Escherichia coli serogroups isolated from streams in Pennsylvania, 1965 to 1972.

Of 3,200 cultures of Escherichia coli isolated from streams in Pennsylvania over a 7-year period, 82.46% or 2,639 were O serogrouped. The largest number of cultures (33.4%) belonged to O groups 1 to 26, and the second highest number (16.8%) belonged to O groups 60 to 88. The individual E. coli O groups most frequently isolated were ADO3, 18ac, 2a, 3, 7, 73, 139, and OX13. Practically every known standard E. coli O group was found in the streams. It was not possible to identify the K and H antigen of every E. coli isolate. Serotypes of E. coli O2a:K1:H6, O26:K60:H11, O55:K59:H27, O86:K62:H2, 112ab:K68:H2, 125ab:K70:H21, 128ab:K67:H2, and O138:K81:H14 known to be pathogenic for humans and animals were identified. Cultures having the same K antigen but a different H antigen for enteropathogenic E. coli O groups 6, 18ab, 18ac, 111ab, 126, 127a, 139, 141, and 147 were also isolated.