Abstract
The genetic properties of 62 R plasmids derived from Escherichia coli isolated from mynahs imported into Japan from Thailand were investigated. Of these, 8 R plasmids showed thermosensitive transfer and 55 showed Fi- (no fertility inhibition) characteristics. About half of the R plasmids inhibited the development of phage λ, T2, T4 or T7. In incompatibility grouping, 8 R plasmids showing thermosensitive transfer were classified into Inc Hl, 14 were classified into W, and 11 were classified into Iα. Only a few were classified into M and FII. These results indicated that genetic properties of the R plasmids in the present study were different from those of Salmonella or E. coli R plasmids from domestic animals in Japan. On the other hand, because the mynahs which carry E. coli having such plasmids are raised at home, it is assumed that they may be potential reservoirs of R plasmids for home-families who raise and have intimate contact with them.
