The long polar fimbriae genes identified in Shiga toxin-producing Escherichia coli are present in other diarrheagenic E. coli and in the standard E. coli collection of reference (ECOR) strains

Long polar fimbriae (LPF) are related to type I fimbriae in genetic organization and were first identified in Salmonella enterica serovar Typhimurium. Four lpfA genetic variants designated lpfA O157/OI-141, lpfA O157/OI-154, lpfA O26 and lpfA O113 have been identified in Shiga toxin-producing Escherichia coli (STEC). In this study, PCR was employed to determine the distribution of STEC- lpfAs in enteropathogenic, enteroaggregative, enterotoxigenic and enteroinvasive E. coli (EPEC, EAEC, ETEC and EIEC) and in the standard E. coli collection of reference (ECOR). Among the 97 diarrheagenic strains from our collection, only 2 EPEC strains of serotypes O55:H7 and O119:NM were positive for both lpfA O157/OI-141 and lpfA O157/OI-154. lpfA O157/OI-141 was also positive in 1 of 25 ETEC strains. lpfA O113 was present in 51 of 97 strains and lpfA O26 in 13 of 97 strains of diverse diarrheagenic categories. STEC- lpfAs were also present in non-pathogenic ECOR strains of all phylogenetic groups. This study showed that the lpfA genes identified in the genome of STEC strains are not specific to this category. Our results suggest that there is a relationship between the lpfA variant and the phylogenetic group.