A total of 593 mastitic pathogens was isolated from the clinical mastitic milk of dairy cattle in Kyonggi area from March 1984 to February 1988. The mastitic pathogens were further studied bacteriologically and examined for susceptibility patterns to 10 antibiotics. 173 pathogens were isolated in the first year of studies, 205 pathogens in the second year, 122 pathogens in the third year and 93 pathogens in the last year. The pathogens isolated from clinical mastitis were more in summer than other seasons. Staphylococcus spp (50%) and Streptococcus spp (18%) were the main pathogens in the first year of studies but coliforms (15%) and other bacteria (40%) were the main pathogens in the last year of studies. Coliform mastitis occurred only in summer and autumn. Antibiotic susceptibility patterns of the same genuses from clinical mastitis infections in different herds and in different years varied greatly. Therefore, treatment should be selected on the basis of susceptibility test results

The present study was carried out to investigate C. jejuni and C. coli in chicken. Also were examined the pathogenicity of the isolates in chicks by experimental inoculation. Thermophilic Campylobacter were isolated from 34 (45.9%) of the 74 specimens, and classified as 21.6 % C. jejuni, and 24.3 % C. coli. In the biotyping of 16 strains of C. jejuni isolates, 37.5 % of the strains were grouped as biotype I, 62.5 % as biotype II. In the case of 18 strains of C. coli isolates, 49.9 % of isolates were grouped as biotype I, 55.6 % as biotype II. In oral inoculation with 10** (4)cfu of Capmylobacter isolates into infant chicks (1 to 3 days-old), 17 days-old and 34 days-old chicks, 32.5 % of the chicks developed diarrhea on day 1, 52.5 % on day 3, 70.0 % on day 5, and 27.5% on day 7, and the peak incidence of diarrhea was reached on day 5. The organisms were found to be discharged in feces one day afterwards. C. jejuni and C. coli strains were detected from the feces in 87.5 % of the chicks on day 5.

Serological study and isolation of Brucellae from dairy cattle were carried out in Kyungbook area of Korea during the period from 1984 to 1985. Biotyping of the isolates was done. Of the 11168 cattle in 2479 herds examined, 27 cattle (0.24%) in the 17 herds (o.69%) were serologically positive for brucellosis. Brucella abortus was recovered from 20 (74.1%) of the 27 infected cattle, and all the strains of the isolates belonged to biotype 1. Of the tissues cultured for brucellae, the supramammary lymph nodes had the highest rate (55.6%) of recovery of brucella organisms

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