title: [Classification of R-factors. Possible errors and their elimination].
abstract: The necessity for classifying plasmids is emphasized. From our results the uniformity of a nosocomial infectious outbreak is only given by the R-factor and not by the infectious agent. Determination of the appropriate pilus groups by sexphages using the HFRT-system and identification of incompatibility as a further means of subdividing the pilus groups into incompatibility groups is described. A distinction is made between incoming- and resident incompatibility. To eliminate possible errors in plasmid classification the following points are considered: 1. Testing in recombination deficient rec A- -strains of E. coli K12 to avoid any recombination of the plasmids. 2. Trypsin addition to remove the possibility of plasmid coded colicin production. 3. A proper choice of the indicator plasmids. 4. Consideration of the spontaneous loss of the indicator plasmid and also an occurrence of transposons coding for an additional pilus type.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003086:Bacteriocin Plasmids; D003090:Coliphages; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D005144:F Factor; D010861:Fimbriae, Bacterial; D011815:R Factors; D011995:Recombination, Genetic; D014357:Trypsin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D014357:Trypsin
vernacular_title: Klassifizierung von R-Faktoren. Fehlermöglichkeiten und deren Beseitigung.