Background . Most healthcare-associated infections (HAI) develop due to a colonization of patients and healthcare workers by hospital strains of pathogens. The aim to study was to assess whether the dust within the health facilities can harbor microorganisms acting as a reservoir of HAIs. Materials and methods . Dust samples collected in the air ducts and ventilation grilles of health facilities underwent a detailed physicochemical analysis by means of scanning electron microscopy, dynamic light scattering, energy-dispersive X-ray spectroscopy, and high-temperature catalytic oxidation. Bacterial and viral diversity was investigated using an automated biochemical analyzer and polymerase chain reaction, respectively. Investigation of the microenvironment included detection of biofilms using a catalase indicator and quantification of viable microorganisms per 1 m 3  air. Results . Dust from the hospital ventilation grilles and air ducts was contaminated with microorganisms in 71.13% of cases. Strikingly, multidrug-resistant and biofilm-forming strains have been found in 69.4% and 48.0% of samples, respectively. The total viable count before and after opening doors and windows was 276 and 462 colony-forming units/m 3  respectively (p = 0.046). Biodiversity was represented by 21 genera of microorganisms which were consistently detected upon 6 months of follow-up. All samples contained a nanosized particulate matter. Chemical elements comprising dust were carbon (16.26–50.69%), oxygen (20.02–37.50%), nitrogen (1.59–25.03%), hydrogen (2.03–6.67%), sulfur (0.15–2.38%), calcium (0.19–7.49%), silicon (0.21–4.64%), chlorine (0.05–2.83%), sodium (0.07–1.86%), aluminum (0.36–1.78%), iron (0.08–1.61%), magnesium (0.11– 1.40%), potassium (0.04–0.85%), and phosphorus (0.04–0.81%). Discussion . A wide range of multidrug-resistant strains of bacteria, detected in a hospital particulate matter with a diverse chemical composition, indicates the persistence of HAI-causing pathogens in the hospital environment. Conclusion . Dust from the ventilation grilles and adjacent air ducts should be considered as an additional reservoir of multidrug-resistant strains of bacteria in the healthcare settings.

Aim . To study the trends in the prevalence of respiratory tract infections in the population of Kemerovo Region and to interrogate the particulate matter as a possible route for the transmission of multidrug-resistant microorganisms into medical organisations. Materials and Methods . We investigated the prevalence of acute respiratory infections and community-acquired pneumonia among the population of Kuzbass (Kemerovo Region) according to the offcial medical records collected from 2004 to 2020. The study included 10,320,384 cases of acute respiratory infections, 145,357 cases of community-acquired pneumonia, 344,703 hospitalisations of the adults (subjects ≥ 18 years of age) and 75,041 hospitalisations of children (< 18 years of age). Collection of particulate matter samples (n = 97) was performed using sterile gloves and containers from ventilation grilles and adjacent air ducts of the exhaust ventilation systems in various healthcare settings. Bacterial composition of the dust was examined using a VITEK 2 Compact biochemical analyzer. Viral diversity was screened by polymerase chain reaction. Results . Over the study period, respiratory infections were common in Kemerovo Region (average prevalence 22,155.9 per 100,000 population) and showed an increasing incidence. Frequency of respiratory infections among the hospitalised patients was 207.14 per 1,000, being 1.63-fold higher in children than in adults (304.15 and 186.02, respectively). In 2020, the proportion of cefotaxime-resistant Klebsiella spp. was 26.20% that was strikingly high compared to 2019. Hospital particulate matter frequently (71.13% samples) harboured multidrug-resistant microorganisms. Conclusions . High prevalence and morbidity from respiratory infections in Kemerovo Region are combined with high prevalence and biodiversity of airborne microorganisms, in particular multidrug-resistant microbes contaminating the hospital particulate matter.

Background. Most healthcare-associated infections (HAI) develop due to a colonization of patients and healthcare workers by hospital strains of pathogens. The aim to study was to assess whether the dust within the health facilities can harbor microorganisms acting as a reservoir of HAIs.Materials and methods. Dust samples collected in the air ducts and ventilation grilles of health facilities underwent a detailed physicochemical analysis by means of scanning electron microscopy, dynamic light scattering, energy-dispersive X-ray spectroscopy, and high-temperature catalytic oxidation. Bacterial and viral diversity was investigated using an automated biochemical analyzer and polymerase chain reaction, respectively. Investigation of the microenvironment included detection of biofilms using a catalase indicator and quantification of viable microorganisms per 1 m3 air.Results. Dust from the hospital ventilation grilles and air ducts was contaminated with microorganisms in 71.13% of cases. Strikingly, multidrug-resistant and biofilm-forming strains have been found in 69.4% and 48.0% of samples, respectively. The total viable count before and after opening doors and windows was 276 and 462 colony-forming units/m3 respectively (p = 0.046). Biodiversity was represented by 21 genera of microorganisms which were consistently detected upon 6 months of follow-up. All samples contained a nanosized particulate matter. Chemical elements comprising dust were carbon (16.26–50.69%), oxygen (20.02–37.50%), nitrogen (1.59–25.03%), hydrogen (2.03–6.67%), sulfur (0.15–2.38%), calcium (0.19–7.49%), silicon (0.21–4.64%), chlorine (0.05–2.83%), sodium (0.07–1.86%), aluminum (0.36–1.78%), iron (0.08–1.61%), magnesium (0.11–1.40%), potassium (0.04–0.85%), and phosphorus (0.04–0.81%).Discussion. A wide range of multidrug-resistant strains of bacteria, detected in a hospital particulate matter with a diverse chemical composition, indicates the persistence of HAI-causing pathogens in the hospital environment.Conclusion. Dust from the ventilation grilles and adjacent air ducts should be considered as an additional reservoir of multidrug-resistant strains of bacteria in the healthcare settings.

Abstract The novel coronavirus SARS-CoV-2 has caused a global health threat. This review summarizes comprehensive research findings about the SARS-CoV-2 persistence in inanimate surfaces and opportunities for applying biocides to limit spread of COVID-19. SARS-CoV2 is highly stable at 4°C but sensitive to heat and extremely stable in a wide range of pH values at room temperature. Coronaviruses also well survive in suspension. Desiccation has a more severe effect. SARS-CoV-2 can survive in the air for hours and on surfaces for days. Hospitals are significant epicenters for the human-to-human transmission of the SARS-CoV-2 for healthcare workers. The most contaminated SARS-CoV-2 zones and objects in isolation wards, in intensive care unit specialized for novel coronavirus pneumonia, are under discussion. SARS-CoV2 is sensitive to standard disinfection methods. Studies revealed that 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite inactivated SARS-CoV2 in 1 minute exposition; while 0.05-0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate were less effective. Both ethanol and isopropanol were able to reduce viral titers after 30-seconds exposure. It was found for reusing personal protective equipment vaporized hydrogen peroxide treatment exhibits the best combination of rapid inactivation of SARS-CoV-2 and preservation of N95 respirator integrity under the experimental conditions. Overall, SARS-CoV-2 can be highly stable in a favourable environment, but it is also susceptible to standard disinfection methods. Environmental infection control of the air and especially for surfaces is considered as a mandatory step in addition to limiting person-to-person contact.

For decades, there have been a number of controversial issues regarding the airborne transmission of hospital pathogens. Here we decided to perform a critical review on this topic in light of the current COVID-19 pandemic. We summarise the existing knowledge on biological aerosols including techniques of their generation, propagation of bioaerosol particles in a hospital environment, particle size-, shape- and composition-dependent airborne transmission, and microorganisms inhabitating such particles. It is still unclear which of the particles transfer the pathogens, which of the pathogens are capable of adhering to the particulate matter, and whether such adhesion affects pathogen virulence. Intriguingly, viruses, bacteria and fungi seemingly have distinct patterns of interactions with the bioaerosols. Moreover, particle formation and their colonization may be separated in time, further complicating the puzzle. Apparently, pathogen interactions with the particulate matter are of paramount importance to better understand the role of bioaerosol particles as a potential pathogen reservoir in the hospital environment and to properly assess the influence of environmental pollutants, novel biomedical materials and treatment technologies on airborne transmission of hospital pathogens.

Aim. To study the microbial diversity and dust organic component in surgical healthcare settings and to assess the risk of dust-mediated transmission of healthcare-associated infections.Materials and Methods. Dust sampling (n = 41) was carried out using sterile gloves and containers from ventilation grilles and adjacent air ducts of the exhaust ventilation systems in various healthcare settings. Size and shape of dust particles were studied by means of scanning electron microscopy and dynamic light scattering. Elemental analysis (CHNSO) was conducted employing high temperature catalytic oxidation. Bacterial composition of the dust was investigated using a VITEK 2 Compact biochemical analyzer while viral diversity was screened by polymerase chain reaction.Results. Dust in healthcare units consisted of globular particles and/or microsized fibers. Regardless of the healthcare setting, globular particles prevailed in the dust structure. Dust nanoparticles was characterised by an average first size peak of 85.6 ± 12.6 nm and an average second peak of 307.1 ± 76.2 nm. Dust collected in non-surgical units contained a higher nitrogen content than surgical settings (p < 0.001). Proportions of hydrogen, carbon, and sulfur did not differ between non-surgical and surgical units. The dust collected from healthcare settings in different cities also varied in nitrogen content (p = 0.033). A wide microbial diversity was detected in dust samples and a high frequency (46.34%) of its contamination was found. In surgical departments, dust contamination was notable for multidrug-resistant bacteria (28.57%), while viruses prevailed in non-surgical departments (23.3%).Conclusions. Dust generated in surgical departments contains nanosized particulate matter, multidrug-resistant microorganisms, and a prominent organic component all defining it as a possible reservoir of multidrug-resistant microorganisms which may potentially cause healthcare-associated infections via airborne transmission.

Relevance. For decades, many aspects of aerosol transmission of hospital pathogens have been and remain the subject of scientific debate. Despite fairly detailed studies of the mechanism of microbial aerosols formation, distribution, the role of particulate matter in the formation of antibiotic resistance and multidrug-resistant hospital clones of microorganisms is still unclear. Aim. To investigate physicochemical properties and microbiological diversity of hospital particulate matter. Materials and Methods . Shape and size of particulates was assessed by means of scanning electron microscopy and dynamic light scattering while elemental analysis was performed using energy-dispersive X-ray spectroscopy and high-temperature catalytic oxidation. Microbial profiling was conducted using polymerase chain reaction and Vitek 2 biochemical analyzer. Results . Hospital particulate matter included globular and fibrillary particles consisting of carbon, oxygen, calcium, silicon, aluminium, and sulfur. Intriguingly, microfiber particles had higher oxygen and calcium content along with the lower level of carbon in mineral but not organic component. Differential localisation of silicon and calcium in elemental mapping suggested that hospital particulate matter was composed of aluminosilicate minerals and calcium compounds. Among the microorganisms, we found multidrug-resistant strains Raoultella ornithinolytica, Staphylococcus pseudintermedius, Pantoea spp., Pseudomonas aeruginosa, Enterococcus faecium and additionally Pasteurella canis in hospital particulate matter samples. Conclusions. Particulate matter in the hospital environment might be considered as a potential reservoir for the evolution of antibiotic resistance and multidrug-resistant strains.

Relevance. For decades, many aspects of aerosol transmission of hospital pathogens have been and remain the subject of scientific debate. Despite fairly detailed studies of the mechanism of microbial aerosols formation, distribution, the role of particulate matter in the formation of antibiotic resistance and multidrug-resistant hospital clones of microorganisms is still unclear. Aim. To investigate physicochemical properties and microbiological diversity of hospital particulate matter. Materials and Methods. Shape and size of particulates was assessed by means of scanning electron microscopy and dynamic light scattering while elemental analysis was performed using energy-dispersive X-ray spectroscopy and high-temperature catalytic oxidation. Microbial profiling was conducted using polymerase chain reaction and Vitek 2 biochemical analyzer. Results. Hospital particulate matter included globular and fibrillary particles consisting of carbon, oxygen, calcium, silicon, aluminium, and sulfur. Intriguingly, microfiber particles had higher oxygen and calcium content along with the lower level of carbon in mineral but not organic component. Differential localisation of silicon and calcium in elemental mapping suggested that hospital particulate matter was composed of aluminosilicate minerals and calcium compounds. Among the microorganisms, we found multidrug-resistant strains Raoultella ornithinolytica, Staphylococcus pseudintermedius, Pantoea spp., Pseudomonas aeruginosa, Enterococcus faecium and additionally Pasteurella canis in hospital particulate matter samples. Conclusions. Particulate matter in the hospital environment might be considered as a potential reservoir for the evolution of antibiotic resistance and multidrug-resistant strains.