2001, Number 3
Evaluation of virulence and serotypes of Streptococcus suis isolated from slaughterhouse workers in the valley of Toluca in the State of Mexico
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ABSTRACTStreptococcus suis represents a potential zoonosis risk in farms and slaughterhouse workers that manage pigs or its products directly. The purpose of this study was to determine virulence and serotypes of Streptococcus suis involved in high risk areas in four municipal slaughterhouses (Mexicaltzingo, Ocoyoacac, Toluca and San Pablo Autopan) in the valley of Toluca in the State of Mexico. Samples were taken from all workers in each specific area of the slaughterhouses giving a total of n= 69; cotton swab samples were taken from tonsils for isolation, and bacteriological identification of Streptococcus suis by bacteriological and biochemical procedures. Evaluation of virulence was carried out using a murine model, and serotipyfication was made by coagglutination. Evaluation of results was analyzed with non parametric statistics (chi square) with P ‹ 0.05. Isolation of Streptococcus suis was obtained in each studied slaughterhouse (4 strains, 5.7%). Strains were classified as medium- and highly virulent reaching a mortality in mice from 45% to 80%. Serotypes found were 2 and 27, and two strains were not typified. Virulence of human isolated strains in these slaughterhouses was higher than the one used as the reference. In the case of serotype 27 strain, it can be claimed that this is the first world report in human beings, and that the two non typified strains could probably account for new serotypes.
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