Asthma among workers in healthcare settings: role of disinfection with quaternary ammonium compounds

Airway Diseases Related to the Use of Cleaning Agents in Occupational Settings

Exposure to disinfectants and cleaning products (DCPs) is now a well-established risk factor for work-related asthma (WRA). However, questions remain on the specific causal agents and pathophysiological mechanisms. Few studies have also reported an association between DCPs and rhinitis or chronic obstructive pulmonary disease. This review discusses the recent evidence pertaining to airway diseases attributable to occupational exposure to DCPs. In contrast to other agents, the incidence of WRA due to DCPs has increased over time. The use of DCPs in spray form has clearly been identified as an added risk factor. The mechanisms for WRA associated with DCPs remain poorly studied; however, both allergic and nonallergic responses have been described, with irritant mechanisms thought to play a major role. An early diagnostic workup based on clinical assessment accompanied by evaluation of lung function and immunological and airway inflammatory markers is important to guide optimal care and exposure avoidance to the implicated agent. Future research should focus on the effects of "green" products, pathophysiological mechanisms, and quantitative exposure assessment including the use of barcode-based methods to identify specific agents. There is an urgent need to strengthen preventive measures and interventions to reduce the burden of airway diseases associated with DCPs.

Health risks of pest control and disinfection workers after the COVID-19 outbreak in South Korea

The exposure patterns of pest control and disinfection workers have changed after the coronavirus disease 2019 (COVID-19) outbreak, but the health risks of chemical exposure have not been assessed. We identified these workers' chemical exposure patterns and risks before and after the COVID-19 outbreak. We used data conducted between 2018 (pre-pandemic) and 2021 (post-pandemic) from three-year cross-sectional surveys on pest control and disinfection workers. Inhalation and dermal exposure concentrations were estimated using equations based on a biocidal product risk assessment model from the Korean National Institute of Environmental Research. The non-carcinogenic and carcinogenic risks of chemicals were calculated using the United States Environmental Protection Agency risk assessment model. We found that the annual work frequency (50th percentile) of foggers using disinfectants increased the most among all the work types, from 140 uses/year to 176 uses/year after the COVID-19 outbreak. Moreover, all chemicals' non-carcinogenic and carcinogenic risks increased regardless of exposure routes. In the worst scenario (95th percentile), the margin of exposure for citric acid, benzethonium chloride, benzyl-C12-16-alkyldimethyl chlorides, and sodium chlorite of inhalation exposure, and isopropyl alcohol and benzyl-C12-16-alkyldimethyl chlorides of dermal exposure were acceptable (>100) before the COVID-19 outbreak but became unacceptable (<100) after the COVID-19 outbreak. Carcinogenic risks of dichlorvos from inhalation and dermal exposure were above acceptable levels (>10-6) before and after the COVID-19 outbreak but comparatively high after the COVID-19 outbreak. Additionally, significantly more workers experienced health symptoms after the COVID-19 outbreak (p<0.05), with the most common being muscle lethargy (31%), skin/face stinging (28.7%), and breath shortness/neck pain (24.1%).

Potential health risks to disinfection workers from exposure to active substances in COVID-19 biocidal products

The importance of disinfection has recently been emphasized due to the increasing risk of the spread of infections such as coronavirus disease-2019 (COVID-19). In addition, disinfection for preventing the spread of COVID-19 is highly recommended. The increased use of biocidal products raises concerns regarding the potential health risks from exposure among disinfection workers. This study aimed to assess these exposure and health risks using questionnaires targeting disinfection workers who were exposed to the active substances in biocidal products used for disinfection during the COVID-19 pandemic. A follow-up survey was conducted among 271 disinfection workers for 10 working days within two weeks, and exposure factors with reference to disinfection were evaluated through interview-administered questionnaires. An exposure algorithm was used to evaluate the exposure of disinfection workers during disinfection. The hazard index (HI) was calculated by dividing the inhalation concentration obtained using the exposure algorithm and the dermal dose according to occupational exposure limits (OEL). A sensitivity analysis was conducted to identify the exposure factors with the greatest impact on the inhalation and dermal exposure algorithms. A logistic regression analysis was performed to verify the relationship with health effects and sociodemographic and exposure characteristics. The average number of disinfections performed during 10 working days was 17.5 ± 12.3 times. The type of disinfection work was divided into 2806 cases of COVID-19 prevention and disinfection and 1956 cases of regular pesticide application to prevent and remove any pests. The HI was ≥1, indicating a potential health risk, with the use of ethanol (6.50E+00), quaternary ammonium compounds (QACs; 1.49E+01), and benzalkonium chloride (BKC; 1.73E+00). Dermal exposure was more hazardous than inhalation exposure for 6 of the 11 active substances in biocidal products. The weight fraction and exposure time were the factors that most significantly influenced the inhalation and dermal exposure algorithms in the sensitivity analysis. Higher exposure concentrations were more likely to affect health (AOR: 3.239, 95% CI: 1.155-9.082). This study provides valuable information regarding the exposure and risk of disinfection workers to 11 biocidal active substances included in common disinfectants. Our results suggest that the use of ethanol, BKC, and QACs has potential health risks to disinfection workers, with a higher possibility of negative health impacts with increasing exposure concentration.

Photochemical fate of quaternary ammonium compounds (QACs) and degradation pathways predication through computational analysis

Quaternary ammonium compounds (QACs) are commonly used in many products, such as disinfectants, detergents and personal care products. However, their widespread use has led to their ubiquitous presence in the environment, posing a potential risk to human and environmental health. Several methods, including direct and indirect photodegradation, have been explored to remove QACs such as benzylalkyldimethyl ammonium compounds (BACs) and alkyltrimethyl ammonium compounds (ATMACs) from the environment. Hence, in this research, a systematic review of the literature was conducted using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) method to understand the fate of these QACs during direct and indirect photodegradation in UV/H2O2, UV/PS, UV/PS/Cu2+, UV/chlorine, VUV/UV/chlorine, O3/UV and UV/O3/TiO2 systems which produce highly reactive radicals that rapidly react with the QACs, leading to their degradation. As a result of photodegradation, several transformation products (TPs) of QACs are formed, which can pose a greater risk to the environment and human health than the parent QACs. Only limited research in this area has been conducted with fewer QACs. Hence, quantum mechanical calculations such as density functional theory (DFT)-based computational calculations using Gaussian09 software package were used here to explain better the photo-resistant nature of a specific type of QACs, such as BACs C12-18 and ATMACs C12, C14, C18, and their transformation pathways, providing insights into active sites participating in the phototransformation. Recognizing that different advanced oxidation processes (AOPs) come with pros and cons in the elimination of QACs, this review also highlighted the importance of implementing each AOP concerning the formation of toxic transformation products and electrical energy per order (EEO), especially when QACs coexist with other emerging contaminants (ECs).

Hygiene requirements for cleaning and disinfection of surfaces: recommendation of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute

This recommendation of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) addresses not only hospitals, but also outpatient health care facilities and compiles current evidence. The following criteria are the basis for the indications for cleaning and disinfection: Infectious bioburden and tenacity of potential pathogens on surfaces and their transmission routes, influence of disinfecting surface cleaning on the rate of nosocomial infections, interruption of cross infections due to multidrug-resistant organisms, and outbreak control by disinfecting cleaning within bundles. The criteria for the selection of disinfectants are determined by the requirements for effectiveness, the efficacy spectrum, the compatibility for humans and the environment, as well as the risk potential for the development of tolerance and resistance. Detailed instructions on the organization and implementation of cleaning and disinfection measures, including structural and equipment requirements, serve as the basis for their implementation. Since the agents for surface disinfection and disinfecting surface cleaning have been classified as biocides in Europe since 2013, the regulatory consequences are explained. As possible addition to surface disinfection, probiotic cleaning, is pointed out. In an informative appendix (only in German), the pathogen characteristics for their acquisition of surfaces, such as tenacity, infectious dose and biofilm formation, and the toxicological and ecotoxicological characteristics of microbicidal agents as the basis for their selection are explained, and methods for the evaluation of the resulting quality of cleaning or disinfecting surface cleaning are presented.

Cleaning Tasks and Products and Asthma Among Health Care Professionals

OBJECTIVE

Health care workers are at risk for work-related asthma, which may be affected by changes in cleaning practices. We examined associations of cleaning tasks and products with work-related asthma in health care workers in 2016, comparing them with prior results from 2003.

METHODS

We estimated asthma prevalence by professional group and explored associations of self-reported asthma with job-exposure matrix-based cleaning tasks/products in a representative Texas sample of 9914 physicians, nurses, respiratory/occupational therapists, and nurse aides.

RESULTS

Response rate was 34.8% (n = 2421). The weighted prevalence rates of physician-diagnosed (15.3%), work-exacerbated (4.1%), and new-onset asthma (6.7%) and bronchial hyperresponsiveness symptoms (31.1%) were similar to 2003. New-onset asthma was associated with building surface cleaning (odds ratio [OR], 1.91; 95% confidence interval [CI], 1.10-3.33), use of ortho-phthalaldehyde (OR, 1.77; 95% CI, 1.15-2.72), bleach/quaternary compounds (OR, 1.91; 95% CI, 1.10-3.33), and sprays (OR, 1.97; 95% CI, 1.12-3.47).

CONCLUSION

Prevalence of asthma/bronchial hyperresponsiveness seems unchanged, whereas associations of new-onset asthma with exposures to surface cleaning remained, and decreased for instrument cleaning.

Applications of quaternary ammonium compounds in the prevention and treatment of oral diseases: State-of-the-art and future directions

OBJECTIVES

The aim of this review is to comprehensively summarize the state-of-the-art developments of quaternary ammonium compounds (QACs) in the prevention and treatment of oral diseases. By discussing the structural diversity and the potential killing mechanism, we try to offer some insights for the future research of QACs.

DATA, SOURCES & STUDY SELECTION

A literature search was conducted in electronic databases (Web of Science, PubMed, Medline, and Scopus). Publications that involved the applications of QACs, especially those related to the prevention and treatment of oral diseases, are included.

RESULTS

We have reviewed the relevant research on QACs over the past two decades. The research results indicate that the current applications are mainly focused on dental material modification and direct pharmacological interventions. Concurrently, challenges such as potential risks to normal tissues and impediments in drug resistance and microbial persistence present certain application constraints. The latest studies have encompassed the exploration of smart materials and nanoparticle formulations.

CONCLUSIONS

The killing mechanism may possess a threshold related to charge density. However, the exact process remains enigmatic. The structural diversity and the exploration of intelligent materials and nanoparticle formulations provide directions in development of novel QACs.

CLINICAL SIGNIFICANCE

The intricate oral anatomy, combined with the multifaceted oral microbiome, necessitates specialized materials for the targeted prevention and treatment of oral pathologies. QACs represent a cohort of compounds distinguished by potent anti-infective and anti-tumor attributes. Innovations in intelligent materials and nanoparticle formulations amplify their potential in significantly advancing the prevention and therapeutic interventions for oral diseases.

Biocides in the Hospital Environment: Application and Tolerance Development

Hospital-acquired infections are a rising problem with consequences for patients, hospitals, and health care workers. Biocides can be employed to prevent these infections, contributing to eliminate or reduce microorganisms' concentrations at the hospital environment. These antimicrobials belong to several groups, each with distinct characteristics that need to be taken into account in their selection for specific applications. Moreover, their activity is influenced by many factors, such as compound concentration and the presence of organic matter. This article aims to review some of the chemical biocides available for hospital infection control, as well as the main factors that influence their efficacy and promote susceptibility decreases, with the purpose to contribute for reducing misusage and consequently for preventing the development of resistance to these antimicrobials.

COVID-19 cleaning protocol changes, experiences, and respiratory symptom prevalence among cleaning services personnel

Introduction

Cleaning protocols were changed in response to the COVID-19 pandemic with unknown occupational health impacts. There is evidence that COVID-19 transmission risks from contaminated surfaces are low and that exposure to cleaning products can increase risks of work-related asthma. The study objective was to investigate relationships between reported COVID-19-related changes in cleaning protocols and prevalence of asthma-related respiratory symptoms for asthmatic and non-asthmatic janitors and maids. A secondary objective was to characterize experiences of respiratory symptoms associated with cleaning and barriers to personal protective equipment (PPE) use.

Methods

Employees from two Tucson-based maid service companies (approximately 30 personnel in total) and one Phoenix-based school district (>300 janitors/custodians) were invited to participate in a written survey and/or a one-on-one interview in Spanish or English. Fisher's exact tests (α = 0.05) were used to test for statistically significant associations between reported respiratory symptoms by self-reported physician-diagnosed asthma status and changes in cleaning protocols. Interviews were transcribed and then analyzed by at least two researchers in English or Spanish.

Results

Eighty-three percent reported that cleaning protocols had changed during COVID-19, with the two most reported changes including increased cleaning frequency (92%) and change of application type (e.g., fog, spray, wipe) (53%). There was a statistically significant association between multiple respiratory symptoms and self-reported physician diagnosed asthma. Reporting a type of application change (e.g., fog, spray, wipe) and being awakened during the night by attack/episode of cough were statistically significantly associated (p = 0.04). Interviews elucidated respiratory issues related to fogging devices.

Discussion

This study provides preliminary evidence that changes in cleaning and disinfection protocols during COVID-19 (namely, the use of fogging/mechanical spraying devices) may have had negative impacts on the health of workers in the cleaning industry with little benefit to reducing COVID-19 risks. Further research is needed to evaluate the generalizability of our findings across larger geographical areas and to develop guidance for employers and employees on how to protect and promote respiratory health.

[Allergenic and chemical pollutants of indoor environments and asthma: Characterization, assessment and eviction]

The environment of an asthmatic patient can contain numerous sources of pollutants that degrade the quality of indoor air and have major repercussions on the occurrence and control of asthma. Assessment and improvement of the quality of indoor air should be assigned a major role in pneumology and allergology consultations. Characterization of an asthmatic's environment entails a search for biological pollutants with mite allergens, mildew, and allergens resulting from the proximity of pets. It is important to evaluate the chemical pollution represented by exposure to volatile organic compounds, which are increasingly present in our lodgings. Active or second-hand smoking must in all circumstances be sought out and quantified. Assessment of the environment is mediated by several methods, of which the application depends not only on the pollutant sought out, but also on enzyme-linked immunosorbent assay (ELISA), which has an essential role in quantification of biological pollutants. Attempts at expulsion of the different indoor environment pollutants is mediated by indoor environment advisors, whose efforts are aimed at obtaining reliable evaluation and control of indoor air. Implemented as a form of tertiary prevention, their methods are conducive to improved asthma control, in adults as well as children.

Exposure frequency, intensity, and duration: What we know about work-related asthma risks for healthcare workers from cleaning and disinfection

The objective of this review was to scope the current evidence base related to three exposure assessment concepts: frequency, intensity, and duration (latency) for cleaning and disinfection exposures in healthcare and subsequent work-related asthma risks. A search strategy was developed addressing intersections of four main concepts: (1) work-related asthma; (2) occupation (healthcare workers/nurses); (3) cleaning and disinfection; and (4) exposure. Three databases were searched: Embase, PubMed, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) database. Data were extracted related to three main components of risk assessment: (1) exposure frequency, (2) exposure intensity, and (3) exposure duration. Latency data were analyzed using an exponential distribution fit, and extracted concentration data were compared to occupational exposure limits. The final number of included sources from which data were extracted was 133. Latency periods for occupational asthma were exponentially distributed, with a mean waiting time (1/λ) of 4.55 years. No extracted concentration data were above OELs except for some formaldehyde and glutaraldehyde concentrations. Data from included sources also indicated some evidence for a dose-response relationship regarding increased frequency yielding increased risk, but this relationship is unclear due to potential confounders (differences in role/task and associated exposure) and the healthy worker effect. Data priority needs to include linking concentration data to health outcomes, as most current literature does not include both types of measurements in a single study, leading to uncertainty in dose-response relationships.

Eye and airway symptoms in hospital staff exposed to a product containing hydrogen peroxide, peracetic acid, and acetic acid

BACKGROUND

Sporicidal products containing hydrogen peroxide (HP), peracetic acid (PAA), and acetic acid (AA) are used widely in multiple industries, including healthcare. Despite widespread use in healthcare, few studies have assessed associations between exposures to HP, PAA, and AA, and work-related symptoms in these settings.

METHODS

In 2018, we performed a health and exposure assessment at a hospital where a sporicidal product consisting of HP, PAA, and AA, was used as the primary cleaner on hospital surfaces. We collected 56 personal and mobile air samples for HP, PAA, and AA on participants while they performed their regular cleaning duties; collected area samples for HP (n = 28), PAA (n = 28), and AA (n = 70) in multiple hospital locations where cleaning was performed; and administered a postshift survey to assess eye, skin, and upper and lower airway symptoms that occurred cross-shift or in the previous 4 weeks.

RESULTS

Full-shift exposure levels for HP (range: <3-559 ppb), PAA (range: <0.2-8 ppb), and AA (range: <5-915 ppb) were all below US occupational exposure limits. We observed positive associations (p < 0.05) between shift, departmental average, and departmental 95th percentile exposures to HP, PAA, and AA vapors, and work-related acute (cross-shift) and chronic (previous 4 weeks) eye, upper airway, and lower airway symptoms after adjusting for age, gender, smoking status, use of other cleaning products containing sensitizers and irritants, allergic status, and stress.

CONCLUSIONS

Our observations of work-related upper and lower airway symptoms among hospital workers exposed to vapors from a sporicidal product containing HP, PAA, and AA indicate a need for a combination of engineering, administrative, and PPE controls to reduce exposure. Additionally, alternative nonchemical disinfection technologies should be further investigated as a means to simultaneously reduce healthcare workers' exposure to disinfectants while also minimizing costly healthcare-acquired infections.

Characterization of the aerosol release from spray cleaning and disinfection products - Spray scenarios in a climate chamber

Cleaning work using spray products has been associated with adverse respiratory effects but little is known of the exposure concentrations. The purpose of this study was to characterize aerosol generation at spray scenarios in a controlled climate chamber. Spraying on vertically and horizontally oriented surfaces, as well as spraying on a cloth, was investigated. Furthermore, the effect of nozzle geometry was tested. The average mass generation rates of six pressurized spray cans and 13 trigger sprays were about 1.7 g/s and did not differ significantly, but the average values of the individual sprays had large variations (0.5-3.1 g/s). The time required to halve the air concentration of aerosol particles, the half-life time, was determined for all spray products. The average half-life time of the total particle mass concentration (TPMC) of the pressurized spray cans was 0.5 h versus 0.25 h for trigger sprays. Gravimetrically determined airborne fractions of pressurized spray cans tended to be higher than those of trigger sprays. However, airborne fractions based on the measured peak TPMC were up to three orders of magnitude smaller. A comparison of different trigger spray nozzles when spraying the same product showed that the TPMC can be up to 18 times higher for the largest emitting nozzle. The distance of the nozzle to a cloth should be 1 cm to significantly reduce the concentration of the generated aerosols. ConsExpo modeling predicted the measured peak TPMC well but less well the decay.

Occupational risk factors and exposure-response relationships for airway disease among health workers exposed to cleaning agents in tertiary hospitals

OBJECTIVES

This study investigated occupational risk factors and exposure-response relationships for airway disease among health workers (HWs) exposed to cleaning agents in two tertiary hospitals in South Africa and Tanzania.

METHODS

In this cross-sectional study, 697 participants completed questionnaire interviews while 654 underwent fractional exhaled nitric oxide (FeNO) testing. Asthma Symptom Score (ASS) was computed based on the sum of answers to five questions on asthma-related symptoms in the past 12 months. For exposure-response analyses, cleaning agent-related self-reported exposure variables were categorised into three levels (cleaning product not used; use of a cleaning product for up to 99 min per week and use of a cleaning product for ≥100 min per week).

RESULTS

Asthma-related outcomes (ASS and FeNO) demonstrated positive associations with medical instrument cleaning agents (orthophthalaldehyde and enzymatic cleaners) and tasks (instruments precleaning and changing sterilisation solutions) as well as patient care activities (disinfection prior to procedures and disinfecting wounds). A particularly pronounced dose-response relationship was observed between work-related ocular-nasal symptoms and medical instrument cleaning agents (orthophthalaldehyde, glutaraldehyde, enzymatic cleaners, alcohols and bleach) (OR range: 2.37-4.56) and tasks (OR range: 2.92-4.44). A strong association was also observed between ASS and use of sprays for fixed surface cleaning (mean ratio 2.81; 95% CI 1.41 to 5.59).

CONCLUSIONS

Specific agents for medical instrument disinfection for example, orthophthalaldehyde and enzymatic cleaners, patient care activities and use of sprays are important occupational risk factors for airway disease among HWs.

Chronic quaternary ammonium compound exposure during the COVID-19 pandemic and the impact on human health

Objective

This review examines a relevant, and underacknowledged, emerging global public health concern—the widespread exposure to quaternary ammonium compounds (QACs) during the COVID-19 pandemic. QACs are a widely used class of cationic surfactants with broad spectrum antimicrobial activity that serve as the active ingredients in antimicrobial products. While these compounds have been used for decades, the production and consumer use of QAC-containing products have steeply risen during the COVID-19 pandemic to control and prevent the spread of the SARS-Cov-2 virus. As a result, human exposure to QACs has also drastically increased.

Methods

This critical review was conducted by searching the key terms “quaternary ammonium compounds,” “disinfectants,” “COVID-19,” “SARS-Cov-2,” “human health,” and “human exposure” in the major search engines, including Google Scholar, PubMed and Science Direct.

Results

QACs are generally considered safe and effective, yet the magnitude of QAC exposure and the subsequent health effects have not been adequately investigated. Recent studies have revealed the potential for bioaccumulation of QACs in blood and tissue. Inhalation and dermal absorption of QACs are identified as the most significant exposure routes for adults, while children and infants may be significantly more vulnerable to QAC exposure and potential adverse health effects.

Conclusions

QACs are an important tool to protect individual and public health, but understanding the impact of widespread QAC exposure is vital to guide best practices for QAC use and minimize the associated health risks. These pandemic era results warrant further investigation and raise additional questions about the short-term and long-term health effects of chronic QAC exposure.

Clinical trial registration

Not applicable.

Identification and characterization of quaternary ammonium compounds in Flemish indoor dust by ion-mobility high-resolution mass spectrometry

Quaternary ammonium compounds (QACs) are a class of surfactants commonly used in disinfecting and cleaning products. Their use has substantially increased during the COVID-19 pandemic leading to increasing human exposure. QACs have been associated with hypersensitivity reactions and an increased risk of asthma. This study introduces the first identification, characterization and semi-quantification of QACs in European indoor dust using ion-mobility high-resolution mass spectrometry (IM-HRMS), including the acquisition of collision cross section values (^DTCCS_N2) for targeted and suspect QACs. A total of 46 indoor dust samples collected in Belgium were analyzed using target and suspect screening. Targeted QACs (n = 21) were detected with detection frequencies ranging between 4.2 and 100 %, while 15 QACs showed detection frequencies > 90 %. Semi-quantified concentrations of individual QACs showed a maximum of 32.23 µg/g with a median ∑QAC concentration of 13.05 µg/g and allowed the calculation of Estimated Daily Intakes for adults and toddlers. Most abundant QACs matched the patterns reported in indoor dust collected in the United States. Suspect screening allowed the identification of 17 additional QACs. A dialkyl dimethyl ammonium compound with mixed chain lengths (C16:C18) was characterized as a major QAC homologue with a maximum semi-quantified concentration of 24.90 µg/g. The high detection frequencies and structural variabilities observed call for more European studies on potential human exposure to these compounds. For all targeted QACs, drift tube IM-HRMS derived collision cross section values (^DTCCS_N2) are reported. Reference ^DTCCS_N2 values allowed the characterization of CCS-m/z trendlines for each of the targeted QAC classes. Experimental CCS-m/z ratios of suspect QACs were compared with the CCS-m/z trendlines. The alignment between the two datasets served as an additional confirmation of the assigned suspect QACs. The use of the 4bit multiplexing acquisition mode with consecutive high-resolution demultiplexing confirmed the presence of isomers for two of the suspect QACs.

Quaternary Ammonium Compounds: A Chemical Class of Emerging Concern

Quaternary ammonium compounds (QACs), a large class of chemicals that includes high production volume substances, have been used for decades as antimicrobials, preservatives, and antistatic agents and for other functions in cleaning, disinfecting, personal care products, and durable consumer goods. QAC use has accelerated in response to the COVID-19 pandemic and the banning of 19 antimicrobials from several personal care products by the US Food and Drug Administration in 2016. Studies conducted before and after the onset of the pandemic indicate increased human exposure to QACs. Environmental releases of these chemicals have also increased. Emerging information on adverse environmental and human health impacts of QACs is motivating a reconsideration of the risks and benefits across the life cycle of their production, use, and disposal. This work presents a critical review of the literature and scientific perspective developed by a multidisciplinary, multi-institutional team of authors from academia, governmental, and nonprofit organizations. The review evaluates currently available information on the ecological and human health profile of QACs and identifies multiple areas of potential concern. Adverse ecological effects include acute and chronic toxicity to susceptible aquatic organisms, with concentrations of some QACs approaching levels of concern. Suspected or known adverse health outcomes include dermal and respiratory effects, developmental and reproductive toxicity, disruption of metabolic function such as lipid homeostasis, and impairment of mitochondrial function. QACs' role in antimicrobial resistance has also been demonstrated. In the US regulatory system, how a QAC is managed depends on how it is used, for example in pesticides or personal care products. This can result in the same QACs receiving different degrees of scrutiny depending on the use and the agency regulating it. Further, the US Environmental Protection Agency's current method of grouping QACs based on structure, first proposed in 1988, is insufficient to address the wide range of QAC chemistries, potential toxicities, and exposure scenarios. Consequently, exposures to common mixtures of QACs and from multiple sources remain largely unassessed. Some restrictions on the use of QACs have been implemented in the US and elsewhere, primarily focused on personal care products. Assessing the risks posed by QACs is hampered by their vast structural diversity and a lack of quantitative data on exposure and toxicity for the majority of these compounds. This review identifies important data gaps and provides research and policy recommendations for preserving the utility of QAC chemistries while also seeking to limit adverse environmental and human health effects.

Longitudinal associations of household use of cleaning agents and asthma symptoms in women: the EGEA study

OBJECTIVE

To evaluate the associations between the evolution of household use of cleaning products with the asthma symptom score and its evolution over 8 years.

METHODS

Our study is based on 509 women participating in the last two surveys of the Epidemiological study on the Genetics and Environment of Asthma (EGEA) study (EGEA2: 2003-2007 (44 years, 19% current smokers) and EGEA3: 2011-2013). We assessed an asthma symptom score and the use of household cleaning products through standardised questionnaires. We studied longitudinal associations of the evolution of weekly use of irritant or spayed cleaning products with (1) the asthma symptom score at EGEA3 and a stable symptom score between EGEA2-EGEA3 (negative binomial models) and (2) the incidence/evolution of asthma symptoms between EGEA2-EGEA3 (logistic/polytomous logistic regressions). Models accounted for familial dependence and were adjusted for age, smoking status, body mass index and occupational exposure to asthmagens.

RESULTS

Persistent and increased (40% and 16%, respectively) weekly use of irritants or sprays were associated with a higher risk of asthma symptoms at EGEA3 (Mean Score Ratio (MSR)=1.51 (95% CI 1.06 to 2.14) and 1.33 (95% CI 0.85 to 2.08), respectively). A decreased use (19%) was associated with a lower risk of symptoms at EGEA3, compared with a persistent use (MSR=0.59 (95% CI 0.39 to 0.88)). We also observed an association between an increased use of sprays and the incidence of asthma symptoms (OR=2.30 (95% CI 1.08 to 4.91)), compared with no weekly use of irritants/sprays.

CONCLUSIONS

This longitudinal study, with repeated assessment of exposure and respiratory health, supports the hypothesis that a persistent or increased weekly use of sprayed cleaning products over time may have an adverse effect on the evolution of asthma symptoms.

Quaternary ammonium compounds of emerging concern: Classification, occurrence, fate, toxicity and antimicrobial resistance

Amplified hygiene and precautionary measures are of utmost importance to control the spread of COVID-19 and future infection; however, these changes in practice are projected to trigger a rise in the purchase, utilisation and hence, discharge of many disinfectants into the environment. While alcohol-based, hydrogen peroxide-based, and chlorine-based compounds have been used widely, quaternary ammonium compounds (QACs) based disinfectants are of significant concern due to their overuse during this pandemic. This review presents the classification of disinfectants and their mechanism of action, focusing on QACs. Most importantly, the occurrence, fate, toxicity and antimicrobial resistance due to QACs are covered in this paper. Here we collated evidence from multiple studies and found rising trends of concern, including an increase in the mass load of QACs at a wastewater treatment plant (WWTP) by 331% compared to before the COVID-19 pandemic, as well as an increases in the concentration of 62% in residential dust, resulting in high concentrations of QACs in human blood and breast milk and suggesting that these could be potential sources of persistent QACs in infants. In addition to increased toxicity to human and aquatic life, increased use of QACs and accelerated use of antibiotics and antimicrobials during the COVID-19 pandemic could multiply the threat to antimicrobial resistance.

Effects of cleaning spray use on eyes, airways, and ergonomic load

BACKGROUND

Cleaning workers are exposed to chemicals and high physical workload, commonly resulting in airway problems and pain. In this study the response in the upper airways and the physical workload following airborne and ergonomic exposure of cleaning spray was investigated.

METHODS

A survey was answered by professional cleaning workers to investigate their use of cleaning sprays and the perceived effects on eyes, airways and musculoskeletal pain. A human chamber exposure study was then conducted with 11 professional cleaning workers and 8 non-professional cleaning workers to investigate the airborne exposure, acute effects on eyes and airways, and physical load during cleaning with sprays, foam application and microfiber cloths premoistened with water. All cleaning products used were bleach, chlorine, and ammonia free. The medical assessment included eye and airway parameters, inflammatory markers in blood and nasal lavage, as well as technical recordings of the physical workload.

RESULTS

A high frequency of spray use (77%) was found among the 225 professional cleaning workers that answered the survey. Based on the survey, there was an eight times higher risk (p < 0.001) of self-experienced symptoms (including symptoms in the nose, eyes and throat, coughing or difficulty breathing) when they used sprays compared to when they cleaned with other methods. During the chamber study, when switching from spray to foam, the airborne particle and volatile organic compound (VOC) concentrations showed a decrease by 7 and 2.5 times, respectively. For the whole group, the peak nasal inspiratory flow decreased (-10.9 L/min, p = 0.01) during spray use compared to using only water-premoistened microfiber cloths. These effects were lower during foam use (-4.7 L/min, p = 0.19). The technical recordings showed a high physical workload regardless of cleaning with spray or with water.

CONCLUSION

Switching from a spraying to a foaming nozzle decreases the exposure of both airborne particles and VOCs, and thereby reduces eye and airway effects, and does not increase the ergonomic load. If the use of cleaning products tested in this study, i.e. bleach, chlorine, and ammonia free, cannot be avoided, foam application is preferable to spray application to improve the occupational environment.

A Novel Application of Risk-Risk Tradeoffs in Occupational Health: Nurses' Occupational Asthma and Infection Risk Perceptions Related to Cleaning and Disinfection during COVID-19

BACKGROUND

Nurses face the risk of new onset occupational asthma (OA) due to exposures to cleaning and disinfection (C&D) agents used to prevent infections in healthcare facilities. The objective of this study was to measure nurses' preferences when presented with simultaneous OA and respiratory viral infection (e.g., COVID-19) risks related to increased/decreased C&D activities.

METHODS

Nurses working in healthcare for ≥1 year and without physician-diagnosed asthma were recruited for an online anonymous survey, including four risk-risk tradeoff scenarios between OA and respiratory infection with subsequent recovery (Infect and Recovery) or subsequent death (Infect and Death). Nurses were presented with baseline risks at hypothetical "Hospital 1", and were asked to choose Hospital 2 (increased OA risk to maintain infection risk), Hospital 3 (increased infection risk to maintain OA risk), or indicate that they were equally happy.

RESULTS

Over 70% of nurses were willing to increase infection risk to maintain baseline OA risk if they were confident they would recover from the infection. However, even when the risk of infection leading to death was much lower than OA, most nurses were not willing to accept a larger (but still small) risk of death to avoid doubling their OA risk. Age, work experience, and ever having contracted or knowing anyone who has contracted a respiratory viral infection at work influenced choices.

CONCLUSIONS

We demonstrate the novel application of a risk-risk tradeoff framework to address an occupational health issue. However, more data are needed to test the generalizability of the risk preferences found in this specific risk-risk tradeoff context.

Characterization of Cleaning and Disinfection Product Use, Glove Use, and Skin Disorders by Healthcare Occupations in a Midwestern Healthcare Facility

Healthcare facility staff use a wide variety of cleaning and disinfecting products during their daily operations, many of which are associated with respiratory or skin irritation or sensitization with repeated exposure. The objective of this study was to characterize the prevalence of cleaning and disinfection product use, glove use during cleaning and disinfection, and skin/allergy symptoms by occupation and identify the factors influencing glove use among the healthcare facility staff. A questionnaire was administered to the current employees at a midwestern Veterans Affairs healthcare facility that elicited information on cleaning and disinfection product use, glove use during cleaning and disinfection, skin/allergy symptoms, and other demographic characteristics, which were summarized by occupation. The central supply/environmental service workers (2% of the total survey population), nurses (26%,), nurse assistants (3%), and laboratory technicians (5%) had the highest prevalence of using cleaning or disinfecting products, specifically quaternary ammonium compounds, bleach, and alcohol. Glove use while using products was common in both patient care and non-patient care occupations. The factors associated with glove use included using bleach or quaternary ammonium compounds and using cleaning products 2-3 or 4-5 days per week. A high frequency of glove use (≥75%) was reported by workers in most occupations when using quaternary ammonium compounds or bleach. The use of alcohol, bleach, and quaternary ammonium compounds was associated with skin disorders (p < 0.05). These research findings indicate that although the workers from most occupations report a high frequency of glove use when using cleaning and disinfection products, there is room for improvement, especially among administrative, maintenance, and nursing workers. These groups may represent populations which could benefit from the implementation of workplace interventions and further training regarding the use of personal protective equipment and the potential health hazards of exposure to cleaning and disinfecting chemicals.

Irritant-Induced Asthma

Irritant-induced asthma (IIA) is a phenotype of asthma caused by the inhalation of irritant agents. Definite, probable, or possible IIA have been described, depending on the concentration of the inhaled irritants and the onset of respiratory symptoms respective to the time of exposure. Definite IIA represents approximately 4% to 14% of all cases of new-onset work-related asthma. Agents responsible for IIA can be encountered as fumes, gases, aerosols, or dusts. The most frequent are chlorine, nitrogen oxides, sulfur dioxide, ammonia, acetic acid, solvents, and cleaning materials. Although the diagnosis of definite IIA is based on a suggestive clinical history along with evidence of reversible airflow limitation and/or nonspecific bronchial hyperresponsiveness, possible IIA cannot be diagnosed with certainty because the relationship between exposure and the onset of symptoms is difficult to establish. This article reviews the epidemiology, pathophysiology, diagnostic approach, and management of IIA.

Quaternary ammonium compounds in hypersensitivity reactions

Quaternary ammonium compounds (QAC) are commonly used disinfectants, antiseptics, preservatives, and detergents due to their antibacterial property and represent the first used biocides before phenolic or nitrogen products. Their common structure consists of one or more quaternary ammonium bound with four lateral substituents. Their amphiphilic structure allows them to intercalate into microorganism surfaces which induces an unstable and porous membrane that explains their antimicrobial activity towards bacteria, fungi, and viruses. QAC are thus found in many areas, such as household products, medicines, hygiene products, cosmetics, agriculture, or industrial products but are also used in medical practice as disinfectants and antiseptics and in health care facilities where they are used for cleaning floors and walls. QAC exposure has already been involved in occupational asthma in healthcare workers or professional cleaners by many authors. They also have been suggested to play a role in contact dermatitis (CD) and urticaria in workers using cosmetics such as hairdressers or healthcare workers, inciting reglementary agencies to make recommendations regarding those products. However, distinguishing the irritant or sensitizing properties of chemicals is complex and as a result, the sensitizing property of QAC is still controverted. Moreover, the precise mechanisms underlying the possible sensitization effect are still under investigation, and to date, only a few studies have documented an immunological mechanism. Besides, QAC have been suggested to be responsible for neuromuscular blocking agents (NMBA) sensitization by cross-reactivity. This hypothesis is supported by a higher prevalence of quaternary ammonium (QA)-specific IgE in the professionally exposed populations, such as hairdressers, cleaners, or healthcare workers, suggesting that the sensitization happens with structurally similar compounds present in the environment. This review summarizes the newest knowledge about QAC and their role in hypersensitivities. After describing the different QAC, their structure and use, the most relevant studies about the effects of QAC on the immune system will be reviewed and discussed.

Multi-route exposure sampling of quaternary ammonium compounds and ethanol surface disinfectants in a K-8 school

The frequency of surface disinfectant use has increased over the last several years in public settings such as schools, especially during the COVID-19 pandemic. Although these products are important for infection control and prevention, their increased use may intensify the exposure to both persons applying the disinfection product as well as bystanders. Safety assessments have demonstrated that these products, when used as intended, are considered safe for use and effective; however, point-of-contact effects (such as respiratory or dermal irritation) may still occur. Additionally, relative exposures may vary significantly due to the wide variation in disinfectant formulation and application methods. Quantitative estimations of exposures to two commonly used active ingredients, quaternary ammonium compounds (QACs) and ethanol, are not well characterized during product use and application scenarios. To assess the potential for health risks attributable to increased use in classroom settings, as well as to quantitatively evaluate the potential exposure to both ethanol and QACs, student and adult bystander surface and air measurements were collected in a K-8 school setting in Ohio, United States, over a three-day period. Direct-reading instruments were utilized to collect real-time air samples that characterized mass fraction concentrations following the use of the QAC- and ethanol-based disinfectants. Furthermore, surface and air sampling of microbial species were conducted to establish the overall bioburden and effectiveness of each disinfectant to inform the comparative risk and health effect impacts from the tested products use scenario. Both tested products were approximately equally effective at reducing bioburdens on desk surfaces. In some classrooms, concentrations of QAC congeners were significantly increased on desk surfaces following the application of the disinfectant spray; however, the magnitude of the change in concentration was small. Ethanol was not measured on surfaces due to its volatility. Airborne concentrations increased immediately following spray of each disinfectant product but rapidly returned to baseline. Each of the QAC congeners listed in the product safety data sheets were detected and measurable on desk surfaces; however, air concentrations were generally below the limit of detection. The 15-min time-weighted averages (TWAs) of both QACs and ethanol in the air were below respective health effects benchmarks, and therefore, the negative impact on health outcomes is considered to be minimal from short-term, repeated use of ethanol- or QAC-based spray products in a school setting when the products are used as directed.

The relationship between cleaning product exposure and respiratory and skin symptoms among healthcare workers in a hospital setting: A systematic review and meta‐analysis

Background and Aims

Several studies from multiple work settings have reported an increase in asthma and asthma‐like respiratory symptoms in workers exposed to cleaning or disinfecting agents. Hospital workers perform many cleaning and disinfecting activities and may be vulnerable to respiratory and skin symptoms caused by these agents. This systematic review and meta‐analysis aim to quantify the risk of asthma and asthma‐like symptoms in hospital workers exposed to cleaning/disinfecting agents. A secondary aim is to assess associated risks of skin symptoms in those studies.

Methods

MEDLINE, EMBASE, CDSR, CENTRAL, CINAHL databases, and references of relevant review articles were searched. NHLBI quality assessment tools were used to assess the quality of the included studies. A total of 2550 articles were retrieved and 34 studies met criteria to be included. The software R version 4.0.5 was used to perform the meta‐analysis. The random‐effects model was used to pool the results due to within‐studies heterogeneity.

Results

Meta‐analysis of 10 studies evaluating the association between occupational cleaning exposures and asthma demonstrated a 35% increased risk in exposed hospital workers (meta‐RR = 1.35, 95% CI: 1.09–1.68). The risk of asthma increased when workers were exposed to bleach compared with nonexposed workers (meta‐RR = 1.51, 95% CI: 0.54–4.18), but was not statistically significant. Two studies investigated the relationship between respiratory and skin symptoms and produced mixed results.

Conclusions

The results suggest a need for preventive practices to reduce the risk of asthma and asthma‐like symptoms in hospital workers exposed to occupational cleaning/disinfecting agents. Trial registration number: CRD42020137804.

Identifying cleaning products associated with short-term work-related respiratory symptoms: A workforce-based study in domestic cleaners

Domestic cleaners have an increased risk of asthma-like and other respiratory symptoms and conditions. Uncertainty exists about which products are most hazardous. We aimed to investigate, among professional domestic cleaners, the associations of ocular/respiratory outcomes with using specific types of products at work and with the ability to choose their own products. Among domestic cleaners employed by "service vouchers" companies in Belgium, we administered an online questionnaire on ocular/respiratory symptoms (frequency and time relation to workdays), frequency of use of 40 types of products, and ability to choose one's own products. Work-relatedness was defined as symptoms improving/disappearing on days off-work. We studied associations between frequency of product-use with work-related outcomes (eye irritation, rhinitis symptoms, sore throat, laryngeal symptoms, asthma symptoms, cough) and with chronic bronchitis, using multivariable logistic and elastic net regression. Adjusted odds ratios (OR) with 95%-confidence intervals were obtained per time a product was used per week. Among 1,586 domestic cleaners (99% women), the number of times sprays were used (median 13/week) was significantly associated with all outcomes (ORs between 1.012 and 1.024 per time sprays were used per week). Bleach/disinfectant-containing liquid products were associated with all outcomes, except for laryngeal symptoms (ORs 1.086 to 1.150); ammonia with work-related upper airway symptoms and chronic bronchitis. Cleaners able to choose their own products had fewer work-related eye symptoms (OR 0.728;0.556-0.954), rhinitis (OR 0.735;0.571-0.946) and cough (OR 0.671;0.520-0.865). Using elastic net regression, work-related rhinitis was most strongly associated with mould removal spray (OR 1.108;1.006-1.248), carpet/seat/curtain spray (OR 1.099;1.001-1.304) and ammonia (OR 1.081;1.002-1.372); work-related asthma with carpet/seat/curtain spray (OR 1.103;1.017-1.322), mould removal spray (OR 1.029;0.995-1.199) and drain cleaner (OR 1.023;0.979-1.302). In a large group of domestic cleaners, we documented that cleaning products have a range of adverse respiratory effects. Empowering cleaners to choose their products may reduce the burden of symptoms.

Asthma Phenotypes and Host Risk Factors Associated With Various Asthma-Related Outcomes in Health Workers

Background: Work-related asthma phenotypes in health workers (HWs) exposed to cleaning agents have not been investigated extensively as other occupational exposures. This study aimed to describe asthma phenotypes and to identify important host risk factors associated with various asthma-related outcomes.

Methods: A cross-sectional study of 699 HWs was conducted in two large tertiary hospitals. A total of 697 HWs completed questionnaire interviews. Sera collected from 682 HWs were analyzed for atopy (Phadiatop) and IgE to occupational allergens (NRL—Hev b5, Hev b6.02; chlorhexidine and ortho-phthalaldehyde—OPA). Methacholine (MCT), bronchodilator challenge (BDR) and fractional exhaled nitric oxide (FeNO) were performed. An asthma symptom score (ASS) used five asthma-related symptoms reported in the past 12 months. Current asthma was based on use of asthma medication or an asthma attack or being woken up by an attack of shortness of breath in the past 12 months. Nonspecific bronchial hyperresponsiveness (NSBH) was defined as having either a positive MCT or a significant bronchodilator response. Two continuous indices of NSBH [continuous index of responsiveness (CIR) and dose-response slope (DRS)] were calculated.

Results: The prevalence of current asthma was 10%, atopic asthma (6%) and non-atopic asthma (4%). Overall, 2% of subjects had work-related asthma. There was a weak positive association between NSBH and FeNO [CIR: Beta coefficient (β) = 0.12; CI: 0.03–0.22 and DRS: β = 0.07; CI: 0.03–0.12]. Combining FeNO ≥ 50 ppb with a BDR [mean ratio (MR) = 5.89; CI: 1.02–34.14] or with NSBH (MR = 4.62; CI: 1.16–18.46) correlated better with ASS than FeNO alone (MR = 2.23; CI: 1.30–3.85). HWs with current asthma were twice as likely to be atopic. FeNO was positively associated with atopy (OR = 3.19; CI: 1.59–6.39) but negatively associated with smoking status (GMR = 0.76; CI: 0.62–0.94). Most HWs sensitized to occupational allergens were atopic.

Conclusion: Atopic asthma was more prevalent than non-atopic asthma in HWs. Most asthma-related outcomes were positively associated with allergic predictors suggesting a dominant role for IgE mechanisms for work-related symptoms and asthma associated with sensitization to OPA or chlorhexidine.

Quaternary ammonium compounds: perspectives on benefits, hazards, and risk

Quaternary ammonium compounds are antimicrobial chemicals that provide significant public health benefits by controlling bacteria and viruses that cause infections such as colds, flu, and COVID. The benefits of antimicrobial QACs are seen in increased quality-of-life measures, such as reduced time away from work and school and reduced medical costs. As active antimicrobial agents, QACs and QAC-containing consumer and professional products are highly regulated by authorities such as the US Environmental Protection Agency and the European Chemicals Agency. A complete database of guideline safety studies, covering human and environmental health, is available and has been reviewed by multiple regulatory agencies globally. The conclusions of regulatory agencies from these studies indicate no concerns regarding reproductive effects, genotoxicity, carcinogenicity, or other systemic adverse effects. In contrast, some published academic studies provide mixed findings on lipid synthesis, reproductive effects, and asthma. However, many of these studies have been found not to be robust in design and lacked appropriate controls to support conclusions of a clear and direct association with an adverse effect. The hazard data for the QACs show that their primary critical effects are point-of-contact effects such as irritation, which exhibit a threshold and occur in a dose–response manner. This review compares toxicity information for QACs, examines human exposures, and quantifies the risks estimated from QAC product use. QACs are an important cleaning and hygiene tool, and the abundance of safety data generated for them provides assurance they can be safely used in professional and household products.

Prior Exposure to Ortho-Phthalaldehyde Augments IgE-Mediated Immune Responses to Didecyldimethylammonium Chloride: Potential for 2 Commonly Used Antimicrobials to Synergistically Enhance Allergic Disease

Health-care workers have an increased incidence of allergic disease compared with the general public and are exposed to a variety of high-level disinfectants. Although exposure to these agents has been associated with allergic disease, findings between epidemiology and animal studies often conflict respecting immunological mechanisms. Therefore, we hypothesized that previous exposure to a representative IgE-mediated sensitizer (ortho-phthalaldehyde [OPA]) alters immune responses to a representative T-cell-mediated sensitizer (didecyldimethlyammonium chloride [DDAC]). Here, BALB/c mice were topically exposed to OPA (0.5%) for 3 days, rested, then topically exposed to DDAC (0.0625%, 0.125%, and 0.25%) for 14 days. Coexposure resulted in phenotypic changes in draining lymph node (dLN) cells, including a decreased frequency of CD8+ T cells and increased frequency and number of B cells compared with DDAC-only treated mice. The coexposed mice also had enhanced Th2 responses, including significant alterations in: dLN Il4 (increased), B-cell activation (increased), CD8+ T-cell activation (decreased), and local and systemic IgE production (increased). These changes were not observed if mice were exposed to DDAC prior to OPA. Exposure to OPA alone shows Th2 skewing, indicated by increased activation of skin type 2 innate lymphoid cells, increased frequency and activation of draining lymph node B cells, and increased levels of type 2 cytokines. These findings suggest that the OPA-induced immune environment may alter the response to DDAC, resulting in increased IgE-mediated immune responses. This data may partially explain the discordance between epidemiological and laboratory studies regarding disinfectants and provide insight into the potential immunological implications of mixed chemical exposures.

Potential classification of chemical immunologic response based on gene expression profiles

Occupational immune diseases are a serious public health burden and are often a result of exposure to low molecular weight (LMW) chemicals. The complete immunological mechanisms driving these responses are not fully understood which has made the classification of chemical allergens difficult. Antimicrobials are a large group of immunologically-diverse LMW agents. In these studies, mice were dermally exposed to representative antimicrobial chemicals (sensitizers: didecyldimethylammonium chloride (DDAC), ortho-phthalaldehyde (OPA), irritants: benzal-konium chloride (BAC), and adjuvant: triclosan (TCS)) and the mRNA expression of cytokines and cellular mediators was evaluated using real-time qPCR in various tissues over a 7-days period. All antimicrobials caused increases in the mRNA expression of the danger signals Tslp (skin), and S100a8 (skin, blood, lung). Expression of the T_H2 cytokine Il4 peaked at different timepoints for the chemicals based on exposure duration. Unique expression profiles were identified for OPA (Il10 in lymph node, Il4 and Il13 in lung) and TCS (Tlr4 in skin). Additionally, all chemicals except OPA induced decreased expression of the cellular adhesion molecule Ecad. Overall, the results from these studies suggest that unique gene expression profiles are implicated following dermal exposure to various antimicrobial agents, warranting the need for additional studies. In order to advance the development of preventative and therapeutic strategies to combat immunological disease, underlying mechanisms of antimicrobial-induced immunomodulation must be fully understood. This understanding will aid in the development of more effective methods to screen for chemical toxicity, and may potentially lead to more effective treatment strategies for those suffering from immune diseases.

Benzalkonium Chloride Disinfectants Induce Apoptosis, Inhibit Proliferation, and Activate the Integrated Stress Response in a 3-D in Vitro Model of Neurodevelopment

We previously found that the widely used disinfectants, benzalkonium chlorides (BACs), alter cholesterol and lipid homeostasis in neuronal cell lines and in neonatal mouse brains. Here, we investigate the effects of BACs on neurospheres, an in vitro three-dimensional model of neurodevelopment. Neurospheres cultured from mouse embryonic neural progenitor cells (NPCs) were exposed to increasing concentrations (from 1 to 100 nM) of a short-chain BAC (BAC C12), a long-chain BAC (BAC C16), and AY9944 (a known DHCR7 inhibitor). We found that the sizes of neurospheres were decreased by both BACs but not by AY9944. Furthermore, we observed potent inhibition of cholesterol biosynthesis at the step of DHCR7 by BAC C12 but not by BAC C16, suggesting that cholesterol biosynthesis inhibition is not responsible for the observed reduction in neurosphere growth. By using immunostaining and cell cycle analysis, we found that both BACs induced apoptosis and decreased proliferation of NPCs. To explore the mechanisms underlying their effect on neurosphere growth, we carried out RNA sequencing on neurospheres exposed to each BAC at 50 nM for 24 h, which revealed the activation of the integrated stress response by both BACs. Overall, these results suggest that BACs affect neurodevelopment by inducing the integrated stress response in a manner independent of their effects on cholesterol biosynthesis.

Are Healthcare Workers at an Increased Risk for Obstructive Respiratory Diseases Due to Cleaning and Disinfection Agents? A Systematic Review and Meta-Analysis

Several reviews have reported an increased risk of obstructive respiratory diseases in workers exposed to cleaning or disinfection agents, but they have focused mainly on professional cleaners. Cleaning and disinfecting are frequently performed activities by healthcare workers. We conducted a systematic review with meta-analysis to quantify the risk of obstructive respiratory diseases in healthcare workers exposed to cleaning and disinfection agents. We searched the Medline and Embase databases until 4 February 2021 to find adequate primary studies. Two independent reviewers screened the titles/abstracts and the full texts of the studies, as well as performing data extraction and quality assessment. The literature search yielded 9432 records, and 8 studies were found through a hand search. After screening, 14 studies were included in the review. All had a high risk of bias, and most studies dealt with nurses, asthma, and hyperresponsiveness (BHR)-related symptoms. Only one study investigated COPD. The meta-analysis estimated an increased risk of new-onset asthma for nurses (Effect size (ES) = 1.67; 95% CI 1.11–2.50) compared with other occupations and found an increase in the risk of new-onset asthma for nurses exposed to cleaning and disinfecting surfaces (ES = 1.43; 95% CI 1.09–1.89) and instruments (ES = 1.34; 95% CI 1.09–1.65). Exposure to specific chemicals such as bleach and glutaraldehyde (GA) increased the risk of asthma in nurses (bleach ES = 2.44; 95% CI 1.56–3.82; GA ES = 1.91, 95% CI 1.35–2.70). A higher risk for BHR-related symptoms was observed for nurses exposed to cleaning surfaces (ES = 1.44; 95% CI 1.18–1.78). Although the overall evidence was rated as low, the limitations found in this review hint at a potential underestimation of the real risk. These findings highlight the need for reinforced prevention practices with regard to healthcare workers. Similar research investigating these associations among other healthcare workers such as rescue service and nursing home personnel is needed.

Occupational Asthma Caused by Quaternary Ammonium Compounds: A Multicenter Cohort Study

BACKGROUND

Quaternary ammonium compounds (QACs) are used extensively for cleaning and disinfection and have been documented in scattered reports as a cause of occupational asthma (OA) through bronchoprovocation tests (BPTs).

OBJECTIVE

To examine the clinical, functional, and inflammatory profile of QAC-induced OA compared with OA caused by other low-molecular weight (LMW) agents.

METHODS

The study was conducted in a retrospective multicenter cohort of 871 subjects with OA ascertained by a positive BPT. Subjects with QAC-induced OA (n = 22) were identified based on a positive BPT to QACs after exclusion of those challenged with cleaning products or disinfectants that contained other potential respiratory sensitizers. They were compared with 289 subjects with OA caused by other LMW agents.

RESULTS

Most subjects with QAC-induced OA were working in the health care sector (n = 14). A twofold or greater increase in the postchallenge level of nonspecific bronchial hyperresponsiveness was recorded in eight of 11 subjects with QAC-induced OA (72.7%) and in 49.7% of those with OA caused by other LMW agents. Although sputum assessment was available in only eight subjects with QAC-induced OA, they showed a significantly greater median (interquartile) increase in sputum eosinophils (18.1% [range, 12.1% to 21.1%]) compared with those with OA caused by other LMW agents (2.0% [range, 0% to 5.2%]; P < .001).

CONCLUSIONS

This study indicates that QAC-induced OA is associated with a highly eosinophilic pattern of airway response and provides further evidence supporting the sensitizing potential of QACs. The findings highlight the heterogeneous nature of the pathobiologic pathways involved in OA caused by LMW agents.

Cleaning agent usage in healthcare professionals and relationship to lung and skin symptoms

BACKGROUND AND OBJECTIVES

Healthcare workers have an increased risk of respiratory symptoms and dermatitis, likely related to cleaning/disinfecting agents. The aim of this study was to identify work tasks and cleaning/disinfecting agents associated with respiratory symptoms and hand dermatitis among healthcare workers in a tertiary hospital.

METHODS

Cleaning agent usage, respiratory symptoms and skin symptoms were recorded by participants using a questionnaire in a cross-sectional study. Age and sex adjusted odds ratios (OR) were used to examine associations between job tasks, exposures, respiratory, and skin outcomes.

RESULTS

Two hundred and thirty healthcare workers who were exposed to cleaning agents were compared with 77 who had no, or minimal, exposure. Exposed workers had an increased risk of respiratory symptoms (adjusted OR = 2.17; 95% CI: 1.18-4.14) and skin symptoms (adjusted OR = 1.77; 95% CI: 1.00 - 3.17). Washing instruments manually, using aerosol products, cleaning operating rooms, cleaning sanitary rooms, preparing disinfectants, and filling devices with cleaning products were cleaning tasks associated with various respiratory symptoms. Bleach was the only cleaning agent associated with a respiratory symptom: tightness in the chest (unadjusted OR = 2.46; 95% CI: 1.01-6.89) but statistical significance did not persist after adjustment for age and sex. Hand dermatitis was associated with actual disinfecting tasks (adjusted OR = 2.19; 95% CI: 1.10-4.66). Bleach was the only cleaning agent significantly associated with hand dermatitis (adjusted OR = 2.54; 95% CI: 1.32-5.13).

CONCLUSIONS

This study provides insight into possible work tasks that need interventions to reduce or prevent respiratory and skin symptoms in healthcare workers.

A review of wipes used to disinfect hard surfaces in health care facilities

BACKGROUND

Despite a plethora of wipes available for use in health care facilities, there is a paucity of articles describing wipe composition, potential interactions between wipes and disinfectants, the manner in which wipes are used, and their relative efficacy. The purpose of this article is to provide an in-depth review of wipes used for disinfection of hard surfaces in health care settings.

METHODS

Comprehensive searches of the Pubmed database and Internet were conducted, and articles published from 1953 through September 2019 and pertinent on-line documents were reviewed. Bibliographies of relevant articles were reviewed.

RESULTS

Wipes vary considerably in their composition, and the disinfectants with which they are used. With reusable dry wipes, the ratio of wipe material to disinfectant and the amount of disinfectant absorbed by the wipe and delivered to surfaces is difficult to standardize, which may affect their efficacy. The manner in which wipes are used by health care personnel is highly variable, due in part to insufficient instructions for use and inadequate education of relevant personnel.

CONCLUSIONS

Additional research is needed regarding the best practices for using different types of wipes, improved methods for educating staff, and establishing the relative efficacy of wipes in reducing environmental contamination and health care-associated infections.

Cleaners and airway diseases

PURPOSE OF REVIEW

Evidence for adverse respiratory effects of occupational exposure to disinfectants and cleaning products (DCPs) has grown in the last two decades. The relationship between DCPs and asthma is well documented but questions remain regarding specific causal agents. Beyond asthma, associations between DCPs and COPD or chronic rhinitis are plausible and have been examined recently. The purpose of this review is to summarize recent advances on the effect of occupational exposure to DCP and chronic airway diseases.

RECENT FINDINGS

Recent epidemiological studies have often focused on healthcare workers and are characterized by efforts to improve assessment of exposure to specific DCPs. Despite increasing knowledge on the effect of DCPs on asthma, the burden of work-related asthma caused by DCPs has not decreased in the past decade, emphasizing the need to strengthen prevention efforts. Novel data suggest an association between occupational exposure to DCPs and other chronic airway diseases, such as rhinitis, COPD, and poor lung function.

SUMMARY

Epidemiological and experimental data showed that many chemicals contained in DCPs are likely to cause airway damage, indicating that prevention strategies should target multiple products. Further research is needed to evaluate the impact of DCP exposure on occupational airway diseases beyond asthma.

Cleaning products and respiratory health outcomes in occupational cleaners: a systematic review and meta-analysis

There is consistent evidence of increased respiratory symptoms in occupational cleaners; however, uncertainty remains on type of respiratory health effects, underlying causal agents, mechanisms and respiratory phenotypes. We aimed to conduct a systematic review and if possible, a meta-analysis of the available literature to characterise and quantify the cleaning-related respiratory health effects. We searched MEDLINE and EMBASE databases and included studies that evaluated the association of any respiratory health outcome with exposure to cleaning occupation or products in occupational cleaners. A modified GRADE was used to appraise the quality of included studies. We retrieved 1124 articles, and after applying our inclusion criteria, 39 were selected for the systematic review. We performed a meta-analysis of the 21 studies evaluating asthma which showed a 50% increased pooled relative risk in cleaners (meta-relative risk (RR)=1.50; 95% CI 1.44 to 1.56). Population-based cross-sectional studies showed more stable associations with asthma risk. No evidence of atopic asthma as dominant phenotype emerged. Also, we estimated a 43% increased risk (meta-RR=1.43; 95% CI 1.31 to 1.56) of chronic obstructive pulmonary disease. Evidence for associations with bronchial-hyper-responsiveness, lung function decline, rhinitis, upper and lower respiratory tract symptoms was weaker. In our systematic review and meta-analysis, we found that working as a cleaner is associated with an increased risk of reversible and even irreversible obstructive airway diseases. All studies lacked quantitative exposure assessment to cleaning products; this would help elucidate underlying causal agents and mechanisms. Exposure control and respiratory surveillance among cleaners is warranted to prevent the associated respiratory health burden. Trial registration number: CRD4201705915.

Quaternary Ammonium Compound Disinfectants Reduce Lupus-Associated Splenomegaly by Targeting Neutrophil Migration and T-Cell Fate

Hypersensitivity reactions and immune dysregulation have been reported with the use of quaternary ammonium compound disinfectants (QACs). We hypothesized that QAC exposure would exacerbate autoimmunity associated with systemic lupus erythematosus (lupus). Surprisingly, however, we found that compared to QAC-free mice, ambient exposure of lupus-prone mice to QACs led to smaller spleens with no change in circulating autoantibodies or the severity of glomerulonephritis. This suggests that QACs may have immunosuppressive effects on lupus. Using a microfluidic device, we showed that ambient exposure to QACs reduced directional migration of bone marrow-derived neutrophils toward an inflammatory chemoattractant ex vivo. Consistent with this, we found decreased infiltration of neutrophils into the spleen. While bone marrow-derived neutrophils appeared to exhibit a pro-inflammatory profile, upregulated expression of PD-L1 was observed on neutrophils that infiltrated the spleen, which in turn interacted with PD-1 on T cells and modulated their fate. Specifically, QAC exposure hindered activation of splenic T cells and increased apoptosis of effector T-cell populations. Collectively, these results suggest that ambient QAC exposure decreases lupus-associated splenomegaly likely through neutrophil-mediated toning of T-cell activation and/or apoptosis. However, our findings also indicate that even ambient exposure could alter immune cell phenotypes, functions, and their fate. Further investigations on how QACs affect immunity under steady-state conditions are warranted.

Chemicals inhaled from spray cleaning and disinfection products and their respiratory effects. A comprehensive review

Spray cleaning and disinfection products have been associated with adverse respiratory effects in professional cleaners and among residents doing domestic cleaning. This review combines information about use of spray products from epidemiological and clinical studies, in vivo and in vitro toxicological studies of cleaning chemicals, as well as human and field exposure studies. The most frequent chemicals in spray cleaning and disinfection products were compiled, based on registrations in the Danish Product Registry. The chemicals were divided into acids, bases, disinfectants, fragrances, organic solvents, propellants, and tensides. In addition, an assessment of selected cleaning and disinfectant chemicals in spray products was carried out. Chemicals of concern regarding respiratory effects (e.g. asthma) are corrosive chemicals such as strong acids and bases (including ammonia and hypochlorite) and quaternary ammonium compounds (QACs). However, the evidence for respiratory effects after inhalation of QACs is ambiguous. Common fragrances are generally not considered to be of concern following inhalation. Solvents including glycols and glycol ethers as well as propellants are generally weak airway irritants and not expected to induce sensitization in the airways. Mixing of certain cleaning products can produce corrosive airborne chemicals. We discuss different hypotheses for the mechanisms behind the development of respiratory effects of inhalation of chemicals in cleaning agents. An integrative assessment is needed to understand how these chemicals can cause the various respiratory effects.

Distance-based paper device using polydiacetylene liposome as a chromogenic substance for rapid and in-field analysis of quaternary ammonium compounds

This work presents an affordable distance-based microfluidic paper-based device (μPAD), using polydiacetylene (PDA) liposome as a chromogenic substance with a smartphone-based photo editor, for rapid and in-field analysis of quaternary ammonium compounds (QACs) (e.g., didecyldimethylammonium chloride (DDAC), benzyldimethyltetradecyl ammonium chloride (BAC), and cetylpyridinium chloride (CPC)). In-field analysis of these compounds is important to ensure their antimicrobial activity and user safety since they are widely utilized as disinfectants in households and hospitals. The μPAD featured a thermometer-like shape consisting of a sample reservoir and a microchannel as the detection zone, which was pre-deposited with PDA liposome. The color change from blue to red appeared in the presence of QACs and the color bar lengths were proportional to the QAC concentrations. Reactions of QACs with the PDA required a specific pH range (from pH 4.0 to 10.0) and a readout time of 7 min. Analytical performance characteristics of the device were tested with DDAC, BAC, and CPC showing acceptable specificity, accuracy (96.1-109.4%), and precision (%RSDs ≤ 9.3%). Limits of detection and quantitation were in the ranges of 20 to 80 and 70 to 250 μM, respectively. Feasibility of the newly developed device was demonstrated for in-field analysis of QACs in fumigation solution providing comparable results with those obtained from a colorimetric assay (P > 0.05). The proposed device shows potentials for further applications of other analytes since it offers speed, simplicity, and affordability for in-field analysis, especially in remote areas where expertise, resources, and infrastructures are limited. Graphical abstract.

Topical Application of the Quaternary Ammonium Compound Didecyldimethylammonium Chloride Activates Type 2 Innate Lymphoid Cells and Initiates a Mixed-Type Allergic Response

Didecyldimethylammonium chloride (DDAC) is an antimicrobial dialkyl-quaternary ammonium compound used in industrial and commercial products. Clinical data suggest that DDAC exposure elicits multiple types of hypersensitivity reactions; here, we confirm this observation in a BALB/c murine model. To examine the immunological mechanism behind this mixed-type response and the potential involvement of type 2 innate lymphoid cells (ILC2s), we assessed early immune responses in the skin following topical DDAC exposure (0.125% and 0.5%). DDAC exposure resulted in a rapid and dramatic increase in the Th2-skewing and ILC2-activating cytokine thymic stromal lymphopoietin. Correspondingly, dermal ILC2s were activated 24 h after DDAC exposure, resulting in increased expression of CD25, ICOS and KLRG1, and decreased CD127 throughout 7 days of exposure. Following ILC2 activation, the Th2 cytokine IL-4 was elevated compared with control mice in total ear protein lysate (0.5% DDAC). Rag2-/- mice were used to determine a functional role for ILC2s in DDAC-induced sensitization. ILC2s from Rag2-/- mice were similarly activated by DDAC and, importantly, produced significant levels of IL-4 and IL-5 in the skin (0.5% DDAC). These data indicate that ILC2s contribute to early Th2 immune responses following DDAC exposure. ILC2s have been previously implicated in allergic responses, but to our knowledge have not been thoroughly investigated in chemical sensitization. These results indicate that following DDAC exposure, skin ILC2s become activated and produce Th2 cytokines, providing a possible mechanism for the development of the mixed-type allergic responses commonly observed with chemical sensitizers.

Cleaning Products and Work-Related Asthma, 10 Year Update

OBJECTIVE

To describe the frequency of work-related asthma (WRA) and characteristics of individuals with exposure to cleaning products 1998 to 2012, compared with 1993 to 1997.

METHODS

Cases of WRA from products used for cleaning or disinfecting surfaces were identified from California, Massachusetts, Michigan (1998 to 2012), New Jersey (1998 to 2011), and New York (2009 to 2012).

RESULTS

There were 1199 (12.4%) cleaning product cases among all 9667 WRA cases; 77.8% women, 62.1% white non-Hispanic, and average age of 43 years. The highest percentages worked in healthcare (41.1%), and were building cleaners (20.3%), or registered nurses (14.1%).

CONCLUSIONS

The percentage of WRA cases from exposure to cleaning products from 1998 to 2012 was unchanged from 1993 to 1997 indicating that continued and additional prevention efforts are needed to reduce unnecessary use, identify safer products, and implement safer work processes.

Occupational exposure to disinfectants and asthma incidence in U.S. nurses: A prospective cohort study

BACKGROUND

Exposure to disinfectants among healthcare workers has been associated with respiratory health effects, in particular, asthma. However, most studies are cross-sectional and the role of disinfectant exposures in asthma development requires longitudinal studies. We investigated the association between occupational exposure to disinfectants and incident asthma in a large cohort of U.S. female nurses.

METHODS

The Nurses' Health Study II is a prospective cohort of 116 429 female nurses enrolled in 1989. Analyses included 61 539 participants who were still in a nursing job and with no history of asthma in 2009 (baseline; mean age: 55 years). During 277 744 person-years of follow-up (2009-2015), 370 nurses reported incident physician-diagnosed asthma. Occupational exposure was evaluated by questionnaire and a Job-Task-Exposure Matrix (JTEM). We examined the association between disinfectant exposure and subsequent asthma development, adjusted for age, race, ethnicity, smoking status, and body mass index.

RESULTS

Weekly use of disinfectants to clean surfaces only (23% exposed) or to clean medical instruments (19% exposed) was not associated with incident asthma (adjusted hazard ratio [95% confidence interval] for surfaces, 1.12 [0.87-1.43]; for instruments, 1.13 [0.87-1.48]). No association was observed between high-level exposure to specific disinfectants/cleaning products evaluated by the JTEM (formaldehyde, glutaraldehyde, bleach, hydrogen peroxide, alcohol quats, or enzymatic cleaners) and asthma incidence.

CONCLUSIONS

In a population of late career nurses, we observed no significant association between exposure to disinfectants and asthma incidence. A potential role of disinfectant exposures in asthma development warrants further study among healthcare workers at earlier career stage to limit the healthy worker effect.

Biocidal spray product exposure: Measured gas, particle, and surface concentrations compared with spray model simulations

The purpose of the study was to compare measured air and surface concentrations after application of biocidal spray products with concentrations simulated with the ConsExpo Web spray simulation tool. Three different biocidal spray products were applied in a 20 m³ climate test chamber with well-controlled environmental conditions (22 ± 1 °C, 50 ± 2% relative humidity, and air exchange rate of 0.5 h^-1). The products included an insect spray in a pressurized spray can, another insect spray product, and a disinfectant, the latter two applied separately with the same pumped spray device. The measurements included released particles, airborne organic compounds in both gas and particle phase, and surface concentrations of organic compounds on the wall and floor in front of the spraying position and on the most remote wall. Spraying time was a few seconds and the air concentrations were measured by sampling on adsorbent tubes at 9-13 times points during 4 hr after spraying. The full chamber experiment was repeated 2-3 times for each product. Due to sedimentation the concentrations of the particles in air decayed faster than explained by the air exchange rate. In spite of that, the non-volatile benzalkonium chlorides in the disinfectant could be measured in the air more than 30 min after spraying. ConsExpo Web simulated concentrations that were about half of the measured concentrations of the active substances when as many as possible of the default simulation parameters were replaced by the experimental values. ConsExpo Web was unable to simulate the observed faster decay of the airborne concentrations of the active substances, which might be due to underestimation of the gravitational particle deposition rates. There was a relatively good agreement between measured surface concentrations on the floor and calculated values based on the dislodgeable amount given in the selected ConsExpo Web scenarios. It is suggested to always supplement simulation tool results with practical measurements when assessing the exposure to a spray product.

Methodological evaluation of human research on asthmagenicity and occupational cleaning: a case study of quaternary ammonium compounds ("quats")

In this paper, we review methodological approaches used in studies that evaluated the association between occupational exposure to quaternary ammonium compounds (quats) and occupational asthma. This association is of interest because quats are a common active ingredient of disinfectants and have been linked to work-related asthma in some circumstances. However, any evidence-based assessment of an exposure-outcome association needs to consider both strengths and limitations of the literature. We focus on publications cited by various US and international organizations. Eighteen investigations included in the review fall into two broad categories: case reports and challenge studies of individual patients and population studies that examined the association between quats and asthma occurrence in groups of subjects. We evaluated these studies guided by questions that address whether: exposure data on specific quat(s) and other agents that may cause asthma were included, new asthma cases were differentiated from asthma exacerbation, and information on respiratory sensitivity versus irritation was given. We also assessed consistency across studies. Studies of individual patients, particularly those that provided detailed information on challenge test results, document cases of asthma induced by exposure to quats. By contrast, studies of occupational groups with the highest potential for quats exposure (e.g., cleaners and farmers) do not consistently report increased incidence of asthma due specifically to quats. The unresolved methodological issues include: poor understanding of exposure pathways considering that quats are non-volatile, lack of quantitative data allowing for identification of an asthmagenicity threshold, insufficient information on whether quats are sensitizers or act via dose-dependent irritation or some other mechanism, and inability to quantify risk of new-onset asthma attributable to quats. Another important area of uncertainty is the lack of information on the specific quats being used. There is also a lack of data capable of distinguishing the effects of quats from those of other chemical and biological workplace exposures. The current state-of-the-science does not allow a proper assessment of the potential link between quats and occupational asthma.