Article

Relationships between fecal indicators and pathogenic microorganisms in a tropical lagoon in Rio de Janeiro, Brazil

Departamento de Biologia Marinha, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Prédio do CCS, Bloco A, sala A1-071, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Rio de Janeiro, Brazil, CEP 21944-970.
Environmental Monitoring and Assessment (Impact Factor: 1.68). 05/2009; 164(1-4):207-19. DOI: 10.1007/s10661-009-0886-9
Source: PubMed

ABSTRACT Rodrigo de Freitas Lagoon is an urban ecosystem undergoing accelerated degradation, therefore selected as a model for microbiological quality studies of tropical lagoons. The aim of this study was to evaluate the abundance and the spatial distribution of fecal pollution indicators and pathogenic microorganisms in the lagoon. The relationships between microbial groups and abiotic measurements were also determined to evaluate the influence of environmental conditions on bacterial distribution and to identify the capability of coliforms and Enterococcus to predict the occurrence of Vibrio, Staphylococcus aureus, and Salmonella. Surface water samples were collected monthly, from December 1999 to October 2000. Analyses were performed by traditional culture techniques. A uniform spatial distribution was observed for all bacterial groups. The fecal pollution indicators occurred in low abundances while potentially pathogenic microorganisms were consistently found. Therefore, our study supported the use of counts of coliforms and Enterococcus to indicate only recent fecal contamination.

0 Followers
 · 
114 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Microbiological pollution in water bodies is characterized through the detection of indicator organisms like total coliform (TC) and fecal coliform (FC) bacteria. The objective of the present paper was to determine the sensibility of these indicators of the presence of pathogenic enterobacteria in four Mexican aquatic systems. Two with major anthropogenic influence: Patzcuaro Lake and Xochimilco Lake ecosystem; and two with less: Metztitlan Lagoon and Zirahuen Lake. TC and FC were quantified with the Most Probable Number technique in water and sediment and enteric bacteria were isolated in water using selective culture media. The sensibility index, the risk attributable, and the presenceabsence of indicators and pathogens were evaluated. Patzcuaro and Xochimilco showed high bacterial pollution. The sediment presented higher concentrations of total and fecal coliforms than water. FC were the most reliable indicators to predict the presence of Salmonella and Shigella, with a sensitivity of 60 and 75%, an attributable risk of 58 and 67% for each genus. FC showed a presence-absence relationship with a percentage of true cases of 82 to 88%. In contrast, TC showed a low attributable risk, inferior to 27% and a high percentage of false positives (65%), which impede to consider it a good indicator. It is convenient to evaluate the presence of indicators and pathogens simultaneously to determine the sanitary risk when characterizing microbial water quality in aquatic ecosystems.
    Hidrobiológica: [revista del Departamento de Hidrobiología] 04/2013; 23(1):87-96. · 0.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: El aumento del uso del agua para diferentes fines y el crecimiento de la población a nivel mundial han contribuido al incremento de los niveles de contaminación de los sistemas acuáticos. La contaminación de estos ecosistemas es una problemática que se presenta en la actualidad, debido al constante vertimiento de desechos domésticos e industriales que constituyen una fuente de deterioro del medio ambiente. El control de la calidad microbiológica del agua de consumo y de vertido, requiere de análisis dirigidos a determinar la presencia de microorganismos patógenos. La alternativa para realizar un control fiable, económico y rápido de la calidad microbiológica del agua es el uso de indicadores de contaminación fecal. Entre los indicadores de contaminación fecal más utilizados se encuentran los coliformes totales y termotolerantes, Escherichia coli y enterococos. Las bacterias indicadoras permiten realizar la clasificación sanitaria de las aguas para diferentes usos, la determinación de criterios para las normas de calidad, la identificación de contaminantes, el control de procesos de tratamiento de agua y estudios epidemiológicos, etc. El presente trabajo aborda los principales aspectos que han sido reportados acerca de la utilidad de las bacterias indicadoras en la evaluación de la calidad del agua. Se exponen estudios que demuestran la factibilidad del uso de E. coli y enterococos como indicadores de contaminación fecal para la evaluación de la calidad de agua y las técnicas utilizadas para su detección, así como el uso de la relación E. coli/enterococos para determinar el origen de la contaminación. Además, se aborda brevemente la situación actual en Cuba con respecto a este tema.
  • [Show abstract] [Hide abstract]
    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.
    Brazilian Journal of Biology 08/2014; 74(3):612-622. DOI:10.1590/1519-6984.26712 · 0.68 Impact Factor