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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?

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Answer:

Take samples from infected people and grow that bacteria on different selective media. Three different culture plates having one of the antibiotic each can be used to grow these bacteria on, it should be able to grow (allow adequate incubation times). Then prepare a culture plate with all three (streptomycin, gentamicin, and penicillin) antibiotics on it at the same time. If the bacterial colonies are able to grow on this plate as well, one can conclude that the genes for resistance lies on the same plasmid.

Hope that answers the question, have a great day!

User Ganapati V S
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Answer: The best way to know is to differentiate between types of plasmids whether or not this resistance is due to a single shared plasmid with all three resistance genes.

Step-by-step explanation:

By way of definition, a plasmid is a small, circular piece of DNA that is different than the chromosomal DNA, which is all the genetic material found in an organism’s chromosomes. It can replicate on their own by using chromosomal DNA. Plasmids are mainly found in bacteria, but can also be found in archaea, multicellular organisms. Plasmids usually carry at least one gene, and many of the genes that plasmids carry are beneficial to their host organisms. Plasmids have separate genes from their hosts, they are not considered to be independent life.

Therefore in a hospital where there has been an outbreak of several species of bacteria, each carrying resistance to three drugs (streptomycin, gentamicin, and penicillin), one of the type of plasmids that shows this resistance is called resistance plasmids or R plasmids.

Resistance or R plasmids contain genes that help a bacterial cell defend against environmental factors such as poisons or antibiotics. Some resistance plasmids can transfer themselves through conjugation. When this happens, a strain of bacteria can become resistant to antibiotics. For example, gonorrhea or tuberculosis infection has become so resistant to a class of antibiotics called quinolones that a new class of antibiotics, called cephalosporins, has started to be in use. The bacteria may even become resistant to these antibiotics within five years. It is important to know that overuse of antibiotics to treat other infections, like urinary tract infections, may lead to the proliferation of drug-resistant strains.

User Brock Hensley
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