Airborne nosocomial infection: a contemporary perspective

Indoor Air Quality and COVID-19: A Scoping Review

Objectives: The COVID-19 pandemic has been a major public health concern for the past 3 years. Scientific evidence on the relationship between SARS-CoV-2 infection and indoor air quality still needs to be demonstrated. This scoping review aims to study the association between air quality indoors and COVID-19. Methods: A scoping review analyzing the association between indoor air quality and epidemiological outcomes was conducted. Papers published between 1 January 2020 and 31 October 2022 were included. Hospital settings were excluded from the study. Results: Eight relevant articles met the inclusion criteria. Indoor settings included workplaces, schools, restaurants, and public transport. Types of ventilation used to improve indoor air quality were dilution methods (opening windows) and mechanical systems with or without filtration or purifier. CO2 sensors were employed in one study. All the studies showed a positive association between indoor air quality and its improvement and epidemiological indicators. Conclusion: The findings of this scoping review indicate that indoor air quality, which can be improved with ventilation methods, may reduce the risk of developing COVID-19. Ventilation could thus be viewed as a possible effective mitigating method.

A cross-case analyses of laboratory professionals-patients interaction for patients accessing laboratory services at University of Cape Coast hospital and Ewim Polyclinic in the Cape Coast Metropolis, Ghana

Background

There is scarcity of data on experiences of patients who access laboratory services during hospital visits in sub-Saharan Africa. This study sought to evaluate the depth of laboratory professionals-patient interactions during pre- and post-sampling period at two hospitals in Ghana.

Methods

This study used real time observations of patient-laboratory staff interactions to collect first-hand data. Additionally, two separate sets of semi-structured questionnaires were used to collect data on the experiences of patients and laboratory professionals. Data were entered into Microsoft Excel and analysed using SPSS version 25.

Results

Inadequate laboratory space is a major factor limiting adequacy of patients-laboratory professionals’ interactions. Overall, even though the laboratory professionals (93.3%) overwhelmingly agreed to the need to inform patients about the turnaround time of the respective laboratory testing, this was not routinely done. Irrespective of patients’ educational attainment, patients were poorly informed about their respective laboratory tests. Although both patients and laboratory professionals (60.0% vs 63.6% respectively) indicated that the test requester has responsibility to inform patients about their laboratory testing, only 29.1% of patients indicated having received such explanations. Furthermore, although 28.1% of patients indicated knowing the specifics of their respective test requisition, only 15% could correctly identify their requested laboratory testing.

Conclusion

There is the need for standard operating protocols to standardize practitioner-patient interaction at the two facilities. Moreover, there is the need for laboratory staff-test requester engagement to clearly delineate who has what responsibilities regarding informing patients about laboratory testing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06560-8.

Evidence of Long-Distance Aerial Convection of Variola Virus and Implications for Disease Control

Two distinct phenomena of airborne transmission of variola virus (smallpox) were described in the pre-eradication era-direct respiratory transmission, and a unique phenomenon of transmission over greater distances, referred to as "aerial convection". We conducted an analysis of data obtained from a systematic review following the PRISMA criteria, on the long-distance transmission of smallpox. Of 8179 studies screened, 22 studies of 17 outbreaks were identified-12 had conclusive evidence of aerial convection and five had partially conclusive evidence. Aerial convection was first documented in 1881 in England, when smallpox incidence had waned substantially following mass vaccination, making unusual transmissions noticeable. National policy at the time stipulated spatial separation of smallpox hospitals from other buildings and communities. The evidence supports the transmission of smallpox through aerial convection at distances ranging from 0.5 to 1 mile, and one instance of 15 km related to bioweapons testing. Other explanations are also possible, such as missed chains of transmission, fomites or secondary aerosolization from contaminated material such as bedding. The window of observation of aerial convection was within the 100 years prior to eradication. Aerial convection appears unique to the variola virus and is not considered in current hospital infection control protocols. Understanding potential aerial convection of variola should be an important consideration in planning for smallpox treatment facilities and protecting potential contacts and surrounding communities.

Self-Sterilizing Laser-Induced Graphene Bacterial Air Filter

Nosocomial infections transmitted through airborne, droplet, aerosol, and particulate-transported modes pose substantial infection risks to patients and healthcare employees. In this study, we demonstrate a self-cleaning filter comprised of laser-induced graphene (LIG), a porous conductive graphene foam formed through photothermal conversion of a polyimide film by a commercial CO₂ laser cutter. LIG was shown to capture particulates and bacteria. The bacteria cannot proliferate even when submerged in culture medium. Through a periodic Joule-heating mechanism, the filter readily reaches >300 °C. This destroys any microorganisms including bacteria, along with molecules that can cause adverse biological reactions and diseases. These molecules include pyrogens, allergens, exotoxins, endotoxins, mycotoxins, nucleic acids, and prions. Capitalizing on the high surface area and thermal stability of LIG, the utility of graphene for reduction of nosocomial infection in hospital settings is suggested.

Bacterial, Fungal and Viral Infections in Surgical Site: Clinical, Diagnostic and Epidemiological Aspects

AbstractSurgical Site Infections (SSI) are infections related to surgical procedures in inpatients and outpatients, indicated with high prevalence in relation to infections linked to preventable health care. Thus, the objective of the study is to perform a review on bacterial, fungal and viral infections in surgical site in relation to clinical, diagnostic and epidemiological aspects. A bibliographic and exploratory research was carried out and the Virtual Health Library (VHL), Capes Periodicals and the Pubmed to search the articles were consulted. As for the clinical aspects, the phlogistic signs that allow to identify an inflammatory picture, being a response of the organism to some aggressive agent. Among the bacterial diagnostic methods, the most used ones are the color smear examination, cultural and biochemical characteristics, ELISA, PCR and SAR. As for the detection of fungi and yeasts are the production of the germ tube, micro-culture in agar-tween 80 agar, assimilation of carbohydrates or nitrogen and fermentation of carbohydrates. For viruses, virus isolation, cell culture, laboratory animals and embryonated eggs may be used. Although bacterial infections account for most surgical infections, fungal and viral infections can also be seen in hospital settings and their diagnosis needs to be performed as soon as possible for proper treatment, reducing costs for medical services and length of stay of the patient in the hospital environment, also reducing other risks of infection.Keywords: Surgical Wound Infection. Bacterial Infections. Mycoses. Virus Diseases.ResumoAs Infecções do Sítio Cirúrgico (ISC) são infecções relacionadas a procedimentos cirúrgicos em pacientes internados e ambulatoriais, indicadas com alta prevalência em relação às infecções ligadas aos cuidados em saúde evitáveis. Neste sentido, o objetivo do estudo é realizar uma revisão sobre as infecções bacterianas, fúngicas e virais em sítio cirúrgico em relação aos aspectos clínicos, diagnósticos e epidemiológicos. Foi realizada uma pesquisa bibliográfica e exploratória e consultada a Biblioteca Virtual em Saúde (BVS), os Periódicos Capes e o Pubmed para busca dos artigos. Quanto aos aspectos clínicos, os sinais flogísticos que permitem identificar um quadro inflamatório, sendo uma resposta do organismo frente a algum agente agressor. Dentre os métodos diagnósticos bacterianos, os mais utilizados são o Exame de esfregaços corados, Características culturais e bioquímicas, ELISA, PCR e o SAR. Quanto à detecção de fungos e leveduras estão a produção do tubo germinativo, micro cultivo em ágar fubá-tween 80, assimilação de carboidratos ou de nitrogênio e fermentação dos carboidratos. Em relação aos vírus, podem ser utilizadas o isolamento dos vírus, a cultura de células, os animais de laboratório e os ovos embrionados. Apesar das infecções bacterianas representarem a maior parte das infecções cirúrgicas, as infecções fúngicas e virais também podem ser vistas em ambientes hospitalares e seu diagnóstico precisa ser realizado o mais rápido possível para um tratamento adequado, reduzindo os custos com serviços médicos e o tempo de permanência do paciente no ambiente hospitalar, diminuindo também outros riscos de infecção.Palavras-chave: Infecção da Ferida Cirúrgica. Infecções Bacterianas. Micoses. Viroses.

The extent of environmental and body contamination through aerosols by hydro-surgical debridement in the lumbar spine

INTRODUCTION

Surgical site infections occur in 1-6% of spinal surgeries. Effective treatment includes early diagnosis, parenteral antibiotics and early surgical debridement of the wound surface.

MATERIALS AND METHODS

On a human cadaver, we executed a complete hydro-surgery debridement including a full surgical setup such as draping. The irrigation fluid was artificially contaminated with Staphylococcus aureus (ATCC 6538). Surveillance cultures were used to detect environmental and body contamination of the surgical team.

RESULTS

For both test setups, environmental contamination was observed in an area of 6 × 8 m. Both test setups caused contamination of all personnel present during the procedure and of the whole operating theatre. However, the concentration of contamination for the surgical staff and the environment was lower when an additional disposable draping device was used.

CONCLUSIONS

The study showed that during hydro-surgery debridement, contaminated aerosols spread over the whole surgical room and contaminate the theatre and all personnel.

Lifting the lid on toilet plume aerosol: a literature review with suggestions for future research

Background

The potential risks associated with “toilet plume” aerosols produced by flush toilets is a subject of continuing study. This review examines the evidence regarding toilet plume bioaerosol generation and infectious disease transmission.

Methods

The peer-reviewed scientific literature was searched to identify articles related to aerosol production during toilet flushing, as well as epidemiologic studies examining the potential role of toilets in infectious disease outbreaks.

Results

The studies demonstrate that potentially infectious aerosols may be produced in substantial quantities during flushing. Aerosolization can continue through multiple flushes to expose subsequent toilet users. Some of the aerosols desiccate to become droplet nuclei and remain adrift in the air currents. However, no studies have yet clearly demonstrated or refuted toilet plume-related disease transmission, and the significance of the risk remains largely uncharacterized.

Conclusion

Research suggests that toilet plume could play a contributory role in the transmission of infectious diseases. Additional research in multiple areas is warranted to assess the risks posed by toilet plume, especially within health care facilities.

Aerobiology and its role in the transmission of infectious diseases

Aerobiology plays a fundamental role in the transmission of infectious diseases. As infectious disease and infection control practitioners continue employing contemporary techniques (e.g., computational fluid dynamics to study particle flow, polymerase chain reaction methodologies to quantify particle concentrations in various settings, and epidemiology to track the spread of disease), the central variables affecting the airborne transmission of pathogens are becoming better known. This paper reviews many of these aerobiological variables (e.g., particle size, particle type, the duration that particles can remain airborne, the distance that particles can travel, and meteorological and environmental factors), as well as the common origins of these infectious particles. We then review several real-world settings with known difficulties controlling the airborne transmission of infectious particles (e.g., office buildings, healthcare facilities, and commercial airplanes), while detailing the respective measures each of these industries is undertaking in its effort to ameliorate the transmission of airborne infectious diseases.

Microbial air monitoring in operating theatres: experience at the University Hospital of Parma

BACKGROUND

Microbial air monitoring in operating theatres has been a subject of interest and debate. No generally accepted sampling methods and threshold values are available.

AIM

To assess microbial air contamination in empty and working conventionally ventilated operating theatres over a three-year period at the University Hospital of Parma, Italy.

METHODS

Air sampling was performed in 29 operating theatres. Both active and passive sampling methods were used to assess bacterial and fungal contamination.

FINDINGS

In empty theatres, median bacterial values of 12 colony-forming units (cfu)/m(3) [interquartile range (IQR) 4-32] and 1 index of microbial air contamination (IMA) (IQR 0-3) were recorded. In working theatres, these values increased significantly (P < 0.001) to 80 cfu/m(3) (IQR 42-176) and 7 IMA (IQR 4-13). Maximum recorded values were 166 cfu/m(3) and 8 IMA for empty theatres, and 798 cfu/m(3) and 42 IMA for working theatres. Combining active and passive samplings, fungi were isolated in 39.13% of samples collected in empty theatres and 56.95% of samples collected in working theatres. Over the three-year study period, bacterial contamination decreased in both empty and working theatres, and the percentage of samples devoid of fungi increased. In working theatres, a significant correlation was found between the bacterial contamination values assessed using passive and active sampling methods (P < 0.001).

CONCLUSION

Microbiological monitoring is a useful tool for assessment of the contamination of operating theatres in order to improve air quality.

Fungal microbiota in air-conditioning installed in both adult and neonatal intensive treatment units and their impact in two university hospitals of the central western region, Mato Grosso, Brazil

To evaluate fungal microbiota in air-conditioning units installed in intensive care units in two university hospitals in Cuiaba city, Mato Grosso, central western region of Brazil, 525 solid environmental samples were collected, 285 from Hospital A and 240 from Hospital B. Collections were performed using sterile swabs on air-conditioning unit components: cooling coils, ventilators, and filters. Mycelial fungi identification was achieved by observation of the macroscopic and micromorphological characteristics in different culture mediums (maize meal, oatmeal and potato dextrose agars and malt extract) using the Ridell technique. Eleven genera and 27 distinct species belonging to the hyphomycetes and ascomycetes classes were isolated and identified. The most frequently detected genera in both hospitals were Aspergillus spp, Penicillium spp, and Cladosporium spp. Values for colony-forming units per gram were 64 and 75%, well above the limits recommended by Health Ministry resolution 176/00 at the locations selected for analysis in Hospitals A and B, respectively. In conclusion, evaluation of fungal microbiota in the air-conditioning units indirectly determined that the air quality was compromised in both university hospitals analyzed, which constitutes a risk factor for the acquisition of infection in the intensive care units.

A new method of assessing aerosolized bacteria generated during orthodontic debonding procedures

INTRODUCTION

The main objective of this study was to assess the efficacy of a new and innovative method of harvesting bacteria that are aerosolized during orthodontic debonding. Additionally, the protection efficacy of several commercially available masks from such aerosols was assessed in a pilot study.

METHODS

Twenty-six subjects were debonded during aerosol sampling, by using an innovative collection system to harvest bonding dust liberated during debonding. Dark-field microscopy, gram-stain microscopy, and chemical identification were used to determine speciation of the collected aerosol from 23 subjects. Three additional subjects were used to test 3 commercial dental or protective masks to determine whether they provide effective protection from the aerosol.

RESULTS

Twenty-one species of oral bacteria were identified by the new sampling technique. Two of the 3 masks that were tested offered no protection against the aerosolized bacteria.

CONCLUSIONS

A new and effective method for collecting airborne bacteria is presented. Some conventional dental masks offer no protection from aerosolized organisms liberated during debonding procedures. Further assessment of mask efficacy is ongoing.

The efficiency of an air filtration system in the hospital ward

A study was conducted to ascertain the efficiency and effectiveness of an air filtration system (Electromedia Model 100C, Clean Air UK, UK) in the hospital ward. The sampling was conducted using a portable Surface Air Sampler (Cherwell Laboratories, Bicester, UK) in conjunction with settle plates. Samples were taken two days before and two days following activation of the filtration system and results compared. A clear, demonstrable, statistically significant reduction in microbial organisms following the activation of the filtration systems is evident (81% settle plates; 24% Surface Air Sampler). This study has implications for the improved health and welfare of patients and healthcare workers who may benefit through the implementation of such a system.

Possible SARS coronavirus transmission during cardiopulmonary resuscitation

Infection of healthcare workers with the severe acute respiratory syndrome–associated coronavirus (SARS-CoV) is thought to occur primarily by either contact or large respiratory droplet transmission. However, infrequent healthcare worker infections occurred despite the use of contact and droplet precautions, particularly during certain aerosol-generating medical procedures. We investigated a possible cluster of SARS-CoV infections in healthcare workers who used contact and droplet precautions during attempted cardiopulmonary resuscitation of a SARS patient. Unlike previously reported instances of transmission during aerosol-generating procedures, the index case-patient was unresponsive, and the intubation procedure was performed quickly and without difficulty. However, before intubation, the patient was ventilated with a bag-valve-mask that may have contributed to aerosolization of SARS-CoV. On the basis of the results of this investigation and previous reports of SARS transmission during aerosol-generating procedures, a systematic approach to the problem is outlined, including the use of the following: 1) administrative controls, 2) environmental engineering controls, 3) personal protective equipment, and 4) quality control.

Searching the health care literature efficiently: from clinical decision-making to continuing education

Searching the health care literature is an activity in which infection control professionals must routinely engage to seek evidence-based answers to specific practice questions and to stay abreast of developments in the field. Without the appropriate tools, the tremendous volume of clinical literature makes both of these daunting tasks. In this article, we illustrate techniques for searching MEDLINE efficiently, both as a means of answering particular clinical questions and for generating periodic updates on topics of general interest. With use of a specific example relevant to infection control, we demonstrate the identification of appropriate Medical Subject Headings terms that capture a given question or topic and the development of effective searches with use of these terms. We also touch on the advantages of targeting systematic reviews and meta-analyses in searching for evidence and staying abreast of the literature in general.

Characterization of infectious aerosols in health care facilities: an aid to effective engineering controls and preventive strategies

Assessment of strategies for engineering controls for the prevention of airborne infectious disease transmission to patients and to health care and related workers requires consideration of the factors relevant to aerosol characterization. These factors include aerosol generation, particle size and concentrations, organism viability, infectivity and virulence, airflow and climate, and environmental sampling and analysis. The major focus on attention to engineering controls comes from recent increases in tuberculosis, particularly the multidrug-resistant varieties in the general hospital population, the severely immunocompromised, and those in at-risk and confined environments such as prisons, long-term care facilities, and shelters for the homeless. Many workers are in close contact with persons who have active, undiagnosed, or insufficiently treated tuberculosis. Additionally, patients and health care workers may be exposed to a variety of pathogenic human viruses, opportunistic fungi, and bacteria. This report therefore focuses on the nature of infectious aerosol transmission in an attempt to determine which factors can be systematically addressed to result in proven, applied engineering approaches to the control of infectious aerosols in hospital and health care facility environments. The infectious aerosols of consideration are those that are generated as particles of respirable size by both human and environmental sources and that have the capability of remaining viable and airborne for extended periods in the indoor environment. This definition precludes skin and mucous membrane exposures occurring from splashes (rather than true aerosols) of blood or body fluids containing infectious disease agents. There are no epidemiologic or laboratory studies documenting the transmission of bloodborne virus by way of aerosols.