鷄由來 病原性 大腸菌에 관한 硏究 2. 大腸菌感染 病鷄로부터 分離한 大腸菌의 抗菌性 藥劑耐性 및 傳達性 耐性因子(R. plasmid)

Studies on Pathogenic Escherichia coli Isolated from Chicken with Colibacillosis 2. Antimicrobial Drug Resistance and Transferable R Plasmid in Escherichia coli

Three hundred and ninety-one strains of Escherichia coli isolated from chicken with colibacillosis were tested for their resistance to 13 antimicrobial drugs by the use of disc diffusion test. The transfer of drug resistance by conjugation was also tested. Ninety percent of the 391 strains tested were resistant to tetracycline, 82.9% to streptomycin, 80.3% sulfonamides, 68.3% to nitrofurantoin, 44.5% to carbenicillin, 32.5% to ampicillin, and 30.2% to chloramphenicol, while percent of strains resistant to neomycin, kanamycin, cephalothin and trimethoprim-sulfamethoxazole was less than 30%, respectively, and 1 strain was resistant to gentamicin, and all of the strains were susceptible to colistin. Three hundred and eighty five strains(98.5%) of 391 were resistant to one or more drugs tested. Fifty five(61.1%) of 90 strains which were resistant to one or more drugs transferred all or a part of their resistance patterns to the recipient strain of E. coli ML 1410. All of five strains resistant to 6 drugs transferred the resistance, and the frequency of resistance transfer increased, as the number of resistant drugs increase.