Removal, Kill, and Transfer of Bacteria from Hands by Antibacterial or Nonantibacterial Soaps After Handling Raw Poultry.

Hand hygiene is broadly recognized as a critical intervention in reducing the spread of disease-causing pathogens in both professional and personal uses. In this study, the impact of antibacterial (AB) or nonantibacterial soaps on the removal and postwash transfer of E. coli following the handling of raw poultry was assessed. Baseline bacterial contamination ranged between 107 and 109 CFU per hand. Hands were washed for 30 s in 40°C ± 2°C tap water using 2 mL of AB soap (0.5% and 1.0% Chloroxylenol, 0.5% Benzalkonium Chloride, or 4.0% Chlorhexidine Gluconate), non-AB soap (cosmetic/plain soap), or water. Postwash, water, and non-AB soap had a mean 3.63 and 3.65 Log10 reduction of E. coli on hands. AB treatments had a mean 4.19-4.35 Log10 reduction. Rinse water had mean bacterial counts of 8.62 and 8.88 Log10 CFU/mL for non-AB soap and water and 5.37-6.90 Log10 CFU/mL for AB treatments. Bacterial transfer was assessed by following the test subject's handling of a sterile polymer knife handle for 30 s postwash. E. coli transfer ranged from 263 to 903 CFU/handle for AB soaps and 1572 or 1709 CFU/handle for water and non-AB soap. Differences between AB and non-AB treatments were statistically significant (p < 0.0001) for hands and rinse water. Differences in transfer from hands to knife handle were not statistically significant (p = 0.139). Combined, these data highlight significant differences in the performance of AB soaps relative to non-AB soaps in a food handling environment-specific usage example and provide an unexplored assessment of the bactericidal vs. removal effects of AB vs. non-AB soaps on bacteria removed from the hands. These data reinforce the importance of hand hygiene, provide new details on the differences between AB vs. non-AB soaps, and highlight potential differences to inform food handling environment operators and public health personnel on how these products may impact food safety.

Effect of handwashing on the reduction of Escherichia coli on children's hands in an urban slum Indonesia.

Poor hand hygiene practice has been linked to an increase in the number of infections among children in urban slums. Hands are considered an intersection for bacterial transmission, but it is unclear whether the handwashing technique affects bacteria elimination. This study investigated the effect of handwashing on the concentration of Escherichia coli (E. coli) and factors related to its reduction among children in an urban slum in Bandung, Indonesia. We observed handwashing and conducted repeated hand swabs before and after handwashing among 137 participants. The mean E. coli concentration on the hands decreased after handwashing, with a higher reduction in E. coli count among students who used soap and had soap contact for more than 10 s during handwashing. Cleaning in-between fingers, using soap, soap contact for more than 10 s, and drying hands with a single-use towel were effective factors for reducing E. coli concentration after handwashing (p < 0.05). More than half of the swab samples (59%) tested positive for E. coli after handwashing, indicating that the children's handwashing technique was not effective in completely removing E. coli from the hands. Moreover, sustained and consistent handwashing practice as a daily behavior in children would maximize the effect.

Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes.

BACKGROUND: The standard operating procedure for testing the susceptibility of adult mosquitoes to neonicotinoid or butenolide insecticides recommends using a vegetable oil ester (Mero) as a surfactant. However, there is growing evidence that this adjuvant contains surfactants that can enhance insecticide activity, mask resistance and bias the bioassay. METHODOLOGY/PRINCIPAL FINDINGS: Using standard bioassays, we tested the effects of commercial formulations of vegetable oil-based surfactants similar to Mero on the activity of a spectrum of active ingredients including four neonicotinoids (acetamiprid, clothianidin, imidacloprid and thiamethoxam) and two pyrethroids (permethrin and deltamethrin). We found that three different brands of linseed oil soap used as cleaning products drastically enhanced neonicotinoid activity in Anopheles mosquitoes. At 1% (v/v), the surfactant reduced the median lethal concentration, LC50, of clothianidin more than 10-fold both in susceptible and in resistant populations of Anopheles gambiae. At 1% or 0.5% (v/v), linseed oil soap restored the susceptibility of adult mosquitoes fully to clothianidin, thiamethoxam and imidacloprid and partially to acetamiprid. By contrast, adding soap to the active ingredient did not significantly affect the level of resistance to permethrin or deltamethrin suggesting that vegetable oil-based surfactants specifically enhance the potency of some classes of insecticides. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that surfactants are not inert ingredients, and their use in susceptibility testing may jeopardize the ability to detect resistance. Further research is needed to evaluate the potential, the limitations and the challenges of using some surfactants as adjuvants to enhance the potency of some chemicals applied in mosquito control.

A controlled forearm washing ex vivo method for assessing the impact of personal cleansing products on skin's acid mantle properties and antimicrobial defence against transient bacteria.

BACKGROUND: An important trend in the personal care industry involves the development of advanced personal cleaning products that not only provide skin mildness but support skin's acid mantle properties and skin's natural antimicrobial defence function. OBJECTIVE: The objective of this study was to develop a controlled forearm washing ex vivo method for assessing the impact of personal cleansing products on skin's acid mantle properties and antimicrobial defence against transient bacteria. METHODS: We developed a controlled forearm washing ex vivo method (ex vivo NET method) to compare the impact of two representative personal cleansing products on skin's acid mantle properties and antimicrobial defence against transient bacteria: one was a low-pH skin cleanser, and the other was high-pH soap cleanser. Skin pH was measured at baseline and 4 h after the product application. Concurrently, D-squame tape stripping procedure was followed to sample the stratum corneum surface layers. Then, two selected transient bacteria, Staphylococcus aureus and Escherichia coli, were inoculated onto the D-squame tapes and incubated under controlled conditions, respectively. The residual bacteria counts can provide an objective measure of skin's acid mantle properties against transient bacteria. Results from the ex vivo NET method were compared with the traditional in vivo cup-scrub RET method. RESULTS: The skin pH was significantly lower 4 h after washing the forearm with the low-pH cleanser versus the high-pH soap, consistent with literatures. Interestingly, the skin surface washed by the low-pH cleanser showed significantly higher hostility against representative transient bacteria as demonstrated by the lower counts of S. aureus by 1.09 log and E. coli by 0.6 log versus the high-pH soap based on the ex vivo NET method. Results from the ex vivo NET method were further supported by the traditional in vivo RET method which also showed the skin washed by the low-pH cleanser had significantly lower counts of S. aureus and E. coli versus the high-pH soap. CONCLUSIONS: The skin's acid mantle properties and antimicrobial defence can be directly impacted by the personal cleansing products. The low-pH skin cleanser works better than the high-pH soap for supporting skin's acid mantle properties and antimicrobial defence against transient bacteria. Results from the ex vivo NET method are consistent with the in vivo RET method. It is important that the ex vivo NET method offers many advantages since it is quicker to run with higher throughput and has better safety without the constraint of inoculating harmful microorganisms onto the human subjects.

CONTEXTE: Une tendance importante du secteur des soins personnels est de développer des produits d'hygiène personnelle sophistiqués qui non seulement rendent la peau plus douce, mais favorisent également les propriétés du manteau acide de la peau et la fonction de défense antimicrobienne naturelle de la peau. OBJECTIF: L'objectif de cette étude était de développer une méthode ex vivo de lavage contrôlé des avant-bras pour évaluer l'impact des produits d'hygiène personnelle sur les propriétés du manteau acide de la peau et la défense antimicrobienne contre les bactéries transitoires. MÉTHODES: Nous avons développé une méthode ex vivo de lavage contrôlé des avant-bras (méthode NET ex vivo) pour comparer l'impact de deux produits d'hygiène personnelle représentatifs sur les propriétés du manteau acide de la peau et la défense antimicrobienne contre les bactéries transitoires: d'une part un nettoyant pour la peau à pH faible, d'autre part un savon nettoyant à pH élevé. Le pH de la peau a été mesuré à l'entrée dans l'étude et quatre heures après l'application du produit. Parallèlement, une procédure de stripping par ruban adhésif D-Squame a été suivie pour prélever des couches de surface de la couche cornée. Ensuite, deux bactéries transitoires sélectionnées, S. aureus et E. coli, ont été inoculées sur les rubans adhésifs D-Squame et incubées dans des conditions contrôlées, respectivement. Le nombre de bactéries résiduelles peut fournir une mesure objective des propriétés du manteau acide de la peau contre les bactéries transitoires. Les résultats de la méthode NET ex vivo ont été comparés à la méthode RET in vivo traditionnelle par coupe-grattage. RÉSULTATS: Le pH de la peau était significativement inférieur quatre heures après le lavage des avant-bras avec le nettoyant à pH faible en comparaison avec le savon à pH élevé, conformément à la littérature. Il est intéressant de noter que la surface de la peau lavée au moyen du nettoyant à pH faible présentait une hostilité significativement plus élevée contre les bactéries transitoires représentatives, comme démontré par le nombre inférieur de S. aureus de 1,09 log et d'E. coli de 0,6 log, en comparaison avec le savon à pH élevé, sur base de la méthode NET ex vivo. Les résultats de la méthode NET ex vivo ont été encore par la méthode RET in vivo traditionnelle, laquelle a également démontré que la peau lavée à l'aide du nettoyant à pH faible présentait des nombres significativement plus faibles de S. aureus et d'E. coli que celle lavée à l'aide du savon à pH élevé. CONCLUSIONS: Les propriétés du manteau acide de la peau et la défense antimicrobienne peuvent être directement affectées par les produits d'hygiène personnelle. Le nettoyant de la peau à pH faible fonctionne mieux que le savon à pH élevé pour ce qui est de favoriser les propriétés du manteau acide de la peau et la défense antimicrobienne contre les bactéries transitoires. Les résultats de la méthode NET ex vivo sont cohérents avec la méthode RET in vivo. Il est important de noter que la méthode NET ex vivo offre de nombreux avantages étant donné qu'elle est plus rapide à exécuter avec une capacité plus élevée et offre une meilleure sécurité sans la contrainte d'inoculer des micro-organismes nocifs à des sujets humains.

Effects of Liquid and Bar Soaps on the Skin of Brazilian Newborns: A Randomized Controlled Trial.

INTRODUCTION: Compared to adults, newborns' skin has a thinner epidermis and stratum corneum with decreased hydration levels, higher transepidermal water loss, and a pH variation between 5.5 and 7.5. These characteristics can predispose to the occurrence of dryness, infections, and dermatological conditions. Water and liquid soap with adequate formulation have shown to be beneficial and safe for newborns' skin. However, studies evaluating the effect of bar soap, products widely used in Brazil and Latin America, are unknown. Therefore, the objective of this study was to compare the effects of liquid and bar soaps on the term newborns' skin. METHODS: This randomized controlled, parallel, single-blind clinical trial was conducted at a public university hospital in São Paulo, Brazil. 100 healthy term newborns with no congenital anomalies, acute diseases, or dermatological conditions were randomized to use liquid soap (experimental group) or bar soap (control group). Skin pH, transepidermal water loss, stratum corneum hydration, sebum content, and skin condition were assessed before and after the first bath, at 48 h, 14 days, and 28 days after birth. These evaluations were performed on the forearm, abdomen, buttocks, and thigh. In addition, the mother's perception of soap use was also evaluated. RESULTS: Data of 100 newborns were analyzed by intention to treat. The rate of retention was 53%. Newborns exposed to the liquid soap presented significantly better skin acidification (p < 0.001) and significantly better stratum corneum hydration (p < 0.001) than the skin of newborns exposed to the bar soap, regardless of the area evaluated. There were no significant differences in transepidermal water loss, sebum content, dryness, erythema, or skin breakdown and the mother's perceptions of the use of the soaps. CONCLUSION: Newborns in the experimental group presented better skin acidification and stratum corneum hydration when compared to newborns in the control group.

Evaluation of antibacterial and antifungal activity of antimicrobial soaps.

Soaps play an important role in our hygiene and health, as they not only have a bactericidal effect but also remove dirt from the human body. To evaluate the effectiveness of soaps with antimicrobial activity from different commercial brands sold in Brazil. Tests of the antimicrobial activity of different soaps were carried out through diffusion in agar against the microorganisms Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Acinetobacter baumannii, Proteus mirabilis, and Candida albicans. All commercial soaps tested transfer antimicrobial inhibition halo formation against S. aureus and P. aeruginosa bacteria. Only two commercial soaps inhibit the species A. baumannii and C. albicans. None of the seven products studied showed inhibition of E. cloacae, P. mirabilis, and E. coli bacteria. When comparing the information contained in the packaging of the products with the results obtained during a survey, divergences were observed. The soaps that provide greater efficiency against the tested microorganisms were presented in presentations 1 and 2, which become useful against the bacteria species S. aureus, P. aeruginosa, and A. baumannii and a fungus species C. albicans. Marks 3, 4, 5, 6, and 7 parallel the same sensitivity result opposite as bacteria of the species S. aureus and P. aeruginosa, with quantitative variation only of the inhibition halo. There was a divergence between the information contained in the packaging of the seven products under study and the results of the experimental tests.

Effect of New Surfactants on Biological Properties of Liquid Soaps.

Liquid soaps are the basic cosmetics used to clean the skin of the hands. Frequent hand washing prevents viral contamination but may damage the skin's hydro-lipid layer, leading to various types of irritation. Therefore, four liquid soap formulas were developed with three amphoteric surfactants: Cocamidopropyl Betaine (LS II), CocamidopropylHydroxysultaine (LS III), and newly synthesized Evening PrimroseaamidopropylSulfobetaine (LS IV). We evaluated the skin irritating potential (zein number, bovine albumin test) and cytotoxicity (AlamarBlue™, Cell viability, and Cell cycle assays) on HaCaT cell line. We observed lower values of the zein number and bovine albumin tests after adding soaps with surfactants (the highest differences in LS IV) compared to the base soap (LS I). However, LS I and LS II did not differ in cytotoxic assays. Therefore, adding LS III and LS IV seems potentially more dangerous to the cells. However, it should be noted that cells were continuously exposed to liquid soaps for more than 24 h, so its cytotoxic effects after dermal use in humans may be unnoticeable. Concluding, results suggest that the newly synthesized LS IV should improve the safety of liquid hand washing soaps.

Effects of Hand Hygiene Using 4% Chlorhexidine Gluconate or Natural Soap During Hand Rubbing Followed by Alcohol-Based 1% Chlorhexidine Gluconate Sanitizer Lotion in the Operating Room.

Objective: Hand hygiene using either 4% chlorhexidine gluconate (CHG) or natural soap during hand rubbing, followed by alcohol-based 1% CHG sanitizer lotion in the operating room was compared to assess bacterial reduction, skin moisture, skin texture, and hand hygiene using qualitative questionnaires. Approach: A crossover study with 36 professional scrub nurses at two medical centers was performed to compare 4% CHG followed by alcohol-based 1% CHG sanitizer lotion, the Two-stage method with handwashing using natural soap followed by alcohol-based 1% CHG sanitizer lotion, and the Waterless method, after a period of 10 days of use. The study completely followed CONSORT, www.consort-statement.org. Results: There was no significant difference in bacterial reduction based on the bacterial colony-forming units between the two methods. The skin moisture and skin roughness scores were not significantly different between the two methods. The Waterless method was significantly better than the Two-stage method regarding "foaming," "quality," "longevity" (p < 0.0001, p < 0.0001, and p < 0.0001, respectively), but "disappearance" was significantly better by the Two-stage method (p = 0.0095) during washing and rubbing. Immediately after washing and rubbing, the Waterless method was significantly better regarding "tightness" and "moisture," whereas the Two-stage method was significantly better regarding "stickiness" (p = 0.0114, p = <0.0001, and 0.0059, respectively) Innovation: The Waterless method using natural soap during handwashing followed by alcohol-based 1% CHG sanitizer lotion was as effective as the Two-stage method of 4% CHG followed by alcohol-based 1% CHG sanitizer lotion. Conclusion: Handwashing using natural soap is simple and superior to hand scrubbing in several aspects.

Rosin Soap Exhibits Virucidal Activity.

Chemical methods of virus inactivation are used routinely to prevent viral transmission in both a personal hygiene capacity but also in at-risk environments like hospitals. Several virucidal products exist, including hand soaps, gels, and surface disinfectants. Resin acids, which can be derived from tall oil, produced from trees, have been shown to exhibit antibacterial activity. However, whether these products or their derivatives have virucidal activity is unknown. Here, we assessed the capacity of rosin soap to inactivate a panel of pathogenic mammalian viruses in vitro. We show that rosin soap can inactivate human enveloped viruses: influenza A virus (IAV), respiratory syncytial virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For IAV, rosin soap could provide a 100,000-fold reduction in infectivity. However, rosin soap failed to affect the nonenveloped encephalomyocarditis virus (EMCV). The inhibitory effect of rosin soap against IAV infectivity was dependent on its concentration but not on the incubation time or temperature. In all, we demonstrate a novel chemical inactivation method against enveloped viruses, which could be of use for preventing virus infections in certain settings. IMPORTANCE Viruses remain a significant cause of human disease and death, most notably illustrated through the current coronavirus disease 2019 (COVID-19) pandemic. Control of virus infection continues to pose a significant global health challenge to the human population. Viruses can spread through multiple routes, including via environmental and surface contamination, where viruses can remain infectious for days. Methods for inactivating viruses on such surfaces may help mitigate infection. Here, we present evidence identifying a novel virucidal product, rosin soap, which is produced from tall oil from coniferous trees. Rosin soap was able to rapidly and potently inactivate influenza virus and other enveloped viruses.

Responses of ticks to immersion in hot bathing water: Effect of surface type, water temperature, and soap on tick motor control.

Preventing bites from undetected ticks through bathing practices would benefit public health, but the effects of these practices have been researched minimally. We immersed nymphal and adult hard ticks of species common in the eastern United States in tap water, using temperatures and durations that are realistic for human hot bathing. The effect of (a) different skin-equivalent surfaces (silicone and pig skin), and (b) water temperature was tested on Amblyomma americanum, Dermacentor variabilis and Ixodes scapularis nymphs. Overall, the type of surface had a much larger effect on the nymphs' tendency to stay in contact with the surface than water temperature did. Most nymphs that separated from the surface did so within the first 10 s of immersion, with the majority losing contact due to the formation of an air bubble between their ventral side and the test surface. In addition, adult Ixodes scapularis were tested for the effect of immersion time, temperature, and soap on tick responsiveness. Some individual adults moved abnormally or stopped moving as a result of longer or hotter immersion, but soap had little effect on responsiveness. Taken together, our results suggest that the surface plays a role in ticks' tendency to stay in contact; the use of different bath additives warrants further research. While water temperature did not have a significant short-term effect on tick separation, ticks that have not attached by their mouth parts may be rendered unresponsive and eventually lose contact with a person's skin in a hot bath. It should be noted that our research did not consider potential temperature effects on the pathogens themselves, as previous research suggests that some tickborne pathogens may become less hazardous even if the tick harboring them survives hot-water exposures and later bites the bather after remaining undetected.

Comparable Environmental Stability and Disinfection Profiles of the Currently Circulating SARS-CoV-2 Variants of Concern B.1.1.7 and B.1.351.

The emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern with increased transmission dynamics has raised questions regarding stability and disinfection of these viruses. We analyzed surface stability and disinfection of the currently circulating SARS-CoV-2 variants B.1.1.7 and B.1.351 compared to wild type. Treatment with heat, soap, and ethanol revealed similar inactivation profiles indicative of a comparable susceptibility towards disinfection. Furthermore, we observed comparable surface stability on steel, silver, copper, and face masks. Overall, our data support the application of currently recommended hygiene measures to minimize the risk of B.1.1.7 and B.1.351 transmission.

Detergentes: De los principios físicos a las aplicaciones biofarmacéuticas (o por qué prevenimos la covid-19 con agua y jabón / Detergents: From physical principles to biopharmaceutical applications (or why we fight covid-19 with toilet soap)

Los detergentes son anfifilos solubles que poseen la capacidad de solubilizar grasas, dando lugar a micelas mixtas lípido-detergente, que son solubles en agua. Los detergentes son ampliamente utilizados en las industrias alimentaria y de bebidas, textil, médica y farmacéutica, entre otras. En biología molecular, los detergentes son herramientas insustituibles en la solubilización de las membranas celulares y la posterior purificación de proteínas de membrana. La presente revisión resume cuatro décadas de investigación sobre detergentes en el laboratorio de los autores. Una introducción sobre los detergentes y las membranas va seguida por una descripción cuantitativa detallada del mecanismo de solubilización de la membrana por los detergentes, y por una discusión crítica del concepto de membranas resistentes a los detergentes en relación con la hipótesis de las balsas lipídicas (rafts). A continuación, se incluye una sección experimental que resume los principales resultados del grupo de los autores. Finalmente, se describen algunas aplicaciones biofarmacéuticas. Como ejemplo práctico, se discute el uso de jabón de tocador en la prevención de la COVID-19

Detergents are soluble amphiphiles that possess the capacity to solubilize fats, giving rise to water-soluble, lipid-detergent mixed micelles. Detergents find an extensive use in food and drink, textile, medical and pharmaceutical industries, among others. In molecular biology, detergents are irreplaceable tools in the solubilization of cell membranes and subsequent membrane protein purification. The present review summarizes four decades of investigation on detergents in the authors' laboratory. An introduction on detergents and membranes is followed by a detailed, quantitative description of the mechanism of membrane solubilization by detergents, and a critical discussion of the concept of detergent-resistant membranes as related to the lipid raft hypothesis. An experimental section follows, summarizing the main results in the authors' group. Finally, some biopharmaceutical applications are described. As a working example, the use of toilet soap in the prevention of COVID-19 is discussed

Evaluating the Efficacy of the Supertowel™ as a Handwashing Product: A Simulation of Real-World Use Conditions.

The Supertowel is a fabric treated with a permanent antimicrobial bonding and has been designed as a soap alternative in emergency situations. The Supertowel has been shown to be as efficacious as handwashing with soap and water when tested under controlled laboratory conditions. It has also been shown to be a practical, acceptable, and desirable product among crisis-affected populations. The aim of this study was to test whether the Supertowel remains as efficacious when used under conditions which mimic real-world hand cleaning in challenging settings. Two rounds of laboratory tests, with 16 volunteers in each, were conducted to test the efficacy of the Supertowel when used for a shorter duration, when less wet, when used with contaminated water, when visibly dirty, and when dry. Volunteers pre-contaminated their hands with nonpathogenic Escherichia coli. Comparisons were made between hand cleaning with the Supertowel and the reference condition (normally handwashing with soap), using a crossover design. The Supertowel was marginally less efficacious than handwashing with soap when used for 15 seconds (P = 0.04) but as efficacious at 30 and 60 seconds durations. All the other Supertowel conditions were as efficient as their reference comparisons meaning that the Supertowel can effectively remove pathogens from hands when it is wet, damp, or completely dry, when it is used with contaminated water, when visibly dirty with mud and/or oil.

Melaleuca alternifolia essential oil soap: a potential alternative for hand hygiene.

This study aimed to compare the antimicrobial action of three soaps for hand hygiene (HH): 2.0% Tea Tree Oil (TTO); 0.5% triclosan; 2.0% chlorhexidine, and to explore the perception of healthcare professionals about TTO. Two-step study: a quantitative, to determine the logarithmic reduction of Escherichia coli K12 colony-forming units before and after HH of 15 volunteers and quali-quantitative, through interviews with 23 health professionals. All the three products demonstrated antimicrobial action (a log10 reduction factor of 4.18 for TTO, 4.31 for triclosan, 3.89 for chlorhexidine, and 3.17 for reference soap). Professionals remarked the pleasant aroma and non-dryness of skin when using soap containing TTO.

Effect of zinc pyrithione shampoo treatment on skin commensal Malassezia.

Malassezia restricta and Malassezia globosa are lipid dependent commensal yeasts associated with dandruff. Antifungal actives such as zinc pyrithione are commonly used in antidandruff shampoos, although their efficacy is not clearly demonstrated. In this study, we assessed the efficacy of antifungal treatments on scalp Malassezia via a combination of culturomic and genomic detection methods. Zinc pyrithione inhibited Malassezia growth at low minimum inhibitory concentrations (MICs). In a longitudinal pilot study, quantitative polymerase chain reaction (qPCR) analysis showed a decrease in M. restricta on the scalp after zinc pyrithione treatment. These findings validate the antifungal efficacy of zinc pyrithione as a dandruff treatment. LAY ABSTRACT: Malassezia yeasts are associated with dandruff and seborrheic dermatitis. Zinc pyrithione is effective against Malassezia growth in vitro and when tested on human skin as a shampoo. These findings will be useful for investigating the role of Malassezia in skin microbiome intervention studies.

Antiviral efficacy of personal care formulations against Severe Acute Respiratory Syndrome Coronavirus 2.

BACKGROUND: Non-therapeutic interventions such as practicing good hand hygiene continue to be the mainstay of protection from SARS-CoV-2 and other emerging respiratory viruses. METHODS: We have evaluated a range of commercially available personal care products including soaps, handwash liquids and alcohol-based hand sanitizers for antiviral efficacy against a clinical isolate of SARS-CoV-2 using internationally accepted standardized protocols at user-relevant contact time-points and product dilutions. RESULTS: All the tested products resulted in 3 to 4 log reduction of SARS-CoV-2 titer. CONCLUSION: Our data re-affirms recommendations by global public health authorities that proper hand hygiene can reduce SARS-CoV-2 viral load significantly which should likely limit spread of the contagion.

Soap and syndets: differences and analogies, sources of great confusion.

OBJECTIVE: Soap has been used by humankind since ancient times and was probably already known to the Sumerians. It is a fatty acid salt obtained from the reaction of a strong base with a fatty substance of animal (tallow) or plant origin (oil). This reaction is called saponification. Syndets, on the other hand, are much more recent and have been in use for about a century. In the case of liquid syndets, they are mainly alkyl sulphates and their derivatives alkyl ether sulphates while isethionates and sarcosinates are more commonly found in solid syndets. Synthetic soaps and detergents are surfactants and, as such, they have detergent properties. The way soap works accounts for its antimicrobial properties. Thanks to its amphiphilic structure, it is able to interact with the lipid membranes of microorganisms (viruses, bacteria, etc.) and inactivate them. In this coronavirus pandemic period, health authorities worldwide recommend hand washing with soap and water. We therefore wanted to provide a summary of the chemical characteristics and applications of soaps, on the one hand, and synthetic detergents, on the other. Soap is not the only product used for hand hygiene and, given the current situation, alternatives are complex and varied.

Synergistic effects of anionic surfactants on coronavirus (SARS-CoV-2) virucidal efficiency of sanitizing fluids to fight COVID-19.

Our surrounding environment, especially often-touched contaminated surfaces, plays an important role in the transmission of pathogens in society. The shortage of effective sanitizing fluids, however, became a global challenge quickly after the coronavirus disease-19 (COVID-19) outbreak in December 2019. In this study, we present the effect of surfactants on coronavirus (SARS-CoV-2) virucidal efficiency in sanitizing fluids. Sodium dodecylbenzenesulfonate (SDBS), sodium laureth sulfate (SLS), and two commercial dish soap and liquid hand soap were studied with the goal of evaporation rate reduction in sanitizing liquids to maximize surface contact time. Twelve fluids with different recipes composed of ethanol, isopropanol, SDBS, SLS, glycerin, and water of standardized hardness (WSH) were tested for their evaporation time and virucidal efficiency. Evaporation time increased by 17-63% when surfactant agents were added to the liquid. In addition, surfactant incorporation enhanced the virucidal efficiency between 15 and 27% according to the 4-field test in the EN 16615:2015 European Standard method. Most importantly, however, we found that surfactant addition provides a synergistic effect with alcohols to inactivate the SARS-CoV-2 virus. This study provides a simple, yet effective solution to improve the virucidal efficiency of commonly used sanitizers.

Assessing the impact of handwashing soaps on the population dynamics of carbapenemase-producing and non-carbapenemase-producing Enterobacterales.

Carbapenemase-producing bacteria have persistent environmental reservoirs in handwashing sinks. This study assessed the impact of handwashing soaps on the population dynamics of carbapenemase-producing Enterobacterales (CPE) and non-CPE. A number of isolates were grown in minimal media with or without two hand soaps marketed for use in health care. Soap A led to increased growth of all isolates except for Escherichia coli. Soap B did not lead to increased growth. The main difference between the formulations was that Soap B contained DMDM hydantoin, a preservative agent and sensitizer. These results show that environmental persistence of CPE may be sustained by common handwashing practices with soap, but further research is required.