Escherichia coli isolates from domestic poultry

Strains (50) of Escherichia coli were isolated from 250 clinical specimens collected from poultry birds; majority of theses were recovered from heart blood. Biochemical characterisation revealed 48.0 and 16.0% atypical strains producing 14,S and urease respectively. Isolates(43) were typed into 17 different 'O' serotypes; 078 was. the predominant. The other serogroups isolated in-decreasing frequency were 02, 019, 020, O90, 038, 01,09, 081, 0148, 0162, 08, 016, 060, 063, 068, 0139 and 0 152, some of which are of zoonotic significance. Six strains remained untypable and I was rough. All the isolates were Congo-red (CR)-positive and 15 produced haemolysis on sheep blood agar. Whole bacterial culture of 45 strains and cell free filtrates of all the isolates caused mortality in mice and chicken embryos. Serotypes 08 and 078 produced enterotoxin in the ligated rabbit ileal loops. A polyvalent adjuvanted vaccine was prepared and found immunogenic.