Hand hygiene: virucidal efficacy of a liquid hand wash product against Ebola virus.

BACKGROUND: Hand washing is an important targeted hygiene intervention for limiting the spread of infectious agents, including the Ebola virus, which continues to re-emerge. We have assessed the virucidal efficacy of a commercially available liquid hand wash product (LHW) for inactivating Ebola virus. METHODS: The ASTM E1052-11 Standard was used to evaluate the efficacy of an LHW containing the microbicidal active salicylic acid for inactivating Ebola virus - Makona variant suspended in an organic load. Three concentrations (12.5%, 25%, 50%) of three lots of LHW prepared in 440 ppm hard water were evaluated at room temperature for 20, 30, and 60 s contact time. RESULTS: A 25% solution of the LHW caused 4.5 log10 and 4.8 log10 reduction in Ebola virus titer within 20 and 30 s, respectively. The efficacy of a 12.5% LHW solution was lower (1.9 and 2.0 log10 reduction in titer within 20 and 30 s, respectively). The efficacy of the 50% LHW solution could not be measured, due to inability to sufficiently neutralize the LHW at the end of exposure. CONCLUSION: These results suggest the potential utility of an appropriately formulated liquid hand wash agent during Ebola virus disease outbreaks for use within healthcare, community, and home settings. Such an LHW should also be effective against other enveloped viruses, such as the pandemic coronavirus SARS-CoV-2.

Use of a small-scale, portable test chamber for determining the bactericidal efficacy of aerosolized glycol formulations.

This study aimed to understand the efficacy and mechanisms of action of an aerosolized glycol-ethanol formulations against bacteria. We validated a small-scale in-house test chamber to determine the microbicidal efficacy of four aerosolized formulations combining dipropylene glycol and ethanol against Staphylococcus aureus and Escherichia coli embedded in alginate. The aerosolized glycol/ethanol formulation decreased bacterial viability by 3 log10 and was more efficacious than an ethanol only control formulation. Electron microscopic examination indicated extensive structural damage in both bacteria, and membrane damage was confirmed with potassium release in S. aureus and DNA release in E. coli. The development of a small test chamber facilitated the measurement of the microbicidal efficacy and experiments to understand the mechanism of action of an aerosolized microbicidal formulation. SIGNIFICANCE AND IMPACT OF THE STUDY: There is an increased interest in developing effective microbicidal-aerosolized formulations. The development of a small in-house test chamber allowed the measurement of the microbicidal efficacy of an aerosolized glycol/ethanol formulation at a low cost. We showed that a glycol/ethanol aerosolized formulation caused extensive structural damage in Gram-negative and -positive bacteria resulting in a 3 log10 reduction in viability.

A quantitative method to assess the role of indoor air decontamination to simultaneously reduce contamination of environmental surfaces: testing with vegetative and spore-forming bacteria.

Indoor air can spread pathogens, which can be removed/inactivated by a variety of means in healthcare and other settings. We quantitatively assessed if air decontamination could also simultaneously reduce environmental surface contamination in the same setting. Two types of vegetative bacteria (Staphylococcus aureus and Acinetobacter baumannii), and a bacterial spore-former (Geobacillus stearothermophilus) were tested as representative airborne bacteria. They were separately aerosolized with a Collison nebulizer into a 24-m3 aerobiology chamber and air samples collected with a programmable slit-to-agar sampler. Settling airborne particles were collected on culture plates placed at, and collected from, five different locations on the floor of the chamber with a custom-built remote plate-placement and -retriever system. Experimentally contaminated air in the chamber was decontaminated for 45 min with a device based on HEPA filtration and UV light. The plates were incubated and CFU counted. The device reduced the viability levels of all tested bacteria in the air by >3 log10 (>99·9%) in 45 min. Based on two separate tests, the average reductions in surface contamination for S. aureus, A. baumannii and G. stearothermophilus were respectively, 97, 87 and 97%. We thus showed that air decontamination could substantially and simultaneously reduce the levels of surface contamination in the same setting irrespective of the type of pathogen present. SIGNIFICANCE AND IMPACT OF THE STUDY: The innovative and generic test protocol described can quantitatively assess the reduction in environmental surface contamination from microbial decontamination of indoor air in the same setting. This added advantage from air decontamination has implications for infection prevention and control in healthcare and other settings without the need for additional expense or effort. Continuous operation of an air decontamination device, such as the one tested here, can lead to ongoing reductions in pathogens in air and on environmental surfaces.

Investigation of antibiotic and antibacterial agent cross-resistance in target bacteria from homes of antibacterial product users and nonusers.

AIM: To describe the relationship between antibiotic and antibacterial resistance in environmental and clinical bacteria from home environments across geographical locations, relative to the use or nonuse of antibacterial products, with a focus on target organisms recognized as potential human pathogens. METHODS AND RESULTS: In a randomized study, environmental and clinical samples were collected from the homes of antibacterial product users (n=30) and nonusers (n=30) for the isolation of target bacteria for antibiotic and antibacterial testing in three geographical areas (in USA and UK). Isolates were tested for antibiotic susceptibility, with selected antibiotic-resistant and antibiotic-susceptible isolates tested against four common antibacterial agents (triclosan, para-chloro-meta-xylenol, pine oil and quaternary ammonium compound). Prequalified users and nonusers at each location were randomly selected after meeting exclusionary criteria. Of 1238 isolates, more target bacteria were recovered from nonuser than user homes. Of Staphylococcus aureus isolates (n=33), none showed resistance to oxacillin or vancomycin; for Enterococcus sp. (n=149), none were resistant to ampicillin or vancomycin; and for Klebsiella pneumoniae (n=54)and Escherichia coli (n=24), none were resistant to third generation cephalosporins. Antibiotic resistance to one or more of the standard test panel drugs for Gram-positive and Gram-negative target bacteria was comparable between nonuser and user homes for both environmental and clinical isolates [e.g. resistance of environmental coagulase-negative (CN) Staphylococcus sp. was 73.8% (124/168) from nonuser homes and 73.0% (111/152) from user homes, and Enterobacteriaceae other than E. coli, 75.9% (186/245) from nonuser homes compared with 78.0% from user homes]. Of 524 Gram-negatives tested against preferred/alternative drugs, 97.1% (509/524) were susceptible to all antibiotics, across both groups. Isolates of S. aureus, Enterococcus sp. and CN Staphylococcus sp. susceptible to all preferred treatment drugs showed comparable antibacterial minimum inhibitory concentration (MIC) results between nonuser and user home isolates. For Gram-positives resistant to one or more preferred drugs, greatest resistance to antibacterial active ingredients was found in the nonuser group. For Gram-negatives, the antibacterial MIC data were comparable for isolates that were fully susceptible and resistant to one or more preferred/alternative treatment antibiotics. CONCLUSIONS: The results showed a lack of antibiotic and antibacterial agent cross-resistance in target bacteria from the homes of antibacterial product users and nonusers, as well as increased prevalence of potential pathogens in nonuser homes. SIGNIFICANCE AND IMPACT OF THE STUDY: It refutes widely publicized, yet unsupported, hypotheses that use of antibacterial products facilitates the development of antibiotic resistance in bacteria from the home environment.

Overview of Lysol scientific studies.

When followed, simple hygienic practices such as handwashing and surface disinfection along with proper food handling techniques can have a positive impact on the health of families and individuals in nonmedical settings like homes, day care and long term care facilities. Several studies have attempted to identify the specific role surface disinfectants can play in this effort. The evidence seems to indicate that these types of products, when properly used, can be beneficial. Because it has been established that environmental surfaces act as intermediates in the transmission of microorganisms throughout the day-care center and in homes, future studies should be developed to quantitate the impact of specific interventions in the reduction of microorganisms.

Effect of a comprehensive infection control program on the incidence of infections in long-term care facilities.

BACKGROUND: Control of infection within the long-term care facility is a daunting problem. Elderly patients are at high risk for contracting infection because of reduced innate immunity, malnutrition, and the presence of chronic medical conditions. This small study tested the effect of developing and implementing a comprehensive preventive infection control program in the long-term care setting and examined the resultant incidence of infections. METHODS: Eight private, freestanding, long-term care facilities in urban and suburban settings were selected for the study. The 4 test sites had a total of 443 beds; there were 447 beds in 4 matched control sites. Data on infection rates were accrued in both preintervention and intervention years. The control homes maintained their existing infection control policies and procedures. The test homes were provided with an infection control educational program and replaced all currently used germicidal products with single-branded products for a 12-month period. A criteria-based standardized infection control surveillance system was used to monitor and report infections in all facilities. RESULTS: In the preintervention year, the test sites experienced 743 infections (incidence density rate, 6.33) and the control homes experienced 614 infections (incidence density rate, 3.39). In the intervention year, the test homes reported 621 infections, a decrease of 122 infections (incidence density rate, 4.15); in the control homes, the number of infections increased slightly, to 626 (incidence density rate, 3.15). The greatest reduction in infections in the test homes was in upper respiratory infections (P =.06). CONCLUSIONS: This study provides additional evidence that a comprehensive infection control program that includes handwashing and environmental cleaning and disinfecting may help reduce infections among the elderly residing in long-term care settings.

Development of a model for evaluation of microbial cross-contamination in the kitchen.

Foods can become contaminated with pathogenic microorganisms from hands, the cutting board, and knives during preparation in the kitchen. A laboratory model was developed to determine occurrence of cross-contamination and efficacy of decontamination procedures in kitchen food-handling practices. Enterobacter aerogenes B199A, an indicator bacterium with attachment characteristics similar to that of Salmonella spp., was used. Chicken meat with skin inoculated with 10(6) CFU of E. aerogenes B199A/g was cut into small pieces on a sterile cutting board. The extent of cross-contamination occurring from meat to the cutting board and from the cutting board to vegetables (lettuce and cucumbers) subsequently cut on the board was determined. Swab samples from the cutting board, hand washings, and lettuce and cucumber samples revealed that approximately 10(5) CFU of E. aerogenes/cm2 were transferred to the board and hands and approximately 10(3) to 10(4) CFU of E. aerogenes/g to the lettuce and cucumbers. The surfaces of the cutting board and hands were treated with antibacterial agents after cutting the meat, and counts of E. aerogenes on the cutting board and vegetables (lettuce and cucumbers) were determined. Results revealed that use of the disinfectant reduced the population of E. aerogenes to almost nondetectable levels on the cutting boards. The average counts after treatment were < 20 CFU/g of vegetable and ranged from < 20 to 200 CFU per cm2 or g on the cutting board and subsequently on the vegetables. These results indicate that bacteria with attachment characteristics similar to Salmonella spp. can be readily transferred to cutting boards during food preparation and then cross-contaminate fresh vegetables if the boards are not cleaned. Application of a kitchen disinfectant can greatly reduce bacterial contamination on cutting boards.

Characterization and quantification of bacterial pathogens and indicator organisms in household kitchens with and without the use of a disinfectant cleaner.

This two year study evaluated the prevalence of indicator bacteria and specific pathogens in 10 'normal' kitchens in the United States. In Phase I, none of the kitchens was cleaned with an antimicrobial cleaner or disinfectant. Eight locations within the kitchens were monitored for: total heterotrophs, staphylococci, Pseudomonas, total coliforms and faecal coliforms. Almost all locations at all households exhibited contamination, with the sink and sponge samples exhibiting large bacterial concentrations. The faecal coliform concentrations in sink and sponge samples were very high, with 63 and 67% of all samples being positive, respectively. Escherichia coli was detected in 16.7% of all sink surfaces and 33.3% of all sponges. Salmonella was detected once and Campylobacter, on two occasions. In a second phase, households were provided with an antimicrobial disinfectant cleaner which families were encouraged to use but not forced to do so; in some cases, the product was used infrequently or not at all. This regimen did not demonstrate any consistent reduction in the incidence of bacterial contamination. By contrast, in the final phase of the study where disinfectant use was targeted for surfaces soon after contamination with foods or hands, the incidence of contamination decreased dramatically. These data show that normal kitchens can easily be contaminated with a variety of bacterial contaminants including faecal coliforms, E. coli, Salmonella and Campylobacter. Irregular use, or not using antimicrobial agents, is unlikely to reduce the risk of these infectious agents. By contrast, targeted use is likely to reduce the incidence of bacterial contaminants.

Impact of an infection control program in a specialized preschool.

BACKGROUND: The purpose of this study was to design and implement a comprehensive infection control program and measure its effects on the number and types of infectious illnesses experienced by children attending a specialized preschool program. METHODS: Participants in the study were children with Down syndrome enrolled in a school-based early intervention program. The ages of the children ranged from 6 weeks to 5 years. Through a series of parental questionnaires, the number and types of infections in the children were chronicled for a year before and a year after the implementation of an infection control intervention program. Interventions included infection control lectures, handouts, posters, and attention to environmental cleaning and disinfection, with an emphasis on toys. Compliance with these measures was monitored and recorded. RESULTS: During the interventional year the median number of total illnesses/child/month decreased significantly from the baseline year (0.70 vs 0.53, p < 0.05), with a trend toward a decrease in the number of respiratory illnesses (0.67 vs 0.42, p < 0.07). Significant decreases were also seen for the median number of physician visits (0.50 vs 0.33, p < 0.05), courses of antibiotics administered (0.33 vs 0.28, p < 0.05), and days of school missed as a result of respiratory illness (0.75 vs 0.40, p < 0.05). CONCLUSIONS: This study demonstrates a decrease in infection rates with the implementation of a comprehensive educational and environmental infection control program in a day care setting.

Hard surface carrier test as a quantitative test of disinfection: a collaborative study.

The hard surface carrier test (HSCT) recently was proposed as a qualitative test for disinfectant efficacy. A collaborative study of HSCT led to a suggested performance standard of < or = 2 or 3 positive carriers out of 60 tested. Subsequently, it was discovered that HSCT can be used as a quantitative test, because the HSCT protocol requires measurement of inoculum level on some carriers. The data allow estimation of the log10 reduction in number of active bacteria. Producers, consumers, and policymakers will be better able to discuss merits of alternative performance standards if the focus is on log reduction of organisms rather than on number of positive carriers. Data from the collaborative study were reanalyzed from this quantitative viewpoint. If the point estimate of log reduction in LR and the 99% lower confidence limit estimate is LLR, the LR values ranged from 7.0 to 9.0 and the LLR values were greater than 6.0 for all disinfectants except the negative control formulation. The total variance for estimated LR is the sum of interlaboratory and intralaboratory variances. The total variance for LR was 0.095 for Pseudomonas aeruginosa, 0.251 for Staphylococcus aureus, and 0.118 for Salmonella choleraesuis. Percentages of the variance due to interlaboratory variability were 11% for P. aeruginosa, 52% for S. aureus, and 25% for S. choleraesuis. Chances of making false-effective and false-ineffective decisions can be calculated for the quantitative HSCT. The performance standard can be based on LLR.

Interruption of rotavirus spread through chemical disinfection.

INTRODUCTION: Rotaviruses, which are among the most important infectious causes of acute diarrhea, frequently cause outbreaks in hospitals, daycare centers, schools, and nursing homes. These viruses can remain viable on inanimate surfaces for many days and infectious rotavirus particles have been recovered from hands and a variety of surfaces and objects. Casual contact can lead to the transfer of these viruses from contaminated to clean surfaces. Therefore, animate and inanimate surfaces may play a complementary role in the spread of these viruses. OBJECTIVE: In this study, we compared the capacity of a disinfectant spray (0.1% o-phenylphenol and 79% ethanol), a domestic bleach (6% sodium hypochlorite diluted to give 800 ppm free chlorine), a quarternary ammonium (quat)-based product (7.05% quat diluted 1:128 in tap water), and a phenol-based product (14.7% phenol diluted 1:256 in tap water) to interrupt the transfer of a human rotavirus (DS-1) from stainless steel disks to fingerpads of volunteers with a 10-second contact at a pressure of 1 kg/cm2. DESIGN: Each disk received a 10 microL inoculum containing 1.0 x 10(4) to 7.0 x 10(4) plaque-forming units (PFU) of the virus suspended in 10% feces. The inoculum was dried for 1 hour and overlaid with 20 microL of either tap water or the test product. RESULTS: A 10-minute exposure to tap water reduced the virus titer by 52.3% +/- 11.7%. The disinfectant spray was able to reduce virus infectivity by > 99.99% after a contact of 3 to 10 minutes. The loss in virus infectivity after a 10-minute treatment with the quat was almost the same (54.7% +/- 17.8%) as seen with tap water. The activities of the bleach and the phenolic were very similar with losses in PFU of 97.9% +/- 0.4% and 95% +/- 5.36%, respectively. No detectable virus was transferred to fingerpads from disks treated with disinfectant spray, the bleach, and the phenolic. Contact of the fingerpads with tap water- or quat-treated disks resulted in the transfer of 5.6% +/- 1.1% and 7.6% +/- 2.5% of the remaining infectious virus, respectively. CONCLUSION: These findings emphasize the care needed in the selection of environmental surface disinfectants in preventing the spread of rotaviral infections.

Chemical disinfection to interrupt transfer of rhinovirus type 14 from environmental surfaces to hands.

Rhinoviruses can survive on environmental surfaces for several hours under ambient conditions. Hands can readily become contaminated after contact with such surfaces, and self-inoculation may lead to infection. Whereas hand washing is crucial in preventing the spread of rhinovirus colds, proper disinfection of environmental surfaces may further reduce rhinovirus transmission. In this study, the capacities of Lysol Disinfectant Spray (0.1% o-phenylphenol and 79% ethanol), a domestic bleach (6% sodium hypochlorite diluted to give 800 ppm of free chlorine), a quaternary ammonium-based product (7.05% quaternary ammonium diluted 1:128 in tap water), and a phenol-based product (14.7% phenol diluted 1:256 in tap water) were compared in interrupting the transfer of rhinovirus type 14 from stainless steel disks to fingerpads of human volunteers upon a 10-s contact at a pressure of 1 kg/cm2. Ten microliters of the virus, suspended in bovine mucin (5 mg/ml), was placed on each disk, and the inoculum was dried under ambient conditions; the input number on each disk ranged from 0.5 x 10(5) to 2.1 x 10(6) PFU. The dried virus was exposed to 20 microliters of the test disinfectant. The Lysol spray was able to reduce virus infectivity by > 99.99% after a contact of either 1 or 10 min, and no detectable virus was transferred to fingerpads from Lysol-treated disks. The bleach (800 ppm of free chlorine) reduced the virus titer by 99.7% after a contact time of 10 min, and again no virus was transferred from the disks treated with it.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of surface-to-human transmission of rotaviruses by treatment with disinfectant spray.

A model was developed to examine the effects of disinfectants on the transmission of infectious rotavirus from a dried surface to humans. The initial experiments were designed to find a method of preserving rotavirus infectivity during drying. Culture-adapted human rotavirus (CJN strain) was dried at room temperature in different organic suspensions, including fecal matter, several laboratory media, and nonfat dry milk (NDM). Recoveries of infectious virus were then compared. Fecal matter provided little protection in this study relative to distilled water, but the other suspensions were quite protective, especially NDM, which consistently allowed recoveries of greater than 50%. When 10(3) focus-forming units of unpassaged CJN virus were dried in NDM and administered to subjects who licked the dried material, 100% (8 of 8) became infected. The effect of Lysol brand disinfectant spray (LDS) was next examined. Although NDM provided some protection against inactivation by LDS, spraying under conditions recommended by the manufacturer consistently caused the CJN virus titer to decrease greater than 5 log10. Consumption of CJN virus (10(3) focus-forming units) sprayed with LDS caused no infection in 14 subjects, whereas 13 of 14 subjects who consumed the unsprayed virus became infected (P less than 0.00001). The methods developed in this study could be used to test the effects of other disinfectants on the spread of infectious rotavirus from inanimate surfaces to humans.