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Development of sustainable sanitation systems for infection control via stable modulation of the environmental microbiome
No full textIntroduzione e scopo della ricerca
Gli ambienti costruiti confinati (come gli ospedali), hanno microbiomi dominati da microbi umani che spesso sviluppano resistenza (AMR), a causa della pressione selettiva esercitata da disinfettanti e antimicrobici. Ciò provoca infezioni ospedaliere (ICA) di difficile trattamento. I disinfettanti mostrano inoltre un’efficacia limitata nel tempo e un elevato impatto ambientale. Per superare questi limiti, sono recentemente state sviluppate procedure di sanificazione alternative. L'approccio da noi studiato (Probiotic Cleaning Hygiene System, PCHS), prevede un detergente ecologico contenente spore di Bacillus probiotici, e ha dimostrato di ridurre i patogeni ospedalieri dell’80%, l’AMR del 99,9% e le ICA del 52%, oltre a inattivare i virus inviluppati. Tuttavia, la sua azione non è immediata ma graduale e aspecifica. Inoltre, mancano dati sui suoi effetti negli ambienti non sanitari e sulla sua sicurezza a lungo termine. Per investigare questi aspetti, il mio progetto di dottorato ha cercato di: 1) migliorare l’azione di decontaminazione rapida e specifica del PCHS; 2) valutare l'applicabilità del PCHS negli ambienti dei trasporti di massa; 3) valutare la sicurezza dei probiotici del PCHS dopo il contatto con agenti patogeni ospedalieri.
Metodi di indagine
Per i tre studi:
1) Studio pre-post condotto in due ospedali italiani per 14 settimane e suddiviso in tre fasi in base al tipo di igienizzazione applicata: 1) disinfezione chimica; 2) PCHS; 3) PCHS con fagi antistafilococco (PCHSφ). La contaminazione microbica indoor è stata monitorata utilizzando analisi colturali (piastre RODAC) e molecolari (qPCR).
2) Studio caso-controllo condotto nella metropolitana di Milano per 12 settimane, durante le quali il PCHS è stato confrontato con la disinfezione mediante cloro, valutando la contaminazione superficiale e aerogena mediante RODAC, qPCR e NGS.
3) Studio che ha analizzato 200 isolati di Bacillus provenienti da ospedali trattati con PCHS, mediante Whole Genome Sequencing (WGS), per valutare l’intero resistoma e viruloma degli isolati. Condotto in collaborazione con l'Università di Oxford.
Risultati/conclusioni
Per i tre studi:
1) L’aggiunta di fagi al PCHS (PCHSφ) ha aumentato significativamente la riduzione dei batteri bersaglio rispetto al solo PCHS (76% vs. 50%), senza modificare i livelli di Bacillus o dei microbi non target. In particolare, il PCHSφ non era compatibile con la disinfezione a base di cloro, che ha interrotto i probiotici e i fagi. Ciò suggerisce che il PCHSφ sia uno strumento efficace per la rapida riduzione del patogeno MDR negli ambienti sanitari.
2) L’applicazione di PCHS ha significativamente diminuito i patogeni rispetto ai disinfettanti chimici negli ambienti dei treni metropolitani, eliminandoli completamente in 12 settimane (-100%), e riducendo anche la loro AMR fino a 2 log. Inoltre, il PCHS ha ridotto la contaminazione da SARS-CoV-2 del 60%, dimostrando la sua efficacia non solo contro batteri e funghi, ma anche contro virus. A differenza di quanto osservato in ambiente ospedaliero, il microbioma complessivo della metropolitana è rimasto stabile, eccetto per la riduzione dei microbi patogeni.
3) I risultati dell'analisi metagenomica hanno permesso di confermare che B. subtilis e B. velezensis sono le specie dominanti sia nel detergente originale PCHS sia negli ospedali trattati, definendo con precisione la composizione delle specie del prodotto. L’analisi filogenetica e il confronto tra le specie originarie di PCHS-Bacillus e i corrispondenti isolati ospedalieri hanno confermato la loro stabilità genetica, dimostrando l’assenza di geni acquisiti di resistenza o virulenza e supportando la loro sicurezza a lungo termine.
Nel complesso, i dati suggeriscono che il PCHS possa rappresentare un’alternativa promettente e sostenibile per il controllo delle infezioni in una prospettiva “One Health”.Background and aim of the research
Confined built environments (BEs) have microbiomes dominated by human-derived microbes, increasing the indoor infection risk. Hospitals exemplify this dynamic, as their microbiomes are a source of human pathogens often resistant to antimicrobials (AMR), due to the continuous selective pressure exerted by disinfectants and antimicrobial drugs. Thus, hospital pathogens are associated with difficult-to-treat healthcare-associated infections (HAIs), posing a global concern. Besides AMR selection, chemical disinfectants also generally show short-term effectiveness and high environmental impact. To overcome these limitations, alternative strategies were recently considered for bioburden control. The approach we investigated (Probiotic Cleaning Hygiene System, PCHS), involves an eco-friendly detergent containing spores of Bacillus probiotics. PCHS was shown to reduce hospital pathogens by 80%, AMR by 99.9%, and HAIs by 52%, and to be also effective against enveloped viruses, like SARS-CoV-2. However, PCHS action is gradual and more addressed to prevention than immediate decontamination. Additionally, its effects in non-hospital crowded spaces and its long-term safety of use following prolonged contact with pathogens remained unexplored.
To address these gaps, my PhD research aimed to: (1) obtain targeted and rapid decontamination, by adding bacteriophages to PCHS; (2) assess PCHS applicability in high-traffic mas transportation areas; (3) evaluate the stability and safety of PCHS-Bacillus strains after contact with hospital pathogens.
Investigation methods
1) This was a pre-post study conducted in two Italian hospitals over 14 weeks subdivided in three phases based on the type of applied sanitation: 1) chemical disinfection; 2) PCHS; 3) PCHS with anti-staphylococcal phages (PCHSφ). Indoor microbial contamination was monitored using culture-based (RODAC plates) and molecular (qPCR) analyses.
2) This was a case-control study performed in Milan subways over 12 weeks, during which PCHS was compared with chlorine disinfection, by evaluating surface and air contamination by RODAC, qPCR, and NGS.
3) This study was conducted in collaboration with the University of Oxford and analysed 200 Bacillus isolates from PCHS-treated hospitals, by whole genome sequencing (WGS), to assess their whole resistome and virulome.
Results/Conclusions
1) The addition of phages to PCHS (PCHSφ) significantly improved the reduction of target bacteria compared to PCHS alone (76% vs. 50%), without affecting Bacillus levels or non-target microbes. Notably, PCHSφ was not compatible with chlorine disinfection, which disrupted probiotics and phages. This suggests PCHSφ as an effective tool for rapid MDR pathogen reduction in healthcare environments.
2) In the subway study, PCHS significantly abated pathogens compared to chemical disinfectants, totally eliminating them in 12 weeks (-100%), also reducing their AMR by up to 2 logs. Additionally, PCHS lowered SARS-CoV-2 contamination by 60%, demonstrating its efficacy against bacterial, fungal, and viral threats. Notably, unlike hospital settings, subway microbiome remained largely stable, aside from reductions in pathogenic microbes.
3) Metagenomic analysis results allowed to confirm B. subtilis and B. velezensis as the dominant species in both the original PCHS detergent and treated hospitals, defining precisely the product species composition. Phylogenetic analysis and comparison between PCHS-Bacillus original species and hospital isolates confirmed their genetic stability, showing the absence of acquired resistance or virulence genes and supporting their long-term safety.
Overall, the research highlights PCHS as a promising, sustainable alternative for infection control within a “One Health” framework
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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