Microbiology Chapter 20

Front 1

Describe what is meant by the term resistant as it relates to antimicrobial drugs

Back 1

microorganisms once susceptible to the action of an antibiotic is no longer affected by the drug

Front 2

Discuss the factors which contribute to antibacterial drug resistance

Back 2

- Globalization
- Widespread misuse of antimicrobial drugs
- Antibiotics/antibacterial drugs in animal feed
- Unnecessary prescriptions
- Unfinished prescriptions

Front 3

Describe the role that spontaneous mutations play in the development of antibacterial drug resistance

Back 3

- The potential for rapid spontaneous mutation is considerable
- Among the mutations that occur are those that allow the survival of an organism exposed to lethal antibiotics and these mutations will be selected
- Bacterial cells that have developed resistance to a given antibiotic are not killed off when treated with the drug
- These resistant cells continue to divide and the resulting population will be completely resistant.
- The combination of mutation and evolutionary pressure has given rise to a rapid increase in populations of bacteria that have become resistant to antibiotics

Front 4

Describe R Plasmids and their role in antibacterial drug resistance

Back 4

- R plasmids are an acquisition of extrachromosomal DNA
- R plasmids (6-7 genes; each of which confers resistance to different antibiotic)
- R plasmids transferred by transduction and conjugation
(MDRO's have plasmids; Create superbugs; Huge problem in medical facilities)

Front 5

Describe the 4 mechanisms by which microorganisms can become resistant to antimicrobial drugs

Back 5

1. In activation of the antibiotic/antibacterial drug
- Enzyme destroy drug
- B lactamases
- Aminoglycosides
- Chloramphenicol
2. Efflux pumping of the antibiotic/antibacterial drug
- Active transport of drug out of bacterial cell
- Tetracyclines
- B Lactams
- fluoroquinolones
3. Modification of the antibiotic target
- Bacterial ribosomes
- PBP's (Penicillin binding proteins)
- Erythromycin
- Rifamycin
- Antimetabolites
4. Alteration of the pathway
- Allows a formerly inhibited reaction or metabolic pathway to occur
- Sulfonamides (makes a different route)

Front 6

Define the term Superbug

Back 6

Multi-Drug resistant organism (MDRO)
2.5 million cases worldwide
100,000 deaths
-MRSA/VRSA
-VRE (Vancomyocin resistant)
-NDM-1 (Klebsiella pneumoniae)
-Resistant Acentobacter baumanii
-Resistant E. coli
XDR - tuberculosis

Front 7

Describe some of the ways by which antibacterial drug resistance can be limited

Back 7

-Drug resistance is not induced by antibiotics, rather it is fostered by environments that contain antibiotics
-Maintaining high levels of antibiotics in a client long enough to kill all pathogens, including resistant mutant, or to inhibit them so the body's defenses can kill them
-Administering two-antibiotics so they can exert an addictive-effect
-Antibiotics should be restricted to essential uses only

Front 8

Define synergism and antagonism as they relate to antibacterial drug resistance

Back 8

Synergism - the addictive effect when two antibiotics are administered at the same time

Antagonism - when some drugs are less effective when used in combination than when used alone

Front 9

All of the following are involved in the spread of antibiotic resistance except
a. travel
b. overuse of antibiotics
c. specific prescriptions for antibiotics
d. improper use of antibiotics
e. none of these

Back 9

c. specific prescriptions for antibiotics

Front 10

Resistance to antibiotics is facilitated by which of the following
a. the antibody response
b. host immunity
c. frequency of use
d. the inflammatory response

Back 10

c. frequency of use

Front 11

All of the following are mechanisms of resistance except
a. activation of the antibiotic
b. efflux pumping
c. modification of target structure
d. inactivation of the antibiotic

Back 11

a. activation of the antibiotic

Front 12

The second most often used mechanism in development of antibiotic resistance is

Back 12

efflux pumping

Front 13

MRSA stands for what?

Back 13

Methicillin-resistant Staphylococcus aureus

Front 14

MRSA organisms are resistant to which of the following?
a. penicillin
b. cephalosporins
c. carbapenems
d. none of the above
e. all the above

Back 14

e. all the above

Front 15

Resistance to antibiotics seen at the level of the ribosome is caused by

Back 15

changes in the shape of the ribosome

Front 16

Increased use of antibiotics can be attributed to the following:
a. an increasing number of large cities
b. emerging infectious diseases
c. increased levels of immunodeficiency diseases
d. all the above

Back 16

d. all the above

Front 17

The best way to deal with antibiotic resistance is to use

Back 17

combinations of antibiotics

Front 18

The useful life of antibiotics can be extended by

Back 18

using combinations of antibiotics