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Some microorganisms, particularly bacteria, can adhere to conductive surfaces and grow as an electroactive biofilm, on which they communicate electrochemically and generate electricity. Here, a bacterial community isolated from anodic electroactive biofilms of a Microbial Fuel Cell planted with Chlorophytum comosom is studied. Seventeen different bacterial strains were isolated from electroactive biofilms and were identified using the 16S rRNA marker gene. The strains were affiliated to 8 bacteria families and 8 genera (Aeromonas, Enterobacter, Alcaligenes, Pseudomonas, Clostridium, Paraclostridium, Enterococcus and Kurthia spp.). After that, it was demonstrated using electrochemical methods, principally imposed potential chronoamperometry under +0.155 mV/SCE, that the consortium constituted of 17 strains was able to exchange electrons with conductive materials. A maximum current density of 345 µA/cm2 was revealed at 48h of the study, using acetate as the sole carbon source and without any additional external mediator., SCOPUS: ar.j, info:eu-repo/semantics/published

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A non-motile, straight-rod-shaped, Gram-stain-positive and facultative anaerobic bacterium (i.e. strain G1T) was isolated from production waters from an Algerian oilfield. Growth was observed in the presence of 0.3–3.5% (w/v) NaCl, at 20–50 °C and at pH 6.0–9.0. Results of phylogenetic analyses based on 16S rRNA gene sequences showed that strain G1T belonged to the genus Microbacterium. Strain G1T was closely related to Microbacterium oxydans (DSM 20578T) and Microbacterium maritypicum (DSM 12512T) with 99.8% sequence similarity and to Microbacterium saperdae (DSM 20169T) with 99.6% sequence similarity. Strain G1T contained MK9, MK10, MK11, MK12 and MK13 as respiratory quinones, and phosphatidylglycerol, diphosphatidylglycerol and glycolipid as the major polar lipids. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0 .The esti-mated DNA G+C content was 69.57 mol% based on its draft genome sequence. Genome annotation of strain G1T predicted the presence of 3511 genes, of which 3483 were protein-coding and 47 were tRNA genes. The DNA–DNA hybridization (DDH) and average nucleotide identity (ANI) values between strain G1T and M. oxydans (DSM 20578T) and M. maritypicum (DSM 12512T) were in both cases far below the respective species boundary thresholds (27.5 and 28.0% for DDH; and 84.40 and 84.82% for ANI, respectively). Based on the data presented above, strain G1T was considered to represent a novel species for which the name Microbacterium algeriense is proposed with the type strain G1T (=DSM 109018T=LMG 31276T)., SCOPUS: ar.j, info:eu-repo/semantics/published

This study aims to investigate the prevalence of clinically relevant carbapenemases genes (bla, bla and bla) in water samples collected over one-year period from hospital (H), raw and treated wastewater of two wastewater treatment plants (WWTPs) as well as along the Zenne River (Belgium). The genes were quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed that absolute abundances were the highest in H waters. Although absolute abundances were significantly reduced in WWTP effluents, the relative abundance (normalized per 16S rRNA) was never lowered through wastewater treatment. Particularly, for the PAB the relative abundances were significantly higher in the effluents respect to the influents of both WWTPs for all the genes. The absolute abundances along the Zenne River increased from upstream to downstream, peaking after the release of WWTPs effluents, in both fractions. Our results demonstrated that bla, bla and bla are widely distributed in the Zenne as a consequence of chronic discharge from WWTPs. To conclude, the levels of carbapenemases genes are significantly lower than other genes conferring resistance to more widely used antibiotics (analyzed in previous studies carried out at the same sites), but could raise up to the levels of high prevalent resistance genes.

The main objective of this study was to investigate the antibiotic resistance (AR) levels in wastewater(WW) and the impact on the receiving river. Samples were collected once per season over one year in theWWof a hospital, in the raw and treated WWof two wastewater treatment plants (WWTPs), as well asupstream and downstream from the release ofWWTPs effluents into the Zenne River (Belgium). Culturedependentmethods were used to quantify Escherichia coli and heterotrophic bacteria resistant toamoxicillin, sulfamethoxazole, nalidixic acid and tetracycline. Six antibiotic resistance genes (ARGs) werequantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed thatWWTPsefficiently removed antibiotic resistant bacteria (ARB) regardless of its AR profile. The ARGs levels werethe highest in the hospital WWand were significantly reduced in both WWTPs. However, ARB and ARGsabundances significantly increased into the Zenne River downstream from the WWTPs outfalls. Thevariation in the relative abundance of ARGs through WW treatment differed depending on the WWTP,fraction, and gene considered. The sul1 and sul2 genes in PAB fraction showed significantly higherrelative abundances in the effluent compared to the influent of both WWTPs. This study demonstratedthat WWTPs could be hotspots for AR spread with significant impacts on receiving freshwater ecosystems.This was the first comprehensive study investigating at the same time antibiotics occurrence, fecal bacteria indicators, heterotrophic bacterial communities, and ARGs (distinguishing PAB and FLB) to assess AR levels in WW and impacts on the receiving river., SCOPUS: ar.j, info:eu-repo/semantics/published

Urban rivers are impacted ecosystems which may play an important role as reservoirs for antibiotic-resistant (AR) bacteria. The main objective of this study was to describe the prevalence of antibiotic resistance along a sewage-polluted urban river. Seven sites along the Zenne River (Belgium) were selected to study the prevalence of AR Escherichia coli and freshwater bacteria over a 1-year period. Culture-dependent methods were used to estimate E. coli and heterotrophic bacteria resistant to amoxicillin, sulfamethoxazole, nalidixic acid and tetracycline. The concentrations of these four antibiotics have been quantified in the studied river. The antibiotic resistance genes (ARGs), sul1, sul2, tetW, tetO, blaTEM and qnrS were also quantified in both particle-attached (PAB) and free-living (FLB) bacteria. Our results showed an effect of treated wastewaters release on the spread of antibiotic resistance along the river. Although an increase in the abundance of both AR E. coli and resistant heterotrophic bacteria was observed from upstream to downstream sites, the differences were only significant for AR E. coli. A significant positive regression was also found between AR E. coli and resistant heterotrophic bacteria. The concentration of ARGs increased from upstream to downstream sites for both particle-attached (PAB) and free-living bacteria (FLB). Particularly, a significant increase in the abundance of four among six ARGs analyzed was observed after crossing urban area. Although concentrations of tetracycline significantly correlated with tetracycline resistance genes, the antibiotic levels were likely too low to explain this correlation. The analysis of ARGs in different fractions revealed a significantly higher abundance in PAB compared to FLB for tetO and sul2 genes. This study demonstrated that urban activities may increase the spread of antibiotic resistance even in an already impacted river., SCOPUS: ar.j, info:eu-repo/semantics/published

This study aims to investigate the prevalence of clinically relevant carbapenemases genes (blaKPC, blaNDM andblaOXA-48) in water samples collected over one-year period from hospital (H), raw and treated wastewater of twowastewater treatment plants (WWTPs) as well as along the Zenne River (Belgium). The genes were quantified inboth particle-attached (PAB) and free-living (FLB) bacteria. Our results showed that absolute abundances werethe highest in H waters. Although absolute abundances were significantly reduced in WWTP effluents, the relativeabundance (normalized per 16S rRNA) was never lowered through wastewater treatment. Particularly, forthe PAB the relative abundances were significantly higher in the effluents respect to the influents of both WWTPsfor all the genes. The absolute abundances along the Zenne River increased from upstream to downstream,peaking after the release of WWTPs effluents, in both fractions. Our results demonstrated that blaKPC, blaNDM andblaOXA-48 are widely distributed in the Zenne as a consequence of chronic discharge from WWTPs. To conclude,the levels of carbapenemases genes are significantly lower than other genes conferring resistance to more widelyused antibiotics (analyzed in previous studies carried out at the same sites), but could raise up to the levels ofhigh prevalent resistance genes., SCOPUS: ar.j, info:eu-repo/semantics/published

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In order to investigate the factors controlling the bacterial community composition (BCC) in reservoirs, we sampled three freshwater reservoirs with contrasted physical and chemical characteristics and trophic status. The BCC was analysed by 16S rRNA gene amplicon 454 pyrosequencing. In parallel, a complete dataset of environmental parameters and phytoplankton community composition was also collected. BCC in the analysed reservoirs resembled that of epilimnetic waters of natural freshwater lakes with presence of Actinobacteria, Alpha- and Betaproteobacteria, Cytophaga-Flavobacteria-Bacteroidetes (CFB) and Verrucomicrobia groups. Our results evidenced that the retrieved BCC in the analysed reservoirs was strongly influenced by pH, alkalinity and organic carbon content, whereas comparatively little change was observed among layers in stratified conditions., SCOPUS: ar.j, info:eu-repo/semantics/published

In this study, we investigated the microbiological quality of the small urban Zenne River which flows through the city of Brussels (Belgium). The abundances of faecal indicator bacteria (FIB) (Escherichia coli and intestinal enterococci) revealed high levels offaecal contamination of the Zenne River, especially in Brussels area and downstream from this area where FIBwere in the range of what is usually observed in secondary treated wastewaters. The origin of this faecal contaminationis mainly attributed to the effluents of the two wastewater treatment plants (WWTPs) located along theriver in Brussels. Comparison of the present situation with the 1990s situation (before the implementation of Brussels WWTPs) showed a sharp improvement of the river microbiological quality. This improvement should however be regarded with care as it was also observedthat, during rain events, combined sewer overflows (CSO) outfalls were responsible of a strong increase offaecal contamination in the river downstream from Brussels, and such CSO occur frequently in Brussels.Altogether, these results document the variations of the microbiological quality of a sewage-polluted urban riverin relation with long-term changes (implementation of WWTP) and the short-term disturbances (CSO)., SCOPUS: ar.j, info:eu-repo/semantics/published

The Zenne River in Brussels (Belgium) and effluents of the two wastewater treatment plants (WWTPs) of Brussels were chosen to assess the impact of disturbance on bacterial community composition (BCC) of an urban river. Organic matters, nutrients load and oxygen concentration fluctuated highly along the river and over time because of WWTPs discharge. Tag pyrosequencing of bacterial 16S rRNA genes revealed the significant effect of seasonality on the richness, the bacterial diversity (Shannon index) and BCC. The major grouping: -winter/fall samples versus spring/summer samples- could be associated with fluctuations of in situ bacterial activities (dissolved and particulate organic carbon biodegradation associated with oxygen consumption and N transformation). BCC of the samples collected upstream from the WWTPs discharge were significantly different from BCC of downstream samples and WWTPs effluents, while no significant difference was found between BCC of WWTPs effluents and the downstream samples as revealed by ANOSIM. Analysis per season showed that allochthonous bacteria brought by WWTPs effluents triggered the changes in community composition, eventually followed by rapid post-disturbance return to the original composition as observed in April (resilience), whereas community composition remained altered after the perturbation by WWTPs effluents in the other seasons., Journal Article, Research Support, Non-U.S. Gov't, SCOPUS: ar.j, info:eu-repo/semantics/published

In the present study, the antimicrobial resistant (AR) bacteria were quantified and identified in different river samples using in parallel a culture-based approach and a culture-independent one. The objective was to evaluate the importance of the cultivation bias when studying antimicrobial resistance among environmental bacteria. Three different river samples covering a gradient of anthropic influence were tested and three different antimicrobial compounds were used as selective agents: amoxicillin, tetracycline and sulfamethoxazole. From a quantitative point of view, our results highlight the importance of the culture media used, as for the same sample and the same selective agent significant differences were observed in the counts of culturable AR bacteria depending on the culture media used. The identification of AR bacteria through culture or culture-independent methods put on evidence AR bacterial communities that differ dramatically: γ-proteobacteria and more specifically Aeromonadaceae dominated among the isolates while β-proteobacteria (Comamonadaceae), dominated among the sequences obtained without culture. Altogether these results highlight the necessity to develop a methodological consensus preferably without culture, to approach this important topic in the coming years., SCOPUS: ar.j, info:eu-repo/semantics/published

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Etude réalisée dans le cadre du programme de interdisciplinaire de recherche PIREN-Seine (CNRS), info:eu-repo/semantics/published

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Etude réalisée dans le cadre du programme de interdisciplinaire de recherche PIREN-Seine (CNRS), info:eu-repo/semantics/published

Etude réalisée dans le cadre du programme de interdisciplinaire de recherche PIREN-Seine (CNRS), info:eu-repo/semantics/published

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Internal pipe surfaces within drinking water distribution systems (DS) are colonised by bacteria forming a biofilm. Detachment of cells from the biofilm leads to a deterioration of the microbiological water quality. This justifies the requirement for biofilm investigation in DS. This paper presents data on biofilm gained over a long period in the different areas of the Parisian suburbs DS. Two different systems were tested to incubate cast-iron coupons in DS to measure biofilm after colonisation in order to study biofilm. It shows that a simple and inexpensive system can be efficiently used for this purpose. Fixed bacterial biomass was routinely estimated, in this study, on cast-iron coupons by potential exoproteolytic activity (PEPA) and sometimes by epifluorescence microscopic enumeration performed after bacteria detachment from the support by sonication. Bacterial biomass in the biofilm ranged from 0.009 to 0.56 μgC cm-2 in the studied distribution systems. Comparing bacterial numbers in the water phase, on one hand, and fixed to pipe walls, on the other hand, showed that fixed cells were much more abundant than the suspended cells in DS (25 times in a 100 mm diameter pipe). The large set of data gained on biofilm within the Parisian suburbs DS allows us to demonstrate, on full scale data, the major role of disinfectant (chlorine) residual and biodegradable dissolved organic carbon (BDOC) as controlling factors of the biofilm in DS., info:eu-repo/semantics/published

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