7. Antibiotics and Resistence Flashcards
____ antibiotics kill bacteria.
Bactericidal
____ antibiotics stop bacterial growth but do not kill the bacteria. This allows the immune system time to mount an effective response which will eliminate the infection.
Bacteriostatic
Infections in ____ sites cannot be treated successfully with bacteriostatic antibiotics.
Example: patients with meningitis.
immunologically privileged
____ antibiotics are effective only against a small range of bacteria.
For example, penicillin G is effective against Gram positive organisms but against very few Gram negatives.
Narrow spectrum
____ antibiotics are effective against a wide range of different organisms.
For example, tetracycline is effective against many Gram positive and Gram negatives.
Broad spectrum
Bacteria are ____. Animals are ____
Prokaryotes; Eukaryoes
it is possible for an antibiotic to be toxic for bacteria without having toxic effects on the host. This is the concept of ____
selective toxicity.
There are fewer effective antimicrobials against ____, ____, and ____ than against bacteria because fungi and parasites are eukaryotes. They are very similar to human cells.
fungi, viruses, and parasites
In order to divide, bacteria have to make a copy of their chromosome. An enzyme called ____ does the copying. It reads the sequence of one strand of a piece of DNA and puts in the correct base on the other strand.
DNA polymerase
Sometimes the DNA polymerase makes a mistake and puts in the wrong base. This is called a ____
mutation
When the bacteria are confronted with ____, all the sensitive organisms die and these mutants (which originally were only a small proportion of the population) survive. They grow and divide leading to larger numbers of resistant organisms.
antibiotics
large scale, wide-spread use of antibiotics causes ____ for the few resistant bacteria that are normally there and leaves us with only resistant organisms.
selection
When a patient starts taking the antibiotic, the ____ bacteria die very quickly. Over time eventually most of the intermediate bacteria die as well. The patient begins to feel much better.
If the patient stops taking the antibiotics, then the highly resistant bacteria (which are essentially the only ones left at this point) start multiplying and making more of these highly resistant bacteria.
highly susceptible
Many antibiotic resistance genes are carried on plasmids called ____ plasmids.
R (resistance)
Bacteria are capable of transferring DNA via ____, ____, and ____. Therefore, sensitive organisms can become resistant by acquiring an R plasmid or a resistance gene from another bacterium
conjugation, transformation, transduction
____ involves the transfer of genes carried on a plasmid from one bacterium to another via the sex pilus. Conjugation only moves DNA in plasmids.
conjugation
conjugation involves the transfer of genes carried on a plasmid from one bacterium to another via the ____. Conjugation only moves DNA in plasmids.
sex pilus
Conjugation only moves DNA in ____.
plasmids
Some bacteria are capable of taking in any DNA which they find in the environment. This is called ____
transformation
If an antibiotic resistant bacterium dies, it breaks open by ____ and releases its DNA. The DNA can then be picked up and taken into any other bacteria in the area by ____. Bacteria which are capable of taking in DNA from their environment are called ____. Transformation can involve DNA originally from plasmids or the chromosome.
autolysis
transformation
competent
____ can involve DNA originally from plasmids or the chromosome.
Transformation
some bacteria produce enzymes that ____ antibiotics by adding methyl, acetyl, or phosphate groups to the antibiotic
inactivate
some bacteria produce enzymes that ____ the antibiotic rendering it inactive. An example is beta-lactamase which cuts the beta lactam ring of the penicillin making the penicillin inactive
cleave
some bacteria become resistant by changing the antibiotic’s ____ molecule slightly so that the target molecule still is functional for the bacteria but can no longer be effected by the antibiotic
target
some bacteria become resistant to antibiotics by changing membrane ____ such that the antibiotic can’t get in to have an effect (often this type of resistance results from changes in LPS or another porin).
permeability
some bacteria become antibiotic resistant by producing a protein called a ____ that pumps the antibiotic back out of the bacteria before the antibiotic can bind to the target.
rapid efflux pump
Methods of antibiotic resistence:
- Changing the antibiotic
- Changing the targer
- Changing the membrane permeability
- Rapid Efflux Pump
