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

To investigate the factors influencing the artificial transformation in Escherichia coli, E. coli C 600 was transformed by pBR322 DNA with tetracycline and ampicillin resistant gene purified by CsCL-EtBr equilibrium density gradient centrifugation from E. coli HB 101. The best conditions for the transformation of E. coli C 600 with pBR322 DNA were treatment with 100mM CaCl2, ice incubation at 0 deg C for 45 minutes, heat shock at 42 deg C for 4 min., 30 min. of ice incubation and incubation at 37 deg C for 100 min. for gene expression in that order

In the conditions of the Republic of Belarus there was created an adhesive antigen on the basis of bacterial suspension of Escherichia which were separated from culture media by means of purification and concentration on membranes UMP-300 and UMP-5 that made it possible to obtain a cleaned-up preparation the specific activity of which was in 2-4 higher that of the unpurified one. In course of the study there was developed a method of purification and concentration of adhesive Escherichia antigens with the help of membrane technology. There were obtained biologically active adhesive antigens E.coli K88, K99, F41, 987P; there were selected the ultrafiltration membranes providing the optimal selectivity and productivity of the process; there were studied the influence of some factors on the process of adhesins concentration by means of ultrafiltration method. During the experiments there was analysed the agglutinating activity of antigents prepared by different methods.