The purpose of this study was the examination for presence of K99 antigen (K99), enterotoxigenicity, 0-groups, colicin and antibiotic susceptibility among E. coil isolated from calves and cows.
A total of 49(18.7%) among 262 strains, isolated from 30(26.5%) out of 113 calves and cows, possesed K99, and thirty three of 49 K99^+ strains produced ST. Of the strains of diarrheal calf origin which less than 15 days old, a high correlation was observed between enterotoxigenic ability and K99: 92.3% of the K99^+ strains produced heat stable enterotoxin(ST).
In O group typing of 33 ST^+ strains, they belonged to O20(48.4%), O8(9.1%), O9(6.1%), O139(6.1%), O149(6.1%), O101(3.0%), O115(3.0%), except six which were untypable or autoagglutinable.
Of 262 E. coil isolates, 30 strains(13.3%) produced colicin and K99 were detected in 6 strains.
One hundred eighty eight strains(71.8%) of 262 E. coil isolates were resistance to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, alone or in combination thereof.
One hundred and fourteen(60.6%) out of 188 drug resistance strains carried R factor(R^+) which were transferable to the recipients by conjugation. Sixty five R^+ strains(57.0%) carried therm osensitive R plasmid.
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