Assessment of the impact of atmospheric pollutants on bacteria viability by an atmospheric simulation chamber

The aim of the PhD project was to make possible systematic studies of the bio-aerosols behavior in different atmospheric conditions, with the final goal to assess the link between pollution levels and bio-aerosol dispersion and impact. The research has been carried out at ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research), a 2.3 m3 stainless steel atmospheric simulation chamber. Experiments conducted inside confined artificial environments, such as the Atmospheric Simulations Chambers (ASCs), where atmospheric conditions and composition are controlled, can provide valuable information on bio-aerosols viability and their interaction with other atmospheric constituents. The first phase of the PhD project was dedicated to the characterization of the chamber, the related instrumentation and the design and development of the experimental set-up. An experimental protocol for chamber studies on bio-aerosols was developed and thoroughly tested with two bacteria model strains (B. subtilis and E. coli). An intense effort has been dedicated to fully characterize the performance of three different nebulization systems specifically designed for bioaerosol applications to assess their application in experiments at ASCs. A WIBS-NEO provides the size-segregated, real-time monitoring of the total bio-aerosol concentration inside the chamber. With a clean atmosphere maintained inside ChAMBRe, the ratio between injected and extracted viable bacteria turned out to be reproducible at 11\u2009% and 13% level with E. coli and B. subtilis respectively. After assessing this way the reproducibility and sensitivity of the whole experimental procedure, the first tests to explore the possible correlation between bacteria viability and air quality were carried out. The two bacteria models, B. subtilis and E. coli, were subjected to high concentrations of nitrogen oxides and soot particles, two of the most common pollutants emitted by anthropogenic sources

ChAMBRe: studi su bio-aerosol in camera di simulazione atmosferica

Nella Sezione di Genova dell\u2019Istituto Nazionale di Fisica Nucleare \ue8 stata recentemente installata, in collaborazione con il Laboratorio di Fisica Ambientale del Dipartimento di Fisica dell\u2019Universit\ue0 di Genova, ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research), la prima Camera di simulazione atmosferica specificatamente concepita per studiare la componente biologica dell\u2019aerosol atmosferico. Presso la camera di simulazione atmosferica CESAM (Cr\ue9teil, Francia) sono sati effettuati alcuni esperimenti pilota recentemente pubblicati [1], che sono stati lo spunto per la costruzione di una struttura dedicata allo studio del comportamento dei pi\uf9 comuni agenti patogeni presenti in atmosfera sotto forma di bioaerosol e in particolare dei meccanismi che controllano le interazioni tra questi e le altre componenti dell\u2019aerosol e pi\uf9 in generale dell\u2019atmosfera. L\u2019attivit\ue0 di ricerca a ChAMBRe si concentrer\ue0 sull\u2019indagine del comportamento del bio-aerosol in differenti condizioni atmosferiche e in presenza di tipici inquinanti antropici (come il monossido di carbonio, gli ossidi di azoto, etc.) che possono influenzare la vitalit\ue0, la morfologia e la dispersione dei batteri in atmosfera. Come primo passo \ue8 necessario innanzitutto mettere a punto un protocollo che garantisca la riproducibilit\ue0 degli esperimenti in una struttura complessa come ChAMBRe. Ci si \ue8 quindi concentrati su aspetti cruciali quali: crescita in vitro e successiva iniezione in camera di una data concentrazione di batteri, seguita da una fase di estrazione, campionamento e misura della vita media all\u2019interno della camera. Gli esperimenti sono volti anche ad identificare eventuali condizioni di stress ambientali e meccaniche per i microrganismi e la loro risposta come singoli individui e come colonie. Sono stati eseguiti esperimenti su due tipologie di ceppi batterici frequentemente utilizzati come organismi modello: il Bacillus subtilis e l\u2019Escherichia coli, appartenenti rispettivamente al gruppo dei Gram-positivi e dei Gram-negativi. I risultati e il protocollo sperimentale messo a punto verranno presentati a PM2018

The impact of chest CT body composition parameters on clinical outcomes in COVID-19 patients

We assessed the impact of chest CT body composition parameters on outcomes and disease severity at hospital presentation of COVID-19 patients, focusing also on the possible mediation of body composition in the relationship between age and death in these patients. Chest CT scans performed at hospital presentation by consecutive COVID-19 patients (02/27/2020-03/13/2020) were retrospectively reviewed to obtain pectoralis muscle density and total, visceral, and intermuscular adipose tissue areas (TAT, VAT, IMAT) at the level of T7-T8 vertebrae. Primary outcomes were: hospitalization, mechanical ventilation (MV) and/or death, death alone. Secondary outcomes were: C-reactive protein (CRP), oxygen saturation (SO2), CT disease extension at hospital presentation. The mediation of body composition in the effect of age on death was explored. Of the 318 patients included in the study (median age 65.7 years, females 37.7%), 205 (64.5%) were hospitalized, 68 (21.4%) needed MV, and 58 (18.2%) died. Increased muscle density was a protective factor while increased TAT, VAT, and IMAT were risk factors for hospitalization and MV/death. All these parameters except TAT had borderline effects on death alone. All parameters were associated with SO2 and extension of lung parenchymal involvement at CT; VAT was associated with CRP. Approximately 3% of the effect of age on death was mediated by decreased muscle density. In conclusion, low muscle quality and ectopic fat accumulation were associated with COVID-19 outcomes, VAT was associated with baseline inflammation. Low muscle quality partly mediated the effect of age on mortality.We assessed the impact of chest CT body composition parameters on outcomes and disease severity at hospital presentation of COVID-19 patients, focusing also on the possible mediation of body composition in the relationship between age and death in these patients. Chest CT scans performed at hospital presentation by consecutive COVID-19 patients (02/ 27/2020-03/13/2020) were retrospectively reviewed to obtain pectoralis muscle density and total, visceral, and intermuscular adipose tissue areas (TAT, VAT, IMAT) at the level of T7-T8 vertebrae. Primary outcomes were: hospitalization, mechanical ventilation (MV) and/or death, death alone. Secondary outcomes were: C-reactive protein (CRP), oxygen saturation (SO2), CT disease extension at hospital presentation. The mediation of body composition in the effect of age on death was explored. Of the 318 patients included in the study (median age 65.7 years, females 37.7%), 205 (64.5%) were hospitalized, 68 (21.4%) needed MV, and 58 (18.2%) died. Increased muscle density was a protective factor while increased TAT, VAT, and IMAT were risk factors for hospitalization and MV/death. All these parameters except TAT had borderline effects on death alone. All parameters were associated with SO2 and extension of lung parenchymal involvement at CT; VAT was associated with CRP. Approximately 3% of the effect of age on death was mediated by decreased muscle density. In conclusion, low muscle quality and ectopic fat accumulation were associated with COVID-19 outcomes, VAT was associated with baseline inflammation. Low muscle quality partly mediated the effect of age on mortality

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

An atmospheric simulation chamber to investigate dust-borne microbiota composition and viability

Dust storm activity from the largest deserts on the earth, in particular from the North Africa regions, is the principal source of dust in the atmosphere, capable of dust dispersion and transport over very long distances. Dust clouds may contain high concentrations of microbiota, e.g. fungal spores, plant pollen, algae, bacteria. Bioaerosols associated with dust events can spread pathogens over long distances and can impact ecosystems equilibria, human health and yield of agricultural products. For many microorganisms long-range and high-altitude transport in the free atmosphere can be very stressful due to strong ultraviolet radiation, low humidity (inducing desiccation), too low or too high temperatures, and complex atmospheric chemistry (e.g. presence of reactive radicals). Only specially resistant organisms are able to survive, so microbiota population composition changes during the long airborne transport to the final site of deposition. In this work we summarize the principal characteristics of ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research), an atmospheric chamber facility recently designed and implemented at the Environmental Physics Laboratory of the Physics Department of the University of Genoa, in cooperation with INFN (National Institute of Nuclear Physics) to investigate bioaerosol evolution and transformation under different atmospheric conditions. Here we present the experimental setup and some protocols established to analyze Gram-positive and Gram-negative model bacteria, Bacillus Subtilis and Escherichia Coli respectively, focusing in particular on the use of Field Emission Scanning Electron Microscopy techniques

AN ATMOSPHERIC SIMULATION CHAMBER TO INVESTIGATE DUST-BORNE MICROBIOTA COMPOSITION AND VIABILITY

Dust stormsfrom the desert areas, in particular from the Sahara, are the principal source of dust in the atmosphere, capable of dust dispersion and transport over very long distances. Dust clouds may contain high concentrations of microbiota, e.g. fungal spores, plant pollen, algae, bacteria. Bioaerosols associated with dust events can spread pathogens over long distances and can impact ecosystem equilibria, human health and yield of agricultural products. For many microorganisms long-range and high-altitude transport in the free atmosphere can be very stressful due to strong ultraviolet radiation, low humidity (inducing desiccation), too low or too high temperatures, and complex atmospheric chemistry (e.g. presence of radicals or other reactive species). Only specially resistant organisms are able to survive, so microbiota population composition can change during the long airborne transport to the final site of deposition. In this work we summarize the first results on the use of ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research), an atmospheric simulation chamber designed and implemented at the Physics Department of the University of Genoa, in cooperation with INFN (National Institute of Nuclear Physics) to investigate bioaerosol evolution and transformation under different atmospheric conditions. ChAMBRe is the first Italian facility of this type, specifically conceived to study the mechanisms of interaction between bioaerosols and other particles or chemical compounds usually present in the atmosphere. We describe the experimental setup and the protocols to inject, monitor, analyze and extract Gram-positive and Gram-negative model bacteria, bacillus subtilis and escherichia coli respectively. In this initial stage we focused primarily on crucial operational aspects such as growth and injection of suitable amounts of bacteria, measurement of the average lifetime inside the chamber, extraction and sampling, identification of the steps involving the major stress for the microorganisms under investigation

ChAMBRe: a new atmospheric simulation chamber for aerosol modelling and bio-aerosol research

International audienceAtmospheric simulation chambers are exploratory platforms used to study various atmospheric processes at realistic but controlled conditions. We describe here a new facility specifically designed for the research on atmospheric bio-aerosol as well as the protocols to produce, inject, expose and collect bio-aerosols. ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research) is installed at the Physics Department of the University of Genoa, Italy, and itis a node of the EUROCHAMP-2020 consortium. The cham-ber is made of stainless steel with a total volume of about2.2 m3. The lifetime of aerosol particle with dimension froma few hundreds of nanometres to a few microns varies fromabout 2 to 10 h. Characteristic parts of the facility are theequipment and the procedures to grow, inject, and extractbacterial strains in the chamber volume while preservingtheir viability. Bacteria are part of the atmospheric ecosys-tem and have impact on several levels as: health related is-sues, cloud formation, and geochemistry. ChAMBRe willhost experiments to study the bacterial viability vs. the airquality level, i.e. the atmospheric concentration of gaseousand aerosol pollutants. In this article, we report the results ofthe characterization tests as well as of the first experimentsperformed on two bacterial strains belonging to the Gram-positive and Gram-negative groups. A reproducibility at the 10 % level has been obtained in repeated injections and col-lection runs with a clean atmosphere, assessing this way thechamber sensitivity for systematic studies on bacterial via-bility vs. environmental conditions