Avaliação da eficiência de métodos rápidos usados para detecção de coliforme totais e coliforme fecais em amostras de água, em comparação com a técnica de fermentação em tubos múltiplos
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Data
2005-06-30
Autores
Greghi, Simone de Queiróz [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A água de consumo humano é um dos importantes veículos de enfermidades diarréicas de natureza infecciosa, o que torna primordial a avaliação da sua qualidade microbiológica. Métodos que permitam a identificação de bactérias indicadoras, como os coliformes, são preferidos para estas análises, pois sua presença indica a possível existência de patógenos. Como existem diversos métodos que podem ser utilizados para esta finalidade, o objetivo deste estudo foi comparar a eficiência dos métodos rápidos Colilert (Idexx) (TSD-C) e Readycult Coliformes (Merck) (TSD-R) com a Técnica de Fermentação em Tubos Múltiplos (TFTM), para a determinação de bactérias coliformes totais, coliformes fecais, em amostras de águas de diversas origens. Foram analisadas 219 amostras divididas em 3 grupos águas de sistemas de abastecimento público, águas de superfície e águas subterrâneas, que foram coletadas no período de dezembro de 2002 a junho de 2003. Para a quantificação de coliformes totais observou-se nos métodos Colilert e Readycult que a sensibilidade e a especificidade foram altas, (> 95%), e o coeficiente kappa foi muito próximo de 1, indicando concordância ótima entre estas técnicas e a TFTM. Para a determinação de coliformes fecais observou-se que a especificidade foi máxima (100%) em ambos os métodos rápidos, a sensibilidade foi alta para o método Readycult (87%), mas menor para o método Colilert (> 76%); o coeficiente kappa foi alto para o método Readycult (0,85), e menor para o método Colilert (0,74) indicando concordâncias ótima e boa, respectivamente. O uso destas técnicas permite a obtenção de resultados em 24 horas, representando grande vantagem pela rapidez e a possibilidade de correção de problemas existentes, principalmente em sistemas de abastecimento.
The water used for human intake is one of the most important vehicles for infective diarrheic diseases, which make the evaluation of its microbiological quality fundamental. Methods that allow the identification of indicative bacteria are preferred for these types of analyses. The presence of faeces contamination such as coliformes, indicates the possible existence of pathogens. Since there are several methods that could be used for this purpose, the objective of this study was to compare the efficiency of the quick methods. The methods Colilert (Idexx) (DST-C) and Readycult Coliforms (Merck) (DST-R) with the Technique of Fermentation in Multiple Tubes (TFTM), were considered for the determination of total coliform, fecal coliforms, in samples of water from several sources. The study analyzed 219 samples collected in the period between December 2002 and June 2003. These samples were divided into 3 groups: general public/ water supply systems; surface waters and underground waters. Colilert and Readyculty methods were used to quantify total coliforms contamination. Sensibility and specificity were high, over 95%. The kappa coefficient was verging on 1, indicating a positive correlation between these techniques and TFTM. To determine fecal contamination it was noticed that the specificity was at it's maximum (100%) in both quick methods and the sensibility was high for the Readycult method (87%), but slightly lower for the Colilert, over 76%. The kappa coefficient was high for the Readycult method (0,85), and lower for the Colilert methods (0,74), indicating a positive correlation. The use of these techniques enables the ability obtain the results in 24 hours, offering great advantages in its speed and the possibility of correcting existing problems, in corrent water supply systems.
The water used for human intake is one of the most important vehicles for infective diarrheic diseases, which make the evaluation of its microbiological quality fundamental. Methods that allow the identification of indicative bacteria are preferred for these types of analyses. The presence of faeces contamination such as coliformes, indicates the possible existence of pathogens. Since there are several methods that could be used for this purpose, the objective of this study was to compare the efficiency of the quick methods. The methods Colilert (Idexx) (DST-C) and Readycult Coliforms (Merck) (DST-R) with the Technique of Fermentation in Multiple Tubes (TFTM), were considered for the determination of total coliform, fecal coliforms, in samples of water from several sources. The study analyzed 219 samples collected in the period between December 2002 and June 2003. These samples were divided into 3 groups: general public/ water supply systems; surface waters and underground waters. Colilert and Readyculty methods were used to quantify total coliforms contamination. Sensibility and specificity were high, over 95%. The kappa coefficient was verging on 1, indicating a positive correlation between these techniques and TFTM. To determine fecal contamination it was noticed that the specificity was at it's maximum (100%) in both quick methods and the sensibility was high for the Readycult method (87%), but slightly lower for the Colilert, over 76%. The kappa coefficient was high for the Readycult method (0,85), and lower for the Colilert methods (0,74), indicating a positive correlation. The use of these techniques enables the ability obtain the results in 24 hours, offering great advantages in its speed and the possibility of correcting existing problems, in corrent water supply systems.
Descrição
Palavras-chave
Agua - Análise - Araraquara (SP), Coliformes fecais, Análise bacteriológica, Escherichia coli, Bacteriologic analysis, Total coliforms bacteria
Como citar
GREGHI, Simone de Queiróz. Avaliação da eficiência de métodos rápidos usados para detecção de coliforme totais e coliforme fecais em amostras de água, em comparação com a técnica de fermentação em tubos múltiplos. 2005. 83 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Farmacêuticas, 2005.