This paper dealt wih the distribution of Shigella spp. on 5 piggeries in Taegu and Kyongbuk during the period from August to October 1987. Isolated Shigella were examined for serogrouping, antimicrobial drug resistance and detection of R plasmid. Genetic properties of R plasmid in Shigella were examined for fertility inhibition (F1) and gel electrophoresis was performed for the isolation of plasmid DNA. Of total 2,978 samples from 5 piggeries, 82 strains (2.8 %) of Shigella spp. were isolated from 82 samples. The isolated strains were identified as S. dysenteriae (60 strains), S. flexneri (20 strains) and S. sonnei (2 strains). Of the 82 strains examined 67 (95.1 %) were resistant to one or more antibiotics, such as ampicillin (Am), chloramphenicol (Cm), kanamycin (Km), nalidixic acid (Na), rifampicin (Rf), streptomycin (Sm), sulfademethoxine (Su), and tetracycline (Tc) and higher resistance to Su (90.2 %), Sm (63.4 %) and Tc (63.4 %). Of the 78 resistant Shigella strains 26 (33.3 %) harbored conjugative R plasmids and the transfer frequency of Sm (50.0 %), Cm (33.3 %) resistance was much higher than that of the other drug resistance. The most common resistant patterns were SmSuTc, Su and AmSmSuTc. Out of the 26 Shigella R plasmids examined for Fi, 14 (53.8 % were Fi + and the remainder were Fi-. The plasmid DNA profiles in Shigella spp. (9 strains) isolated from pigs were confirmed as being 2 to 9 fragments by the gel electrophoresis. Their molecular size ranged 2.17 to 87.62 kilobase (Kb). All strains of Shigella spp. consisted in 15.4 Kb plasmids.

This paper deals with the genetic properties of R plasmids in Salmonella originated from pigs and cattle. The plasmid DNA was examined for incompatibility, stability and fertility inhibition (F1), and gel electrophoresis was performed for isolation of plasmid DNA. Among the 66 conjugative R plasmids from 44 pigs and 22 cattle, 61 R plasmids (92.4 %) were Fi-, whereas the remainder were Fi+. The Inc groups of 66 R plasmids were determined with 7 standard plasmids. Twenty-six R plasmids were classified into Inc group Ialpha, H1, H2 or F1, 40 R plasmids being not classified with standard plasmids used, and the Inc group Ialpha (57.7 %) was most frequent. 3. Inc groups Ialpha H1, and F1 were identified in strains from swine, Inc groups H2 and F1 from cattle. The plasmid DNA profiles in 16 Salmonella isolated from pigs and cattle were confirmed as being 1 to 10 fragments by the gel eletrophoresis. Their molecular weight ranged 1.0 to 90 megadalton. The molecular weight of conjugative plasmids ranged 1.0 to 80 megadalton in 4 Salmonella (P-4, P-5, P-7 and P-8) isolated from pigs.

Nine strains of Yersinia species isolated from pigs and dogs in Korea, comprising 5 strains of Yersinia enterocolitica, 2 strains of Y. kristensenii and each strain of Y. pseudo-tuberculosis and Y. intermedia, were examined for the presence of virulence-associated plasmids, calcium dependency and provocation of guinea pig conjunctivitis (Sereny test). Three strains of Y. enterocolitica isolated from pigs were positive in calcium dependency and harbored one plasmid of about 45 megadalton, but negative in Sereny test

To investigate the epidemiological trait of intestinal diseases of animals caused by thermophilic Campylobacter spp., isolation of etiological agent was carried out and the profiles of plasmids and the transfer of resistance plasmid in the isolated Camplyobacter spp. were examined. A total of 110 isolates of C jejuni and C coli were subjected to the test for the presence of plasmid DNA. Of the isolates examined, 60 % of the isolates were noted to harbor plasmid DNA. Plasmid occurrence rate from pigs, chickens and cattle were 76.2 %, 61.7 % and 37.7 %, respectively. The plasmids of a large molecular weight, ranging from 36 Md to 86Md, were identified with the strains of tetracycline resistant. Transfer frequency of tetracycline resistant plasmids was higher in the case of the filter mating method than in the broth mating method by the factor of 10-1,000. Tetracycline resistant plasmids of C jejuni were transferarble to C jejuni and C coli by conjugation. In a low frequency, the transfer of tetracycline plasmid was also possible to Vibrio parahemolyticus. However, it was impossible to transfer to Streptococcus fecalis, E. coli and Vibrio cholerae. Tetracycline resistant plasmids of C jejuni were impossible to transfer to Campylobacter spp. and related bacteria by transformation