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September lectures yr 3 (2018) > Introduction to the major groups of antimicrobials > Flashcards

Introduction to the major groups of antimicrobials Flashcards

1
Q

What are examples of beta-lactams?

A

penicillins, cephalosporins, carbapenems

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2
Q

What is an example of a quinolone?

A

ciprofloxacin

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3
Q

What is an example of a macrolide?

A

erythromycin

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4
Q

What is an example of an aminoglycoside?

A

gentamicin

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5
Q

What is an example of a glycopeptide?

A

vancomycin

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6
Q

What is an example of a tetracycline?

A

oxytetracycline

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7
Q

What are examples of folate antagonist?

A

trimethoprim / sulphonamide

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8
Q

What is an example of an imidazole?

A

metronidazole

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9
Q

What are the different types of penicillins?

A

natural = penicillin G/V=> s pnuemoniae

semi-synthetics

  • flucloxacillin => staph aureus (not MRSA)
  • Piperacillin + tazobactam (tazocin) => pseudomonas, enterobacteriaceae, s. aureus, anaerobes
  • ampicillin, amoxicillin (non-beta lactamase producing enterobacteriaceae, h.influenzae)
  • amoxicillin + clavulanic acid (co-amoxiclav) => beta-lactamase producing haemophilus influenzae, s.pneumoniae, s.aureus anaerobes
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10
Q

What are the different types of cephalosporins?

A

1st gen = cefalexin, cefradine
2nd gen = cefuroxime
3rd gen = cefotaxime, ceftazidine
4th gen = cefpirome

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11
Q

What organisms are resistant to cephalosporins?

A

ESBL producing organisms

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12
Q

What are some examples of carbapenems and what are they good against?

A

imipenem
meropenem
ertapenem

generally stable to most GNB beta-lactamases - rare resistance but it is increasing particularly against hospital acinetobacter/pseudomonas and carbapenemase producing klebsiella/e.coli

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13
Q

What are carbepenems not effective against?

A

no against against MRSA/VRE but covers lots of other common pathogens e.g. s pneumoniae and group A strept

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14
Q

What is avibactam ?

A

broader spectrum of activity than currently available beta lactamase inhibitors

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15
Q

What is class A of the ambler DNA sequence classification of beta-lactamases?

A 
active site = serine 
selected examples:
- staphylococcal penicillinase
- broad spectrum penicilinaes 
- serine carbapenemases
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16
Q

What is class B of the ambler DNA sequence classification of beta-lactamases?

A

active site: zinc
selected examples:
- metallo-carbapenemases

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17
Q

What is class C of the ambler DNA sequence classification of beta-lactamases?

A

active site serine
selected examples:
- chromosomal cephalosporinases AmpC plasmidic

18
Q

What is class D of the ambler DNA sequence classification of beta-lactamases?

A

active site = serine
selected examples:
- oxacillinases broad spectrum not inhibited by clav/taz
- OXA-48 carbapenemase

19
Q

What is penicillin hypersensitivity?

A

true life threatening is v. rare but dramatic - angioneurotic oedema
10% patients of patients ask will say they are allergic - mainly due to skin rash
skin testing can be used to identify these patients

patients on ampicillin/amoxicillin can get a maculopapular rash ++++glandular fever

can use carbapenems/aztreonam

20
Q

What are the different types of allergic reaction people could have against penicillin?

A

immunoglobulin E mediated reaction (immediate) = urticaria, angioedema, wheezing, SOB, anaphylaxis

Non-IgE reaction (delayed) = . exfoliative dermatitis, steven johnsons syndrome, serum sickness, haemolytic anaemia, maculopapular rash etc

21
Q

What are glycopeptides important for treating?

A

vancomycin and teicoplanin

  • important for MRSA and resistant enterococci
  • c diff diarrhoea - used for severe disease orally 125mg QDS as not absorbed
  • potentially nephrotoxic (IV only)
22
Q

What are quinolones important against?

A

ciprofloxacin, levofloxacin, moxifloxacin

active against gram ve and -ve but NOT MRSA streptococci

useful for UTIs(resistant bacteria)
resistance is rising

pseudomonas - resistance can emerge by mutation, safe but c.diff issues

23
Q

How do aminoglycosides work?

A

bind to 30S subunit of mRNA

24
Q

How do macrolides work?

A

prevent binding of the 50S subunit to mRNA

25
Q

How do tetracyclines work?

A

prevent transport of amino acids into ribosome by tRNA

26
Q

How does chloramphenicol work?

A

prevents attachment of amino acids to the polypeptide chain

27
Q

What are macrolides used for?

A

erythromycin, clarithromycin

active against s.pneumoniae (+resistance), beta-haemolytic strepts, s.aureus, h influenzae, legionella, mycoplasma

not active against:
- enterobacteriaceae, enterococci, or pseudomonas

28
Q

What are aminoglycosides effective against?

A

gentamicin, tobramycin, amikacin
- relatively nephrotoxic - only given od only iv/im

active against pseudomonas, GNBs including some nosocomial staph aureus

not active against streptococci, anaerobes

29
Q

What are tetracyclines used for?

A

oxytetracycline, minocycline (better absorbed but expensive), tigecycline (active against MRSA and acinetobacter)

do not give in pregnancy - children teeth

uses: chlamydiae, COPD, Acne

poorly absorbed with antacids

30
Q

What are some other antibacterial agents “orphans”?

A 
chloramphenicol
fusidic acid 
linezolid
mupirocin 
nitrofurantoin 
daptomycin 
fidaxomicin 
metronidazole
31
Q

What is chloramphenicol used for?

A

rarely used in UK

- good against gram +ves

32
Q

What is fusidic acid used for?

A

related to steroid hormones - specific activity against staphylococci

33
Q

What is linezolid used for?

A

valuable anti-staphylococcal agent - good for MRSA and VRE - oral and IV
- can be toxic over 2 weeks - monitor WBC

34
Q

What is mupirocin used for?

A

topical nasal decolonisation of MRSA carriage

35
Q

What is daptomycin used for?

A

potent iV anti-MRSA agent v cidal good in endocarditis and foreign body infections, increase CPK sometimes

36
Q

What is nitrofurantoin used for?

A

lower UTI - now first in line

37
Q

What is fidaxomicin used for?

A

macrocyclic alternative to metronidazole/vancomycin for c. diff - £1300/course

38
Q

What are sulphomides used against?

A

widespread resistance - only used against stenotrophomonas and as co-trimoxazole for pneumocystitis jirovecii

39
Q

What is trimethoprim used for?

A

cheap, oral, heavily used for UTI

resistance 20-30%

40
Q

What is co-trimoxazole used for?

A

trimethoprim combined with sulphamethoxazole

no advantage in UTI

41
Q

What is metronidazole used for?

A

active agent almost all anaerobes
long term use => peripheral neuropathy
antabuse effect with alcohol

September lectures yr 3 (2018) (56 decks)

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