Antibiotics Flashcards

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1
Q

what are antibiotics and what do they do?

A

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

used to control/limit the impact of bacterial disease

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2
Q

what is antibiotic resistance?

A

the ability of bacteria to escape the action of antibiotics

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3
Q

what does bacteriostatic mean?

A

inhibit the growth of bacteria

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4
Q

what does bactericidal mean?

A

kill the bacteria

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5
Q

antibiotics are not a substitute for what? why?

A

a non-functional immune system.

As they reduce bacteria to aid in immune response.

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6
Q

what does pharmodynamics of antibiotics mean?

A

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

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7
Q

what does pharmokinetics of antibiotics mean?

A

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

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8
Q

describe the ideal antibiotic, 4 things

A

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

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9
Q

Antibiotics have selective toxicity -> have targets.

the most successful antibiotics target what?

A

the cell wall

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

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10
Q

penicillins are an antibiotic that targets what?

A

the cell wall

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11
Q

what is the general structure of penicillins?

A
  • Contain B-lactam ring
    Can attach different side chains to have different spectrum and resistance to bacteria
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12
Q

are penicillins narrow or broad spectrum antibiotics?

A

range from narrow to broad

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13
Q

state 3 limitations of penicillins

A

Allergic
Rapid excretion via kidneys so frequent dosing
Resistance

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14
Q

what are the last line antibiotics?

A

carbapenems (B-lactam)

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15
Q

what does amoxycillin target?

A

cell wall

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16
Q

what is the most commonly prescribed antibiotic? why?

A

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)

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17
Q

what does amoxycillin target?

A

cell walls

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18
Q

what is the structure of amoxycillin?

A

B-lactam

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19
Q

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

A

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

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20
Q

what does erythromycin target?

A

proteins synthesis

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21
Q

what is used for patients who have a penicillin allergy?

A

erythromycin

22
Q

what does metronidazole target?

A

nucelic acid synthesis inhibitor

23
Q

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

A

metronidazole

24
Q

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

A

metronidazole

25
Q

Resistance is extremely rare to which antibiotic?

A

metronidazole

26
Q

which antibiotic has adverse reactions with alcohol?

A

metronidazole

27
Q

name 2 examples of natural resistance

A

Target not present or accessible
Persistor cells

28
Q

what are persistor cells?

A

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

29
Q

what do persistor cells do?

A

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

30
Q

how does acquired resistance occur?

A

by change to the microbe e.g. mutation

31
Q

how does acquired resistance spread?

A

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

32
Q

broad spectrum antibiotics increase the risk of what?

A

Clost. Difficile infection in the elderly.

33
Q

what are the high risk antibiotics for clost. difficile?

A

4Cs
Cephalosporins
Co-amoxiclav
Ciprofloxacin
Clindamycin

34
Q

what are the 3 key messages when prescribing antibiotics?

A

Keep prescribing to a minimum
Consider local measures
Consult guidelines

35
Q

state 3 antimicrobial drug resistance mechanisms?

A

altered permeability

inactivation of B-lactam ring by B-lactamases

altered target on cell wall

36
Q

how does altered permeability cause antimicrobial drug resistance?

A

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

37
Q

extended spectrum B-lactamases causes resistance to what antimicrobials?

A

all penicillins

38
Q

carbapenemase causes resistance to what antimicrobials

A

resistant to all penicillins, cephalosporins and carbapenems

39
Q

why does carbapenemase pose a major healthcare risk?

A

as carbapenems are the last line antibiotics

40
Q

what is MRSA?

A

methicillin resistant S.aureus

41
Q

what causes MRSA?

A

altered target on cell wall

42
Q

MRSA is resistant to what antibiotic?

A

flucloxicillin (which replaced meticillin)

43
Q

resistance is rare to what antibiotic? why?

A

metronidazole
as its inactive till in the cell

44
Q

resistance to metronidazole is due to what?

A

possibly having genes that cause resistance

45
Q

which bacteria is of concern with metronidazole resistance?

A

prevotella

46
Q

what is emperic prescribing?

A

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

47
Q

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

A

When they are not responding as you would expect

48
Q

what patient considerations are there when prescribing antibiotics?

A

Allergies

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

49
Q

what is the major issue with antibiotics to the patient?

A

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)

50
Q
A