Epidemiologia delle infezioni da amebe a vita libera

Le amebe a vita libera (spesso conosciute come Free-Living Amoebae, FLA) sono protozoi presenti in tutte le matrici ambientali a diffusione cosmopolita. L’etichetta di organismi “a vita libera” deriva dal fatto che il loro serbatoio è l’ambiente acquatico naturale, e quello realizzato dall’uomo è un habitat secondario favorevole. Sono protozoi unicellulari che possono vivere all’interno di un ospite in condizioni di parassitismo facoltativo o avere un’esistenza autonoma. Per tale proprietà sono anche definite amebe anfizoiche. In particolare, anche se in realtà è Acanthamoeba spp. il protozoo più frequentemente rilevabile nell’ambiente, amebe a vita libera sono state isolate da suolo, sedimenti, polveri, aria, acque naturali e reflue, dolci, marine, termali, e sono state anche rilevate in acque confezionate, potabilizzate e sottoposte a trattamenti di disinfezione (acque destinate al consumo umano e di piscina) e in biofilm. Numerose specie di amebe a vita libera sono state segnalate in torri di raffreddamento, impianti di climatizzazione, deumidificatori, unità di dialisi, riuniti dentistici, apparecchi per il trattamento domestico dell’acqua e su lenti a contatto. Individuate nell’uomo e in animali a sangue caldo e freddo, in soggetti malati sono state isolate da ferite, dalla cornea, dai polmoni e dal sistema nervoso centrale, anche se la loro presenza è stata dimostrata anche in individui sani. La loro distribuzione e diversità nell’ambiente sono fortemente influenzate da temperatura, umidità, pH, disponibilità di nutrienti e appare chiara l’esistenza di un loro andamento stagionale. In condizioni ambientali ostili le amebe producono cisti che excistano solo in condizioni favorevoli liberando trofozoiti. Sopravvivenza e moltiplicazione sono anche associate sia alla presenza di batteri, soprattutto Gram-negativi, sia alla concentrazione degli stessi batteri. Infatti, con rapporti di concentrazione ameba: batteri di 1:104, lo sviluppo dei protozoi è inibito. Per il basso numero di infezioni riscontrate, le amebe non hanno mai rappresentato un argomento sanitario di interesse prioritario, anche se la mancanza di farmaci efficaci e l’esito quasi sempre fatale delle malattie indotte da alcune specie, le hanno sempre rese oggetto di interesse e di studio. Negli ultimi decenni tuttavia, un’attenzione particolare è stata loro rivolta per il ruolo che rivestono come veicolo di trasmissione di microrganismi patogeni presenti nell’ambiente idrico. Infatti, circa un quarto degli isolati di origine ambientale, clinica o derivanti da lenti a contatto contengono microrganismi endosimbionti, definiti Amoeba-Resistant Microorganisms (ARM), microrganismi resistenti alle amebe, che sono in grado di mantenere la loro vitalità a livello intracellulare. Le amebe fungono così da riserva per altri microrganismi, proteggendoli da fattori ambientali ostili e fornendo condizioni favorevoli alla loro replicazione. Per questa circostanza, nel 2017, presso la III Sezione del Consiglio Superiore di Sanità, presieduta dalla Prof.ssa Anna Teresa Palamara, e coordinata dalla Dott.ssa Anna Gaspardone, è stato istituito un Gruppo di Lavoro il cui compito è stato quello sia di approfondire gli aspetti sanitari associati alle amebe a vita libera rilevabili nelle acque, sia di valutare la rilevanza del problema in un’ottica di salvaguardia della salute. A seguito delle attività del Gruppo di lavoro è stato quindi predisposto il documento condiviso e di seguito presentato che produce informazioni sulle caratteristiche tassonomiche ed ecologiche di questi organismi, sulle loro possibili implicazioni di carattere sanitario, sul loro adattamento nelle reti di distribuzione idrica e sulle dinamiche di interazione con gli altri microrganismi. Inoltre, il volume fornisce un indirizzo metodologico univoco e specifiche raccomandazioni per minimizzare il rischio associato alla presenza di amebe nell’ambiente idrico, nonché, in Appendice, metodi analitici colturali e molecolari per la ricerca di questi organismi nelle acque

Quality assessment of medical record as a tool for clinical risk management: a three year experience of a teaching hospital Policlinico Umberto I, Rome

Introduction: The medical record was defined by the Italian Ministry of Health in 1992 as "the information tool designed to record all relevant demographic and clinical information on a patient during a single hospitalization episode". Retrospective analysis of medical records is a tool for selecting direct and indirect indicators of critical issues (organizational, management and technical). The project’s aim being the promotion of an evaluation and self-evaluation process of medical records as a Clinical Risk Management tool to improve the quality of care within hospitals. Methods: The Authors have retrospectively analysed, using a validated grid, 1,184 medical records of patients admitted to the Teaching Hospital “Umberto I” in Rome during a three-year period (2013-2015). Statistical analysis was performed using SPSS for Windows © 19:00. All duly filled out criteria (92) were examined. “Strengths” and "Weaknesses" were identified through data analysis and Best and Bad Practice were identified based on established criteria. Conclusion: The data analysis showed marked improvements (statistically significant) in the quality of evaluated clinical documentation and indirectly upon behaviour. However, when examining some sub-criteria, critical issues emerge; these could be subject to future further corrective action

Search for top squarks in the four-body decay mode with single lepton final states in proton-proton collisions at s \sqrt{s} = 13 TeV

A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark (t∼1), is presented. The search targets the four-body decay of the t∼1, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino (χ∼01), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb−1 of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between m(t∼1) and m(χ∼01). The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for m(t∼1) − m(χ∼01) = 10 and 80 GeV, respectively

Search for Higgs Boson Decay to a Charm Quark-Antiquark Pair in Proton-Proton Collisions at √s = 13 TeV

A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H→c¯c, produced in association with a leptonically decaying V (W or Z) boson is presented. The search is performed with proton-proton collisions at √s=13  TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138  fb−1. Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z→c¯c in VZ events, leading to its first observation at a hadron collider with a significance of 5.7 standard deviations. The observed (expected) upper limit on σ(VH)B(H→c¯c) is 0.94 (0.50+0.22−0.15)pb at 95% confidence level (C.L.), corresponding to 14 (7.6+3.4−2.3) times the standard model prediction. For the Higgs-charm Yukawa coupling modifier, κc, the observed (expected) 95% C.L. interval is 1.1<|κc|<5.5 (|κc|<3.4), the most stringent constraint to date

Measurement of the cross section of top quark-antiquark pair production in association with a W boson in proton-proton collisions at s \sqrt{s} = 13 TeV

The production of a top quark-antiquark pair in association with a W boson $(t\bar{t}W)$ is measured in proton-proton collisions at a center-of-mass energy of 13 TeV. The analyzed data was recorded by the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 138 fb$^{−1}$. Events with two or three leptons (electrons and muons) and additional jets are selected. In events with two leptons, a multiclass neural network is used to distinguish between the signal and background processes. Events with three leptons are categorized based on the number of jets and of jets originating from b quark hadronization, and the lepton charges. The inclusive $(t\bar{t}W)$ production cross section in the full phase space is measured to be 868 ± 40(stat) ± 51(syst) fb. The $(t\bar{t}W)+$ and $(t\bar{t}W)−$ cross sections are also measured as 553 ± 30(stat) ± 30(syst) and 343 ± 26(stat) ± 25(syst) fb, respectively, and the corresponding ratio of the two cross sections is found to be 1.61±0.15(stat)$^{+0.07}_{−0.05}$(syst). The measured cross sections are larger than but consistent with the standard model predictions within two standard deviations, and represent the most precise measurement of these cross sections to date

Measurement of inclusive and differential cross sections for single top quark production in association with a W boson in proton-proton collisions at s \sqrt{s} = 13 TeV

Measurements of the inclusive and normalised differential cross sections are presented for the production of single top quarks in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data used were recorded with the CMS detector at the LHC during 2016-2018, and correspond to an integrated luminosity of 138 fb$^{−1}$. Events containing one electron and one muon in the final state are analysed. For the inclusive measurement, a multivariate discriminant, exploiting the kinematic properties of the events is used to separate the signal from the dominant $t\bar{t}$ background. A cross section of 79.2 ± 0.9 (stat) $^{+7.7}_{−8.0}$ (syst) ± 1.2 (lumi) pb is obtained, consistent with the predictions of the standard model. For the differential measurements, a fiducial region is defined according to the detector acceptance, and the requirement of exactly one jet coming from the fragmentation of a bottom quark. The resulting distributions are unfolded to particle level and agree with the predictions at next-to-leading order in perturbative quantum chromodynamics

Search for long-lived particles decaying to a pair of muons in proton-proton collisions at s \sqrt{s} = 13 TeV

An inclusive search for long-lived exotic particles decaying to a pair of muons is presented. The search uses data collected by the CMS experiment at the CERN LHC in proton-proton collisions at s√ = 13 TeV in 2016 and 2018 and corresponding to an integrated luminosity of 97.6 fb−1. The experimental signature is a pair of oppositely charged muons originating from a common secondary vertex spatially separated from the pp interaction point by distances ranging from several hundred μm to several meters. The results are interpreted in the frameworks of the hidden Abelian Higgs model, in which the Higgs boson decays to a pair of long-lived dark photons ZD, and of a simplified model, in which long-lived particles are produced in decays of an exotic heavy neutral scalar boson. For the hidden Abelian Higgs model with m(ZD) greater than 20 GeV and less than half the mass of the Higgs boson, they provide the best limits to date on the branching fraction of the Higgs boson to dark photons for cτ(ZD) (varying with m(ZD)) between 0.03 and ≈0.5 mm, and above ≈0.5 m. Our results also yield the best constraints on long-lived particles with masses larger than 10 GeV produced in decays of an exotic scalar boson heavier than the Higgs boson and decaying to a pair of muons

Measurement of the Higgs boson inclusive and differential fiducial production cross sections in the diphoton decay channel with pp collisions at s \sqrt{s} = 13 TeV

The measurements of the inclusive and differential fiducial cross sections of the Higgs boson decaying to a pair of photons are presented. The analysis is performed using proton-proton collisions data recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 137 fb$^{−1}$. The inclusive fiducial cross section is measured to be $σ_{fid}$=73.4$^{+5.4}_{−5.3}$(stat)$^{+2.4}_{−2.2}$(syst) fb, in agreement with the standard model expectation of 75.4 ± 4.1 fb. The measurements are also performed in fiducial regions targeting different production modes and as function of several observables describing the diphoton system, the number of additional jets present in the event, and other kinematic observables. Two double differential measurements are performed. No significant deviations from the standard model expectations are observed