RESUMEN
INTRODUCTION: Freshwater ecosystems provide propitious conditions for the acquisition and spread of antibiotic resistance genes (ARGs), and integrons play an important role in this process. MATERIAL AND METHODS: In the present study, the diversity of putative environmental integron-cassettes, as well as their potential bacterial hosts in the Velhas River (Brazil), was explored through intI-attC and 16S rRNA amplicons deep sequencing. RESULTS AND DISCUSSION: ORFs related to different biological processes were observed, from DNA integration to oxidation-reduction. ARGs-cassettes were mainly associated with class 1 mobile integrons carried by pathogenic Gammaproteobacteria, and possibly sedentary chromosomal integrons hosted by Proteobacteria and Actinobacteria. Two putative novel ARG-cassettes homologs to fosB3 and novA were detected. Regarding 16SrRNA gene analysis, taxonomic and functional profiles unveiled Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria as dominant phyla. Betaproteobacteria, Alphaproteobacteria, and Actinobacteria classes were the main contributors for KEGG orthologs associated with resistance. CONCLUSIONS: Overall, these results provide new information about environmental integrons as a source of resistance determinants outside clinical settings and the bacterial community in the Velhas River.
Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Bacterias/genética , Farmacorresistencia Microbiana/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Integrones/genética , Bacterias/clasificación , Brasil , Ecosistema , Variación Genética , ARN Ribosómico 16S/genética , Ríos/microbiologíaRESUMEN
This paper presents an advanced characterization of the organic fraction of the top deposit layer collected in a French vertical flow treatment wetland (first stage) in operation in Brazil (two units with different organic deposit layer accumulation times), and compares the results with those obtained from studies in France. The organic and inorganic constituents of the samples collected were analysed by biological, chemical and thermochemical methods. The unit with the organic deposit with longer accumulation time (almost 10 years) was characterized as a mature one (organic matter - OM: 51.3 and 52.7%, thermal index - RTGA: 0.79 and 0.85, humification index - HI: 0.61 and 1.16, respectively for the depths of 0-5 cm and 5-10 cm). The unit with the deposit organic with less than three years of accumulation also presented characteristics of a mature deposit (OM: 61.2%, RTGA: 0.79, HI: 1.01 for the depth of 0-5 cm), indicating a rapid mineralization of the deposit under the existing subtropical environment. Despite several differences in term of conception, hydraulic and mass loading rates and accumulation rates, the characteristics of the OM of Brazilian deposits were found to be quite similar to the French ones.