Non-myeloma light chain cast nephropathy: a multicenter retrospective study on clinicopathological characteristics

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Distribution of Genes Encoding Putative Virulence Factors and Fragment Length Polymorphisms in the vrrA Gene among Brazilian Isolates of Bacillus cereus and Bacillus thuringiensis

One hundred twenty-one strains of the Bacillus cereus complex, of which 80 were isolated from a variety of sources in Brazil, were screened by PCR for the presence of sequences (bceT, hblA, nheBC, plc, sph, and vip3A) encoding putative virulence factors and for polymorphisms in variable-number tandem repeats (VNTR), using a variable region of the vrrA open reading frame as the target. Amplicons were generated from isolates of B. cereus and Bacillus thuringiensis for each of the sequences encoding factors suggested to play a role in infections of mammals. Intriguingly, the majority of these sequences were detected more frequently in Bacillus thuringiensis than in B. cereus. The vip3A sequence, which encodes an insecticidal toxin, was detected exclusively in B. thuringiensis. VNTR analysis demonstrated the presence of five different fragment length categories in both species, with two of these being widely distributed throughout both taxa. In common with data generated from previous studies examining European, Asian, or North American populations, our investigation of Brazilian isolates supports the notion that B. cereus and B. thuringiensis should be considered to represent a single species

Distribution of airborne Mycosphaerella graminicola inoculum at the field scale

A network of 10 Burkard 7-day spore-recording traps was set up in the Walloon region in Belgium to monitor the airborne inoculum of wheat pathogens. Three spore traps were used to analyse the distribution of Mycosphaerella graminicola inoculum at the field scale, at 1 m above ground level. Two traps were set up in a wheat field 100 m apart. The third trap was placed 70 m away in a sugar beet field adjacent to the wheat field. Total DNA from each fragment of spore trap tape corresponding to 1 day sampling was extracted and the quantity of M. graminicola was assessed using real-time polymerase chain reaction (PCR) assay. The experiment was conducted from July to October 2009. Positive detections were obtained for between 33 and 36 days, depending on the spore traps. When detected, the daily quantities of cDNA, collected from a volume of 14.4 m3, fluctuated between 4.84E+00 and 6.10E+03. Correlation coefficients higher than 0,82 and no significant differences were observed between the quantities of M. graminicola collected by the three spore traps, indicating that, at 1 m above ground level, the distribution of inoculum can be considered as homogenous at the tested field scale. This study confirms that spore traps coupled with real-time PCR could be used to assess the airborne inoculum of M. graminicola and to understand the development of the disease at this scale

Spore traps network : a new tool for predicting epidemics of wheat yellow rust

A network of Burkard 7-day spore - recording traps was set up in the Walloon Region in Belgium to monitor the airborne inoculum of wheat pathogens. The relationship between the airborne inoculum of Puccinia striiformis f.sp. tritici, the causal agent of stripe rust, and the disese incidence on plants in untreated plots locaed near each spore traps was studied during the 2008-2009 season. The presence of airborne inoculum was tested in four locations on tapes collected from the Burkard spore traps from 1 April to 14 June 2009. Total DNA from each fragment of spore trap tape corresponding to 1 day sampling was extracted. P. striiformis f. sp. tritici was quantified by real-time polymerase chain reaction(PCR) assay using specific primers and SYBRGreen. The airborne inoculum of P.striiformis was frist detected between 7 and 13 April 2009, depending on the location in the Walloon Region. The first syptoms of sripe rust were observed in the fields between 15 May and 2 June 2009. The onset of the disease symptoms was always preceded by a higher peak of airborne inoculum about 15 days earlier. When P. striiformis f.sp. tritici was detected, the daily quantities of spores, collected from a volume of air of 14.4m3, fluctuated between O.23 and 154.66. This study shows that spore traps coupled with realtime PCR could be used to assess the airborne inoculum of P. Striiformis in order to understand and predict stripe rust outbreaks

Mixtures effect of antibiotics on soil microbial nitrogen processes

Background and objective :During the last two decades, the environmental concern regarding the antibiotics has increased considerably. The persistence of both antibiotics and antimicrobial resistances in the environment has become a major human health and research issue. However their ecotoxicological impacts on microbial ecosystem functions involving in biogeochemical processes, are still not well-understood (Roose-Amsaleg & Laverman, 2016). Furthermore, the environmental risk assessment, based on existing guidelines for other chemicals, may overlook adverse effects of antibiotics on environmental microorganisms and related functions (Boxall et al., 2012), due to the lack of representativeness of ecotoxicological tests for bacterial toxicity in guidelines for environmental risk assessment of antibiotics. In addition, while ecosystems are contaminated by mixtures of chemicals rather than individual substances, toxicity mixture effects of antibiotics on key microbial processes have been not investigated (Brandt et al., 2015). The scope of this study was to unravel the mixture toxicity of antibiotics on soil microbial nitrification and denitrification processes, to improve knowledge of suitable ecotoxicological endpoints, for risk assessment.Methods and results : The tested antibiotics were belonged to several classes (tetracycline, sulfonamide, macrolide, fluoroquinolone) with various modes of action. The effects of each antibiotic individually and as mixtures were assessed across dose-response approaches (performed with R software, DRC package) on potential nitrification in slurry bioassay (NF EN ISO 14238) and denitrification (Roose-Amsaleg et al., 2013) of soil microbial communities. Antibiotic mixtures were built-up in order to test additivity, based on Toxic Unit (TU) ratio, in addition to other mixtures close to environmental surveys (literature data). The antibiotic exposure was verified by measuring the concentrations of antibiotics at the beginning and the end of the experience. Complementary investigations were realized on community structure parameters of specific N-cycling microbial guilds with molecular approaches, to help us in identifying key actors involving in structure – function relationships (species interaction). The first results demonstrated strong differences of magnitude effect among each antibiotic individually, in relation with the mode of action of AB and different levels of sorption on soil components, influencing their bioavailability in the nitrification bioassay. The results of the experimental approaches were analyzed regarding mathematical modeling interpretation based on the concepts of concentration addition or independent action. In many cases, independent action concept better predicted mixture toxicity of different classes of antibiotics, harboring different mode of action. The responses of structural parameters of microbial guilds were observed at higher concentration than the functional endpoints. The decreases of abundances of several microbial groups were correlated with those of the respective activities.Discussion and conclusion : Ecotoxicological effects were recorded at very low concentrations, in our bioassays, based on model microbial communities, in optimal growth conditions. These conditions are not representative of the bulk soil conditions but can correspond to some microbial hot-spots in functional domains, in soils (i.e. rhizosphere). Whilst many previous studies have mainly focused on normalized single species bioassay, significant well-designed studies, improving the integration of ecotoxicological endpoints at the community level, should grab the existing gap on understanding and environmental assessment of mixture impact on microbial ecosystem processes. The archeal nitryfiers / bacterial nitrifyers ratio seems to be related to the magnitude of nitrification responses, only for some antibiotic and the mixture (Konopka et al., 2015). These results can be explained by the lower sensitivity of Archeae to certain antibiotics, notably those targeting the bacterial cell-wall components

Ecotoxicological impact of antibiotic mixtures on soil nitrogen cycling microbial guilds

Ecotoxicological impact of antibiotic mixtures on soil nitrogen cycling microbial guilds. 1st International Conference on the Risk Assessment of PHarmaceuticals in the Environmen

Three cases of post-cataract surgery endophthalmitis due to Rhizobium (Agrobacterium) radiobacter.

WOS: 000302148700067International audienceWe present three unrelated post-cataract surgery endophthalmitis cases caused by Rhizobium radiobacter, hospitalized in three different hospitals. Early diagnosis was obtained in two cases by bacterial DNA detection in vitreous samples. All patients recovered from infection, but pars plana vitrectomy was needed in two patients due to rapid clinical deterioration