title: Characterization of the microbial community in a lotic environment to assess the effect of pollution on nitrifying and potentially pathogenic bacteria.
abstract: This study aimed to investigate microbes involved in the nitrogen cycle and potentially pathogenic bacteria from urban and rural sites of the São Pedro stream. Water samples were collected from two sites. A seasonal survey of bacterial abundance was conducted. The dissolved nutrient content was analysed. PCR and FISH analysis were performed to identify and quantify microbes involved in the nitrogen cycle and potentially pathogenic bacteria. The seasonal survey revealed that the bacterial abundance was similar along the year on the rural area but varied on the urban site. Higher concentration of dissolved nutrients in the urban area indicated a eutrophic system. Considering the nitrifying microbes, the genus Nitrobacter was found, especially in the urban area, and may act as the principal bacteria in converting nitrite into nitrate at this site. The molecular markers napA, amoA, and nfrA were more accumulated at the urban site, justifying the higher content of nutrients metabolised by these enzymes. Finally, high intensity of amplicons from Enterococcus, Streptococcus, Bacteroides/Prevotella/Porphyromonas, Salmonella, S. aureus, P. aeruginosa and the diarrheagenic lineages of E. coli were observed at the urban site. These results indicate a change in the structure of the microbial community imposed by anthrophic actions. The incidence of pathogenic bacteria in aquatic environments is of particular importance to public health, emphasising the need for sewage treatment to minimise the environmental impacts associated with urbanisation.
authors.affiliation: Departament of Biology, Institute of Biological Science, Federal University of Juiz de Fora - UFJF, Juiz de Fora, MG, Brazil.
authors.forename: J D
authors.initials: JD
authors.lastname: Medeiros
authors.affiliation: Departament of Biology, Institute of Biological Science, Federal University of Juiz de Fora - UFJF, Juiz de Fora, MG, Brazil.
authors.forename: L X
authors.initials: LX
authors.lastname: Araújo
authors.affiliation: Departament of Parasitologyy, Microbiology and Immunolog, Institute of Biological Science, Federal University of Juiz de Fora - UFJF, Juiz de Fora, MG, Brazil.
authors.forename: V L
authors.initials: VL
authors.lastname: da Silva
authors.affiliation: Departament of Parasitologyy, Microbiology and Immunolog, Institute of Biological Science, Federal University of Juiz de Fora - UFJF, Juiz de Fora, MG, Brazil.
authors.forename: C G
authors.initials: CG
authors.lastname: Diniz
authors.affiliation: Departament of Biology, Institute of Biological Science, Federal University of Juiz de Fora - UFJF, Juiz de Fora, MG, Brazil.
authors.forename: D E
authors.initials: DE
authors.lastname: Cesar
authors.affiliation: Federal Institute of Southeastern of Minas Gerais, Juiz de Fora, MG, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Del'Duca
authors.affiliation: Departament of Biology, Institute of Biological Science, Federal University of Juiz de Fora - UFJF, Juiz de Fora, MG, Brazil.
authors.forename: C M
authors.initials: CM
authors.lastname: Coelho
mesh_terms: D001419:Bacteria / Q000145:classification / Q000378:metabolism* / Q000472:pathogenicity; D015169:Colony Count, Microbial; D004784:Environmental Monitoring; D009573:Nitrites / Q000378:metabolism*; D012424:Rural Population; D012621:Seasons; D012722:Sewage / Q000382:microbiology*; D014505:Urban Population; D014876:Water Pollution
chemical_list: D009573:Nitrites; D012722:Sewage