The method used to dry washed hands affects the number and type of transient and residential bacteria remaining on the skin

Impact of different hand-drying methods on surrounding environment: aerosolization of virus and bacteria, and transfer to surfaces

BACKGROUND

In recent years, hand drying has been highlighted as a key step in appropriate hand hygiene, as moisture on hands can increase the transfer of micro-organisms from hands to surfaces and vice versa.

AIM

To understand bacterial and viral aerosolization following hand drying, and study the transfer of micro-organisms from hands to surfaces after drying using different methods.

METHODS

Groups of five volunteers had their hands pre-washed with soap, rinsed and dried, then inoculated with a concentrated mixture of Pseudomonas fluorescens and MS2 bacteriophage. Volunteers entered an empty washroom, one at a time, and rinsed their hands with water or washed their hands with soap prior to drying with a jet dryer or paper towels. Each volunteer applied one hand successively to various surfaces, while their other hand was sampled using the glove juice method. Both residual bacteria and viruses were quantified from the washroom air, surface swabs and hand samples.

FINDINGS

P. fluorescens and MS2 bacteriophages were rarely aerosolized while drying hands for any of the drying methods studied. Results also showed limited, and similar, transfer of both micro-organisms studied on to surfaces for all drying methods.

CONCLUSION

The use of jet dryers or paper towels produces low levels of aerosolization when drying hands in a washroom. Similarly, all drying methods result in low transfer to surfaces. While the coronavirus disease 2019 pandemic raised concerns regarding public washrooms, this study shows that all methods tested are hygienic solutions for dry washed hands.

Hand hygiene status and its associated factors among housemaids working in communal living residences in Jimma city, southwest Ethiopia

Objective

Hand hygiene is a milestone, cost-effective, and convenient strategy to prevent the transfer of pathogenic micro-organisms. However, housemaids operating inside a kitchen can be the source of infection. In addition, hand hygiene among housemaids working in dwellings was underexplored. This study aimed to assess the hand hygiene status and associated factors among housemaids working in communal living residences in Jimma City, Southwest Ethiopia.

Methods

A total of 230 housemaids were included in this cross-sectional study. Total samples were proportionally allocated for each residence and a simple random sampling technique was applied to select the study participants. Hand hygiene status and relevant characteristics were collected through face-to-face interviews and observations. Hand swab samples were collected and tested for bacterial contaminants. Then, it was inoculated aseptically using streak-plating methods on mannitol salt agar (MSA), MacConkey agar (MCA), salmonella-shigella agar (SSA), and eosin methylene blue (EMB) agar and then incubated at 37 °C for 24 h. Data was edited, cleaned, and double-entered into Epidata version 3.1 and then exported to the statistical package for social science statistics version 26 for further analysis. Binary logistic regression was used to identify associated factors. Statistically significant was declared at P value < 0.05.

Results

Two hundred twenty-five housemaids were interviewed with a response rate of 97.8 %. The results showed that the proportion of good hand hygiene status among the housemaids was only 28.0 %. Although the majority of participants reported washing their hands frequently, the prevalence of bacterial contaminants on their hands was high at 72 %. The study identified several factors associated with hand hygiene status, including the occupational status of heads of households (AOR = 0.030, 95 % CI: 0.003, 0.348; P = 0.0050), the effectiveness of the heads of household (AOR = 13.955, 95 % CI: 1.442, 13.500; P = 0.0230), and the removal of accessories during handwashing (AOR = 20.844, 95 % CI: 2.190, 9.842; P = 0.0080).

Conclusion

Overall, the hand hygiene status of housemaids was found to be poor and influenced by demographics and other relevant characteristics. The study emphasizes the need for a multimodal strategy involving household heads, local and national authorities, and other stakeholders to raise awareness and advocate for hand hygiene to prevent communicable diseases in the wider community, particularly in the study area.

Effect of Long-Term Use of Alcohol-Containing Handwashing Gels on the Biofilm-Forming Capacity of Staphylococcus epidermidis

The spread of coronavirus disease 2019 (COVID-19) has promoted the use of hand sanitizers among the general population as recommended by health authorities. Alcohols, which are used in many hand sanitizers, have been shown to promotes the formation of biofilms by certain bacteria and to increase bacterial resistance to disinfection. We investigated the effect of continued use of alcohol-based gel hand sanitizer on biofilm formation by the Staphylococcus epidermidis resident strain isolated from the hands of health science students. Hand microbes were counted before and after handwashing, and the ability to produce biofilms was investigated. We found that 179 (84.8%) strains of S. epidermidis isolated from hands had the ability to form biofilm (biofilm-positive strains) in an alcohol-free culture medium. Furthermore, the presence of alcohol in the culture medium induced biofilm formation in 13 (40.6%) of the biofilm-negative strains and increased biofilm production in 111 (76.6%) strains, which were classified as low-grade biofilm-producing. Based on our findings, there is no clear evidence that the continued use of alcohol-based gels results in the selection of strains with the capacity to form biofilms. However, other disinfectant formulations that are more commonly used in clinical settings, such as alcohol-based hand-rub solutions, should be tested for their long-term effects.

Effect of Optimal Alcohol-Based Hand Rub among Nurse Students Compared with Everyday Practice among Random Adults; Can Water-Based Hand Rub Combined with a Hand Dryer Machine Be an Alternative to Remove E. coli Contamination from Hands?

Efficient hand hygiene is essential for preventing the transmission of microorganisms. Alcohol-based hand rub (ABHR) is a recommended method. We compared health personnel (skilled nurse students) with random adults to study the effect of an ABHR procedure. A water-based hand rub (WBHR) procedure, using running tap water and a hand-drying machine, was also investigated. The study included 27 nurse students and 26 random adults. Hands were contaminated with Escherichia coli, and concentrations of colony forming units (CFU/mL) were determined before and after ABHR or WBHR. Concentrations after ABHR were 1537 CFU/mL (nurse students) and 13,508 CFU/mL (random adults) (p < 0.001). One-third of participants reported skin irritation from daily ABHR. Concentrations after WBHR were 41 CFU/mL (nurse students) and 115 CFU/mL (random adults) (p < 0.011). The majority of participants (88.5%) preferred the WBHR method. Results from 50 air samples from filtered air from the hand dryer outlet showed no CFU in 47 samples. A significant difference between the two groups was shown for the ABHR method, indicating that training skills are important for efficient hand hygiene. Surprisingly, the WBHR method seemed to have a significant effect in largely removing transient bacteria from hands.

Handwashing Practice of Food Establishment Customers, Microbial Quality of Handwashing Water, and Associated Factors in Ginjo Kebele, Jimma Town, Southwest Ethiopia

Handwashing plays a major role in preventing the spread of infection and, if poorly implemented, leads to different illnesses. However, the quality of water meant for handwashing and handwashing practice and hand hygiene conditions of food establishment customers are overlooked issues, unlike drinking water and hygienic conditions and practice of food handlers. This study aimed to assess the microbial quality of water used for handwashing and hygienic practice and the status of customers of food establishments and associated factors in Ginjo Kebele, Jimma town, Southwest, Ethiopia. A cross-sectional study design was employed in July 2022. Forty water and 40 hand swab samples were taken and analyzed for total coliform and E. coli using the spread plate method. Handwashing facility conditions and the handwashing practices of customers were assessed using a checklist and questionnaire. The data were analyzed by SPSS version 23 software. The median handwashing water total coliform count was 390.0 CFU/ml. The median hand swab samples' total coliform and E. coli load were 21.6 and 4.8 CFU/cm², respectively after handwashing practice. There was an uphill correlation between the handwashing water and hand swab sample total coliform load (r = .34, P = .032). The mean handwashing efficacy for the removal of total coliform was 25.8%. The microbial load was varied with the type of water container used, method of taking water from the container, handwashing practice, and hand drying. The microbial quality of handwashing water and hand swab samples didn't comply with the acceptable limit. Thus, governmental bodies should work to improve the handwashing practice of communities. Food establishment owners should treat water for handwashing, clean the water containers, handle the water properly, and avail soap and poster demonstrators to the handwashing facilities. The customers should also comply with proper hand washing practices and reduce hand contamination.

A review of HTM 01-05 through an environmentally sustainable lens

Patients deserve to be treated in a safe and clean environment with consistent standards of care every time they receive treatment. It is essential that the risk of person-to-person transmission of infections be minimised, yet it is also essential that planetary harm (and therefore public harm) is minimised with respect to resource consumption, air pollution, environmental degradation etc.In 2013, the Department of Health introduced the Health Technical Memorandum (HTM) 01-05 providing dental practices with advice on patient safety when decontaminating reusable instruments in primary care. This paper provides a commentary on HTM 01-05 and similar decontamination guidance. We believe all decontamination documents needs to reflect the so-called 'triple bottom line' - the finance, social cost and impact on the planet.The authors provide an environmental commentary on a number of items mentioned in decontamination documents, including autoclaves (including the use of helix tests), disposable paper towels, undertaking hand hygiene, using a log book, plastic bag use, the use of personal protective equipment, remote decontamination units, single use instruments, single use wipes, disinfection chemicals (for example, sodium hypochlorite) thermal disinfection and wrapping of instruments.It is hoped, in the spirit of the ever-increasing numbers of papers published to highlight how healthcare (and dentistry) could become more sustainable, that these critiques will be taken in the spirit of providing a beginning of further discussion from an environmental perspective.

A quantitative microbial risk assessment for touchscreen user interfaces using an asymmetric transfer gradient transmission mode

The ubiquitous use of public touchscreen user interfaces for commercial applications has created a credible risk for fomite-mediated disease transmission. This paper presents results from a stochastic simulation designed to assess this risk. The model incorporates a queueing network to simulate people flow and touchscreen interactions. It also describes an updated model for microbial transmission using an asymmetric gradient transfer assumption that incorporates literature reviewed empirical data concerning touch-transfer efficiency between fingers and surfaces. In addition to natural decay/die-off, pathogens are removed from the system by simulated cleaning / disinfection and personal-touching rates (e.g. face, dermal, hair and clothing). The dose response is implemented with an exponential moving average filter to model the temporal dynamics of exposure. Public touchscreens were shown to pose a considerable infection risk (∼3%) using plausible default simulation parameters. Sensitivity of key model parameters, including the rate of surface disinfection is examined and discussed. A distinctive and important advancement of this simulation was its ability to distinguish between infection risk from a primary contaminated source and that due to the re-deposition of pathogens onto secondary, initially uncontaminated touchscreens from sequential use. The simulator is easily configurable and readily adapted to more general fomite-mediated transmission modelling and may provide a valuable framework for future research.

Aerosols and Bacteria From Hand Washing and Drying in Indoor Air

Effective hand drying is an important part of hand hygiene that can reduce the risk of infectious disease transmission through cross-contamination of surfaces by wet hands. However, hand drying methods may also cause aerosolisation of pathogenic microorganisms if they are present in washed hands. This study investigated experimentally the impact of washing hands and different hand drying methods on the concentration and size distribution of aerosols and bacteria in indoor air. In this experiment, aerosol and bacteria concentrations were measured in indoor air while volunteers rinsed their hands with water or washed with soap and water prior to drying them with paper towels or jet air dryers. Results showed that the concentration of aerosols and bacteria in air increased with people walking in the room and washing hands, with a further increase during the hand drying process. The concentration of aerosols decreased with particle size, with maximum concentrations after drying hands of 6.63 × 10⁶ ± 6.49 × 10⁵ and 2.28 × 10⁴ ± 9.72 × 10³ particles m⁻³ for sizes 0.3 to <0.5 and ≥5.0 μm, respectively. The concentration of bacteria in indoor air after drying hands increased to a maximum of 3.81 × 10² ± 1.48 × 10² CFU m⁻³ (jet air dryers) and 4.50 × 10² ± 4.35 × 10¹ CFU m⁻³ (paper towels). This study indicates that the increase of aerosols and bacteria in air after drying hands with jet air dryers or paper towels are comparable and not statistically different from concentrations associated with walking and washing hands in the same environment. This work can support the development of hand hygiene practices and guidelines for public washrooms.

A Journey on the Skin Microbiome: Pitfalls and Opportunities

The human skin microbiota is essential for maintaining homeostasis and ensuring barrier functions. Over the years, the characterization of its composition and taxonomic diversity has reached outstanding goals, with more than 10 million bacterial genes collected and cataloged. Nevertheless, the study of the skin microbiota presents specific challenges that need to be addressed in study design. Benchmarking procedures and reproducible and robust analysis workflows for increasing comparability among studies are required. For various reasons and because of specific technical problems, these issues have been investigated in gut microbiota studies, but they have been largely overlooked for skin microbiota. After a short description of the skin microbiota, the review tackles methodological aspects and their pitfalls, covering NGS approaches and high throughput culture-based techniques. Recent insights into the "core" and "transient" types of skin microbiota and how the manipulation of these communities can prevent or combat skin diseases are also covered. Finally, this review includes an overview of the main dermatological diseases, the changes in the microbiota composition associated with them, and the recommended skin sampling procedures. The last section focuses on topical and oral probiotics to improve and maintain skin health, considering their possible applications for skin diseases.

Modelling disease transmission from touchscreen user interfaces

The extensive use of touchscreens for all manner of human-computer interactions has made them plausible instruments of touch-mediated disease transmission. To that end, we employ stochastic simulations to model human-fomite interaction with a distinct focus on touchscreen interfaces. The timings and frequency of interactions from within a closed population of infectious and susceptible individuals was modelled using a queuing network. A pseudo-reproductive number R was used to compare outcomes under various parameter conditions. We then apply the simulation to a specific real-world scenario; namely that of airport self-check-in and baggage drop. A counterintuitive result was that R decreased with increased touch rates required for touchscreen interaction. Additionally, as one of few parameters to be controlled, the rate of cleaning/disinfecting screens plays an essential role in mitigating R, though alternative technological strategies could prove more effective. The simulation model developed provides a foundation for future advances in more sophisticated fomite disease-transmission modelling.

Comparison of electric hand dryers and paper towels for hand hygiene: a critical review of the literature

Numerous studies are published on the benefits of electric hand dryers vs paper towels (PT) for drying hands after washing. Data are conflicting and lacking key variables needed to assess infection risks. We provide a rapid scoping review on hand-drying methods relative to hygiene and health risks. Controlled vocabulary terms and keywords were used to search PubMed (1946-2018) and Embase (1947-2018). Multiple researchers independently screened abstracts for relevance using predetermined criteria and created a quality assessment scoring system for relative study comparisons. Of 293 papers, 23 were included in the final analysis. Five studies did not compare multiple methods; however, 2 generally favoured electric dryers (ED); 7 preferred PT; and 9 had mixed or statistically insignificant results (among these, 3 contained scenarios favourable to ED, 4 had results supporting PT, and the remaining studies had broadly conflicting results). Results were mixed among and within studies and many lacked consistent design or statistical analysis. The breadth of data does not favour one method as being more hygienic. However, some authors extended generalizable recommendations without sufficient scientific evidence. The use of tools in quantitative microbial risk assessment is suggested to evaluate health exposure potentials and risks relative to hand-drying methods. We found no data to support any human health claims associated with hand-drying methods. Inconclusive and conflicting results represent data gaps preventing the advancement of hand-drying policy or practice recommendations.

Microbiological Assessment of the Different Hand Drying Methods and Washroom Environment Cross-Contamination

Proper hand drying is a fundamental part of the hand hygiene process looking at optimizing the elimination of potentially pathogenic microbes. This research compared the effectiveness of three different hand drying methods—paper towels, the use of warm air dryers in stationary hands position, and the use of air drying while hand rubbing—and their potential for cross-contamination of other users and the surrounding environment. One hundred sixty samples were collected from finger pads and palms, before and after drying. The outlet of the air dryers, air current emitted from the air dryers, and washroom environment air were also tested. The study reported that paper towels were more successful in eliminating bacteria and lead to less contamination to the washroom environment compared to the air dryers. The average number of bacteria obtained from volunteers using hand air dryer while hand rubbing was significantly higher than drying with air dryer while holding hands stationary. Plates exposed to the turned-off dryer for 5 minutes gave an average of only 25 colonies/plate, while plates exposed to the air outlet of the turned-on warm air dryers provided 292 colonies/plate. Placing Petri dishes at least one meter away from the dryer in the washroom for 30 minutes gave 72.5 colonies/plate. The current research also documented frequent contamination of public washroom environments and showed dissemination of potential pathogens, including Escherichia coli (E. coli), Klebsiella species, Bacillus cereus (B. cereus), Staphylococcus aureus (S. aureus), and coagulase-negative Staphylococci. Over 70.0% of Staphylococci were resistant to at least three antibiotics and 50.0% revealed coresistance to at least four antibiotics including penicillin, erythromycin, clindamycin, and co-trimoxazole. The method of hand drying may serve as a risk factor of cross-contamination from users to the environment and subsequent users and as reservoirs of drug-resistant bacteria in public washrooms.

COVID-19 and hand hygiene: the vital importance of hand drying

The significance of hand hygiene for preventing the transmission of microorganisms and reducing the spread of infection has been brought into sharp focus following the global coronavirus (COVID-19) pandemic. In the months since the initial outbreak, international public health campaigns and practitioner education has concentrated on hand washing and hand sanitising, with very little reference to hand drying, if any at all. However, hand drying is integral to effective hand hygiene, and is important in controlling the spread of microorganisms and maintaining healthy skin integrity. This research commentary will focus on two issues of importance with regards to hand drying: microbial transmission and skin irritation, with implications for healthcare practitioners and practice considered. It is argued that a more holistic approach to hand hygiene must be the ambition if health professional and public behaviour is to become embedded and sustained.

Microbiological evaluation of different hand drying methods for removing bacteria from washed hands

Proper drying of hands after washing is an integral part of hand hygiene. An experimental study on 30 subjects using multiple comparisons of six hand drying methods including 1) drying on own clothes, 2) drying with one paper towel, 3) drying with two paper towels, 4) drying with a warm air dryer while holding hands stationary for 20 s, 5) drying with a warm air dryer while hand rubbing for 20 s, and 6) drying with a jet air dryer until complete dryness was achieved. It aimed to determine the effectiveness of different hand drying methods for removing bacteria from washed hands, so as to identify the optimum method using minimum resources. Our study demonstrated that the use of jet air dryers is the best method to eliminate bacteria on hands, whereas drying hands on one's own clothes is the least effective. Drying hands in a stationary position could remove more bacteria than rubbing hands when using a warm air dryer for 20 s, which mimics people's usual hand-drying practice. No significant difference in bacteria reduction was detected between the use of one or two paper towels for hand drying; therefore, using fewer resources is recommended to maintain environmental sustainability.