Full text
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| Author(s): |
Camila Carlos
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2010-02-24 |
| Examining board members: |
Laura Maria Mariscal Ottoboni;
Valeria Maia de Oliveira;
Luciana Campos Paulino
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| Advisor: | Laura Maria Mariscal Ottoboni |
| Abstract | |
The detection of fecal coliforms and enterecocci in water indicates the presence of waterborne pathogens such as Salmonella and Giardia. The identification of the source of fecal contamination is important for the effective management of superficial water pollution. The development of methods for the identification of the source of fecal contamination is essential to preserve the quality of the water systems and to protect the public health. Until now, there is no universal method for this analysis and, in Brazil, there is no research in this area. In this way, the aim of this work was to obtain host-specific molecular markers in Escherichia coli for the identification of the source of fecal contamination in superficial water. For this work it was used, 174 strains from humans, 50 from cows, 39 from pigs, 29 from sheep, 16 from goat, 16 from chickens, 44 from sewage, 36 from water reservoirs whose the expected contamination source is human and 30 from water reservoirs and rivers whose the expected contamination source is animal. The determination of the phylogenetic groups of all strains was performed by the detection of the genes chuA and yjaA and the fragment Tspe4.C2 by PCR. The results showed that the distribution of the phylogenetic groups A, B1, B2 and D differs among the hosts analyzed, which allowed the prediction of the contamination source of most of the environmental samples. One hundred strains from humans, 50 from cows, 39 from pigs, 29 from sheep, 16 from goat and 16 from chickens were analyzed by BOX- and (GTG)5-PCR. The BOX-PCR presented an overall rate of correct assignment of 63.70%, the (GTG)5-PCR of 49.10% and, when the two methods were used, the rate was 57.61%. Thirty two other strains from humans and 28 strains from sewage were analyzed by BOX-PCR and compared with the profiles previously obtained. 59.4% of the human strains were correctly assigned as human and 85.2% of the sewage strains were assigned as human. Twenty strains from humans, 15 from cows and 16 from chickens were analyzed by Fourier transform infrared spectroscopy (FT-IR). The use of a PLS-DA model with the second derivative of spectra at the region 2816 and 3026 cm-1 made it possible to completely discriminate the strains according to the animal source. Therefore, the FT-IR spectroscopy was considered the most promising method for the identification of fecal contamination. (AU) | |