Discuss the cellular factors that might make a drug's spectrum of action narrow rather than broad
What will be an ideal response?
When a drug is labeled "narrow-spectrum," meaning that it has activity against only a limited number of microbes, generally the reason is that many microbes possess some form of natural resistance against the drug. For example, many drugs work better against Gram-positive organisms than Gram-negative ones because Gram-negative cells possess an outer membrane that does not allow these drugs to enter the cell as readily as they enter Gram-positive cells. Other cellular factors that can have an effect on the spectrum of action of a particular drug include the presence of R-plasmids in the cell that carries resistance genes, the presence of altered cytoplasmic membrane or cell wall proteins that prevent the passage of some types of drugs, and alterations in a cell's metabolic pathways, which can make the cell more resistant to certain types of drugs.
Other antimicrobials have a narrow spectrum of action because they target a metabolic or structural feature unique to a single pathogen or small group of pathogens. One example of this type of narrow-spectrum antimicrobial is antisense RNA, which complements a specific nucleotide sequence that may be present in only one pathogen. Another example is isonizid which blocks the synthesis of a cell wall component unique to the Mycoplasmas.
Bloom's Taxonomy: Application
Section: Clinical Considerations in Prescribing Antimicrobial Drugs
Learning Outcome: 10.14
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A ____ consists of all the individuals of a given species that live and reproduce in a particular place
Fill in the blank with the appropriate word.
If a trait has a large inherited component, then concordance among monozygotic twins will be
A) considerably higher than that of dizygotic twins. B) considerably lower than that of dizygotic twins. C) about the same as that of dizygotic twins. D) 100%.
What is the name of the meristematic tissue that gives rise to future vascular tissue?
A. dermal tissue B. ground meristem C. protoderm D. cork cambium E. procambium
Which of the following is the proper way to type a scientific name
What will be an ideal response?