Expression of type I pili is abolished in verotoxin-producing Escherichia coli O157

Verotoxin-producing Escherichia coli (VTEC) were examined for production of type I pili. None of 34 strains of VTEC serogroup O157 examined expressed any pill, whereas 26 strains of 27 VTEC serogroup O26 and seven strains of nine non-VTEC O157 produced type I pill. These VTEC strains were collected from sporadic human cases and cattle in Okinawa in 1997. The genes encoding the major structural component (FimA) and the adhesin (FimH) of type I pil l were detected in all 70 strains examined. The inability to express type I pill could be a unique character of VTEC O157 and this trait could be a ne w candidate to identify the organisms. (C) 1999 Federation of European Micr obiological Societies. Published by Elsevier Science B.V. All rights reserv ed.