Among 16 strains of diphtheroid isolated from conjunctiva, 7 strains belonged to Corynebacterium xerosis, 6 to C. Pyogenes and 3 were unidentified. And 3 types of different plasmid profiles were observed from 6 strains of them; i.e., one of them was mol. wt. of 37 Mdal., resistant to chloramphenicol and erythromycin from 3 strains, another was mol wt. of 38 Mdal., resistant to chloramphenicol and streptomycin from 1 strain, and the other was mol wt. of 30 Mdal., resistant to chloramphenicol, erythromycin and kanamycin from 2 strains.
These 3 types of plasmid were confirmed with restriction enzyme treatment.
Various experiments for curing were carried out with ethidium bromide and mitomycin C, however, unable to detect the cured ones from the diphtheroid strains isolated.
|