Designation of O174 and O175 to temporary O groups OX3 and OX7, and six new E-coli O groups that include Verocytotoxin-producing E-coli (VTEC):: O176, O177, O178O179O180 and O181

Two temporary Escherichia coli O group strains OX3 and OX7 are given permanent status as 0174 and 0175, respectively. Both these test strains were originally isolated from cases of human diarrhoea. Whereas the 0174 strain is negative for known virulence genes, the O175 strain is positive with the probe derived from the CVD432 plasmid associated with the aggregative adherence phenotype, the Enteroaggregative heat-stable enterotoxin I gene (astA) and daaC (F1845 afimbrial adhesin) associated with the diffuse adherence (DA) phenotype. Additionally, six E. coli strains are established as antigenic test strains for six new 0 groups, designated O176, O177, 0178, 0179, 0180 and 0181. All six strains produced Verocytotoxin and were positive for vtxl, vtx2, or both genes. Additional virulence genes associated with diarrhoeal disease in humans were found in four of the strains. 0176 and 0177 strains were isolated from calves, 0178 and 0181 strains from meat, the 0179 strain was from human bloody diarrhoea, and the 0180 strain from swine. Preliminary data on the occurrence and epidemiology of these eight new 0 groups amongst groups of diarrhoeagenic E. coli are reviewed.