UV filters and their impact on marine life: state of the science, data gaps, and next steps.

Sunscreens containing broad-spectrum ultraviolet (UV) filters play an essential role in protecting the skin against the damage induced by sun overexposure. However, the widespread use of sunscreens and other personal care products containing these filters has led to these compounds being widely detected in the environment and being identified as emerging pollutants in marine waters. Concerns raised by laboratory studies investigating the potential impact of UV filters on coral communities have already led to bans on the use of some sunscreens in a few tourist hotspots. Although UV filter pollution may be just one of the many environmental factors impacting coral health worldwide, the media attention surrounding these studies and the legislative changes may lead patients to question dermatologists about the environmental safety of some sunscreen products. This review provides an overview of current knowledge on the impact of UV filters on marine ecosystems, concentrating on recent studies examining the effects of commonly used filters on organisms at low trophic levels and of how alternative approaches, such as metabolomics, can be used to further assess UV filter ecotoxicity. Current gaps in our knowledge are also discussed, most notably the need to increase our understanding of the longer-term fate and behaviour of UV filters in the marine environment, develop more adapted standardized ecotoxicity tests for a wider range of marine species, and evaluate the impact of UV filters on the marine food web. We then discuss future perspectives for the development of new, more environmentally friendly, filters that may enable the use of the most toxic compounds to be reduced without compromising the effectiveness of sunscreen formulations. Finally, we consider how dermatologists play a key role in educating patients on the need for a balanced approach to sun exposure, sun protection, and conservation of the marine environment.

Evaluation of the degradation capacity of WWTP sludge enrichment cultures towards several organic UV filters and the isolation of octocrylene-degrading microorganisms.

Organic UV filters are present in wastewater treatment plants (WWTPs) due to the use of these compounds in many personal care products (PCPs) and their subsequent release into the wastewater system from showering/bathing. Once in the wastewater system, organic UV filters generally partition into the solid phase but might also undergo other processes, such as degradation by microorganisms. To further understand the fate of organic UV filters in WWTPs, the degradation of 7 UV filters by WWTP sludge was investigated The UV filters 2-ethylhexyl salicylate (ES), homosalate (HS), butyl methoxydibenzoylmethane (BM) and octocrylene (OC) were degraded after 20-60 days. The rest of the filters tested, namely, bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT) and diethylhexyl butamido triazone (DBT), did not degrade even after 120 days of incubation. The microbial community from the microcosms degrading ES, HS, OC and BM was transferred every 30 days into new microcosms to enrich for microorganisms capable of utilizing the individual UV filters for growth. The enrichment cultures continued to degrade throughout 20 transfers. The microbial community was clearly different between the enrichments degrading ES, HS, OC and BM, meaning that the microbial community was strongly influenced by the UV filter present. Furthermore, several strains were isolated from OC-degrading cultures and two of these strains, Gordonia sp. strain OC_S5 and Sphingopyxis sp. strain OC_4D, degraded OC with and without other carbon sources present. These experiments show that several organic UV filters can be degraded by a specific set of microorganisms. The lack of degradation observed for BEMT, MBBT and DBT is probably due to limited bioavailability. Indeed, this is the first biodegradation study of these filters, in addition to being the first description of ES and HS degradation in microcosm experiments.

Efficient degradation of the organic UV filter benzophenone-3 by Sphingomonas wittichii strain BP14P isolated from WWTP sludge.

Benzophenone-3 (BP3) is a widely used organic UV filter present in many environmental compartments. One way BP3 is released into the environment is through effluents from wastewater treatment plants (WWTPs). These plants are possible sources for degradation activity and WWTP sludge may potentially degrade BP3. Our goal was to identify any BP3 degrading microorganism(s) in WWTP sludge and to investigate whether the degradation was co-metabolic. Initial WWTP sludge microcosms spiked with BP3 showed 100% degradation after 20 days. Multiple transfers of these microcosms, while maintaining a strong selective pressure for BP3 degradation capabilities, resulted in the dominance of one bacterial strain. This strain was identified as Sphingomonas wittichii BP14P and was subsequently isolated. It was shown to degrade BP3 in a growth dependent manner. Strain BP14P utilized BP3 as the sole energy and carbon source and completely degraded BP3 after 7 days in minimal media. We tested the capability of BP14P to degrade nine other UV filters, but the degradation ability seemed to be restricted to BP3. However, whether this specificity is due to the lack of degradation genes, cellular transport or low bioavailability of the other UV filters remained unclear. The efficient degradation of BP3 by a group of bacteria well known for their potential for xenobiotic degradation is an important step forward for a complete risk assessment of the long-term environmental impact of BP3.

In-depth prospection of Avène Thermal Spring Water reveals an uncommon and stable microbial community.

BACKGROUND: Avène Thermal Spring Water (TSW) exhibits therapeutic properties in the treatment of skin pathologies. Arising from a dolomitic aquifer system, its physico-chemical properties are well-established and its bacteriological quality regularly monitored. The microbiota of this aquifer have been characterized. OBJECTIVES: We aimed to describe the structure of the bacterial community inhabiting the deep aquifer and to examine its dynamics over time. METHODS: The Avène TSW was collected at the catchment point and filtered through 0.1 µm pore size filters. The sampling was carried out every 3 months to generate a 4-year time series. The DNA extracted from filters was analysed using high-throughput 16S rRNA gene amplicon sequencing, and the microorganisms and their contribution were characterized by the taxonomic assignment of sequence variants generated from each sample. RESULTS: Bacteria were distributed into 39 phyla. Nitrospirae and Proteobacteria were the most prevalent, accounting for 38% and 23% of the total community on average, respectively. A stable pattern was observed throughout the study. A few bacterial species were always detected, forming a core community of likely chemolithoautotrophic organisms which might use energy sources and nutrients produced from water-bedrock interactions. Most of the species were distantly related to organisms described to date. CONCLUSIONS: Avène TSW provided by the deep aquifer system harbours a unique microbial community, shaped by the physico-chemical characteristics of the deep environment. Its remarkable stability over time has revealed a high level of confinement of the water resource.

Les eaux thermales : quand minéralité et signature biologique se combinent pour expliquer leurs propriétés: Thermal waters: when minerality and biological signature combine to explain their properties.

Thermal waters have their origins in the depths of the Earth. It is during their long way to the surface that they are enriched with chemical properties and trace elements and they also get their biological properties. Their sources are often exploited because of the properties of these waters and they must be protected to avoid infiltration related to human activities on the surface of watersheds. Depending on the soil from which it originates, water is used for various therapeutic orientations. However, they are true ecosystems with multiple interactions and they all have biological properties that are most often unknown. Thermal waters like all waters on earth (surface water, groundwater, oceanic,…) are rich in microorganisms that are essential and very useful for humans and ecosystems. The properties of thermal waters also come from the microorganisms that live there and which are often very specific to the minerality of these waters. Their diversity can be important and when isolated and grown in the laboratory, we can extract and concentrate the active ingredients to exploit them on an industrial scale. © 2020 Elsevier Masson SAS. All rights reserved.

La peau : un écosystème microbien: The skin: a microbial ecosystem.

Human hosts a large number of microorganisms that constitute its microbiome and the vast majority of them are very useful and even essentials. The human microbiome is a complex ecosystem where live populations of transient or resident microorganisms. The process of co-development or co-adaptation played a major role in the establishment of indigenous communities and help explain the dominance of positive interactions (commensal, symbiotic or mutualistic) in the human-microorganism relationship. The assimilation of nutrients, production of anti-inflammatory compounds, defense against pathogens, vitamin production or stimulating the immune system are some of the key benefits of the indigenous microorganisms. Understanding the skin microbiome opens new exploratory fields and represents a real challenge for both the academic knowledge and the development of new therapeutic approaches.

Rapid quantification of viable Legionella in nuclear cooling tower waters using filter cultivation, fluorescent in situ hybridization and solid-phase cytometry.

AIMS: To develop a rapid and sensitive method to quantify viable Legionella spp. in cooling tower water samples. METHODS AND RESULTS: A rapid, culture-based method capable of quantifying as few as 600 Legionella microcolonies per litre within 2 days in industrial waters was developed. The method combines a short cultivation step of microcolonies on GVPC agar plate, specific detection of Legionella cells by a fluorescent in situ hybridization (FISH) approach, and a sensitive enumeration using a solid-phase cytometer. Following optimization of the cultivation conditions, the qualitative and quantitative performance of the method was assessed and the method was applied to 262 nuclear power plant cooling water samples. CONCLUSIONS: The performance of this method was in accordance with the culture method (NF-T 90-431) for Legionella enumeration. SIGNIFICANCE AND IMPACT OF THE STUDY: The rapid detection of viable Legionella in water is a major concern to the effective monitoring of this pathogenic bacterium in the main water sources involved in the transmission of legionellosis infection (Legionnaires' disease). The new method proposed here appears to be a robust, efficient and innovative means for rapidly quantifying cultivable Legionella in cooling tower water samples within 48 h.

Response to UVB radiation and oxidative stress of marine bacteria isolated from South Pacific Ocean and Mediterranean Sea.

Marine bacterial strains isolated from South Pacific and Mediterranean Sea were studied for their resistance to UVB radiation, their repair capacity under photoreactivating light, as well as their oxidative stress response using concentrated hydrogen peroxide (H(2)O(2)), as an oxidizer. A total of 30 marine bacteria were isolated from the hyper-oligotrophic waters of the South Pacific Gyre to the eutrophic waters of the Chilean coast during the BIOSOPE cruise (2004), and 10 strains from surface Mediterranean coastal waters. One third of bacteria presented a high resistance to UVB and almost all isolates presented an efficient post-irradiation recovery. Only few strains showed cell survival to high concentration of H(2)O(2). No correlation between the sampling sites and the bacterial UVB resistance was observed. Two marine bacteria, Erythrobacter flavus and Ruegeria mobilis, were of particular interest, presenting a good response to the three parameters (UVB and H(2)O(2) resistance/efficient repair). Unexpectedly, two resistant strains were again identified as Ruegeria species underlining that this geographically widespread genus, resist to UVB regardless the environment from which the isolates originate.

Total and viable Legionella pneumophila cells in hot and natural waters as measured by immunofluorescence-based assays and solid-phase cytometry.

A new method was developed for the rapid and sensitive detection of viable Legionella pneumophila. The method combines specific immunofluorescence (IF) staining using monoclonal antibodies with a bacterial viability marker (ChemChrome V6 cellular esterase activity marker) by means of solid-phase cytometry (SPC). IF methods were applied to the detection and enumeration of both the total and viable L. pneumophila cells in water samples. The sensitivity of the IF methods coupled to SPC was 34 cells liter(-1), and the reproducibility was good, with the coefficient of variation generally falling below 30%. IF methods were applied to the enumeration of total and viable L. pneumophila cells in 46 domestic hot water samples as well as in cooling tower water and natural water samples, such as thermal spring water and freshwater samples. Comparison with standard plate counts showed that (i) the total direct counts were always higher than the plate counts and (ii) the viable counts were higher than or close to the plate counts. With domestic hot waters, when the IF assay was combined with the viability test, SPC detected up to 3.4 × 10(3) viable but nonculturable L. pneumophila cells per liter. These direct IF methods could be a powerful tool for high-frequency monitoring of domestic hot waters or for investigating the occurrence of viable L. pneumophila in both man-made water systems and environmental water samples.

Impact of seawater-quality and water treatment procedures on the active bacterial assemblages at two desalination sites.

Inorganic and organic compounds, particles and microorganisms in intake waters are mainly responsible for fouling of reverse osmosis membranes, which reduces the efficiency of the desalination process. The characterization of seawater quality to better predict its fouling potential remains a challenge for the desalination field and little is known about the seasonal variability of water quality parameters in the coastal waters used to supply desalination plants. In this study, standard water quality methods were combined with flow cytometry and molecular methods (16S rRNA sequencing and fingerprinting) to assess in parallel, the physicochemical properties, the microbial abundance and the active microbial community composition of the intake waters and their associated pretreated waters at two desalination sites from July 2007 to July 2008. The overall assessment of quality parameters revealed that microfiltration followed by slow sand filtration were the most efficient in removing microorganisms than the conventional dual media filtration routinely used in full-scale desalination plants, and that all treatments were inefficient for organic matter reduction. Temporal variation of the environmental parameters such as temperature, turbidity and silt density index only moderately affected the bacterial community structure in raw waters, but that interestingly, water treatment compartments changed the composition and diversity of the metabolically active bacterial populations and thus create distinct ecological post-treatment niches.

Sensitive counting of viable Enterobacteriaceae in seawaters and relationship with fecal indicators.

A fluorescent in situ hybridization based assay was used to enumerate viable Enterobacteriaceae members in seawaters by solid phase cytometry. The method was specific, highly sensitive (1cell/100ml) and allowed the quantification of VNC Enterobacteriaceae cells during an osmotic stress. Investigations on contaminated coastal seawater revealed a strong correlation between Enterobacteriaceae counts and standard fecal indicators.

Dynamic bacterial communities on reverse-osmosis membranes in a full-scale desalination plant.

To better understand biofouling of seawater reverse osmosis (SWRO) membranes, bacterial diversity was characterized in the intake water, in subsequently pretreated water and on SWRO membranes from a full-scale desalination plant (FSDP) during a 9 month period. 16S rRNA gene fingerprinting and sequencing revealed that bacterial communities in the water samples and on the SWRO membranes were very different. For the different sampling dates, the bacterial diversity of the active and the total bacterial fractions of the water samples remained relatively stable over the sampling period whereas the bacterial community structure on the four SWRO membrane samples was significantly different. The richness and evenness of the SWRO membrane bacterial communities increased with usage time with an increase in the Shannon diversity index of 2.2 to 3.7. In the oldest SWRO membrane (330 days), no single operational taxonomic unit (OTU) dominated and the majority of the OTUs fell into the Alphaproteobacteria or the Planctomycetes. In striking contrast, a Betaproteobacteria OTU affiliated to the genus Ideonella was dominant and exclusively found in the membrane used for the shortest time (10 days). This suggests that bacteria belonging to this genus could be one of the primary colonizers of the SWRO membrane. Knowledge of the dominant bacterial species on SWRO membranes and their dynamics should help guide culture studies for physiological characterization of biofilm forming species.

High diversity and abundance of Legionella spp. in a pristine river and impact of seasonal and anthropogenic effects.

The diversity and dynamics of Legionella species along a French river watershed subject to different thermal and wastewater discharges during an annual cycle were assessed by 16S rRNA gene sequencing and by a fingerprint technique, single-strand conformation polymorphism. A high diversity of Legionella spp. was observed at all the sampling sites, and the dominant Legionella clusters identified were most closely related to uncultured bacteria. The monthly monitoring revealed that Legionella sp. diversity changes were linked only to season at the wastewater site whereas there was some evidence for anthropogenic effects on Legionella sp. diversity downstream of the thermal bath. Quantification of Legionella pneumophila and Legionella spp. by culture and quantitative PCR (qPCR) was performed. Whereas only L. pneumophila was quantified on culture media, the qPCR assay revealed that Legionella spp. were ubiquitous and abundant from the pristine source of the river to the downstream sampling sites. These results suggest that Legionella spp. may be present at significant concentrations in many more freshwater environments than previously thought, highlighting the need for further ecological studies and culturing efforts.

Improved method for bacterial cell capture after flow cytometry cell sorting.

Fixed cells with different nucleic acid contents and scatter properties (low nucleic acid [LNA], high nucleic acid 1 [HNA1], and HNA2) were sorted by flow cytometry (FCM). For each sort, 10,000 cells were efficiently captured on poly-l-lysine-coated microplates, resulting in efficient and reproducible PCR amplification.

Rapid detection of Escherichia coli in waters using fluorescent in situ hybridization, direct viable counting and solid phase cytometry.

AIMS: We developed an improved Fluorescent In Situ Hybridization FISH-based method to detect viable Escherichia coli cells by solid phase cytometry (SPC), and results were compared to those obtained by the standard culture method. METHODS AND RESULTS: The method includes a direct viable count (DVC) assay, multi-probes labelled and unlabelled (helpers) to detect specifically viable E. coli cells and to enhance SPC cell counts. We demonstrate that helpers increase the fluorescence intensity of hybridized E. coli cells as detected by SPC and assess the high specificity of the DVC-FISH procedure on a large panel of cultured strains. Application to seawater, freshwater and wastewater samples showed a good correlation between SPC cells counts and standard plate counts. CONCLUSION: The high specificity of the procedure was demonstrated as well as its accuracy for detecting and counting viable E. coli cells in environmental samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The developed approach may be used to monitor faecal contamination sources and to investigate the occurrence of viable E. coli in natural environments.

Effect of a transient perturbation on marine bacterial communities with contrasting history.

AIMS: To evaluate the importance of the bacterial composition on the resilience of the organic matter assimilation in the sea. METHODS AND RESULTS: Chemostats were inoculated with coastal and offshore bacterial communities. Bacterial density and protein synthesis increased before stabilizing, and this response to confinement was more marked in the offshore chemostats. Before the toluene perturbation the community structure in the coastal chemostats remained complex whereas the offshore chemostats became dominated by Alteromonas sp. After the perturbation, bacterial protein synthesis was inhibited before peaking briefly at a level fivefold to that observed before the perturbation and then stabilizing at a level comparable to that before the perturbation. Alteromonas dominated both the coastal and the offshore communities immediately after the perturbation and the coastal communities did not recover their initial complexity. CONCLUSIONS: Cell lysis induced by the toluene perturbation favoured the growth of Alteromonas which could initiate growth rapidly in response to the nutrient pulse. Despite their different community structure in situ, the resilience of protein synthesis of coastal and offshore bacterial communities was dependent on Alteromonas, which dominated in the chemostats. SIGNIFICANCE AND IMPACT OF THE STUDY: Here we show that although Alteromonas sp. dominated in artificial offshore and coastal communities in chemostats, their response time to the shock was different. This suggests that future perturbation studies on resilience in the marine environment should take account of ecosystem history.

Rapid enumeration of Escherichia coli in marine bathing waters: potential interference of nontarget bacteria.

AIMS: To compare the Escherichia coli quantification given by the 'Coliplage' assay, based on the direct measurement of the beta-D-glucuronidase (GLUase) activity and the reference Most Probable Number (MPN) method from seawater sites and investigate the possible interference of non-E. coli strains in the GLUase activity measurement. METHODS AND RESULTS: Comparison performed from 69 French coastal bathing sites (1401 samples) showed nonconcordance between both methods, only for 8% of samples. Non-E. coli 4-methylumbelliferyl-beta-D-glucuronide (MUG+) were isolated from nonconcordant samples. Phylogenetic analysis showed that Gammaproteobacteria were dominants and mainly represented by Vibrio species, which displayed GLUase activities on the same order of magnitude and sometimes much higher as E. coli reference strains. CONCLUSIONS: The'Coliplage' assay is a rapid method for the quantification of E. coli showed few discordances with the standard MPN method. Some Vibrio species could interfere on the direct GLUase activity measurement of E. coli. SIGNIFICANCE AND IMPACT OF THE STUDY: Data present the first qualitative investigation on disagreement between Coliplage and the MPN results. If the interference of Vibrio species is confirmed in situ, appropriate treatments should be developed to remove the interfering signal.

Potential effect of freshwater virus on the structure and activity of bacterial communities in the Marennes-Oléron Bay (France).

Batch culture experiments using viral enrichment were conducted to test the response of a coastal bacterial community to autochthonous (i.e., co-existing) or allochthonous riverine viruses. The effects of viral infections on bacterial dynamics and activity were assessed by epifluorescence microscopy and thymidine incorporation, respectively, whereas the effect of viral infection on bacterial community composition was examined by polymerase chain reaction-single strand conformation polymorphism 16S ribosomal RNA fingerprinting. The percentages of high nucleic acid-containing cells, evaluated by flow cytometry, were significantly correlated (r2=0.91, n=12, p<0.0001) to bacterial production, making this value a good predictor of active cell dynamics along the study. While confinement and temperature were the two principal experimental factors affecting bacterial community composition and dynamics, respectively, additions of freshwater viruses had significant effects on coastal bacterial communities. Thus, foreign viruses significantly reduced net bacterial population increase as compared to the enrichment treated with inactivated virus. Moreover, freshwater viruses recurrently and specifically affected bacterial community composition, as compared to addition of autochthonous viruses. In most cases, the combined treatment viruses and freshwater dissolved organic matter helped to maintain or even enhance species richness in coastal bacterial communities in agreement to the 'killing the winner' hypothesis. Thus, riverine virus input could potentially influence bacterial community composition of the coastal bay albeit with modest modification of bulk bacterial growth.

Efficient method to isolate and purify viruses of bacteria from marine environments.

AIM: To isolate viruses of specific heterotrophic bacterial strains from marine environments using a host addition/virus amplification protocol (HAVAP) for use in phage/host systems. METHODS AND RESULTS: Bacteria-free seawater samples containing natural viruses assemblages were inoculated with a single laboratory grown bacterial host of interest in a nutrient-enriched [peptone, Fe(III) and yeast extract] seawater suspension. These conditions enhanced the replication of only those virus(s) capable of infecting the host bacterium. After incubation, free viruses were recovered at concentrations ranging 10(5)-10(10) infectious virus particles per ml of seawater. Using this approach, 15 viruses were isolated and represented 12 unique phage/host systems. Two of the hosts tested were infected by more than one virus. CONCLUSIONS: Isolation of high concentrations of specific viruses is possible even if their initial concentrations in native waters are low. This approach allows the recovery of phage/host systems that may not be numerically dominant. SIGNIFICANCE AND IMPACT OF THE STUDY: This host enrichment protocol for virus detection and isolation is well-suited for aquatic viral ecology studies that require phage/host systems.

High throughput, real-time detection of Naegleria lovaniensis in natural river water using LED-illuminated Fountain Flow Cytometry.

AIMS: To test Fountain Flow Cytometry (FFC) for the rapid and sensitive detection of Naegleria lovaniensis amoebae (an analogue for Naegleria fowleri) in natural river waters. METHODS AND RESULTS: Samples were incubated with one of two fluorescent labels to facilitate detection: ChemChrome V6, a viability indicator, and an R-phycoerytherin (RPE) immunolabel to detect N. lovaniensis specifically. The resulting aqueous sample was passed as a stream in front of a light-emitting diode, which excited the fluorescent labels. The fluorescence was detected with a digital camera as the sample flowed toward the imager. Detections of N. lovaniensis were made in inoculated samples of natural water from eight rivers in France and the United States. FFC enumeration yielded results that are consistent with other counting methods: solid-phase cytometry, flow cytometry, and hemocytometry, down to concentrations of 0.06 amoebae ml(-1), using a flow rate of 15 ml min(-1). CONCLUSIONS: This study supports the efficacy of using FFC for the detection of viable protozoa in natural waters and indicates that use of RPE illuminated at 530 nm and detected at 585 nm provides a satisfactory means of attenuating background. SIGNIFICANCE AND IMPACT OF THE STUDY: Because of the severe global public health issues with drinking water and sanitation, there is an urgent need to develop a technique for the real-time detection of viable pathogens in environmental samples at low concentrations. FFC addresses this need.