Occurrence of F42 colonization factor in Escherichia coli strains isolated from piglets with diarrhea

Inglés. The objective of this study was to determine the presence of the colonization factor F42 in 168 strains of Escherichia coli isolated from diarrheic stools of newborn piglets. The presence of F42 in 12 (7.1%) strains was detected with the agglutination test. Through the Polymerase Chain Reaction (PCR) of F42 positive strains, gene encoding enterotoxins (ST-I, ST-II, LT-I and LT-II) were detected. The finding of ST-I/ST-II genes in 50% of the strains, ST-I (16%) and ST-II (25%) indicates a strong association of FC F42 with heat-stable enterotoxins (91%). In contrast, the thermolabile enterotoxin (LT-I and LT-II) genes were not detected. Serogroups of F42 positive strains were determined, serogroup O8 being the most prevalent (41,7%). Other serogroups, as there are O9, O11, O18, O32, O35, O98 and O101, were also identified. Thus, FC F42 was confirmed as an additional factor of virulence in the pathogenesis of porcine colibacillosis.

Portugués. Este estudo determinou a presença do fator de colonização (FC) F42 em 168 amostras de Escherichia coli isoladas de suínos neonatos com diarréia. Ensaios de soroaglutinação determinaram a presença de F42 em 12 (7,1%) das amostras bacterianas. As amostras de E. coli F42 positivas foram estudadas através de PCR quanto à presença de genes das enterotoxinas (ST-I, ST-II, LT-I e LT-II). 50% das amostras apresentaram genes para ST-I/ST-II, 16% apresentaram genes para ST-I e 25% genes para ST-II. Não foram observados resultados positivos para as enterotoxinas termo-lábeis (LT-I e LT-II), indicando forte associação do FC F42 com as enterotoxinas termoestáveis (91%). O sorogrupo das amostras F42 positivas foi determinado, sendo o sorogrupo O8 prevalente (41,7%) e uma amostra dos sorogrupos O9, O11, O18, O32, O35, O98, e O101. Assim, o FC F42 foi confirmado como um fator de virulência adicional na patogênese da diarréia neonatal suína.