7. Antibiotics and Resistence

Question 1

____ antibiotics kill bacteria.

Answer 1

Bactericidal

Question 2

____ 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.

Answer 2

Bacteriostatic

Question 3

Infections in ____ sites cannot be treated successfully with bacteriostatic antibiotics.

Example: patients with meningitis.

Answer 3

immunologically privileged

Question 4

____ 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.

Answer 4

Narrow spectrum

Question 5

____ antibiotics are effective against a wide range of different organisms.

For example, tetracycline is effective against many Gram positive and Gram negatives.

Answer 5

Broad spectrum

Question 6

Bacteria are ____. Animals are ____

Answer 6

Prokaryotes; Eukaryoes

Question 7

it is possible for an antibiotic to be toxic for bacteria without having toxic effects on the host. This is the concept of ____

Answer 7

selective toxicity.

Question 8

There are fewer effective antimicrobials against ____, ____, and ____ than against bacteria because fungi and parasites are eukaryotes. They are very similar to human cells.

Answer 8

fungi, viruses, and parasites

Question 9

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.

Answer 9

DNA polymerase

Question 10

Sometimes the DNA polymerase makes a mistake and puts in the wrong base. This is called a ____

Answer 10

mutation

Question 11

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.

Answer 11

antibiotics

Question 12

large scale, wide-spread use of antibiotics causes ____ for the few resistant bacteria that are normally there and leaves us with only resistant organisms.

Answer 12

selection

Question 13

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.

Answer 13

highly susceptible

Question 14

Many antibiotic resistance genes are carried on plasmids called ____ plasmids.

Answer 14

R (resistance)

Question 15

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

Answer 15

conjugation, transformation, transduction

Question 16

____ involves the transfer of genes carried on a plasmid from one bacterium to another via the sex pilus. Conjugation only moves DNA in plasmids.

Answer 16

conjugation

Question 17

conjugation involves the transfer of genes carried on a plasmid from one bacterium to another via the ____. Conjugation only moves DNA in plasmids.

Answer 17

sex pilus

Question 18

Conjugation only moves DNA in ____.

Answer 18

plasmids

Question 19

Some bacteria are capable of taking in any DNA which they find in the environment. This is called ____

Answer 19

transformation

Question 20

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.

Answer 20

autolysis

transformation

competent

Question 21

____ can involve DNA originally from plasmids or the chromosome.

Answer 21

Transformation

Question 22

some bacteria produce enzymes that ____ antibiotics by adding methyl, acetyl, or phosphate groups to the antibiotic

Answer 22

inactivate

Question 23

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

Answer 23

cleave

Question 24

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

Answer 24

target

Question 25

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).

Answer 25

permeability

Question 26

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.

Answer 26

rapid efflux pump

Question 27

Methods of antibiotic resistence:

Answer 27

1. Changing the antibiotic
2. Changing the targer
3. Changing the membrane permeability
4. Rapid Efflux Pump