose of this study is to evaluate the adsorption change and antimicrobial activity due to the ageing of the disinfecting wipe over storage time with and without atmospheric Double Barrier Dielectric (DBD) plasma pre-treatment. The main questions to be answered are: i) How does the adsorption of active ingredients onto textile substrate change with storage time; ii) How does the antimicrobial efficacy vary by time. The study of the adsorption of QACs in storage is important to ensure hospitals daily workflow and to complement the products’ user manual of disinfectant and wipes in the market. Methods: Plasma–treated and untreated commercial wiping materials of polyester (PET), 55% cellulose/45%PET and 100% cotton were immerged into QACs solution with a certain liquor ration for 30 min, 3, 7, 15 and 30 days. The absorption and adsorption of quats onto wiping material were measured by UV spectrophotometer. Standards ASTM E 2149-13a was carried out to assess the antimicrobial efficacy. Results: There was evident increase of QACs adsorption in all wipes including plasma treated ones in function of the storage time. Plasma–treated PET showed a small increase in adsorption (~5%) while cotton wipes display a decrease in QACs adsorption (~5%). Surprisingly, the plasma-treated blend wipes are able to adsorb almost the double of the untreated ones (from 15% to around 30%). Cotton sample shows the lowest antimicrobial effect in all the cases. In PET and blend wipes the storage time has a significant influence on the Log reduction of E.coli. in both untreated and plasma treated samples. Conclusion: The use of blend wipes is recommended due to the best performance between adsorption and antimicrobial effect. Moreover, plasma treatment can significantly improve Gram-negative bactericidal effect if necessary.Fundação para a Ciência e Tecnologia (FCT), Portugal, for (SFRH/BD/ 130028/2017) and COST for the complete funding of the conference under CA 15114. iFCT Research Contract (IF/00071/2015) and the project POCI-01-0145-FEDER-007136 under the COMPETE and FCT/MCTES(PIDDAC) co-financed by European funds (FEDER) through the PT 2020 progra

Regulation von Signaltransduktionselementen über Ankerproteine

Lokalisation von PKA-Aktivität über A-Kinase-Ankerproteine (AKAPs) ist einer der wichtigsten Regulationsmechanismen, durch den spezifisch die Phosphorylierung von Substraten innerhalb eines Zellkompartimentes gesteuert wird. Um ein besseres Verständnis der Funktion der AKAP/R-Signalkomplexe zu erreichen, müssen die Wechselwirkungen der vier Isoformen der R-Untereinheiten von PKA (RI$\alpha$), RI$\beta$), RII$\alpha$) und RII$\beta$) mit den 75 mittlerweile bekannten AKAPs genau charakterisiert werden. In dieser Arbeit konnten die Interaktionen der einzelnen R-Isoformen mit verschiedenen AKAPs durch Bestimmung der Geschwindigkeits- und Gleichgewichtsbindungskonstanten an Biacore®-Maschinen mittels Surface Plasmon Resonance (SPR) genau bestimmt werden. Ein neuer Regulationsmechanismus der PKA/AKAP-Interaktion konnte beschrieben werden, bei dem durch CDK1-spezifische Phosphorylierung der RII$\alpha$-Untereinheit am Threonin 54 die Assoziation und Dissoziation von AKAP450 und RII$\alpha$ während der Mitose gesteuert wird

Antimicrobial efficiency and surface interactions of quaternary ammonium compound absorbed on Dielectric Barrier Discharge (DBD) plasma treated fiber-based wiping materials

The physico-chemical interactions between alkyldimethylbenzylammonium chloride (ADBAC) as disinfectant and 3 commercial wiping materials made from 100% polyester (PET), 55%cellulose/45%PET (blend) and 100% cellulose were investigated after treatment with dielectric barrier discharge (DBD) plasma at atmospheric pressure. Wipe material type in terms of cellulose content, liquor ratio and immersion time demonstrated a significant influence on the adsorption of ADBAC. The higher the content of cellulose in the material, the higher is the adsorption of ADBAC active ingredient. The antimicrobial tests confirm that the ADBAC adsorbed on pure cellulosic material are inactivated losing their bactericidal activity, while 100% PET and blend wipes showed good antimicrobial efficacy. XPS analysis demonstrates the strong interactions of ADBAC with the plasma-generated oxygen species in the polyester-containing wipes surface. Unexpectedly, plasma-treated blend wipe displays a reverse antimicrobial effect compared to untreated samples, performing better in Gram-negative bacteria. The best result was obtained in the plasma treated 100% polyester wipe showing an improved of about 20% in Gram-positive bacteria and an excellent performance in Gram-negative ones. This method allows the unprecedented use of pure polyester as effective wiping material for surface disinfection eliminating the major drawback of pure polyester, its high hydrophobicity.This work was funded by European Regional Development funds (FEDER) through the Competitiveness and Internationalization Operational Program (POCI) – COMPETE and by National Funds through Fundação para a Ciência e Tecnologia (FCT)—under the project POCI- 01-0145-FEDER-007136 and UID/CTM/00264/2019. Xinyu Song (SFRH/BD/130028/2017) acknowledges FCT, Portugal, for its doctoral grant financial support. Andrea Zille also acknowledges financial support of the FCT through an Investigator FCT Research contract (IF/00071/2015) and the project PTDC/CTM-TEX/28295/2017 financed by FCT, FEDER and POCI in the frame of the Portugal 2020 program

Chemical, thermo-mechanical and antimicrobial properties of DBD plasma treated disinfectant-impregnated wipes during storage

Disinfectant-impregnated wipes are broadly used in hospitals, as an important approach for infection prevention and control. But their ageing performance has rarely been studied. Untreated and Dielectric Barrier Discharge (DBD) plasma pre-treated wiping materials made of nonwoven 100% polyester (W1), nonwoven 55% cellulose/45% polyester (W2) and woven cotton (W3) were impregnated with a quaternary ammonium compound solution (ADBAC) for 30 min, 3, 7, 15, and 30 days of storage time and characterized in term of chemical, thermo-mechanical and antimicrobial efficacy. X-ray photoelectron spectroscopy analysis on the plasma-treated polyester wipes demonstrates the incorporation of reactive oxygen species on the fiber surface. Laser scanning microscopy demonstrates the plasma etching effect in smoothing the surface of the cotton wipe reducing the adsorption of ADBAC. The result showed no significant changes in breaking force and elongation during storage for W1 and W2. However, plasma treatment affects W3 in weft direction reducing the force at break in water and ADBAC treated wipes. Dynamic mechanical analysis results show that ADBAC and plasma treatment have a significant influence in W1 and W3 viscoelastic properties improving the elastic response limiting the polymeric chains mobility and the non-elastic response due to the etching effect, respectively. Overall, the plasma pre-treatment of ADBAC-impregnated wipes is able to enhance the antimicrobial performance and the storage time of polyester-containing wipes.This work was funded by European Regional Development funds (FEDER) through the Competitiveness and Internationalization Operational Program (POCI) – COMPETE and by National Funds through Fundação para a Ciência e Tecnologia (FCT)—under the project POCI-01-0145-FEDER-007136 and UID/CTM/00264/2019. Xinyu Song (SFRH/BD/130028/2017) acknowledges FCT, Portugal, for its doctoral grant financial support. A. Zille also acknowledges financial support of the FCT through an Investigator FCT Research contract (IF/00071/2015) and the project PTDC/CTM-TEX/28295/2017 financed by FCT, FEDER and POCI in the frame of the Portugal 2020 program

Evaluation of a microscale quantitative suspension test to determine the bactericidal and yeasticidal activity of glutaral – one step to improve sustainability in disinfectant testing

Aims: To evaluate a newly developed microscale quantitative suspension test compared to the existing standard suspension test using determination of the bactericidal and yeasticidal activity of glutaral as one step to improve the sustainability of disinfectant testing.Methods: The testing principles of the quantitative suspension test according to VAH method 9 (comparable to EN 13727) was used as a standard suspension test using 8.0 mL product test solution, 1.0 mL organic load and 1.0 mL test suspension. In addition, a micro-scale suspension test was performed in 96-well plates with 160 µL product test solution, 20 µL organic load and 20 µL test suspension. ATCC 6538, ATCC 15442 and ATCC 10231 were test organisms. Glutaral was tested at concentrations of 0.05%, 0.1%, 0.2% and 0.3% with exposure times of 1, 5 and 15 min. Polysorbate 80 (30 g/L), lecithin (9 g/L), L-histidine (1 g/L) and glycine (1/L) were used as validated neutralizers. After serial dilution of the disinfectant-neutralizer-mixture, plates were incubated for 48 h at 36°C (bacteria) or 72 hours at 30°C () and colony forming units (cfu) counted. The lg reduction was calculated as the difference between the results of the water control and the disinfectant at the end of the exposure time. All experiments were done in triplicate under clean conditions. Means of lg reduction were compared with the unpaired test, p<0.05 was considered to be significant.Results: Sufficient bactericidal activity according the VAH test requirements of at least 5 lg was found with both methods in 16 data sets of 24 data sets in total, and insufficient bactericidal activity of less than 5 lg was found with both methods in 7 data sets. In one data set, the mean lg reduction was above 5 lg with the microscale method and g with the VAH method, with no significant difference between the data sets (p=0.3096; 0.2% glutaral, 1 min, ). A sufficient yeasticidal activity of at least 4 lg was found with both methods in one data set, an insufficient yeasticidal activity of less than 4 lg was found with both methods in 8 data sets. With one exception, no significant differences were detected between the two methods below the efficacy threshold.Conclusions: The microscale quantitative suspension test proved to provide results similar to those of VAH method 9 when the bactericidal and yeasticidal activity of glutaralwas evaluated, with 32 out of 33 evaluations yielding consistent results in terms of efficacy. Its suitability should be confirmed with additional bacterial species, additional biocidal active substances and in other laboratories