Airborne fungal spores and invasive aspergillosis in hematologic units in a tertiary hospital during construction: a prospective cohort study

Invasive aspergillosis: A comprehensive review

Invasive aspergillosis (IA) is a severe fungal infection caused by Aspergillus species, particularly Aspergillus fumigatus, although new species, sometimes resistant to antifungals are becoming more common. IA predominantly affects immunocompromised patients, such as those with haematological malignancies, solid organ transplant recipients, and critically ill patients. However, new at-risk populations have emerged in recent years, such as IA associated with severe viral infections. Advanced diagnostic methods are crucial, especially considering the rising concern of antifungal resistance. Early detection is critical for successful treatment, typically involving antifungal medications like voriconazole or amphotericin B, but new antifungals are arriving to complete the therapeutic strategies. Despite advancements, mortality rates remain high, underscoring the importance of timely interventions and ongoing research. Healthcare providers should maintain a high index of suspicion, especially in immunocompromised patients and other new risk factors that are arising, to promptly diagnose and manage invasive aspergillosis.

Practices to prevent non-ventilator hospital-acquired pneumonia: a narrative review

Nosocomial infection has significant consequences in health care, both at the individual level due to increased morbidity and mortality, and at the organizational level due to increased costs. Hospital-acquired pneumonia (HAP) is the most common nosocomial infection, and is associated with high excess mortality, frequent use of broad-spectrum antimicrobials and increased length of stay. This review explores the preventative strategies that have been examined in non-ventilator HAP (NV-HAP). The management of aspiration risk, interventions for oral hygiene, role of mobilization and physiotherapy, modification of environmental factors, and vaccination are discussed. Many of these interventions are low risk, acceptable to patients and have good cost-benefit ratios. However, the evidence base for prevention of NV-HAP is weak. This review identifies the lack of a unified research definition, under-recruitment to studies, and variation in intervention and outcome measures as limitations in the existing literature. Given that the core risk factors for acquisition of NV-HAP are increasing, there is an urgent need for research to address the prevention of NV-HAP. This review calls for a unified definition of NV-HAP, and identification of a core outcome set for studies in NV-HAP, and suggests future directions for research in NV-HAP. Improving care for people with NV-HAP will reduce morbidity, mortality and healthcare costs significantly.

Risk Factors and Environmental Preventive Actions for Aspergillosis in Patients with Hematological Malignancies

(1) Background: Aspergillus spp. is a widely distributed filamentous fungus in the environment due to its high sporulation capacity. Currently, invasive aspergillosis (IA) is the most common invasive fungal infection in patients with hematologic malignancies, with high rates of mortality and morbidity. The multifactorial nature of the disease requires appropriate risk stratification to enable the most appropriate preventive measures to be adapted and implemented according to the characteristics of the patient. In this sense, the present research aims to identify recent risk factors and environmental control measures against invasive aspergillosis to establish preventive actions to reduce the incidence of invasive aspergillosis in hospitals. (2) Methods: We conducted a qualitative systematic review of the scientific literature on environmental risk factors and preventive measures for invasive aspergillosis in patients with hematologic malignancies. The Medline, Cochrane, and Scopus databases were consulted, following the PRISMA and STROBE guidelines. (3) Results: Adequate implementation of environmental control measures is presented as the most efficient intervention in terms of prevention to decrease the incidence of invasive aspergillosis in hospitals. Neutropenia, fungal contamination, insufficient environmental control measures in hospital and home settings, length of hospital stay, and anemia, are identified as independent risk factors. We show that HEPA, LAF, and Plasmair® systems are suitable methods to reduce the concentration of airborne fungal spores. Antifungal prophylaxis did not significantly influence IA reduction in our study. (4) Conclusions: Proper professional training and environmental control measures in hospitals are essential for the prevention of invasive aspergillosis. We should optimize risk stratification for patients with hematologic malignancies. Antifungal prophylaxis should be complementary to environmental control measures and should never be substituted for the latter. Studies should also be undertaken to evaluate the efficiency of environmental control measures against IA at patients' homes.

Environmental monitoring for filamentous fungal pathogens in hematopoietic cell transplant units

The incidence of invasive fungal disease (IFD) is on the rise due to increasing numbers of highly immunocompromized patients. Nosocomial IFD remains common despite our better understanding of its risk factors and pathophysiology. High-efficiency particulate air filtration with or without laminar air flow, frequent air exchanges, a positive pressure care environment, and environmental hygiene, amongst other measures, have been shown to reduce the mould burden in the patient environment. Environmental monitoring for moulds in areas where high-risk patients are cared for, such as hematopoietic cell transplant units, has been considered an adjunct to other routine environmental precautions. As a collaborative effort between authors affiliated to the Infection Prevention and Control Working Group and the Fungal Infection Working Group of the International Society of Antimicrobial Chemotherapy (ISAC), we reviewed the English language literature and international guidance to describe the evidence behind the need for environmental monitoring for filamentous fungi as a quality assurance approach with an emphasis on required additional precautions during periods of construction. Many different clinical sampling approaches have been described for air, water, and surface sampling with significant variation in laboratory methodologies between reports. Importantly, there are no agreed-upon thresholds that correlate with an increase in the clinical risk of mould infections. We highlight important areas for future research to assure a safe environment for highly immunocompromized patients.

What's New in Prevention of Invasive Fungal Diseases during Hospital Construction and Renovation Work: An Overview

The goal of the overview was to give insight into the recent data of invasive fungal diseases (IFDs) associated with construction and renovation in healthcare settings as well as the recent evidence about available prevention and infection control measures. The number of studies describing IFD outbreaks associated with construction or renovation is on the rise again. Applying adequate prevention measures is still a challenge not just for healthcare workers but also for architects and construction workers as well. The role of multidisciplinary teams in the planning and monitoring of prevention measures cannot be overemphasized. Dust control is an inevitable part of every prevention plan. HEPA filters are helpful in the prevention of fungal outbreaks in hematologic patients, but further studies are needed to clarify the extent in which they contribute as specific control measures. The cut-off value for a "threating" level of fungal spore contamination still remains to be defined. The value of antifungal prophylaxis is difficult to assess because other preventive measures are simultaneously applied. Recommendations are still based on few meta-analyses, a large number of descriptive reports, and the opinion of respective authorities. Outbreak reports in the literature are a valuable resource and should be used for education as well as for preparing outbreak investigations.

Impact of Fungal Spores on Asthma Prevalence and Hospitalization

Despite making up a significant proportion of airborne allergens, the relationship between fungal spores and asthma is not fully explored. Only 80 taxa of fungi have so far been observed to exacerbate respiratory presentations, with Cladosporium spp., Aspergillus spp., Penicillium spp., and Alternaria spp. found to comprise the predominant allergenic airborne spores. Fungal spores have been found in indoor environments, such as hospitals and housing due to poor ventilation. Meanwhile, outdoor fungal spores exhibit greater diversity, and higher abundance and have been associated with hospitalizations from acute asthma presentations. In addition, fungal spores may be the underlying, and perhaps the “missing link”, factor influencing the heightened rate of asthma presentations during epidemic thunderstorm asthma events. To improve our knowledge gap on fungal spores, airborne allergen monitoring must be improved to include not only dominant allergenic fungi but also provide real-time data to accurately and quickly warn the general public. Such data will help prevent future asthma exacerbations and thus save lives. In this review, we examine the health risks of prominent allergenic fungal taxa, the factors influencing spore dispersal and distribution, and why improvements should be made to current sampling methods for public health and wellbeing.

Do closed waste containers lead to less air contamination than opened? A clinical case study at Jena University Hospital, Germany

Nosocomial infections are a growing challenge at hospitals. This clinical study aimed to investigate the influence of waste container construction ((open (O), closed (C), and hands-free opening (HF)) on microbial air contamination in a hospital setting. The results are intended to help develop guidelines for waste containers for the collection of non-infectious waste at hospitals and medical facilities. The clinical experiment was conducted at the University Hospital Jena, Germany. Air Impactor samples were performed and microbiologically evaluated for bacteria and fungi both quantitatively and qualitatively. The results were statistically determined using generalized estimating equations. Quantitatively, the lowest bacterial counts in ambient air were found around closed waste containers (114.74 CFU/m³) in comparison to HF (129.28 CFU/m³) and O (126.28 CFU/m³). For fungi, the surrounding air of C (2.08 CFU/m³) and HF (1.97 CFU/m³) waste containers showed a lower impact of fungal air contamination than for O (2.32 CFU/m³). Overall, it was shown that C are more preferable to HF and O waste containers from the point of view of microbial air contamination at hospitals.

Fungi in the indoor air of critical hospital areas: a review

Invasive fungal infection is an important cause of mortality and morbidity in neonates, especially in low-birthweight neonates. The contribution of fungi in the indoor air to the incidence of mucocutaneous colonization and to the risk of invasive fungal infection in this population is uncertain. This review aimed to identify and to summarize the best available evidence on the fungal contamination in the indoor air of critical hospital areas with an emphasis on pediatric/neonatal ICUs. Publications from 2005 to 2019 were searched in the databases Scientific Electronic Library Online (SciELO), US National Library of Medicine National Institutes of Health Search (PubMed), and Latin American Caribbean Health Sciences (LILACS). Descriptors in Health Sciences (DeCS) were used. Research papers published in Portuguese, English, and Spanish were included. Twenty-nine papers on all continents except Australia were selected. The results showed that the air mycobiota contained several fungal species, notably Aspergillus, Penicillium, Cladosporium, Fusarium, and yeast (Candida) species. The selected papers point out the risks that fungi pose to neonates, who have immature immune system, and describe simultaneous external factors (air humidity, seasonality, air and people flow, use of particulate filters, and health professionals' hand hygiene) that contribute to indoor air contamination with fungi. Improving communication among health professionals is a great concern because this can prevent major health complications in neonates, especially in low-birthweight neonates. The results reinforced the need to monitor environmental fungi more frequently and efficiently in hospitals, especially in neonatal ICUs.

Evaluation of Nosocomial Infection Control Measures to Minimize the Risk of Aspergillus Dispersion During Major Demolition Work: A Case Study of a Japanese University Hospital

OBJECTIVES

To verify the effectiveness of our infection control measures based on the infection control risk assessment (ICRA) to minimize the risk of Aspergillus dispersion before, during, and after demolition work in a university hospital.

BACKGROUND

It is widely accepted that invasive aspergillosis is associated with construction, renovation, and demolition activities within or close to hospital sites. However, the risk is underestimated, and only limited preventive measures are taken in Japanese hospitals.

METHOD

The demolition process, carried out in July 2014, was supervised by our facility management in collaboration with the infection prevention team and followed an adapted ICRA tool. Dust containment measures were implemented to reduce the risk of airborne Aspergillus contamination. Air sampling was performed at four wards in the adjacent hospital buildings to assess the containment measures' effectiveness.

RESULTS

A high, undetermined number of colonies of bacteria and molds were detected on all outside balconies before demolition. During demolition, Aspergillus spp. was detected only in the ward closest to the demolition site. However, no case of aspergillosis was reported. The difference-in-difference analysis revealed that the interaction between the demolition activity, height of the ward, and distance of the air intake to the demolition activities resulted in a significant increase in the numbers of Aspergillus spp.

CONCLUSIONS

When large-scale demolition work occurs in hospital premises, Aspergillus spp. may increase in the ward where the vertical and horizontal distance of air intake from the demolition site is close, even though infection control measures based on the ICRA are implemented.

Mold and Yeast-Like Fungi in the Seaside Air of the Gulf of Gdańsk (Southern Baltic) after an Emergency Disposal of Raw Sewage

The aim of this study was to determine the correlation between the meteorological factors and the number of molds and yeast-like fungi in the air in the five coastal towns in the years 2014-2017, and in 2018, after emergency disposal of raw sewage to the Gdańsk Gulf. In the years 2014-2018, a total number of 88 air samples were collected in duplicate in the five coastal towns of Hel, Puck, Gdynia, Sopot, and Gdańsk-Brzeźno. After the application of the (PCA) analysis, this demonstrated that the first principal component (PC1) had a positive correlation with the water temperature, wind speed, air temperature, and relative humidity. The second principal component (PC2) had a positive correlation with the relative humidity, wind speed, wind direction, and air temperature. In 2018, potentially pathogenic mold and yeast-like fungi (Candida albicans, Stachybotrys chartarum complex, Aspergillus section Fumigati) were detected in the seaside air. While the detected species were not observed in the years 2014-2017. We suggest that it is advisable to inform residents about the potential health risk in the event of raw sewage disposal into the water. Moreover, in wastewater treatment plants, tighter measures, including wastewater disinfection, should be introduced.

Transcriptomic, Protein-DNA Interaction, and Metabolomic Studies of VosA, VelB, and WetA in Aspergillus nidulans Asexual Spores

Filamentous fungi produce a vast number of asexual spores that act as efficient propagules. Due to their infectious and/or allergenic nature, fungal spores affect our daily life. Aspergillus species produce asexual spores called conidia; their formation involves morphological development and metabolic changes, and the associated regulatory systems are coordinated by multiple transcription factors (TFs).

In filamentous fungi, asexual development involves cellular differentiation and metabolic remodeling leading to the formation of intact asexual spores. The development of asexual spores (conidia) in Aspergillus is precisely coordinated by multiple transcription factors (TFs), including VosA, VelB, and WetA. Notably, these three TFs are essential for the structural and metabolic integrity, i.e., proper maturation, of conidia in the model fungus Aspergillus nidulans. To gain mechanistic insight into the complex regulatory and interdependent roles of these TFs in asexual sporogenesis, we carried out multi-omics studies on the transcriptome, protein-DNA interactions, and primary and secondary metabolism employing A. nidulans conidia. RNA sequencing and chromatin immunoprecipitation sequencing analyses have revealed that the three TFs directly or indirectly regulate the expression of genes associated with heterotrimeric G-protein signal transduction, mitogen-activated protein (MAP) kinases, spore wall formation and structural integrity, asexual development, and primary/secondary metabolism. In addition, metabolomics analyses of wild-type and individual mutant conidia indicate that these three TFs regulate a diverse array of primary metabolites, including those in the tricarboxylic acid (TCA) cycle, certain amino acids, and trehalose, and secondary metabolites such as sterigmatocystin, emericellamide, austinol, and dehydroaustinol. In summary, WetA, VosA, and VelB play interdependent, overlapping, and distinct roles in governing morphological development and primary/secondary metabolic remodeling in Aspergillus conidia, leading to the production of vital conidia suitable for fungal proliferation and dissemination.

Trends on Aspergillus Epidemiology-Perspectives from a National Reference Laboratory Surveillance Program

Identification of Aspergillus to species level is important since sibling species may display variable susceptibilities to multiple antifungal drugs and also because correct identification contributes to improve the knowledge of epidemiological studies. Two retrospective laboratory studies were conducted on Aspergillus surveillance at the Portuguese National Mycology Reference Laboratory. The first, covering the period 2017–2018, aimed to study the molecular epidemiology of 256 Aspergillus isolates obtained from patients with respiratory, subcutaneous, or systemic infections and from environmental samples. The second, using our entire collection of clinical and environmental A. fumigatus isolates (N = 337), collected between 2012 and 2019, aimed to determine the frequency of azole-resistant A. fumigatus isolates. Aspergillus fumigatus sensu stricto was the most frequent species in both clinical and environmental samples. Overall, and considering all Aspergillus sections identified, a high frequency of cryptic species was detected, based on beta-tubulin or calmodulin sequencing (37% in clinical and 51% in environmental isolates). Regarding all Fumigati isolates recovered from 2012–2019, the frequency of cryptic species was 5.3% (18/337), with the identification of A. felis (complex), A. lentulus, A. udagawae, A. hiratsukae, and A. oerlinghauensis. To determine the frequency of azole resistance of A. fumigatus, isolates were screened for azole resistance using azole-agars, and 53 possible resistant isolates were tested by the CLSI microdilution reference method. Nine A. fumigatus sensu stricto and six Fumigati cryptic isolates showed high minimal inhibitory concentrations to itraconazole, voriconazole, and/or posaconazole. Real-time PCR to detect cyp51A mutations and sequencing of cyp51A gene and its promoter were performed. The overall frequency of resistance to azoles in A. fumigatus sensu stricto was 3.0%. With this retrospective analysis, we were able to detect one azole-resistant G54R mutant A. fumigatus environmental isolate, collected in 2015. The TR₃₄/L98H mutation, linked to environmental transmission route of azole resistance, was the most frequently detected mutation (N = 4; 1.4%). Our findings underline the demand for correct identification and susceptibility testing of Aspergillus isolates.