Ability of Hand Hygiene Interventions Using Alcohol-Based Hand Sanitizers and Soap To Reduce Microbial Load on Farmworker Hands Soiled during Harvest

Anti-microbial efficacy of a scientifically developed and standardized herbal-alcohol sanitizer

Hands are the primary mode of transmission of microbe-based infections, as they harbor normal microbiota and pathogenic microbes. SARS-CoV-2 has endangered lives worldwide, and WHO has recommended good hygiene practices, especially hand hygiene. In addition, other infectious diseases like diphtheria, measles, tuberculosis, HIV, malaria, etc. are spreading in the shadow of the COVID-19 pandemic. The anti-microbial efficiency of two in-house developed herbal-alcohol based hand sanitizers containing Azadirachta indica, Citrus limon, Zingiber officinale, and Aloe vera (HS1) and Zingiber officinale replaced with Ocimum sanctum (HS2) was evaluated. HS1, with Zingiber officinale, and HS2, with Ocimum sanctum, herbal sanitizers showcased in-vitro anti-viral activity on MDCK cells using the reference strain of influenza A virus, A/PR/8/34 (H1N1), and reduced 99.99% of microbial load within 30 s of contact time, estimated by the Antimicrobial Susceptibility Testing Method. On volunteers, HS1 and HS2 were more effective than alcohol-based WHO sanitizers. Moreover, HS2 sanitizer is more effective against viruses and has better efficiency and hedonic qualities in volunteers than HS1. These sanitizers don't irritate or dry up the skin and have a longer shelf life. Overall, findings reveal that herbal-alcohol-based sanitizers are promising hand hygiene products with the capability of reducing microbial load.

Quantitative Risk Assessment for the Introduction of Carbapenem-Resistant Enterobacteriaceae (CPE) into Dutch Livestock Farms

Early detection of emerging carbapenem-resistant Enterobacteriaceae (CPE) in food-producing animals is essential to control the spread of CPE. We assessed the risk of CPE introduction from imported livestock, livestock feed, companion animals, hospital patients, and returning travelers into livestock farms in The Netherlands, including (1) broiler, (2) broiler breeder, (3) fattening pig, (4) breeding pig, (5) farrow-to-finish pig, and (6) veal calf farms. The expected annual number of introductions was calculated from the number of farms exposed to each CPE source and the probability that at least one animal in an exposed farm is colonized. The total number of farms with CPE colonization was estimated to be the highest for fattening pig farms, whereas the probability of introduction for an individual farm was the highest for broiler farms. Livestock feed and imported livestock are the most likely sources of CPE introduction into Dutch livestock farms. Sensitivity analysis indicated that the number of fattening pig farms determined the number of high introductions in fattening pigs from feed, and that uncertainty on CPE prevalence impacted the absolute risk estimate for all farm types. The results of this study can be used to inform risk-based surveillance for CPE in livestock farms.

Scientific Evidence Supports the Use of Alcohol-Based Hand Sanitizers as an Effective Alternative to Hand Washing in Retail Food and Food Service Settings When Heavy Soiling Is Not Present on Hands

ABSTRACT

Suboptimal food worker health and hygiene has been a common contributing factor in foodborne disease outbreaks for many years. Despite clear U.S. Food and Drug Administration (FDA) Model Food Code recommendations for hand washing and glove use, food worker compliance with hand washing recommendations has remained poor for >20 years. Food workers' compliance with recommended hand washing guidelines is adversely impacted by a number of barriers, including complaints of time pressure, inadequate number and/or location of hand washing sinks and hand washing supplies, lack of food knowledge and training regarding hand washing, the belief that wearing gloves obviates the need for hand washing, insufficient management commitment, and adverse skin effects caused by frequent hand washing. Although many of the issues related to poor hand washing practices in food service facilities are the same as those in health care settings, a new approach to health care hand hygiene was deemed necessary >15 years ago due to persistently low compliance rates among health care personnel. Evidence-based hand hygiene guidelines for health care settings were published by both the Centers for Disease Control and Prevention in 2002 and by the World Health Organization in 2009. Despite similar low hand washing compliance rates among retail food establishment workers, no changes in the Food Code guidelines for hand washing have been made since 2001. In direct contrast to health care settings, where frequent use of alcohol-based hand sanitizers (ABHSs) in lieu of hand washing has improved hand hygiene compliance rates and reduced infections, the Food Code continues to permit the use of ABHSs only after hands have been washed with soap and water. This article provides clear evidence to support modifying the FDA Model Food Code to allow the use of ABHSs as an acceptable alternative to hand washing in situations where heavy soiling is not present. Emphasis on the importance of hand washing when hands are heavily soiled and appropriate use of gloves is still indicated.

HIGHLIGHTS

The Cantaloupe Farm Environment Has a Diverse Genetic Pool of Antibiotic-Resistance and Virulence Genes

Cantaloupes contaminated with pathogens have led to many high-profile outbreaks and illnesses. Since bacterial virulence genes (VGs) can act in tandem with antibiotic-resistance and mobile genetic elements, there is a need to evaluate these gene reservoirs in fresh produce, such as cantaloupes. The goal of this study was to assess the distribution of antibiotic-resistance, virulence, and mobile genetic elements genes (MGEGs) in cantaloupe farm environments. A total of 200 samples from cantaloupe melons (n = 99), farm workers' hands (n = 66), and production water (n = 35) were collected in México. Each sample was assayed for the presence of 14 antibiotic-resistance genes, 15 VGs, and 5 MGEGs by polymerase chain reaction. Our results indicated that tetracycline (tetA and tetB) (18% of cantaloupe, 45% of hand samples) and sulfonamide (sul1) (30% of cantaloupe, 71% of hand samples) resistance genes were frequently detected. The colistin resistance gene (mcr1) was detected in 10% of cantaloupe and 23% of farm workers' hands. Among VGs, Salmonella genes invA and spiA were the most abundant. There was a significantly higher likelihood of detecting antibiotic-resistance, virulence, and MGEGs on hands compared with water samples. These results demonstrate a diverse pool of antibiotic-resistance and VGs in cantaloupe production.

Toxicology of alcohol-based hand rubs formulated with technical-grade ethanol

Alcohol-based hand rubs (ABHRs) formulated with technical-grade ethanol were temporarily permitted in Canada and the U.S beginning April 2020 to meet the current demand due to COVID-19. ABHRs formulated with technical-grade ethanol are low risk for general use. In this review, we discuss the toxicity of common contaminants found in technical-grade ethanol, as well as contaminants that may have been introduced into the products during formulation and packaging of ABHRs. Although primary route of exposure is via dermal absorption and inhalation, there have been reported elevated concerns regarding to ingestion of ABHRs. Overall, the highest risks were associated with methanol (for its toxicity), ethyl acetate (skin defattening), and acetaldehyde (carcinogenic and teratogenic). For these reasons Health Canada and the United States Food and Drug Administration have issued recalls on products containing some of these contaminants. More vigilant policing by regulatory agencies and general product users are required to ensure compliance, safety, and efficacy of these new products, as demand continue to rise during this unprecedented pandemic.

A two-component intervention to improve hand hygiene practices and promote alcohol-based hand rub use among people who inject drugs: a mixed-methods evaluation

Background

Inconsistent hand hygiene puts people who inject drugs (PWID) at high risk of infectious diseases, in particular skin and soft tissue infections. In healthcare settings, handwashing with alcohol-based hand rubs (ABRH) is recommended before aseptic procedures including intravenous injections. We aimed to evaluate the acceptability, safety and preliminary efficacy of an intervention combining ABHR provision and educational training for PWID.

Methods

A mixed-methods design was used including a pre-post quantitative study and a qualitative study. Participants were active PWID recruited in 4 harm reduction programmes of France and followed up for 6 weeks. After baseline assessment, participants received a face-to-face educational intervention. ABHR was then provided throughout the study period. Quantitative data were collected through questionnaires at baseline, and weeks 2 (W2) and 6 (W6) post-intervention. Qualitative data were collected through focus groups with participants who completed the 6-week study.

Results

Among the 59 participants included, 48 (81%) and 43 (73%) attended W2 and W6 visits, respectively. ABHR acceptability was high and adoption rates were 50% (W2) and 61% (W6). Only a minority of participants reported adverse skin reactions (ranging from 2 to 6%). Preliminary efficacy of the intervention was shown through increased hand hygiene frequency (multivariable linear mixed model: coef. W2 = 0.58, p = 0.002; coef. W6 = 0.61, p = 0.002) and fewer self-reported injecting-related infections (multivariable logistic mixed model: AOR W6 = 0.23, p = 0.021). Two focus groups were conducted with 10 participants and showed that young PWID and those living in unstable housing benefited most from the intervention.

Conclusions

ABHR for hand hygiene prior to injection are acceptable to and safe for PWID, particularly those living in unstable housing. The intervention’s educational component was crucial to ensure adoption of safe practices. We also provide preliminary evidence of the intervention’s efficacy through increased hand hygiene frequency and a reduced risk of infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05895-1.

Both Handwashing and an Alcohol-Based Hand Sanitizer Intervention Reduce Soil and Microbial Contamination on Farmworker Hands during Harvest, but Produce Type Matters

Hand hygiene interventions are critical for reducing farmworker hand contamination and preventing the spread of produce-associated illness. Hand hygiene effectiveness may be produce-commodity specific, which could influence implementation strategies. This study's goal was to determine if produce commodity influences the ability of handwashing with soap and water or two-step alcohol-based hand sanitizer (ABHS) interventions to reduce soil and bacteria on farmworker hands. Farmworkers (n = 326) harvested produce (cantaloupe, jalapeño, and tomato) for 30 to 90 minutes before engaging in handwashing, two-step ABHS (jalapeño and cantaloupe), or no hand hygiene. Hands were rinsed to measure amounts of soil (absorbance at 600 nm) and indicator bacteria (coliforms, Enterococcus sp., generic Escherichia coli, and Bacteroidales universal [AllBac] and human-specific [BFD] 16S rRNA gene markers). Without hand hygiene, bacterial concentrations (0.88 to 5.1 log₁₀ CFU/hand) on hands significantly differed by the produce commodity harvested. Moderate significant correlations (ρ = -0.41 to 0.56) between soil load and bacterial concentrations were observed. There were significant produce-commodity-specific differences in the ability of handwashing and two-step ABHS interventions to reduce soil (P < 0.0001), coliforms (P = 0.002), and Enterococcus sp. (P = 0.003), but not the Bacteroidales markers AllBac (P = 0.4) or BFD (P = 0.3). Contamination on hands of farmworkers who harvested cantaloupe was more difficult to remove. Overall, we found that a two-step ABHS intervention was similar to handwashing with soap and water at reducing bacteria on farmworker hands. In summary, produce commodity type should be considered when developing hand hygiene interventions on farms.IMPORTANCE This study demonstrated that the type of produce commodity handled influences the ability of handwashing with soap and water or a two-step alcohol-based hand sanitizer (ABHS) intervention to reduce soil and bacterial hand contamination. Handwashing with soap and water, as recommended by the FDA's Produce Safety Rule, when tested in three agricultural environments, does not always reduce bacterial loads. Consistent with past results, we found that the two-step ABHS method performed similarly to handwashing with soap and water but also does not always reduce bacterial loads in these contexts. Given the ease of use of the two-step ABHS method, which may increase compliance, the two-step ABHS method should be further evaluated and possibly considered for implementation in the agricultural environment. Taken together, these results provide important information on hand hygiene effectiveness in three agricultural contexts.

The impact of daily soap use in rural areas of Senegal on respiratory infectious diseases, fevers and skin microbiota

OBJECTIVES

Children aged <5 years are the group most affected by infectious diseases, more specifically in underdeveloped countries. A study was performed to assess the effects of daily soap use on the incidence of diarrhoea, fever, respiratory infection, and the prevalence of pathogenic bacteria on the skin.

METHODS

Soap was distributed to the population of the village of Ndiop (test) for use in their daily hygiene but not to the population of the village of Dielmo (control). Fieldworkers daily recorded the clinical events in the two villages and encouraged the use of soap in Ndiop.

RESULTS

A total of 638 people participated in the study. The incidence rates of cough, runny nose and fever significantly decreased in 2016 compared with 2015, unlike that of diarrhoea. In 2016, significant reductions in the incidence rates of cough, runny nose and fever were observed in children aged <15 years in Ndiop. The prevalence of Streptococcus pneumoniae, Staphylococcus aureus and Streptococcus pyogenes in the palms of the hands significantly dropped in Ndiop.

CONCLUSION

Using soap reduces the incidence of respiratory infections, fevers and the prevalence of pathogenic bacteria on the skin. However, for diarrhoea, additional strategies are needed to improve outcomes.

Evaluation of Risk of Zoonotic Pathogen Transmission in a University-Based Animal Assisted Intervention (AAI) Program

Introduction: Previous studies have shown that apparently healthy animals participating in Animal-Assisted Interventions (AAI) have the potential to asymptomatically carry and even transmit zoonotic pathogens to people, which is of particular concern for therapy animal teams visiting healthcare settings. This two-part study was designed to investigate the risk of zoonotic pathogen transmission within a university-based AAI program as a combination of the prevalence of these pathogens in the animal population as well as the handlers' understanding of the risks of zoonoses in AAI and their adherence to infection control practices.

Methods: In part one of the study, AAI program records were retrospectively reviewed and infectious disease screening test results were compiled from 22 dogs and 2 cats. Screening tests for dogs and cats included a zinc sulfate fecal float, fecal culture, and nasal and perianal skin swabs for methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudointermedius (MRSP). Additional tests for cats were blood cultures for Bartonella henselae and Toxoplasmosis IgG and IgM antibody titers. In part two, a survey was conducted of 40 registered therapy animal handlers to assess knowledge, attitudes, and perceptions regarding risk of infectious disease transmission in AAI settings, including risk to the animal, the handler, and those being visited.

Results: In part one, there were 17 total positive results of the 118 infectious disease screenings performed, 14 of which were potentially zoonotic organisms. In part two of the study, a majority (70%) of respondents expressed they had no concerns regarding infectious disease transmission in AAI settings. Despite handler education and guidelines, adherence to infection control practices was lacking.

Discussion: The results of this study support prior findings that animals participating in AAI can be asymptomatic carriers of zoonotic organisms. Compliance with infection control practices and hand hygiene are paramount to mitigate risk of zoonotic disease transmission, but was inconsistent among this group of handlers. Given the popularity of AAI programs in the U.S., similar studies should be performed on a larger scale to determine the level of adherence to currently recommended practices and potential need for improvement in infectious disease control education and/or policies.

Growth of Yersinia pseudotuberculosis Strains at Different Temperatures, pH Values, and NaCl and Ethanol Concentrations

Maximum growth temperature and growth limits in Luria-Bertani broth at different pH values and NaCl and ethanol concentrations were determined for 49 Yersinia pseudotuberculosis strains representing serotypes O:1, O:2, O:3, O:4, and O:5. In addition, the ability of the strains to grow at 0°C and the growth parameters at 1°C were determined. The maximum growth temperatures measured by Gradiplate temperature incubator varied between 42.2 and 43.7°C. All strains were able to grow at 0°C in Luria-Bertani broth within 17 days of incubation. At 1°C, differences were observed among strains in the maximum growth rates and area under the curve values based on optical density data, which suggests that some Y. pseudotuberculosis strains adapt faster to colder conditions. The mean maximum growth rates and area under the curve values at 1°C, as well as the mean maximum growth temperatures, were statistically significantly higher among serotype O:1 strains compared with O:3 strains and among biotype 1 compared with biotype 2 strains. All strains grew at pH 4.5, whereas none of the strains were able to grow at pH 4.2. The highest pH at which growth was observed varied between 9.0 and 9.3. For 14 strains the maximum NaCl concentration at which growth was observed was 4.8%, whereas 35 of the strains were able to grow at 5.0% NaCl. None of the strains showed growth at 5.2% NaCl. All strains were able to grow at 4.5% ethanol concentration (v/v), whereas 5.0% ethanol concentration was completely inhibitory to all strains. The observed limited physiological diversity among various Y. pseudotuberculosis strains may stem from the genetic homogeneity of the species.

Food Safety at Farmers' Markets: A Knowledge Synthesis of Published Research

Farmers' markets are increasingly popular venues in North America for the sale of fresh produce and other foods. However, the nature of their operation can present possible food safety issues, challenges, and risks to consumers. A knowledge synthesis was conducted to identify, characterize, and summarize published research on the microbial food safety issues and implications associated with farmers' markets. A scoping review was conducted using the following steps: comprehensive search strategy, relevance screening of abstracts, and characterization of relevant articles. Two subsets of data were prioritized for more detailed systematic review (data extraction and risk-of-bias assessment) and meta-analysis: (i) studies comparing the microbial safety of foods from farmers' markets versus other sources and (ii) studies evaluating the use of food safety practices at farmers' markets. Overall, 83 relevant studies were identified. The majority of studies were published as journal articles (64%), used a cross-sectional design (81%), and were conducted in the United States (78%). Most studies (39%; n = 32) investigated stakeholder, mostly consumer (n = 22), attitudes toward food safety at farmers' markets. Limited but heterogeneous evidence indicated a higher prevalence of Campylobacter and Salmonella in chicken meat from farmers' markets versus other retail sources, but there was no difference in the microbial contamination of fresh produce. Studies evaluating the use of food safety practices at farmers' markets identified some gaps; for example, the average prevalence of vendor hand washing was 4% (95% confidence interval: 0 to 11%; I² = 27%; n = 5 studies). Twelve foodborne outbreaks and case reports were identified, resulting in a total of 411 illnesses, 38 hospitalizations, and two deaths from 1994 to 2016. Only five intervention studies were identified. Key knowledge gaps and areas warranting future research, training, and education are highlighted and discussed.

Removal of Escherichia coli and Enterococcus faecalis after Hand Washing with Antimicrobial and Nonantimicrobial Soap and Persistence of These Bacteria in Rinsates

Food handlers are important sources of contamination in the agricultural environment. This study was conducted (i) to evaluate the activity of antimicrobial soaps against Escherichia coli and Enterococcus faecalis using a hand washing model with soiled hands and (ii) to determine the survival and persistence of these bacteria in rinsates. Sterilized agricultural soil from tomato and pepper farms was inoculated with E. coli or E. faecalis at 10³ or 10⁶ CFU/g. Decontaminated hands were placed in contact with contaminated soil for 2 min and were then washed with soaps with or without antimicrobial compounds (citric extracts, chloroxylenol, triclosan, or chlorhexidine gluconate). As the control, hands were washed with sterile distilled water. The levels of bacteria remaining on the hands and recovered from the rinsates were determined using a membrane filtration method and selective media. Antimicrobial soaps removed levels of E. coli similar to those removed by distilled water and nonantimicrobial soap on hands contaminated with E. coli at 10³ CFU/g. However, when hands were contaminated with E. coli at 10⁶ CFU/g, more E. coli was removed with the chlorhexidine gluconate soap. When hands were contaminated with E. faecalis at 10³ CFU/g, bacteria were removed more effectively with soaps containing chloroxylenol or chlorhexidine gluconate. When hands were contaminated with E. faecalis at 10⁶ CFU/g, all of the antimicrobial soaps were more effective for removing the bacteria than were distilled water and nonantimicrobial soap. E. coli grew in all of the hand washing rinsates except that containing triclosan, whereas E. faecalis from the 10⁶ CFU/g treatments grew in rinsates containing chlorhexidine gluconate and in the distilled water rinsates. Washing with antimicrobial soap was more effective for reducing bacteria on soiled hands than was washing with water or nonantimicrobial soap. However, persistence or growth of bacteria in these rinsates poses health risks.

A Method to Test the Efficacy of Handwashing for the Removal of Emerging Infectious Pathogens

Handwashing is widely recommended to prevent infectious disease transmission. However, little comparable evidence exists on the efficacy of handwashing methods in general. Additionally, little evidence exists comparing handwashing methods to determine which are most efficacious at removing infectious pathogens. Research is needed to provide evidence for the different approaches to handwashing that may be employed during infectious disease outbreaks. Here, a laboratory method to assess the efficacy of handwashing methods at removing microorganisms from hands and their persistence in rinse water is described. Volunteers' hands are first spiked with the test organism and then washed with each handwashing method of interest. Generally, surrogate microorganisms are used to protect human subjects from disease. The number of organisms remaining on volunteers' hands after washing is tested using a modified "glove juice" method: the hands are placed in gloves with an eluent and are scrubbed to suspend the microorganisms and make them available for analysis by membrane filtration (bacteria) or plaque assay (viruses/bacteriophages). Rinse water produced from the handwashing is directly collected for analysis. Handwashing efficacy is quantified by comparing the log reduction value between samples taken after handwashing to samples with no handwashing. Rinse water persistence is quantified by comparing rinse water samples from various handwashing methods to samples collected after handwashing with just water. While this method is limited by the need to use surrogate organisms to preserve the safety of human volunteers, it captures aspects of handwashing that are difficult to replicate in an in vitro study and fills research gaps on handwashing efficacy and the persistence of infectious organisms in rinse water.

Contamination of Fresh Produce by Microbial Indicators on Farms and in Packing Facilities: Elucidation of Environmental Routes

To improve food safety on farms, it is critical to quantify the impact of environmental microbial contamination sources on fresh produce. However, studies are hampered by difficulties achieving study designs with powered sample sizes to elucidate relationships between environmental and produce contamination. Our goal was to quantify, in the agricultural production environment, the relationship between microbial contamination on hands, soil, and water and contamination on fresh produce. In 11 farms and packing facilities in northern Mexico, we applied a matched study design: composite samples (n = 636, equivalent to 11,046 units) of produce rinses were matched to water, soil, and worker hand rinses during two growing seasons. Microbial indicators (coliforms, Escherichia coli, Enterococcus spp., and somatic coliphage) were quantified from composite samples. Statistical measures of association and correlations were calculated through Spearman's correlation, linear regression, and logistic regression models. The concentrations of all microbial indicators were positively correlated between produce and hands (ρ range, 0.41 to 0.75; P < 0.01). When E. coli was present on hands, the handled produce was nine times more likely to contain E. coli (P < 0.05). Similarly, when coliphage was present on hands, the handled produce was eight times more likely to contain coliphage (P < 0.05). There were relatively low concentrations of indicators in soil and water samples, and a few sporadic significant associations were observed between contamination of soil and water and contamination of produce. This methodology provides a foundation for future field studies, and results highlight the need for interventions surrounding farmworker hygiene and sanitation to reduce microbial contamination of farmworkers' hands.IMPORTANCE This study of the relationships between microbes on produce and in the farm environment can be used to support the design of targeted interventions to prevent or reduce microbial contamination of fresh produce with associated reductions in foodborne illness.

Handwashing and Ebola virus disease outbreaks: A randomized comparison of soap, hand sanitizer, and 0.05% chlorine solutions on the inactivation and removal of model organisms Phi6 and E. coli from hands and persistence in rinse water

To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94-3.01 log reduction in E. coli concentration without, and 2.18-3.34 with, soil load; and a 2.44-3.06 log reduction in Phi6 without, and 2.71-3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28-4.77 log reduction in remaining E. coli without, and 0.21-4.49 with, soil load and a 1.26-2.02 log reduction in Phi6 without, and 1.30-2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001). Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence.