The risks and benefits of chemical fumigation in the health care environment

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.

Inactivation of human coronaviruses using an automated room disinfection device

The emergence of more virulent and epidemic strains of viruses, especially in the context of COVID-19, makes it more important than ever to improve methods of decontamination. The objective of this study was to evaluate the potential of on-demand production of chlorine species to inactivate human coronaviruses. The commercial prototype disinfection unit was provided by Unipolar Water Technologies. The Unipolar device generates active chlorine species using an electrochemical reaction and dispenses the disinfectant vapour onto surfaces with an aspirator. The minimum effective concentration and exposure time of disinfectant were evaluated on human hepatoma (Huh7) cells using 50% tissue culture infectious dose (TCID50) assay and human coronavirus 229E (HCoV-229E), a surrogate for pathogenic human coronaviruses. We showed that chlorine species generated in the Unipolar device inactivate HCoV-229E on glass surfaces at ≥ 400 parts per million active chlorine concentration with a 5 min exposure time. Here, inactivation refers to the inability of the virus to infect the Huh7 cells. Importantly, no toxic effect was observed on Huh7 cells for any of the active chlorine concentrations and contact times tested.

Chargeability study of disinfectants and the optimization of design parameters of a handheld electrostatic disinfection device for small scale applications

Apart from aerosols, contaminated surfaces with SARS-CoV-2 virus are the significant carriers of virus transmission. The disinfection and sanitization of the indoor and outdoor places are one among the powerful and effective strategies to avoid the surface-to-human transmission of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) through frequent touch and physical contact. Electrostatic spraying is one of the effective and efficient methods to apply the liquid-based sprays on surfaces to be disinfected or sanitized. This technique covers the directly exposed and obscured surfaces uniformly and reaches to hidden areas of the target. In this paper, the design and performance parameters of a motorized pressure-nozzle based handheld electrostatic disinfection device were optimized and the chargeability of ethanol (C2H5OH), formaldehyde (CH2O), glutaraldehyde (C5H8O2), hydrogen peroxide (H2O2), phenol (C6H5OH) and sodium hypochlorite (NaClO) has been critically investigated. The chargeability indicator for disinfectants was presented in terms of the charge-to-mass ratio. The significant value of the charge-to-mass ratio of 1.82 mC/kg was achieved at an applied voltage of 2.0 kV, the liquid flow rate and pressure of 28 ml/min and 5 MPa, respectively. The experimental results are well aligned to the proposed theoretical context.

Usos y limitaciones de la lámpara ultravioleta germicida portátil para la desinfección de superficies

RESUMENLa morbimortalidad causada por infecciones vinculadas a la atención sanatoria ha llevado a cuestionar si los métodos de desinfección convencionales son inadecuados y se requieren métodos complementarios, como la fumigación de la habitación y la irradiación ultravioleta. Ello ha dado lugar a la preocupación por que estos métodos alternativos puedan poner en riesgo al personal sanitario y a los pacientes.Objetivos. (1) Determinar la eficacia de la lámpara ultravioleta C germicida portátil para la desinfección de superficies, (2) evaluar el cambio de la humedad relativa (HR) y las distintas distancias específicas en las tasas de letalidad bacteriana, y (3) evaluar los posibles problemas a que conlleva la exposición.Métodos. En el presente estudio se investiga si una lámpara germicida portátil puede desinfectar de forma eficaz superficies tratadas con esporulación o germinación bacteriana y se evalúa el efecto de condiciones ambientales cambiantes, como la humedad relativa (HR), la posición y las distancias específicas, en las tasas de letalidad germicida.Resultados. Se constató una mejor tasa de letalidad con una HR de 40-65% y en un rango de temperatura de 21-24°C. Tanto la HR alta como la HR baja interfirieron con la capacidad de la radiación UV-C para inactivar la germinación microbiana. En el caso de la esporulación bacteriana, el aumento del secado de la superficie fue el factor de mayor importancia para aumentar la tasa de letalidad.Conclusiones. En esta investigación se demostró la eficacia de la radiación UV-C bajo condiciones óptimas, irradiación directa y una distancia específica corta (12.7 cm). Sin embargo, cuando es utilizada en condiciones que no son óptimas existen limitaciones. El aumento de la distancia y los ángulos de irradiación indirecta resultaron en tasas de letalidad más bajas. Cabe señalar que durante su uso es importante minimizar la exposición innecesaria de pacientes y personal sanitario.

The Hitchhiker's Guide to Hydrogen Peroxide Fumigation, Part 1: Introduction to Hydrogen Peroxide Fumigation

INTRODUCTION

When working with pathogens in laboratories, animal or production facilities, and even hospitals, the potential need for room fumigation for decontamination purposes must be taken into consideration. Questions regarding the choice of fumigant, technical aspects of the room, its ventilation, the fumigation system to be used, and other issues will arise and will have to be addressed.

METHODS

This article is based on literature searches and was compiled using the authors' long-time personal experience in room and filter fumigation using various fumigation systems.

RESULTS

The article can be used as a guide to establish an effective fumigation system in a laboratory or an animal facility setting and may be adapted for use in hospitals. Different systems for hydrogen peroxide fumigation on the market are presented. Also, technical aspects are discussed.

DISCUSSION

Hydrogen peroxide is used in various forms for fumigation of rooms, equipment, and filters. Regardless of the individual limitations of these forms, hydrogen peroxide is a versatile fumigation method. However, it is important to consider numerous technical requirements when planning to implement hydrogen peroxide fumigation at an institution.

CONCLUSIONS

Subsequent to the present overview of different fumigation systems based on hydrogen peroxide on the market and their technical requirements, part 2 of this article will focus on validation and verification of hydrogen peroxide fumigation while considering the entire fumigation process. The two parts together will serve users as a guide to establishing hydrogen peroxide fumigations at their facilities.

Photolysis-driven indoor air chemistry following cleaning of hospital wards

Effective cleaning techniques are essential for the sterilization of rooms in hospitals and industry. No-touch devices (NTDs) that use fumigants such as hydrogen peroxide (H₂ O₂ ), formaldehyde (HCHO), ozone (O₃ ), and chlorine dioxide (OClO) are a recent innovation. This paper reports a previously unconsidered potential consequence of such cleaning technologies: the photochemical formation of high concentrations of hydroxyl radicals (OH), hydroperoxy radicals (HO₂ ), organic peroxy radicals (RO₂ ), and chlorine radicals (Cl) which can form harmful reaction products when exposed to chemicals commonly found in indoor air. This risk was evaluated by calculating radical production rates and concentrations based on measured indoor photon fluxes and typical fumigant concentrations during and after cleaning events. Sunlight and fluorescent tubes without covers initiated photolysis of all fumigants, and plastic-covered fluorescent tubes initiated photolysis of only some fumigants. Radical formation was often dominated by photolysis of fumigants during and after decontamination processes. Radical concentrations were predicted to be orders of magnitude greater than background levels during and immediately following cleaning events with each fumigant under one or more illumination condition. Maximum predicted radical concentrations (1.3 × 10⁷ molecule cm^-3 OH, 2.4 ppb HO₂ , 6.8 ppb RO₂ and 2.2 × 10⁸ molecule cm^-3 Cl) were much higher than baseline concentrations. Maximum OH concentrations occurred with O₃ photolysis, HO₂ with HCHO photolysis, and RO₂ and Cl with OClO photolysis. Elevated concentrations may persist for hours after NTD use, depending on the air change rate and air composition. Products from reactions involving radicals could significantly decrease air quality when disinfectants are used, leading to adverse health effects for occupants.

Mortality of Different Stages of Plodia interpunctella (Lepidoptera: Pyralidae) at Three Temperatures in Controlled Atmosphere of High Nitrogen

The lethal exposure time to controlled atmospheres of high nitrogen at stored grain temperatures is an important information for control of stored-product insects. The mortality of 1-d-old egg, 1-wk-old (first or second instar) larva, 3-wk-old (fourth or fifth instar) larva, and 1-d-old pupa of Plodia interpunctella (Hübner) was determined at 18 ± 1, 23 ± 1, and 28 ± 1°C in 98% N2 mixed with air. At 18°C, the lethal exposure times to achieve 100% mortality were 12.7 ± 0.7, 16.3 ± 0.3, 19.7 ± 0.7, and 14.7 ± 0.7 d for 1-d-old egg, 1-wk-old larva, 3-wk-old larva, and 1-d-old pupa, respectively. Temperature had significant effect on the lethal exposure time, and increase of the temperature significantly decreased the lethal exposure time. The order of the insect stages from the highest to lowest for LT50 values was follows: 3-wk-old larva > 1-wk-old larva > 1-d-old pupa ≥ 1-d-old egg. The minimum lethal exposure times required to kill all stages of P. interpunctella were about 20, 16, and 12 d at 18, 23, and 28°C, respectively.

An overview of automated room disinfection systems: When to use them and how to choose them

Conventional disinfection methods are limited by reliance on the operator to ensure appropriate selection, formulation, distribution, and contact time of the agent. Automated room disinfection (ARD) systems remove or reduce reliance on operators and so they have the potential to improve the efficacy of terminal disinfection. The most commonly used systems are hydrogen peroxide vapor (H₂O₂ vapor), aerosolized hydrogen peroxide (aHP), and ultraviolet (UV) light. These systems have important differences in their active agent, delivery mechanism, efficacy, process time, and ease of use. The choice of ARD system should be influenced by the intended application, the evidence base for effectiveness, practicalities of implementation, and cost considerations.

Validation of environmental disinfection efficiency of traditional Ayurvedic fumigation practices

Environmental disinfection greatly reduces the occurrence of nosocomial or healthcare associated infections (HCAIs) which are the major healthcare problems worldwide. In India, Ayurvedic traditional fumigation with natural plant products is used to disinfect environment. In the present study, environmental disinfection efficiency of traditional fumigation practice has been evaluated by using natural plant products such as garlic (Allium sativum) peel, turmeric (Curcuma longa) powder, Carom (Trachyspermum ammi) seeds (Ajwain) and Loban (resin of Styrax benzoin and Boswellia species). The efficiency of traditional fumigation using these natural products to disinfect air and surface was evaluated. The effect of traditional fumigation on the microbiological quality of air was revealed by active air sampling. In addition, the ability of the traditional fumigation using garlic peel to disinfect inanimate surface was evaluated using three strains of methicillin resistant Staphylococcus aureus (MRSA). Glass slide was artificially contaminated with the bacteria and fumigated whereas non-fumigated slide served as control. The control and fumigated slides were analyzed for surviving bacteria and subjected to scanning electron microscopy (SEM) analysis. Traditional fumigation performed separately with three grams of garlic peel, turmeric, carom seeds and loban powder reduced the average air borne bacterial colony forming units (cfu)/m³ compared to non-fumigated control. The SEM analysis showed reduced number of bacteria in garlic peel fumigated surface samples. The results of the study strongly suggested that the traditional Ayurvedic fumigation with natural plant products is effective in reducing air-borne bacteria and in disinfecting inanimate surfaces. The traditional fumigation with herbal products has huge potential to address the problem of nosocomial infections.

The uses and limitations of a hand-held germicidal ultraviolet wand for surface disinfection

The morbidity and mortality from healthcare associated infections has raised concern that conventional disinfection methods are inadequate and that other adjunct methods such as room fumigation and ultraviolet irradiation may be needed. There is also concern that these alternative methods may pose a risk to workers and patients.

OBJECTIVES

(1) Determine the efficacy of a germicidal UV-C wand for surface disinfection, (2) evaluate changing relative humidity (RH) and different target distances on bacteria kill rates, and (3) assess potential exposure concerns.

METHODS

This study investigates whether a hand-held germicidal wand can efficaciously disinfect surfaces treated with either a vegetative or spore forming bacterium and to evaluate the effect of changing environmental conditions such as relative humidity (RH), target position, and target distances on microbial kill rates.

RESULTS

Kill rate was best at 40-65% RH at a temperature range of 21-24°C. Both high and low RH interfered with the ability of UV-C to kill the vegetative microbe. In the case of the spore forming bacterium, increased surface drying time was the most significant factor increasing kill rate.

CONCLUSIONS

This research demonstrates that UV-C was efficacious under optimal conditions, a direct beam exposure, and a short target distance (12.7 cm). However, there are limitations when used in non-optimal conditions. Increased distance and indirect beam angles resulted in lower kill rates. It is also important to minimize unnecessary patient and worker exposure during its use.

Technology in the OR: AORN Members' Perceptions of the Effects on Workflow Efficiency and Quality Patient Care

This collaborative study sought to describe technology used by AORN members at work, inclusive of radio-frequency identification or barcode scanning (RFID), data collection tools (DATA), workflow or dashboard management tools (DASHBOARD), and environmental services/room decontamination technologies (ENVIRON), and to identify the perceived effects of each technology on workflow efficiency (WFE) and quality patient care (QPC). The 462 respondents to the AORN Technology in the OR survey reported use of technology (USE) in all categories. Eleven of 17 RFID items had a strong positive correlation between the designated USE item and the perceived effect on WFE and QPC. Five of the most-used technology items were found in the DATA category. Two of the five related to Intraoperative Nursing Documentation and the use of the Perioperative Nursing Data Set. The other three related to Imaging Integration for Radiology Equipment, Video Camera Systems, and Fiber-optic Systems. All three elements explored in the DASHBOARD category (ie, Patient Update, OR Case, OR Efficiency) demonstrated approximately 50% or greater perceived effectiveness in WFE and QPC. There was a low reported use of ENVIRON technologies, resulting in limited WFE and QPC data for this category.

Control of Clostridium difficile infection in the hospital setting

Clostridium difficile infection (CDI) has emerged as a leading challenge in the control of healthcare-associated infection (HCAI). The epidemiology of CDI has changed dramatically, this is associated with emergence of 'hypervirulent' strains, particularly PCR ribotype 027. Despite the epidemic spread of these strains, there are recent reports of decreasing incidence from healthcare facilities where multi-facetted targeted control programs have been implemented. We consider these changes in epidemiology and reflect on the tools available to control CDI in the hospital setting. The precise repertoire of measures adopted and emphasis on different interventions will vary, not only between healthcare systems, but also within different institutions within the same healthcare system. Finally, we consider both the sustainability of reductions already achieved, and the potential to reduce CDI further. This takes account of newly emerging data on more recent changes in the epidemiology of CDI, and the potential of novel interventions to decrease the burden of disease.

A guide to no-touch automated room disinfection (NTD) systems

Conventional disinfection methods are limited by reliance on the operator to ensure appropriate selection, formulation, distribution and contact time of the agent. ‘No-touch’ automated room disinfection (NTD) systems remove or reduce reliance on operators and so they have the potential to improve the efficacy of terminal disinfection. The most commonly used systems are hydrogen peroxide vapour (H₂O₂ vapour), aerosolised hydrogen peroxide (aHP) and ultraviolet (UV) radiation. These systems have important differences in their active agent, delivery mechanism, efficacy, process time and ease of use. The choice of NTD system should be influenced by the intended application, the evidence base for effectiveness, practicalities of implementation and cost constraints.

Fumigation in Ayurveda: potential strategy for drug discovery and drug delivery

ETHNOPHARMACOLOGICAL RELEVANCE

Ayurveda has its unique perceptions and resultant methodologies for defining and treating human diseases. Fumigation therapy is one of the several treatment methods described in Ayurveda whereby fumes produced from defined drug formulations are inhaled by patients. This therapeutic procedure offers promising research opportunities from phytochemical and ethnopharmacological viewpoints, however, it remains under-noticed. Considering these facts, this review is primarily aimed at introducing said Ayurvedic fumigation therapy and discussing its scientific gaps and future challenges.

METHODOLOGY

A search of multiple bibliographical databases and traditional Ayurvedic text books was conducted and the articles analyzed under various key themes, e.g., Ayurvedic fumigation, fumigation therapy, medicinal fumigation, inhalation of drugs and aerosol therapy.

RESULT

Ayurveda recommends fumigation as a method of sterilization and therapeutic procedure for various human diseases including microbial infections and psychological disorders. However, it has not gained much attention as a prospective field with multiple research opportunities.

CONCLUSION

It is necessary to have a more detailed and systematic investigation of the phytochemical and pharmacodynamic properties of Ayurvedic fumigation therapy in order to facilitate the identification of novel bioactive compounds and more effective drug administration methods.

Linking pesticide exposure and dementia: what is the evidence?

There has been a steep increase in the prevalence of dementia in recent decades, which has roughly followed an increase in pesticide use some decades earlier, a time when it is probable that current dementia patients could have been exposed to pesticides. This raises the question whether pesticides contribute to dementia pathogenesis. Indeed, many studies have found increased prevalence of cognitive, behavioral and psychomotor dysfunction in individuals chronically exposed to pesticides. Furthermore, evidence from recent studies shows a possible association between chronic pesticide exposure and an increased prevalence of dementia, including Alzheimer's disease (AD) dementia. At the cellular and molecular level, the mechanism of action of many classes of pesticides suggests that these compounds could be, at least partly, accountable for the neurodegeneration accompanying AD and other dementias. For example, organophosphates, which inhibit acetylcholinesterase as do the drugs used in treating AD symptoms, have also been shown to lead to microtubule derangements and tau hyperphosphorylation, a hallmark of AD. This emerging association is of considerable public health importance, given the increasing dementia prevalence and pesticide use. Here we review the epidemiological links between dementia and pesticide exposure and discuss the possible pathophysiological mechanisms and clinical implications of this association.

Effect of low-dose gaseous ozone on pathogenic bacteria

Background

Treatment of chronically infected wounds is a challenge, and bacterial environmental contamination is a growing issue in infection control. Ozone may have a role in these situations. The objective of this study was to determine whether a low dose of gaseous ozone/oxygen mixture eliminates pathogenic bacteria cultivated in Petri dishes.

Methods

A pilot study with 6 bacterial strains was made using different concentrations of ozone in an ozone-oxygen mixture to determine a minimally effective dose that completely eliminated bacterial growth. The small and apparently bactericidal gaseous dose of 20 μg/mL ozone/oxygen (1:99) mixture, applied for 5min under atmospheric pressure was selected. In the 2^nd phase, eight bacterial strains with well characterized resistance patterns were evaluated in vitro using agar-blood in adapted Petri dishes (10⁵ bacteria/dish). The cultures were divided into 3 groups: 1- ozone-oxygen gaseous mixture containing 20 μg of O₃/mL for 5 min; 2- 100% oxygen for 5 min; 3- baseline: no gas was used.

Results

The selected ozone dose was applied to the following eight strains: Escherichia coli, oxacillin-resistant Staphylococcus aureus, oxacillin-susceptible Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii, Acinetobacter baumannii susceptible only to carbapenems, and Pseudomonas aeruginosa susceptible to imipenem and meropenem. All isolates were completely inhibited by the ozone-oxygen mixture while growth occurred in the other 2 groups.

Conclusion

A single topical application by nebulization of a low ozone dose completely inhibited the growth of all potentially pathogenic bacterial strains with known resistance to antimicrobial agents.

The role of 'no-touch' automated room disinfection systems in infection prevention and control

BACKGROUND

Surface contamination in hospitals is involved in the transmission of pathogens in a proportion of healthcare-associated infections. Admission to a room previously occupied by a patient colonized or infected with certain nosocomial pathogens increases the risk of acquisition by subsequent occupants; thus, there is a need to improve terminal disinfection of these patient rooms. Conventional disinfection methods may be limited by reliance on the operator to ensure appropriate selection, formulation, distribution and contact time of the agent. These problems can be reduced by the use of 'no-touch' automated room disinfection (NTD) systems.

AIM

To summarize published data related to NTD systems.

METHODS

Pubmed searches for relevant articles.

FINDINGS

A number of NTD systems have emerged, which remove or reduce reliance on the operator to ensure distribution, contact time and process repeatability, and aim to improve the level of disinfection and thus mitigate the increased risk from the prior room occupant. Available NTD systems include hydrogen peroxide (H(2)O(2)) vapour systems, aerosolized hydrogen peroxide (aHP) and ultraviolet radiation. These systems have important differences in their active agent, delivery mechanism, efficacy, process time and ease of use. Typically, there is a trade-off between time and effectiveness among NTD systems. The choice of NTD system should be influenced by the intended application, the evidence base for effectiveness, practicalities of implementation and cost constraints.

CONCLUSION

NTD systems are gaining acceptance as a useful tool for infection prevention and control.

Methodology to reduce formaldehyde exposure during laboratory fumigation

Laboratory fumigations achieve disinfection and are performed following the non-contained release of infectious agents. Gaseous formaldehyde remains the most commonly used fumigant but evidence relates formaldehyde exposure to the development of nasopharyngeal cancer. Laboratory personnel must be confident and competent in the procedure to protect themselves, others and the environment. The present study outlines methodology to reduce worker exposure to formaldehyde during essential fumigation training. A simulation fumigation protocol significantly shorter than a genuine fumigation was devised using aromatic cajuput oil to train staff in the fumigation technique without potentially harmful exposure to formaldehyde. Personnel reported increased confidence and compliance of the fumigation procedure after the simulation suggesting that this model protocol would be a valuable training tool for any individual that may be required to undertake genuine formaldehyde fumigations.

Isolation and characterization of the environmental bacterial and fungi contamination in a pharmaceutical unit of mesenchymal stem cell for clinical use

Design and implementation of an environmental monitoring program is vital to assure the maintenance of acceptable quality conditions in a pharmaceutical manufacturing unit of human mesenchymal stem cells. Since sterility testing methods require 14 days and these cells are only viable for several hours, they are currently administered without the result of this test. Consequently environmental monitoring is a key element in stem cell banks for assuring low levels of potential introduction of contaminants into the cell products. The aim of this study was to qualitatively and quantitatively analyze the environmental microbiological quality in a pharmaceutical manufacturing unit of human mesenchymal stem cells production for use in advanced therapies. Two hundred and sixty one points were tested monthly during one year, 156 from air and 105 from surfaces. Among the 6264 samples tested, 231 showed contamination, 76.6% for bacteria and 23.4% for fungi. Microbial genuses isolated were Staphylococcus (89.7%), Microccocus (4.5%), Kocuria (3.2%) and Bacillus (2.6%). In the identification of fungi, three genuses were detected: Aspergillus (56%), Penicillium (26%) and Cladosporium (18%). The origin of the contamination was found to be due to personnel manipulation and air microbiota. For all sampling methods, alert limits were set and corrective measures suggested.