title: Concurrent transfer and recombination between plasmids encoding for heat-stable enterotoxin and drug resistance in porcine enterotoxigenic Escherichia coli.
abstract: The frequency of and genetic mechanisms for simultaneous transfer of genes encoding for tetracycline and sulpha-streptomycin resistance, heat-labile (LT) and heat-stable (ST-mouse) enterotoxin production in porcine enterotoxigenic Escherichia coli to Escherichia coli K12 were investigated. Seven E. coli strains of 0-group 149 were studied by conjugation and transformation experiments. All strains transferred tetracycline-resistance plasmids at a high frequency. No interaction was observed between these plasmids and those encoding for LT production. However, most tetracycline-resistant recipient cells were ST-mouse+ following recombination events between plasmids encoding for colicin B and ST-mouse production and plasmids encoding for tetracycline resistance. Alternatively, when selecting for sulpha or streptomycin resistance a majority of the transconjugants were also ST-mouse+, as plasmids coding for sulpha and streptomycin were mobilized by the colicin B and ST-mouse encoding plasmid. Since the simultaneous transfer of genes encoding for drug resistance, colicin B and ST-mouse production are common events in vitro, they might also occur frequently in vivo during antibiotic selective pressure.
mesh_terms: D000818:Animals; D003227:Conjugation, Genetic / Q000187:drug effects; D004352:Drug Resistance, Microbial; D004355:Drug Stability; D004768:Enterotoxins / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D005815:Genetic Code / Q000187:drug effects; D006358:Hot Temperature; D051379:Mice; D010957:Plasmids / Q000187:drug effects; D011995:Recombination, Genetic / Q000187:drug effects; D013552:Swine / Q000382:microbiology; D014169:Transformation, Bacterial / Q000187:drug effects
chemical_list: D004768:Enterotoxins