家畜 腸內細菌의 抗生物質에 對한 感受性 및 傳達性 耐性因子에 關한 硏究

Resistance and R plasmids of enteric bacteria isolated from domestic animals

Five hundred and nine strains of Esherichia coli isolated from domestic animals and 23 strains of Salmonella isolated from 237 pigs were tested for drug resistance and distribution of R plasmids. Seventy two per cent of E. coli strains isolated from domestic animals fed with antibiotics-containing feeds were resistant to tetracycline(TC), streptomycin(SM), chloramphenicol(CM), ampicillin(AM) and kanamycin(KM), alone or in combination thereof, but about 2% of E. coli strains isolated from domestic animals received no antitiotics were resistant to TC and SM. Among resistant strains, 45.4% were found to be singly resistant to TC, SM or KM, whereas 54.6% were resistant to two or more antibiotics. The most common resistance pattern was double resistant to TC and SM(33.7%) and followed by triple ones to TC, SM and AM(4.9%). About 67% of resistant E. coli carried R factors which were transferable to the recipients by conjugation. Seventy eight per cent of Salmonella strains isolated from pigs were resistant to TC, SM, AM, and KM, alone or in combination thereof, and the most common resistance pattern was resistant to TC and SM(38.9%) slimilary to E. coli and about one half of resistant Salmonella carried R factors. There was no difference in numbers of TC-resistant Coliform for 6 weeks after stopping administration of antibiotics, but they were decreased to one seventh at the 13th week.