title: Practical significance of extrachromosal elements.
mesh_terms: D000818:Animals; D002417:Cattle; D003428:Cross Infection; D004196:Disease Outbreaks / Q000382:microbiology; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae; D004926:Escherichia coli; D005827:Genetics, Microbial; D010403:Penicillin Resistance