Prevalência, epidemiologia, caracterização sorológica e molecular de Listeria monocytogenes isoladas na criação intensiva de novilhos superprecoces e em abatedouros frigoríficos no Estado de São Paulo / Prevalence, epidemiology, serology and molecular characterization of Listeria monocytogenes isolates in intensive creation of steers in São Paulo State abbatoirs

RESUMO

O Brasil é um dos principais exportadores de carne bovina. A maioria do gado é criada a pasto, porém uma parte já é confinada, como na criação de Novilhos Superprecoces. Este confinamento pode favorecer a contaminação por L. monocytogenes (Lm) do rebanho, bactéria responsável pela listeriose, doencia que provoca aborto, neuropatias e gastrenterites. Com isto, pesquisou-se a presença e característica sorotípicas e moleculares de Lm durante o confinamento de cinco raças de novilhos e em suas carcaças no frigorífico A, assim como amostras de carcaças, utensílios, equipamentos e ambiente em outro frigorífico(B). Foram utilizadas para tipar as cepas técnicas de sorotipagem por multiplex PCR, soroaglutinação PFGE...

ABSTRACT

Brazil is one of the most important beef producer/exporter country worldwide. The majority of the cattle is raised extensively, but some of them are feedloted. Confinement conditions can stress the animals and favor the contamination and proliferation for Listeria monocytogenes (Lm), agent of listeriosis which causes abortion, stillbirths, nervous dysfunctions and gastroenteritis. The aim of this study was to verify the presence of this microorganism and its molecular and serotype characteristics. Two groups of samples were analyzed first, during the confinement of five different breeds of steers and on their carcasses (abattoir A). Second, at the slaughter and processing of other groups of beef cattle (abattoir B). The Lm strains were serotyped with commercial antisera and by multiplex PCR, and subtyped by PFGE. No Lm was found among the 645 samples of feces, environment, feed and water during the confinement, but 13/48 of the refrigerated carcasses were contaminated, as well as the floor and the wall of the cold room at the abattoir A. Amongst the 516 samples of slaughter and processing environments, carcasses, utensils and equipment collected from abattoir B, 27 harbored Lm, being the majority from the c1ean area. Serotype 1/2b and 4b were the most frequent Lm serotypes in the carcasses of the steers in abattoir 1, and 1/2b and 1/2c in the abattoir B. The molecular typing by PFGE resulted in 15 Ascl and 13 Apal profiles, and 21 composite profiles, resulting in seven clonal groups. In these beef production chains the most important critical point for Lm contamination is the c1ean area of meat processing. Same clonal groups could be isolated in both abattoirs and in different areas on abattoir B, demonstrating high dissemination capability of these strains. Therefore, these results could aid the development of good manufacturing practices and HACCP, to prevent or eliminate the contamination for this pathogen...