Plasmid DNA analysis by agarose gel electrophoresis on an epidemic-associated strain of trimethoprim resistant Shiga's bacillus from Gimira Wereda (Keffa administrative region, southwest Ethiopia).

A combination of genetic mating experiments and plasmid DNA analysis by gel electrophoresis was carried out on an epidemic-associated Shiga's bacillus with resistance type ACSSuTTp, isolated in 1983 from Gimira Wereda, Keffa Administrative Region, South West Ethiopia. The donor strain contained 9 plasmid species. Their sizes in megadaltons (Mdal) were: 120, 40, 35, 12.5, 6.0, 5.1, 4.3, 2.5 and 1.7. Analysis of Escherichia coli K12 transconjugants revealed that the 40, 35, and 4.3 Mdal plasmids coded for tetracyline-trimethoprim, ampicillin -chloramphenicol and streptomycin-sulphadiazine resistance respectively.