Antibiotics

Question 1

what are antibiotics and what do they do?

Answer 1

small molecules that kill or inhibit the growth of prokaryotes/bacteria

used to control/limit the impact of bacterial disease

Question 2

what is antibiotic resistance?

Answer 2

the ability of bacteria to escape the action of antibiotics

Question 3

what does bacteriostatic mean?

Answer 3

inhibit the growth of bacteria

Question 4

what does bactericidal mean?

Answer 4

kill the bacteria

Question 5

antibiotics are not a substitute for what? why?

Answer 5

a non-functional immune system.

As they reduce bacteria to aid in immune response.

Question 6

what does pharmodynamics of antibiotics mean?

Answer 6

How it kills the target organisms: conc., exposure time …

Question 7

what does pharmokinetics of antibiotics mean?

Answer 7

How your body deals with and interacts with the drug: absorption, excretion …

Question 8

describe the ideal antibiotic, 4 things

Answer 8

Minimal toxicity to host

Long half-life -> not having to constantly take it

Appropriate tissue distribution -> goes to the right tissue

No adverse drug interactions or side effects

Question 9

Antibiotics have selective toxicity -> have targets.

the most successful antibiotics target what?

Answer 9

the cell wall

They inhibit the synthesis of the cell wall, so degradation continues without synthesis resulting in gaps in the cell wall

Question 10

penicillins are an antibiotic that targets what?

Answer 10

the cell wall

Question 11

what is the general structure of penicillins?

Answer 11

• Contain B-lactam ring
  Can attach different side chains to have different spectrum and resistance to bacteria

Question 12

are penicillins narrow or broad spectrum antibiotics?

Answer 12

range from narrow to broad

Question 13

state 3 limitations of penicillins

Answer 13

Allergic
Rapid excretion via kidneys so frequent dosing
Resistance

Question 14

what are the last line antibiotics?

Answer 14

carbapenems (B-lactam)

Question 15

what does amoxycillin target?

Answer 15

cell wall

Question 16

what is the most commonly prescribed antibiotic? why?

Answer 16

amoxycillin
as has broadest spectrum of bacteria it covers
Stable in presence of stomach acid so can be taken at any time (don’t have to eat before)

Question 17

what does amoxycillin target?

Answer 17

cell walls

Question 18

what is the structure of amoxycillin?

Answer 18

B-lactam

Question 19

Penicillin V may be better first choice than amoxycillin. why?

Answer 19

Narrower spectrum
so less impact on GI as does not affect enterococci which is found normally in the GI

Question 20

what does erythromycin target?

Answer 20

proteins synthesis

Question 21

what is used for patients who have a penicillin allergy?

Answer 21

erythromycin

Question 22

what does metronidazole target?

Answer 22

nucelic acid synthesis inhibitor

Question 23

what is the only antibiotic that can kill both bacteria and protozoa?

Answer 23

metronidazole

Question 24

which antibiotic is Better under anaerobic conditions so affects anaerobes more effectively

Answer 24

metronidazole

Question 25

Resistance is extremely rare to which antibiotic?

Answer 25

metronidazole

Question 26

which antibiotic has adverse reactions with alcohol?

Answer 26

metronidazole

Question 27

name 2 examples of natural resistance

Answer 27

Target not present or accessible Persistor cells

Question 28

what are persistor cells?

Answer 28

metabolically inert the bacteria can persist as antibiotics wont target and degrade it (naturally resistant to antibiotics in this state)

Question 29

what do persistor cells do?

Answer 29

Enrich the biofilm to be more tolerant to antibiotic Linked to reinfection

Question 30

how does acquired resistance occur?

Answer 30

by change to the microbe e.g. mutation

Question 31

how does acquired resistance spread?

Answer 31

horizontal gene transfer: a resistance gene can be passed between species thus spreading resistance - Enrich the biofilm with more resistance

Question 32

broad spectrum antibiotics increase the risk of what?

Answer 32

Clost. Difficile infection in the elderly.

Question 33

what are the high risk antibiotics for clost. difficile?

Answer 33

4Cs Cephalosporins Co-amoxiclav Ciprofloxacin Clindamycin

Question 34

what are the 3 key messages when prescribing antibiotics?

Answer 34

Keep prescribing to a minimum Consider local measures Consult guidelines

Question 35

state 3 antimicrobial drug resistance mechanisms?

Answer 35

altered permeability inactivation of B-lactam ring by B-lactamases altered target on cell wall

Question 36

how does altered permeability cause antimicrobial drug resistance?

Answer 36

Don’t take drug up or is exerted faster than taken up

Question 37

extended spectrum B-lactamases causes resistance to what antimicrobials?

Answer 37

all penicillins

Question 38

carbapenemase causes resistance to what antimicrobials

Answer 38

resistant to all penicillins, cephalosporins and carbapenems

Question 39

why does carbapenemase pose a major healthcare risk?

Answer 39

as carbapenems are the last line antibiotics

Question 40

what is MRSA?

Answer 40

methicillin resistant S.aureus

Question 41

what causes MRSA?

Answer 41

altered target on cell wall

Question 42

MRSA is resistant to what antibiotic?

Answer 42

flucloxicillin (which replaced meticillin)

Question 43

resistance is rare to what antibiotic? why?

Answer 43

metronidazole as its inactive till in the cell

Question 44

resistance to metronidazole is due to what?

Answer 44

possibly having genes that cause resistance

Question 45

which bacteria is of concern with metronidazole resistance?

Answer 45

prevotella

Question 46

what is emperic prescribing?

Answer 46

When prescribing don’t know the cause of organism Site of infection gives clues as to what bacteria is present

Question 47

targeted prescribing requires testing and checking. when is this used?

Answer 47

When they are not responding as you would expect

Question 48

what patient considerations are there when prescribing antibiotics?

Answer 48

Allergies Patient compliance -> following guidelines e.g. child, disability, elderly, dementia, busy so cant fit around meal times etc.

Question 49

what is the major issue with antibiotics to the patient?

Answer 49

affect on GI tract -> secondary infection due to change in GI environment Fungi can grow in the absence of bacteria e.g. antibiotic sore mouth (candida albicans)