Search results for "Water microbiology"
showing 10 items of 94 documents
Ecological effects of aquaculture on living and non-living suspended fractions of the water column: a meta-analysis.
2006
The effects of aquaculture on the ecology of the water column have been extensively studied in the last two decades. However, to date, it has not been possible to extrapolate homogeneous information from the peer-reviewed literature. In the present study, 68 peer-reviewed articles were analysed and about 1087 study cases were used to test whether worldwide cultivations of aquatic organisms (shrimps, fish, bivalves and polyculture) have a differential effect on living and non-living fractions of the water column (suspended matter, chlorophyll-a, particulate organic carbon, nitrogen and phosphorus, bacteria and plankton). Meta-analysis feasibility depends on obtaining an estimate of the effec…
NaCl-saturated brines are thermodynamically moderate, rather than extreme, microbial habitats
2018
NaCl-saturated brines such as saltern crystalliser ponds, inland salt lakes, deep-sea brines and liquids-of-deliquescence on halite are commonly regarded as a paradigm for the limit of life on Earth. There are, however, other habitats that are thermodynamically more extreme. Typically, NaCl-saturated environments contain all domains of life and perform complete biogeochemical cycling. Despite their reduced water activity, ∼0.755 at 5 M NaCl, some halophiles belonging to the Archaea and Bacteria exhibit optimum growth/metabolism in these brines. Furthermore, the recognised water-activity limit for microbial function, ∼0.585 for some strains of fungi, lies far below 0.755. Other biophysical c…
Enrichment, isolation and biodegradation potential of psychrotolerant polychlorinated-biphenyl degrading bacteria from the Kongsfjorden (Svalbard Isl…
2016
Persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), have been detected in abiotic Arctic matrices: surface sediments and seawater from coastal areas in the Kongsfjorden were collected and analyzed. Levels of PCBs varied depending on the sampling site. Total PCB concentrations were between 11.63 (site C2W) and 27.69 pg l-1 (site AW). These levels were comparable to those reported previously in lake sediments from the northern Svalbard. The occurrence and biodegradation potential of cold-adapted PCB-oxidizing bacteria in seawater and sediment along the fjord was also evaluated. After enrichment with biphenyl, 246 isolates were obtained with 45 of them that were abl…
High prevalence and moderate diversity of Pseudomonas aeruginosa in the U-bends of high-risk units in hospital
2017
The presence of P. aeruginosa in water supply is clearly identified as a risk factor for P. aeruginosa infection in critical care units, even if routes of transmission are often unclear and remain a matter of debate. We determined here the frequency of U-bends contaminated with P. aeruginosa in high-risk units and described the population structure of this opportunistic pathogen in a non-outbreak situation. Eighty-seven U-bends from sinks of rooms in five wards were sampled 3 times and P. aeruginosa was detected in 121 of the 261 (46.4%) U-bend samples. We genotyped 123 P. aeruginosa isolates with pulsed-field gel electrophoresis and multilocus sequence typing and found 41 pulsotypes distri…
Long-term dynamics in microbial eukaryotes communities: a palaeolimnological view based on sedimentary DNA
2016
International audience; Assessing the extent to which changes in lacustrine biodiversity are affected by anthropogenic or climatic forces requires extensive palaeolimnological data. We used high-throughput sequencing to generate time-series data encompassing over 2200 years of microbial eukaryotes (protists and Fungi) diversity changes from the sedimentary DNA record of two lakes (Lake Bourget in French Alps and Lake Igaliku in Greenland). From 176 samples, we sequenced a large diversity of microbial eukaryotes, with a total 16 386 operational taxonomic units distributed within 50 phylogenetic groups. Thus, microbial groups, such as Chlorophyta, Dinophyceae, Haptophyceae and Ciliophora, tha…
Occurrence of enteric viruses in reclaimed and surface irrigation water: relationship with microbiological and physicochemical indicators.
2016
Aims To assess the prevalence of enteric viruses in different irrigation water sources and in the irrigated produce, and the possible links with microbiological and physicochemical water characteristics. Methods and results The prevalence and levels of Escherichia coli, Norovirus (NoV) genogroup I (GI) and II (GII), as well as Hepatitis A virus were assessed in three types of water: surface water (surface-W), reclaimed water subjected to secondary treatment (secondary-W) and reclaimed water subjected to tertiary treatment (tertiary-W), as well as in zucchini irrigated with these irrigation water sources. Chemical oxygen demand (COD), turbidity, total suspended solids, alkalinity, and maximu…
Wild eel microbiome reveals that skin mucus of fish could be a natural niche for aquatic mucosal pathogen evolution
2017
Background Fish skin mucosal surfaces (SMS) are quite similar in composition and function to some mammalian MS and, in consequence, could constitute an adequate niche for the evolution of mucosal aquatic pathogens in natural environments. We aimed to test this hypothesis by searching for metagenomic and genomic evidences in the SMS-microbiome of a model fish species (Anguilla Anguilla or eel), from different ecosystems (four natural environments of different water salinity and one eel farm) as well as the water microbiome (W-microbiome) surrounding the host. Results Remarkably, potentially pathogenic Vibrio monopolized wild eel SMS-microbiome from natural ecosystems, Vibrio anguillarum/Vibr…
Fine metagenomic profile of the Mediterranean stratified and mixed water columns revealed by assembly and recruitment
2018
Background: The photic zone of aquatic habitats is subjected to strong physicochemical gradients. To analyze the fine-scale variations in the marine microbiome, we collected seven samples from a single offshore location in the Mediterranean at 15 m depth intervals during a period of strong stratification, as well as two more samples during the winter when the photic water column was mixed. We were able to recover 94 new metagenome-assembled genomes (MAGs) from these metagenomes and examine the distribution of key marine microbes within the photic zone using metagenomic recruitment. Results: Our results showed significant differences in the microbial composition of different layers within th…
Early detection of SARS-CoV-2 infection cases or outbreaks at nursing homes by targeted wastewater tracking
2021
Objectives Near-source tracking of SARS-CoV-2 RNA in the sewage drains serving particular buildings may allow rapid identification of SARS-CoV-2 infection cases or local outbreaks. In this pilot study, we investigated whether this was the case for nursing homes (NH). Methods The study involved five NH (from A to E) affiliated to the Clínico-Malvarrosa Health Department, Valencia (Spain). These were nursing or mixed nursing/care homes of different sizes, altogether providing care for 472 residents attended by a staff of 309. Near-source sewage samples were screened for presence of SARS-CoV-2 RNA by RT-qPCR at least 5 days per week during the study period. SARS-CoV-2 RNA testing in nasopharyn…
Molecular detection of Borrelia burgdorferi sensu lato – An analytical comparison of real-time PCR protocols from five different Scandinavian laborat…
2017
Introduction Lyme borreliosis (LB) is the most common tick transmitted disease in Europe. The diagnosis of LB today is based on the patient A s medical history, clinical presentation and laboratory findings. The laboratory diagnostics are mainly based on antibody detection, but in certain conditions molecular detection by polymerase chain reaction (PCR) may serve as a complement. Aim The purpose of this study was to evaluate the analytical sensitivity, analytical specificity and concordance of eight different real-time PCR methods at five laboratories in Sweden, Norway and Denmark. Method Each participating laboratory was asked to analyse three different sets of samples (reference panels; a…