Evaluation of experimental conditions for quantification of LT produced by human derived enterotoxigenic Escherichia coli strains

Brazilian Journal of Microbiology

Melissa Ang-simões Lasaro²  Juliana Falcão Rodrigues²  Joaquim Cabrera-crespo¹  Maria Elisabete Sbrogio-almeida¹  Marcio De Oliveira Lasaro²  Luís Carlos Souza Ferreira² 

[1] ,Universidade de São Paulo Instituto de Ciências Biomédicas Departamento de MicrobiologiaSão Paulo SP ,Brasil

关键词: heat-labile toxin;    LT;    ETEC;    cELISA;    toxina termo-lábil;    LT;    ETEC;    cELISA;   

DOI  :  10.1590/S1517-83822007000300012

来源: SciELO

【 摘 要 】

The heat-labile toxin (LT) is a key virulence-associated factor associated with the non-invasive secretory diarrhea caused by enterotoxigenic Escherichia coli (ETEC) strains either in humans or domestic animals. Several LT detection methods have been reported but quantification of the toxin produced by wild-type ETEC strains is usually performed by the GM1 ganglyoside enzyme-linked immunosorbent assay (GM1 ELISA). In this study we conducted the optimization of an alternative LT-quantification method, the antibody-capture ELISA (cELISA). Detailed analysis of the appropriate dilutions of capture and detecting LT-specific antibodies significantly improved the sensitivity of the method. Additionally, testing of different LT extraction techniques indicated that sonic disruption of the bacterial cells enhanced LT recovery yields, in contrast to the usual procedure based on addition of polymyxin B to the culture medium as well as extraction methods based on chloroform or Triton X-100. Moreover, the present data indicate that performance of the LT extraction method based on polymyxin B treatment can vary among wild ETEC strains.

【 授权许可】

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