Antibiotics

Question 1

What is the role of antibiotics?

Answer 1

to inhibit the growth of and/or kill bacteria

Question 2

What is an antimicrobial?

Answer 2

An all encompassing term for all compounds which are active against one type of microbe, including:

• antivirals
• antibiotics
• antifungals
• antimalarials

Question 3

What reasons can antibiotics be used for?

Answer 3

• treatment of bacterial infection

- prophylaxis to prevent bacterial infection (e.g pre/post surgery, contacts in outbreaks)

Question 4

What are the areas that bacterial target?

Answer 4

• cell wall synthesis inhibitors
• cell membrane
• nucleic acid synthesis
• protein synthesis

Question 5

What are the classes of antibiotics in clinical use?

Answer 5

• Beta lactams
• glycopeptides
• aminoglycosides
• tetracyclines
• chloramphenicol
• macrolides

Question 6

How do you decide which antibiotic to use?

Answer 6

in the clinical evaluation, the doctor will consider the typical pathogen in the site and agents that are proven to be effective for that infection. In the lab, the isolation of the pathogen will be considered as well as the susceptibility of the pathogen

Question 7

What is the MIC?

Answer 7

• minimum inhibitory conc

- dilution of a drug that inhibits growth

Question 8

What factors limit antimicrobial efficacy?

Answer 8

• speed of action
• sensitivity of target
• adverse events

Question 9

What is the breakpoint concentration?

Answer 9

the concentration below which bacteria are classes as susceptible

Question 10

What are the three different outcomes for treating an illness with multiple antibiotics?

Answer 10

• synergy (greater effect)
• antagonism (less of an effect)
• indifference (no increase or decrease)

Question 11

What are pharmokinetics?

Answer 11

• serum conc over time

- penetration to site of infection

Question 12

What are pharmacodynamics?

Answer 12

• susceptibility/potency of a drug
• concentration/time dependent killing
• PAE (post antibiotic effect)

Question 13

What routes can you give antibiotics?

Answer 13

• topical
• oral
• intravenous
• intramuscular

Question 14

How do you choose the route and dosage of antibiotics?

Answer 14

using the PK properties of each drug and adverse reactions to decide

Question 15

What are the differences between antibiotics and vaccines?

Answer 15

• toxicity of antibiotics can potentially be high whereas in vaccines it is usually low
• duration of effect is usually longer in a vaccine than in an antibiotic
• the duration of treatment is usually longer for antibiotics although vaccines sometimes require a booster
• the effectiveness of antibiotics is usually very high compared to vaccines which are low-moderate

Question 16

How does antibiotic resistance arise?

Answer 16

• mutations in chromosomal genes (clonal spread of resistant organism)
• acquisition of foreign DNA e.g plasmids this can be caused by the spread of a resistant organism, transfer of plasmids to new strains/species, mutation in and/or recombination of genetic material

Question 17

What are the results of antibiotic resistance?

Answer 17

• 120,000 addition surgical site infections and infections after chemotherapy
• 6300 infection related deaths
• longer time to recover from infection
• some drugs no longer effective
• some surgeries/cancer treatments no longer viable due to risk of infection

Question 18

What happened in the 2011 global call for action?

Answer 18

antibiotic resistance must be seen as a global crisis akin to AIDs appropriate measures must be taken to reduce impacts in a ll areas of human activity