1 ml of 10 1 through 10 5 were plated on minimal media containing raffinose as the sole carbon source o salts and nalidixic acid o raf nal to select for nalidixic acid resistant cells which had acquired the ability to ferment raffinose these plates were incubated for 72 hours at 37 u00b0 c 9 colonies arising on o raf nal were restreaked on o raf nal to insure purity and incubated for 48 hours at 37 u00b0 c 10 the plasmid content of the repurified colonies was determined by the examination of cell lysates via agarose gel electrophoresis one strain designated ag750 was shown to contain the original b44 plasmids and to have additionally acquired the k88 raf plasmid from p155 pathogenicity of e coli atcc no 39076 for calves and piglets e coli atcc no 39076 was shown to be capable of inducing scours in both calves and piglets the nalidixic acid resistant e coli was isolated from the feces of the infected animals to determine the plasmid content of the strain being excreted a calves four calves were inoculated with atcc 39076 on day one post infection all demonstrated evidence of scours and feces were plated on emb nal plates to determine cell count per gram of feces either 25 or 50 colonies were picked from emb nal plates and plated onto drigalski raffinose plates all the.