The oil emulsion and alhydrogel pilli vaccines were prepared from a strain (O9: K35, K99, F41) of enterotoxigenic Escherichia coli isolated from calves with diarrhea and their immunogenicity was tested in guinea-pigs, pregnant goats and cows. Serum antibody responses to K99 and F41 antigens in guinea-pigs given experimental oil and gel vaccines peaked at 4 and 6 weeks after vaccinations. At that time, the mean hemagglutination inhibition titers to K99 and F41 antigens in guinea pigs given oil vaccine were 1:25 and 1:1,218 and those given gel vaccine were 1:54 and 1:724 respectively

This paper deals with the 0 groups of citrate utilizing variants of Escherichia coli (Cit+ E. Coli) isolated from cattle, the production of colicin, hemolysin, K99 antigen, heat stable enterotoxin, and the isolation of plasmid DNA. Among 42 Cit + E. Coli, 12 strains were 020, 9 strains 08, 5 strains 045, 3 strains 0115, 1 strain 064, 1 strain 0139 and remaining strains (11) were untypable. Thirty-nine(81.3%)out of 48 Cit + E. Coli produced colicin and 13(27.0%) produced hemolysin. Of 12 cit + E. coli bearing K99 antigen, 6(50.0%) produced heat stable enterotoxin. In gel electrophoresis for the isolation of plasmid DNA, the number of plasmids varied from 1 to 7 in 10 Cit+ E. Coli. Its molecular weight ranged from 2 to 50 Mdalton, and 50 Mdalton plasmid commonly existed in all strains

The prevalence of diarrhea caused by enterotoxigenic Escherichia coli was surveyed on 445 calves in 6 farms which were located in the central part of Korea. The incidence of enterotoxigenic Escherichia coli in calves with diarrhea was investigated by detecting the K99 and F41 antigens from the isolated strains of Escherichia coli. The incidence of colibacillosis in calves was 23.3%. Of 238 strains of Escherichia coli isolated from calves with diarrhea, 73 strains (30.6%) were proved possessing the K99 antigen by mannose-resistant hemagglutination (MRHA) using horse red blood cells and 79(33.1%) possessing F41 antigens by MRHA using guinea-pig red blood cells

This study was conducted to isolate etiological agents from the 103 scouring piglets in Kyongnam area and also carried out antimicrobial drug susceptibility test and epidemiogical survey. The incidence of scouring piglet was most prevalent in 81.6% at the age of 2 to 4 weeks after birth, while the rate was less than 10% at the age of 5 to 6 weeks and under 1 week after birth. When comparing the isolation frequency of each etiological agent, enteropathogenic E. coli was most prevalent in 46.6%, thermophilic Campylobacter in 26.2% and Salmonellae was in 8.7% in that order. In the OK serotyping for 117 isolates of enteropathogenic E. coli, type 0141 : K85(20.5%), 0157:K88ac(14.5%), 0138:K81 and 0149:K91 (13.3%) were encountered most frequently. In the biotyping for 27 isolates of thermophilic Campylobacter, most strains of C. jejuni belonged to type I (50.0%) and II (25.0%), and most strains of C. coli belonged to biotype I (78.9%). In the serotyping for 9 strains of Salmonellae, 3 strains were grouped as D, 2 strains as C and 1 strain each was group B and E. The other 2 strains were untypable. The 117 isolates of enteropathogenic E. coli were resistant more than 90% to erythromycin, penicillin, tetracycline and streptomycin, whereas about 90% of the isolates were sensitive to kanamycin and gentamicin. In the case of Salmonellae, all of the isolates were resistant to penicillin, but about 89% of the isolates were sensitive to gentamicin and colistin. All of C. jejuni and C. coli isolates were resistant to cephalothin, but more than 89% of C. jejuni and C. coli were sensitive to kanamycin and gentamicin