Prevalence and transfer of R- plasmids in Escherichia coli isolates from healthy adults

摘要

A total of 111 Escherichia coli strains were isolated from healthy adults for their susceptibility to tetracycline (Tc). Chloramphenicol (Cm), Streptomycin (Sm), Rifampicin (Rif) and Kanamycin (Kin). 42.6,37.89, 17.38,10.06 and 4.43% strains showed resistance to Tc, Sm, Cm, Rif and Kin. respectively, of which about 14.01% strains were multiresistant. The resistant strains showed a wide range of resistance level (MIC values i 2.5 to 3200 #mu#g/ml). Most of the fecal samples were resistant to Tc (83.76%), Sm (79.3%). Cm (57.7%), Cm (57.7%), Rif (32.4%) and Km (18.9%). Fifty strains, each showing resistance to Tc, Cm and Sm. were selected and mated individually with E. Coli AK 529 strain. In 25 and 38 strains very high frequency transfer of Tc and Cm resistance respectively, was detected; in 14 strains simultaneously transfer of Tc and Cm resistance occurred at high frequency. The data indicated that in these strains Tc and Cm resistance genes might be located on self-transmissible/mobilizable plasmids.