Search results for "Water microbiology"
showing 10 items of 94 documents
Seasonal and spatial dynamics of enteric viruses in wastewater and in riverine and estuarine receiving waters
2018
International audience; Enteric viruses represent a global public health threat and are implicated in numerous foodborne andwaterborne disease outbreaks. Nonetheless, relatively little is known of their fate and stability in the environment. In this studywe used carefully validatedmethods tomonitor enteric viruses, namely adenovirus (AdV), JC polyomavirus (JCV), noroviruses (NoVs), sapovirus (SaV) and hepatitis A and E viruses (HAV and HEV) fromwastewater source to beaches and shellfish beds. Wastewater influent and effluent, surface water, sediment and shellfish samples were collected in the Conwy catchment (North Wales, UK) once a month for one year. High concentrations of AdV and JCV wer…
High Nutrient Concentration Can Induce Virulence Factor Expression and Cause Higher Virulence in an Environmentally Transmitted Pathogen
2016
Environmentally transmitted opportunistic pathogens shuttle between two substantially different environments: outside-host and within-host habitats. These environments differ from each other especially with respect to nutrient availability. Consequently, the pathogens are required to regulate their behavior in response to environmental cues in order to survive, but how nutrients control the virulence in opportunistic pathogens is still poorly understood. In this study, we examined how nutrient level in the outside-host environment affects the gene expression of putative virulence factors of the opportunistic fish pathogen Flavobacterium columnare. The impact of environmental nutrient concen…
Evaluation of viability PCR performance for assessing norovirus infectivity in fresh-cut vegetables and irrigation water
2016
Norovirus (NoV) detection in food and water is mainly carried out by quantitative RT-PCR (RT-qPCR). The inability to differentiate between infectious and inactivated viruses and the resulting overestimation of viral targets is considered a major disadvantage of RT-qPCR. Initially, conventional photoactivatable dyes (i.e. propidium monoazide, PMA and ethidium monoazide, EMA) and newly developed ones (i.e. PMAxx and PEMAX) were evaluated for the discrimination between infectious and thermally inactivated NoV genogroup I (GI) and II (GII) suspensions. Results showed that PMAxx was the best photoactivatable dye to assess NoV infectivity. This procedure was further optimized in artificially inoc…
Control and prevention measures for legionellosis in hospitals: A cross-sectional survey in Italy
2018
Abstract Risk assessment, environmental monitoring, and the disinfection of water systems are the key elements in preventing legionellosis risk. The Italian Study Group of Hospital Hygiene of the Italian Society of Hygiene, Preventive Medicine, and Public Health and the Italian Multidisciplinary Society for the Prevention of Health Care-Associated Infections carried out a national cross-sectional survey to investigate the measures taken to prevent and control legionellosis in Italian hospitals. A multiple-choice questionnaire was developed, comprising 71 questions regarding hospital location, general characteristics, clinical and environmental surveillance, and control and preventive measur…
Detection of temporal clusters of health care-associated infections or colonizations with Pseudomonas aeruginosa.
2016
International audience; We investigated temporal clusters of Pseudomonas aeruginosa cases between 2005 and 2014 in 1 French university hospital, overall and by ward, using the Kulldorff method. Clusters of positive water samples were also investigated at the whole hospital level. Our results suggest that water outlets are not closely involved in the occurrence of clusters of P aeruginosa cases.
Persistent Endemicity of Salmonella bongori 48:z 35 :− in Southern Italy: Molecular Characterization of Human, Animal, and Environmental Isolates
2002
ABSTRACT From 1984 to 1999, we collected 31 isolates of the rare serovar Salmonella bongori 48:z 35 :− in southern Italy. Twenty-four of the isolates were from cases of acute enteritis in humans. Pulsed-field gel electrophoresis analysis showed that all but one of our isolates were at least 80% similar. Our findings suggest that genetically related S. bongori 48:z 35 :− strains are endemically circulating in southern Italy.
Can technical, functional and structural characteristics of dental units predict Legionella pneumophila and Pseudomonas aeruginosa contamination?
2011
Legionella pneumophila and Pseudomonas aeruginosa are common colonizers of water environments, particularly dental unit waterlines. The aim of this study was to assess whether the technical, functional and structural characteristics of dental units can influence the presence and the levels of opportunistic pathogens. Overall, 42 water samples were collected from dental units in a teaching hospital in Palermo, Italy, including 21 samples from the 21 taps supplied by the municipal water distribution system and 21 samples from oral rinsing cups at 21 dental units. L. pneumophila was present in 16 out of 21 water samples (76.2%) from dental units, and the median concentration was higher in samp…
[Legionella spp. contamination in indoor air: preliminary results of an Italian multicenter study].
2014
Obiettivo. Rilevare la presenza di Legionella spp. nell’aria attraverso un protocollo standardizzato, a fianco dei tradizionali metodi impiegati per la rete idrica. Disegno. In dieci strutture sanitarie è stato selezionato un bagno, la cui acqua presentava una contaminazione da Legionella >1.000 unità formanti colonie (ufc)/litro. La contaminazione dell’aria è stata valutata tramite campionamento attivo (Surface Air System, SAS) e passivo, impiegando piastre di sedimentazione per la valutazione dell’Indice Microbico Aria (Index of Microbial Air, IMA). I campionamenti sono stati effettuati per 8 ore consecutive, a circa 1 m dal pavimento e a 50 cm dal rubinetto. Con il campionamento attivo, …
Archaea in boreal Swedish lakes are diverse, dominated by Woesearchaeota and follow deterministic community assembly
2020
Despite their key role in biogeochemical processes, particularly the methane cycle, archaea are widely underrepresented in molecular surveys because of their lower abundance compared to bacteria and eukaryotes. Here, we use parallel high‐resolution small subunit rRNA gene sequencing to explore archaeal diversity in 109 Swedish lakes and correlate archaeal community assembly mechanisms to large‐scale latitudinal, climatic (nemoral to arctic), and nutrient (oligotrophic to eutrophic) gradients. Sequencing with universal primers showed the contribution of archaea was on average 0.8% but increased up to 1.5% of the three domains in forest lakes. Archaea‐specific sequencing revealed that freshwa…
Elimination of cyanobacteria and microcystins in irrigation water—effects of hydrogen peroxide treatment
2020
AbstractCyanobacterial blooms pose a risk to wild and domestic animals as well as humans due to the toxins they may produce. Humans may be subjected to cyanobacterial toxins through many routes, e.g., by consuming contaminated drinking water, fish, and crop plants or through recreational activities. In earlier studies, cyanobacterial cells have been shown to accumulate on leafy plants after spray irrigation with cyanobacteria-containing water, and microcystin (MC) has been detected in the plant root system after irrigation with MC-containing water. This paper reports a series of experiments where lysis of cyanobacteria in abstracted lake water was induced by the use of hydrogen peroxide and…