[Identification and characteristics of the conjugative R plasmids of conditionally pathogenic E. coli isolated from chronic pyelonephritis patients].

The study on 63 strains of conditionally pathogenic E. coli isolated from patients with chronic pyelonephritis showed that the bacteria of the 47 strains (74.6%) were resistant to one or several antibiotics. 7 strains of such bacteria carried R-plasmids capable of transferring into the cells of E. coli K-12 during conjugation. Most of the identified 9 R-plasmids belonged to the class of the F-like plasmids and were characterized by similar lots of antibiotic resistance markers. DNA of the detected R-plasmids were treated with endonuclease (restrictase) EcoRI. After that the fragments were analysed by means of electrophoresis in agarose gel. On the basis of the restrictogrames it was concluded that the plasmids studied were not identical. A possibility of detecting complexes consisting of different plasmids carrying similar lots of antibiotic resistance markers in the cells of the same strain was shown.