Lacustrine Arcellinina (Testate Amoebae) as Bioindicators of Arsenic Contamination

Arcellininids (testate amoebae) were examined from 61 surface sediment samples collected from 59 lakes in the vicinity of former gold mines, notably Giant Mine, near Yellowknife, Northwest Territories, Canada to determine their utility as bioindicators of arsenic (As), which occurs both as a byproduct of gold extraction at mines in the area and ore-bearing outcrops. Cluster analysis (Q-R-mode) and detrended correspondence analysis (DCA) reveal five arcellininid assemblages, three of which are related to varying As concentrations in the sediment samples. Redundancy analysis (RDA) showed that 14 statistically significant environmental parameters explained 57 % of the variation in faunal distribution, while partial RDA indicated that As had the greatest influence on assemblage variance (10.7 %; p < 0.10). Stress-indicating species (primarily centropyxids) characterized the faunas of samples with high As concentrations (median = 121.7 ppm, max > 10000 ppm, min = 16.1 ppm, n = 32), while difflugiid dominated assemblages were prevalent in substrates with relatively low As concentrations (median = 30.2 ppm, max = 905.2 ppm, min = 6.3 ppm, n = 20). Most of the lakes with very high As levels are located downwind (N and W) of the former Giant Mine roaster stack where refractory ore was roasted and substantial quantities of As were released (as As2O3) to the atmosphere in the first decade of mining. This spatial pattern suggests that a significant proportion of the observed As, in at least these lakes, are industrially derived. The results of this study highlight the sensitivity of Arcellinina to As and confirm that the group has considerable potential for assessing the impact of As contamination on lakes.

Effetto di composti d'aroma sulla risposta fisiologica di Listeria monocytgenes

La citofluorimetria è una tecnica applicata per misurare le caratteristiche fisiche, morfologiche e fisiologiche di cellule microbiche ed ha il pregio di generare un dato per ogni singola particella (cellula) analizzata. Poiché è noto che l’assenza di sviluppo in piastra non implica necessariamente l’assenza di forme microbiche vitali, questa tecnica ha un grande potenziale nello studio dei trattamenti termici che mirano alla stabilizzazione ed alla sicurezza igienico-sanitaria dei prodotti alimentari. Infatti, nel contesto industriale la tendenza è quella di ridurre l’entità di questi trattamenti (tempi/temperature). Ciò può avvenire anche grazie all’utilizzo di composti d’aroma, la cui attività antimicrobica è ben documentata, poiché il trattamento termico, incrementando la tensione di vapore di queste sostanze, ne potenzia l’attività antimicrobica. Questa tesi è incentrata su due aspetti: da una parte, l’effetto dell’esposizione di L. monocytogenes a diverse concentrazioni di timolo e carvacrolo (terpenoidi prevalenti in oli essenziali di Labiatae tra cui timo e origano), dall’altra la valutazione degli effetti di trattamenti termici subletali (45, 50, 55°C), anche in presenza di composti d’aroma, sulla disattivazione e sul successivo recupero di L. monocytogenes. I risultati hanno confermato la forte sinergia tra trattamento termico e presenza di sostanze terpeniche. È stato inoltre dimostrato che la presenza di tali composti incide drasticamente sulle potenzialità di recupero degli eventuali sopravvissuti dopo il trattamento termico. I risultati a volte discordanti tra l’analisi citofluorimetrica (focalizzata sull’integrità della membrana) e i conteggi in piastra hanno evidenziato come i due approcci debbano essere utilizzanti in modo complementare. L’utilizzo di altri coloranti legati ad altre funzioni biologiche e metaboliche permetterà l’ottenimento di informazioni aggiuntive circa la risposta fisiologica di questo microrganismo.

Effetto di olio essenziale di Satureja Montana ed estratto di Cotinus coggygria sulle curve di morte termica di Listeria monocytogenes e Saccharomyces cerevisiae

Negli ultimi anni, è aumentato notevolmente l'interesse per piante e prodotti vegetali, e composti da essi derivati od estratti, in alternativa ai conservanti chimici per prevenire o ritardare lo sviluppo microbico negli alimenti. Questo deriva dalla percezione negativa, ormai diffusa a livello pubblico, nei confronti di sostanze di sintesi che sono ampiamente utilizzate come conservanti nell’industria alimentare. Sono stati effettuati diversi studi sull’attività antimicrobica di questi composti negli alimenti, anche se il loro utilizzo a livello industriale è limitato. Ciò dipende dalla difficile standardizzazione di queste sostanze, dovuta alla variabilità della matrice alimentare che ne può alterarne l’attività antimicrobica. In questa sperimentazione si sono utilizzati l’olio essenziale di Sateureja montana e l’estratto di Cotinus coggygria e sono state fatte delle prove preliminari, determinandone le componenti volatili tramite gas-cromatografia abbinata a microestrazione in fase solida. Sono stati selezionati un ceppo di Listeria monocytogenes (Scott A) e uno di Saccharomyces cerevisiae (SPA), e sono stati utilizzati per realizzare curve di morte termica in sistema modello e in sistema reale. Dai risultati ottenuti si può affermare che Satureja montana e Cotinus coggygria possono essere presi in considerazione come antimicrobici naturali da impiegare per la stabilizzazione di alimenti, nonché per ridurre l’entità dei trattamenti termici atti a salvaguardare le proprietà nutrizionali ed organolettiche di alimenti, come ad esempio succhi di frutta, garantendone la sicurezza e qualità microbiologica.

Studio propedeutico del potenziale di crescita di Listeria monocytogenes durante la shelf life di confezioni monoporzione di battuta di vitello

Scopo della tesi è la valutazione del potenziale di crescita (δ) di Listeria monocytogenes espressa come differenza tra il carico cellulare (log10 ufc/g) alla fine e all’inizio della prova, in monoporzioni di battuta di vitello (tartare) confezionate sottovuoto e conservate a temperatura di refrigerazione. Si tratta di un alimento ready to eat – RTE – prodotto dalla Ditta INALCA Spa e destinato ad una catena di ristorazione. I challenge test hanno lo scopo di fornire informazioni sul comportamento in determinate condizioni di conservazione, di L. monocytogenes inoculata artificialmente in un alimento. L. monocytogenes è un microrganismo patogeno ubiquitario nell’ambiente e resistente a diverse condizioni ambientali. E’ stato dimostrato che il batterio è responsabile della contaminazione post-processo degli alimenti, in quanto è stato isolato da impianti di trasformazione, macchine per l’imballaggio, nastri trasportatori, guanti, congelatori e guarnizioni. Sono state oggetto di studio: - i) 3 u.c. inoculate con soluzione fisiologica sterile su cui sono stati valutati Aw, pH, carica aerobia mesofila, batteri lattici, Pseudomonas, Enterobacteriaceae, muffe e lieviti; - ii) 1 u.c. non soggetta ad alcun inoculo per la ricerca qualitativa/quantitativa di L. monocytogenes; - iii) 9 u.c. contaminate con una miscela di 5 ceppi di L. monocytogenes (circa 100 ufc/g). Le confezioni inoculate sono state conservate per 21 giorni (pari alla shelf-life commerciale), di cui i primi 7 alla temperatura di +3°C, ed i successivi 14 giorni a +5°C. Il valore δ è risultato pari a 0.57: essendo superiore, seppure di poco, al valore soglia 0.5, le tartare in esame sono classificate come alimenti pronti che costituiscono terreno favorevole alla crescita di L. monocytogenes (categoria 1.2); in base al regolamento (CE) 2073/2005, il microrganismo deve essere assente in 25 g alla produzione e < 100 ufc/g durante la shelf–life (nota 5 e 7).

Two years survival rate of Class II ART restorations in primary molars using two ways to avoid saliva contamination

AIM To compare the survival rates of Class II Atraumatic Restorative Treatment (ART) restorations placed in primary molars using cotton rolls or rubber dam as isolation methods. METHODS A total of 232 children, 6-7 years old, both genders, were selected having one primary molar with proximal dentine lesion. The children were randomly assigned into two groups: control group with Class II ART restoration made using cotton rolls and experimental group using rubber dam. The restorations were evaluated by eight calibrated evaluators (Kappa > 0.8) after 6, 12, 18 and 24 months. RESULTS A total of 48 (20.7%) children were considered dropout, after 24 months. The cumulative survival rate after 6, 12, 18 and 24 months was 61.4%, 39.0%, 29.1% and 18.0%, respectively for the control group, and 64.1%, 55.1%, 40.1% and 32.1%, respectively for the rubber dam group. The log rank test for censored data showed no statistical significant difference between the groups (P = 0.07). The univariate Cox Regression showed no statistical significant difference after adjusting for independent variables (P > 0.05). CONCLUSION Both groups had similar survival rates, and after 2 years, the use of rubber dam does not increase the success of Class II ART restorations significantly.

Fungal contamination of sandpits from recreational parks and schools: a potential risk for human health

Sandpits used by children are frequently visited by wild life which constitutes a source of fungal pathogens and allergenic fungi. This study aimed to take an unannounced snapshot of the urban levels of fungal contaminants in sands, using for this purpose two public recreational parks, three elementary schools and two kindergartens. All samples were from Lisbon and neighboring municipalities and were tested for fungi of clinical interest. Potentially pathogenic fungi were isolated from all samples besides one. Fusarium dimerum (32.4%) was found to be the dominant species in one park and Chrysonilia spp. in the other (46.6%). Fourteen different species and genera were detected and no dermatophytes were found. Of a total of 14 species and genera, the fungi most isolated from the samples of the elementary schools were Penicillium spp. (74%), Cladophialophora spp. (38%) and Cladosporium spp. (90%). Five dominant species and genera were isolated from the kindergartens. Penicillium spp. was the only genus isolated in one, though with remarkably high counts (32500 colony forming units per gram). In the other kindergarten Penicillium spp. were also the most abundant species, occupying 69% of all the fungi found. All of the samples exceeded the Maximum Recommended Value (MRV) for beach sand defined by Brandão et al. 2011, which are currently the only quantitative guidelines available for the same matrix. The fungi found confirm the potential risk of exposure of children to keratinophilic fungi and demonstrates that regular cleaning or replacing of sand needs to be implemented in order to minimize contamination.

Hospital surfaces contamination with antineoplastic drugs: influence of cleaning procedures

Introduction: The raising frequency of cancer diseases is leading to a widespread application of antineoplastic drugs, thus increasing the probability of workplace surfaces contamination. Most of these drugs are classified by the International Agency for Research on Cancer as known or suspected human carcinogens. Skin absorption is the main route for antineoplastic drugs exposure in occupational settings, therefore cleaning protocols have paramount influence in surfaces contamination and, consequently, in exposure. The aim of this study was to assess surfaces contamination in a Portuguese chemotherapy unit before and during drug administration, in both preparation and administration facilities. Methods: Samples were collected by wipe-sampling from potentially contaminated surfaces selected by previous protocol observation. Samples were analyzed by HPLCDAD. Cyclophosphamide (CP), 5-fluorouracil (5FU), and paclitaxel (PTX) were used as surrogate markers for surfaces contamination for all cytotoxic drugs. Results: From the 34 samples collected before any preparation and administration activities, 41.2% were contaminated with 5-FU (4.0-84.7 ng/cm2) and 23.5% of the samples were contaminated with CP (19.8-139.6 μg/cm2). Only 2 samples presented contamination by PTX (5.9%) with a maximum value of 3.7 ng/cm2. Of the 37 samples collected during preparation and administration of antineoplastic drugs, 48.7% were contaminated with 5-FU (1.9-88.7 ng/cm2) and 24.3% with CP (12.0-93.9 μg/cm2). None of the samples showed contamination with PTX. Discussion: Data showed differences in contamination levels before and after the handling of antineoplastic drugs in preparation and in administration settings. These results point out the importance of cleaning procedures. This is well in accordance to previous studies that showed how the type of cleaning procedures and products used can be determinant for surfaces decontamination.

Fungal contamination in coffee samples: a public health concern

Introduction - Fungi are natural coffee contaminants and under certain environmental conditions have the potential to produce toxins. Many studies revealed that the important toxigenic fungal genera (Aspergillus and Penicillium) are natural coffee contaminants, and are present from the field to storage. Aspergilli from the Circumdati and Nigri sections are known to produce high levels of ochratoxin A, a mycotoxin known as nephrotoxic for animals and humans. This work aimed to evaluate fungal distribution and also the prevalence of Aspergillus sections Fumigati, Flavi, Nigri and Circumdati from Coffea arabica (Arabica coffee) and Coffea canephora (Robusta coffee) green samples.

Bacterial contamination in hotel rooms during the cleaning activity

Introduction - Some studies point to human activities as one of the responsible for most bacterial concentration. However, there is no information regarding bacteria contamination in hotel room during the cleaning activity. Aim of the study - This study aims to assess and characterize the occupational exposure of bacterial contamination in hotel rooms, more precisely in a room with carpet floor and another room without carpet, during the cheaning activity.

Etude pilote des apports en contaminants par la Seine : niveaux de contamination, variations saisonnières et flux d'éléments traces a poses en 1990 et 1991

Le présent rapport constitue une première présentation des résultats de l'Etude pilote des apports en contaminants par la Seine. Il est consacré aux métaux et à l'arsenic et traite de leurs niveaux de concentration, de leurs variations saisonnières et des flux à l'estuaire. Il comporte des fiches-annexes qui contiennent les méthodes de prélèvement, de filtration et de dosage ainsi que des résumés des résultats. A partir des conclusions, des recommandations sont faites quant aux méthodes à privilégier pour tirer les meilleurs enseignements du suivi des contaminants métalliques et de l'arsenic à la limite amont de l'estuaire de la Seine. Les données contenues dans ce rapport ont été produites par la Cellule de lutte contre la pollution (Service de navigation de la Seine), le laboratoire Chimie des contaminants et modélisation (IFREMER) et le Laboratoire municipal et régional de Rouen.

Fungal contamination in one hotel room: does carpet coating in the floor enhance fungal contamination?

Interest in bioaerosol exposure has increased significantly because it is now recognized that exposure to fungal agents is associated with a wide range of adverse health effects with a major impact on public health. Fungi are able to grow on almost all natural and synthetic materials, especially if they are hygroscopic or wet. Aim of the study: Several materials used indoors can contribute to enhance fungal contamination indoors. This study intended to understand the carpet influence on fungal contamination when used in the floor of a hotel room.

A multitracer approach to assess the spatial contamination pattern of hake (Merluccius merluccius) in the French Mediterranean

Chemical contamination levels and stable isotope ratios provide integrated information about contaminant exposure, trophic position and also biological and environmental influences on marine organisms. By combining these approaches with otolith shape analyses, the aim of the present study was to document the spatial variability of Hg and PCB contamination of the European hake (Merluccius merluccius) in the French Mediterranean, hypothesizing that local contaminant sources, environmental conditions and biological specificities lead to site-specific contamination patterns. High Hg concentrations discriminated Corsica (average: 1.36 ± 0.80 μg g− 1 dm) from the Gulf of Lions (average values < 0.5 μg g− 1 dm), where Rhône River input caused high PCB burdens. CB 153 average concentrations ranged between 4.00 ± 0.64 and 18.39 ± 12.38 ng g− 1 dm in the Gulf of Lions, whatever the sex of the individuals, whereas the highest values in Corsica were 6.75 ± 4.22 ng g− 1 dm. Otolith shape discriminated juveniles and adults, due to their different habitats. The use of combined ecotracers was revealed as a powerful tool to discriminate between fish populations at large and small spatial scale, and to enable understanding of the environmental and biological influences on contamination patterns.