Plasmid pattern analysis of natural bacterial isolates and its epidemiological implication

Abstract

SUMMARYNatural isolates ofEscherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, andProvidencia stuartiiwere analysed to determine their plasmid content. This data allowed the identification of nosocomial strains ofK. pneumoniaeandP. stuartiiand helped in the differentiation of epidemic strains ofE. coli0111 andS. typhimurium. Phenotypically similar isolates ofS. typhimuriumcould be shown to be of independent origin using plasmid pattern analysis. The dissemination of a particular plasmid through different strains ofS. typhimuriumresulted in a simulation of a very widely distributed epidemic strain, because the plasmid interfered with the phage type of its host strain in addition to determining re sistance properties. Plasmid pattern analysis disclosed two independently existing but interacting epidemic processes: a bacterial ‘epidemic’ strain may become disseminated over a large territory and may predominate there for a long time; a single plasmid, however, may also become distributed through many different bacterial strains and may spread over a large territory. Plasmid pattern analysis provides a valuable and universal epidemiological laboratory method.

Phenotypic and Genotypic Analyses of Enterohemorrhagic Escherichia coli O145 Strains from Patients in Germany

“…Plasmid profiles were determined in freshly isolated EHEC O145 strains with a procedure described by Tietze and Tschäpe (33). Plasmids R27 (169 kb), R100 (90 kb) (Roche Molecular Biochemicals, Mannheim, Germany), and the 54-kb plasmid of strain V517 (17) were used as molecular size markers.…”

Diversity of virulence patterns among shiga toxin-producing Escherichia coli from human clinical cases — need for more detailed diagnostics

“…The determination of number and size of plasmid DNA (plasmid profiles) has been described earlier (Tietze and Tscha¨pe, 1983), the repFIIA, repIa, repFIA, repFIB, and genes of the plasmids under question, respectively, were identified by Southern blots using the 539-bp PstI fragment of the reference plasmids pULB2401 (pBR322, repFIIA), the 1.1-kbp EcoRI/PstI fragment of the reference plasmid pULB2428 (pBR322, repIa), the 917-bp EcoRI fragment of the reference plasmid pULB2154 (pBR322, repFIA), and the 1.2-kbp EcoRI/PstI fragment of the reference plasmid pULB2404 (pBR322, repFIB), respectively, as probes (Table 1) according to Couturier et al (1988).…”

“…Plasmid DNA was isolated according to Tietze and Tscha¨pe (1983) and separated by agarose gel electrophoresis in a 0.7% agarose gel. Plasmid DNA was then transferred to a positively charged nylon membrane (Boehringer) by vacuum blotting as recommended by the supplier (Pharmacia) and fixed to the membrane by cross-linking (GS Gene Linker TM , Bio-Rad).…”

“…The labelled probes were hybridised to the membrane-bound nucleic acids and detected with the chemiluminescent substrate CSPD (see Boehringer Kit: Detection of DIG-labelled Nucleic Acids). As plasmid references R222 (repFIIA), pO157 (repFIIA, repFIA, repFIB, repFIC) and R64 (repIa) were applied (see Tietze and Tscha¨pe, 1983). Calderwood et al (1996).…”

VerotoxinogenicCitrobacter freundiiassociated with severe gastroenteritis and cases of haemolytic uraemic syndrome in a nursery school: green butter as the infection source

“…The methods of determination of plasmid numbers and size of plasmid DNA (plasmid profiles), together with the plasmid grouping indicative of their phenotypic traits (plasmid pattern) have been described before [24]. Southern hybridization and DNA probing specific for sltl and sltuI were carried out as described earlier [25].…”