Virucidal activity of a plant-oil-based oral rinse against respiratory viruses.

BACKGROUND: Respiratory viruses have been reported to infect the salivary glands and the throat, which are potential reservoirs for virus replication and transmission. Therefore, strategies to reduce the amount of infective virus particles in the oral mucous membranes could lower the risk of transmission. METHODS: The viral inactivation capacity of a plant-oil-based oral rinse (Salviathymol®) was evaluated in comparison with chlorhexidine (Chlorhexamed® FORTE) using a quantitative suspension test according to EN 14476. FINDINGS: Salviathymol efficiently inactivated severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), respiratory syncytial virus (RSV) and two influenza strains to undetectable levels. CONCLUSION: Salviathymol has potential as preventive measure to lower transmission of respiratory viruses.

Evaluation of temperature, drying time and other determinants for the recovery of Gram-negative bacterial pathogens in disinfectant efficacy testing.

BACKGROUND: In the clinical setting, surface disinfection is an important measure to reduce the risk of cross transmission of micro-organisms and the risk of nosocomial infections. Standardized methods can be used to evaluate disinfection procedures, as well as the effectiveness of the active ingredients used for disinfection. However, despite standardization, the results of such methodologies are still determined by several factors, and incorrect results may lead to invalid assumptions about the effectiveness of a disinfectant, posing significant health risks for patients and health personnel. AIM: The objective of this study was to evaluate several determinants for the recovery of Pseudomonas aeruginosa and other test organisms to establish their influence on the results of standardized disinfection methodologies, and to find Gram-negative strains that can be used as suitable replacements for P. aeruginosa. METHODS: The effects of inoculum application method, drying time, temperature and carrier material on the survival and recovery of the test organisms were evaluated using Student's t-test, one-way analysis of variance and Tukey's multiple comparison test. FINDINGS AND CONCLUSIONS: Temperature, drying time, application method and carrier material were found to affect the recovery of P. aeruginosa cells significantly, and therefore influence the outcome of the methodologies used. This study also showed thatP. aeruginosa could be replaced with the Gram-negative species Acinetobacter baumannii, a test organism used in many standardized methodologies, which responds better under the same circumstances and has a behaviour similar to that of P. aeruginosa in disinfectant efficacy tests.

Superiority of manual disinfection using pre-soaked wipes over automatic UV-C radiation without prior cleaning.

BACKGROUND: The efficacy of ultraviolet C (UV-C) radiation against a broad spectrum of micro-organisms has been demonstrated in several studies, but differences in the specific doses and the extent of microbial reduction were found. Furthermore, the conditions of laboratory tests differ greatly from reality, such that efficacy achieved in tests may not necessarily be assumed in reality. Consequently, it is important to investigate the effectiveness of UV-C in representative field trials. The aim was therefore to develop and establish a field test to evaluate automatic UV-C in comparison to manual disinfection. METHODS: Before and after disinfection, samples were repeatedly collected from naturally highly contaminated surfaces using the swab technique to obtain representative data sets for disinfected and non-disinfected surfaces. Subsequently, the log reduction values (LRV) and the disinfection success were evaluated for UV-C radiation and full compliant manual disinfection using alcohol-based wipes. RESULTS: Surfaces that are naturally contaminated with bacteria on a regular and nearly uniform basis have been identified as particularly suitable for field testing. Mean contamination was reduced from 23.3 to 1.98 cfu/cm2 (LRV 0.9) and 29.7 to 0.26 cfu/cm2 (LRV 1.2) for UV-C and manual disinfection, respectively. UV-C disinfection achieved 75.5% successful disinfected surfaces, whereas manual disinfection showed 98.1%. CONCLUSIONS: Full compliant manual disinfection showed slightly higher LRVs and disinfection success than automatic UV-C disinfection. Successful, operator-independent UV-C disinfection still has the potential to improve disinfection performance in addition to manual disinfection.

Evolving the EN 1500 test method for alcohol-based hand rub closer to clinical reality by reducing the organic load on hands and enabling product to be applied to dry hands.

BACKGROUND: The methods currently used in Europe and North America to evaluate the bactericidal efficacy of hand hygiene products have some limitations (e.g. selection of test organism, method of contamination), and none of the methods allow prediction of actual clinical efficacy. Therefore, the World Health Organization has proposed the development of methods that better reflect typical clinical reality. METHODS: In Experiment 1, two contamination methods (immersion method according to EN 1500 and low-volume method according to ASTM E2755) were tested with the EN 1500 test organism Escherichia coli using 60% v/v iso-propanol. Experiment 2 compared the two contamination methods with Enterococcus faecalis. Experiment 3 compared the two test organisms using the low-volume contamination method. Data within each experiment were compared using the Wilcoxon test for paired samples, and data from all experiments were combined and fit to linear mixed-effects models. RESULTS: Mixed-effects analysis confirmed that both the test organism and the contamination method impacted the pre-values, and all three factors influenced log10 reductions. Higher pre-values resulted in significantly higher log10 reductions, immersion contributed to significantly higher log10 reductions, and E. coli showed significantly lower log10 reductions. CONCLUSION: An efficacy evaluation against E. faecalis with a low-volume contamination method could be considered as an alternative to the EN 1500 standard. This could help to improve the clinical relevance of the test method by including a Gram-positive organism and reducing the soil load, allowing product application closer to reality.

Evaluation of the substitution of poliomyelitis virus for testing virucidal activities of instrument and surface disinfection.

The Global Polio Eradication initiative has the goal to eradicate poliomyelitis worldwide. This means that poliomyelitisvirus type 1 strain LSc 2ab (PV-1) can no longer be used for the evaluation of virucidal activity of chemical disinfectants. This study evaluated murine parvovirus ATCC VR 1346 (minute virus of mice) as suitable surrogate for PV-1 when testing virucidal activity of biocides in instrument and surface disinfectants. Suspension testing in different laboratories with two commercially available active biocidal substances based on glutaraldehyde (0.01-0.25%) and peracetic acid (0.005-0.1%) with an exposure time of 30 min was performed. Both pathogens showed comparable susceptibility and dose-dependent reduction of virus titres following German and European Guidelines.

Virucidal activity of nasal sprays against severe acute respiratory syndrome coronavirus-2.

The highest viral loads of severe acute respiratory syndrome coronavirus-2 are detectable in the oral cavity, so a potential reduction of infectious virus by nasal and oral sprays could reduce transmission. Therefore, the inactivation capacity of nine nasal and oral sprays was evaluated according to EN 14476. One nasal spray based on sodium hypochlorite and one oral spray containing essential oils reduced viral titres by two to three orders of magnitude. Although clinical data are still sparse, nasal and oral sprays display a more convenient application for elderly people or those who are unable to rinse/gargle.

Virucidal efficacy of an ozone-generating system for automated room disinfection.

Besides conventional prevention measures, no-touch technologies based on gaseous systems have been introduced in hospital hygiene for room disinfection. The whole-room disinfectant device Sterisafe Pro, which creates ozone as a biocidal agent, was tested for its virucidal efficacy based on Association Française de Normalisation Standard NF T 72-281:2014. All test virus titres were reduced after 150 and 300 min of decontamination, with mean reduction factors ranging from 2.63 (murine norovirus) to 3.94 (simian virus 40). These results will help to establish realistic conditions for virus inactivation, and assessment of the efficacy of ozone technology against non-enveloped and enveloped viruses.

An automated room disinfection system using ozone is highly active against surrogates for SARS-CoV-2.

BACKGROUND: The presence of coronaviruses on surfaces in the patient environment is a potential source of indirect transmission. Manual cleaning and disinfection measures do not always achieve sufficient removal of surface contamination. This increases the importance of automated solutions in the context of final disinfection of rooms in the hospital setting. Ozone is a highly effective disinfectant which, combined with high humidity, is an effective agent against respiratory viruses. Current devices allow continuous nebulization for high room humidity as well as ozone production without any consumables. AIM: In the following study, the effectiveness of a fully automatic room decontamination system based on ozone was tested against bacteriophage Φ6 (phi 6) and bovine coronavirus L9, as surrogate viruses for the pandemic coronavirus SARS-CoV-2. METHODS: For this purpose, various surfaces (ceramic tile, stainless steel surface and furniture board) were soiled with the surrogate viruses and placed at two different levels in a gas-tight test room. After using the automatic decontamination device according to the manufacturer's instructions, the surrogate viruses were recovered from the surfaces and examined by quantitative cultures. Then, reduction factors were calculated. FINDINGS: The ozone-based room decontamination device achieved virucidal efficacy (reduction factor >4 log10) against both surrogate organisms regardless of the different surfaces and positions confirming a high activity under the used conditions. CONCLUSION: Ozone is highly active against SARS-CoV-2 surrogate organisms. Further investigations are necessary for a safe application and efficacy in practice as well as integration into routine processes.

Virucidal efficacy of different formulations for hand and surface disinfection targeting SARS CoV-2.

In the ongoing SARS CoV-2 pandemic, effective disinfection measures are needed, and guidance based on the methodological framework of the European Committee for Standardization (CEN) may enable the choice of effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming 'virucidal activity against enveloped viruses' as specified in the European Standard EN 14476 as well as in the German Association for the Control of Viral Diseases/Robert Koch Institute (DVV/RKI) guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in the EN 14476 and DVV/RKI guidelines. Thus, chemical disinfectants claiming 'virucidal activity against enveloped viruses' based on the EN 14476 and DVV/RKI guidelines will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

Comparison of the in-vitro efficacy of different mouthwash solutions targeting SARS-CoV-2 based on the European Standard EN 14476.

The outbreak of the SARS-CoV-2 pandemic is triggering a global health emergency alert. Until vaccination becomes available, a bundle of effective preventive measures is desperately needed. Recent research is indicating the relevance of aerosols in the spread of SARS-CoV-2. Thus, in this study commercially available antiseptic mouthwashes based on the active ingredients chlorhexidine digluconate and octenidine dihydrochloride (OCT) were investigated regarding their efficacy against SARS-CoV-2 using the European Standard 14476. Based on the requirement of EN 14476 in which reduction of at least four decimal logarithms (≥4 log10) of viral titre is requested to state efficacy, the OCT-based formulation was found to be effective within a contact time of only 15 s against SARS-CoV-2. Based on this in-vitro data the OCT mouthwash thus constitutes an interesting candidate for future clinical studies to prove its effectiveness in a potential prevention of SARS-CoV-2 transmission by aerosols.

Improved method for tuberculocidal and mycobactericidal activity testing of disinfectants based on the European Standard EN 14348.

Safe measurements to prevent the transmission of (multidrug-resistant) mycobacteria such as disinfection are essential in healthcare settings. In Europe chemical disinfectants are tested for their tuberculocidal and mycobactericidal efficacy by the internationally accepted test procedure described in EN 14348. However, especially for amine-based disinfectants, invalid results may occur by this procedure due to insufficient neutralization. In this multi-laboratory study the procedure described in EN 14348 was optimized by a combination of chemical neutralization and membrane filtration in order to obtain a valid and secure method especially for amine-based disinfectants.

In-vitro activity of active ingredients of disinfectants against drug-resistant fungi.

The biocidal activities of peracetic acid and ethanol were tested against nine clinical fungal isolates and four reference strains. Ethanol was active (≥4.0 log10 reduction) against yeasts at a concentration of 50% v/v and against moulds at 80% v/v. Exposure times in both cases were 1 min. Peracetic acid was active as a 0.25% solution against yeasts and as a 0.5% solution against moulds; exposure times in both cases were 5 min. Compared with the reference strains, clinical isolates, including multi-drug-resistant strains, showed similar or higher sensitivity to the active ingredients of disinfectants in vitro.

Interlaboratory reproducibility of a test method following 4-field test methodology to evaluate the susceptibility of Clostridium difficile spores.

BACKGROUND: Sporicidal surface disinfection is recommended to control transmission of Clostridium difficile in healthcare facilities. EN 17126 provides a method to determine the sporicidal activity in suspension and has been approved as a European standard. In addition, a sporicidal surface test has been proposed. AIM: To determine the interlaboratory reproducibility of a test method for evaluating the susceptibility of a C. difficile spore preparation to a biocidal formulation following the 4-field test (EN 16615 methodology). METHODS: Nine laboratories participated. C. difficile NCTC 13366 spores were used. Glutaraldehyde (1% and 6%; 15 min) and peracetic acid (PAA; 0.01% and 0.04%; 15 min) were used to determine the spores' susceptibility in suspension in triplicate. FINDINGS: One-percent glutaraldehyde revealed a mean decimal log10 reduction of 1.03 with variable results in the nine laboratories (0.37-1.49) and a reproducibility of 0.38. The effect of 6% glutaraldehyde was stronger (mean: 2.05; range: 0.96-4.29; reproducibility: 0.86). PAA revealed similar results. An exemplary biocidal formulation based on 5% PAA was used at 0.5% (non-effective concentration) and 4% (effective concentration) to determine the sporicidal efficacy (4-field test) under clean conditions in triplicate with a contact time of 15 min. When used at 0.5% it demonstrated an overall log10 reduction of 2.68 (range: 2.35-3.57) and at 4% of 4.61 (range: 3.82-5.71). The residual contamination on the three primarily uncontaminated test fields was <50 cfu/25 cm2 in one out of nine laboratories (0.5%) and in seven out of nine laboratories (4%). CONCLUSION: The interlaboratory reproducibility seems to be robust.

Randomized controlled clinical trial on the antiseptic efficacy of polihexanide 0.04% on acute traumatic wounds.

Prevention of wound infections is a challenge in clinical practice. The aim of this study was to assess the efficacy of polyhexamethylene biguanide (PHMB, polihexanide) 0.04% on acute traumatic wounds. It was a randomized, double-blind, placebo-controlled prospective trial which included 61 patients. The polihexanide group showed a significant decrease in log10 colony-forming units (cfu) (P < 0.001) after 60 min treatment in comparison to baseline cfu, whereas the Ringer solution group did not show a significant change in cfu during 60 min treatment. Treatment of polihexanide 0.04% resulted in a significant reduction of bacterial load in acute traumatic wounds.

[Migration speed of uropathogens : Determination in the ureteral splint in a practice-like in vitro model]. / Wanderungsgeschwindigkeit von uropathogenen Erregern : Bestimmung im Ureterkatheter im praxisnahen In-vitro-Modell.

BACKGROUND: A urostomy with an ileum conduit or a skin fistula leads to a high infection risk for the kidneys and the ureter of the patient. Therefore, the prevention of retrograde colonization of the artificial drain (splint) with e. g. contaminated urine is the most important objective of infection prevention measurements. We performed an in vitro experiment to determine the migration speed of clinically relevant bacteria in a commercially available splint catheter system. METHODS: The migration speed of bacteria in commonly used splint catheters was determined in a practice-like in vitro model. Two storage vessels were connected with splints. The second vessel contained a bacterial suspension of the test bacteria Escherichia coli, Proteus mirabilis, and Staphylococcus aureus in artificial urine. The two vessels were incubated at 36 °C for 24-72 h. The microbial count in the catheters was determined after each experiment to investigate the migration distance. RESULTS: The average migration speed was 0.63 cm/h for E. coli, 0.80 cm/h for S. aureus, and 0.94 cm/h for P. aeruginosa. This results in a colonization distance of approximately 80 cm in 3 days. CONCLUSION: If the system, e. g., the stoma pouch is contaminated, it can be expected that during the common application time of a splint of 10-14 days, the complete splint will be contaminated due to the high bacteria migration speed. Consequently there is a high infection risk for kidneys and ureters. A return stop feature in the stoma pouch should minimize this risk. However, it is of upmost importance to not applying the splint through the return stop to prevent any contact with potentially contaminated urine.

[The influence of viscosity of synthetic urine on the flow rate through catheters]. / Der Einfluss der Viskosität von künstlichem Harn auf die Durchflussgeschwindigkeit in Kathetern.

BACKGROUND: There are special requirements for draining a pouch, e.g. length, flexibility and ability to drain highly viscous urine. METHODS: We checked in vitro the flow time of pure and synthetic urine thickened with hydroxyethylcellulose (0.125% and 0.250%, HEC) on selected catheters. RESULTS: We found for SpeediCath Compact Male (SCCM) as a CH12 catheter the shortest flow times for undiluted and urine thickened with 0.125% and for SafetyCath Plus for urine thickened with 0.250%. For catheters with CH14 we found significantly shorter flow times for all tested solutions. The flow time does not depend on amount and area of the catheter eyes; we found no difference in the flow time for 4-eye (MobiStom) and 2-eye catheters.

Polihexanide for wound treatment--how it began.

The essential role of wound antiseptics was discovered in the 18th century. Since then, many different procedures and substances have been developed and used for this indication. In the 1980s, polihexanide was introduced by Prof. Willenegger in Switzerland. Today, consensus recommendations confirm the potential of this substance for wound treatment. Various polihexanide-containing wound care products are available and these are now also gaining in importance throughout Europe and throughout the world.