Some plasmids can replicate in several distinct species of bacteria.Frequently these plasmids have transposons carrying several different antibiotic resistance genes.In a hospital that has an outbreak of several species of bacteria each carrying resistance to three drugs (streptomycin, gentamicin, and penicillin), what is the best way to determine whether or not this resistance is due to a single shared plasmid with all three resistance genes?
A)Demonstrate that all the resistant bacteria have a plasmid.
B)Isolate plasmids from all resistant bacterial species and demonstrate that drug-sensitive cells from these same species become resistant to all three drugs when this plasmid is transformed.Confirm that the same plasmids are present in all species by sequencing the plasmid DNA.
C)Sequence the genomes of the resistant species and demonstrate mutations in the same homologous genes.
D)Isolate plasmids from one resistant species and transform a drug-sensitive strain of the other bacterial species to see if resistance occurs in the transformants.

Question

Quizplus · Accepted Answer

To determine if the resistance is due to a single shared plasmid with all three resistance genes, isolating plasmids from all resistant bacterial species and demonstrating that drug-sensitive cells from these same species become resistant to all three drugs when this plasmid is transformed is the most comprehensive approach. Confirming that the same plasmids are present in all species by sequencing the plasmid DNA provides direct evidence of the shared plasmid and its resistance genes.

Some Plasmids Can Replicate in Several Distinct Species of Bacteria