Virulence factors of Escherichia coli in relation to the importance of vaccination in pigs/Fatores de virulencia da escherichia coli associados a importancia da vacinacao nos suinos

Enterotoxigenic Escherichia coli (ETEC) is the major cause of diarrhea in newborn and weaned pigs. Bacteria adhesion to the host cell is considered a specific phenomenon among fimbrial and nonfimbrial adhesins with their respective receptors on enterocytes. Enteric disorders are related with the fimbriae F4 (K88), F5 (K99), F6 (987P), F41, and F18. In addition to ETEC, another category of E. coli, porcine pathogenic E. coli (PEPEC),can cause diarrhea in pigs; it produces the porcine attaching and ejfacing-associated (Paa) adhesin in, which is capable to cause a typical lesion known as an attaching and effacing (A/E) lesion. Immunization of sows with adhesin is important to stimulate the production of antibodies and their subsequent transfer to piglets through colostrum. The aim of this paper is to illustrate the main impacts of enteric diseases caused by E. coli in swine production and to highlight the importance of continuing research on this bacterium to improve disease prevention through vaccination. Key words: colibacillosis, diarrhea, vaccines, swine, colostrum. Escherichia coli (E. coli) enterotoxigenica (ETEC) e considerada importante causa de diarreia em suinos neonatos e desmamados. A adesao da bacteria a celula do hospedeiro e considerada um fenomeno especifico entre as adesinas fimbriais e nao fimbriais com seus respectivos receptores nos enterocitos. Os disturbios entericos estao relacionados com as fimbrias F4 (K88), F5 (K99), F6 (987P), F41 e F18. Alem da ETEC, outra categoria de E. coli pode causar diarreia nos suinos, denominada de PEPEC (porcine pathogenic E. coli), a qual produz a adesina Paa (Porcine attaching adherence), capaz de provocar uma lesao tipica denominada A/E (attaching and effacing). A imunizacao das matrizes com adesinas e importante para estimular a producao de anticorpos e a consequente transferencia atraves do calostro aos leitoes. O objetivo deste trabalho foi mostrar os principais impactos das doencas entericas causadas por Escherichia coli na producao de suinos, e mostrar a importancia de atualizar o estudo dessa bacteria para prevenir a doenca atraves da vacinacao. Palavras-chave: colibacilose, diarreia, vacinas, suinos, calostro.