Resumo

ESPINOSA, Ivette; BAEZ, M; PERCEDO, María Irian  e  MARTINEZ, Siomara. Evaluation of simplified DNA extraction methods for Streptococcus suis typing. Rev Salud Anim. [online]. 2013, vol.35, n.1, pp. 59-63. ISSN 0253-570X.

Streptococcus suis is a gram-positive bacterium that causes serious diseases in pigs and in humans with occupational risk. The DNA extraction methods for amplification of gene fragments by PCR for typing S.suis may be complex, and expensive chemical reagents and time consuming. The aim of this study was to evaluate a method for the rapid release of the genomic DNA from S.suis colonies by using a physical method based on heating and freezing; in this case, temperatures of 100^oC and 95^oC were tested. The results showed that DNA extraction directly from colonies by heating at 100^oC could be useful for an easy genotyping of S.suis strains in a short time, while 95^oC was not sufficient for DNA release. The detection limit of the PCR assay using DNA obtained by chemical purification was 0.5ng; considering the size of S.suis genome, it is possible to estimate that an adequate amount of cells are in a single S.suis colony to ensure the sensitivity of the PCR assay.

Palavras-chave : Streptococcus suis; direct colony PCR.

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