Anti Biotics Flashcards

1
Q

Group represents of beta lactams

A

Penicillins, cephalosporins, carbapenems

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2
Q

Group representatives of quinolones

A

Ciprofloxacin

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3
Q

Group representatives of macroslides

A

Erythromycin

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4
Q

Group representatives of aminoglycosides

A

Gentamicin

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5
Q

Group representatives of glycopeptides

A

Vancomycin

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6
Q

Group representatives of tetracycline

A

Oxytetracyclines

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7
Q

Group representatives of folate antagonists

A

Trimethoprim/sulphonamide

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8
Q

Group representatives of imidazoles

A

Metronidazole

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9
Q

What are beta lactams selective for

A

Peptidoglycan cell wall

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10
Q

Penicillin hypersensitivity

A

Rare and dramatic - angiogenic oedema
Cross reaction in 10% with cephalosporins
Can use carbapenems and aztreonam
Skin testing does NOT work
Patients on amoxicillin/ampicillin can get a maculopapular rash
So its usage is dependent on the severity of the infection and if there are alternative treatments

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11
Q

Carbapenems

A

E.g.
Imipenem
Meropenen
Ertapenem
Fantastically stable to all GNB beta lactaminases
Only rare acinetobacter/pseudomonas resistant and New Delhi metallobetalactamase NDM
No activity against MRSA/VRE but covers lots of other common pathogens

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12
Q

Glycopepetides

A

E.g.
Vancomycin
Teicoplanin
Important for MRSA and resistant enterococci
Clostridium difficile - taken orally not absorbed
Potentially nephrotoxic - i.v. Only
Can be given by bolus - no red man syndrome - used for prophylaxis
Best treatment for c diff. - fecal transplant

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13
Q

Quinolones

A

Nalidixic acid
Ciprofloxacin
Levofloxacin
Moxifloxacin
Expensive - better gram +ve activity and -ve but not MRSA
Particularly valuable for uni resistant bacteria
Resistance rising 15-20%
Pseudomonas - resistance can emerge by mutation - targets DNA gyrase
Safe but c diff issues

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14
Q

Macrolides

A

Erythromycin

Clarityromycin

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15
Q

Aminoglycosides

A

Gentamicin
Tobramycin
Amikacin

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16
Q

Tetracycline

A

Oxytetracyclines
Minocycline (better absorbed, expensive)
Tigecycline ( new compound active against MRSA and acinebacter)

17
Q

Antibacterial orphans

A
Chloramphenicol
Fusidic acid 
Linezolid
Mupirocin
Nitrofurantoin
Daptomycin
Fidaxomicin
Metronidazole
18
Q

Folate antagonists

A

Sulphonamide
Trimethoprim
Co-trimoxazole
Metronidazole

19
Q

What do beta lactams do?

A

Bind to and inhibit enzymes which catalyse the link between subunits that from the peotidoglycan cell wall

20
Q

What do glycopeptodes do

A

Bind to terminal D-ala-D-ala, prevent incorporation of subunit into growing peptidoglycan

21
Q

Carbapenems facts

A

Stable to all Gram negative bacteria beta lactamases
Only rare acinetobacter/pseudomonas resistant and New Delhi metallobetalactamase NDM
No activity against MRSA or VRE (vancomycin resistant enterococcus)

Action against
S. Pneumoniae, group A strep

22
Q

Glycopeptides facts

A

Important for MRSA and resistant enterococci
C diff diarrhoea - used for severe disease oral not absorbed
Potentially nephrotoxic (I.v. Only)

23
Q

Quinolones facts

A

Active against Gram+ve and -ve but NOT MRSA streptococci
Particularly valuable for UTI (resistant bacteria)
Resistance rising (15-20%)
Pseudomonas: resistance can emerge by mutation (target DNA gyrase), safe but c diff issues

Expensive but better Gram +ve activity

24
Q

Macrolides facts

A
Active:
S pneumonia (+ resistance) 
Beta-haemolytic strepts 
S aureus (+resistance) 
H influenzae 
Legionella, mycoplasma 
NOT active: 
Enterobacteriaceae 
Enterococci 
Pseudomonas

Safe particularly penicillin allergy

Adverse effects:
Vomiting
Hunger pains

25
Q

Aminoglycosides facts

A

Relatively nephrotoxic toxic so: given only I.v./i.m.
Active: pseudomonas, GNBs including some nosocomial staph aureus
NOT active: streptococci, anaerobes

26
Q

Tetracycline facts

A

Do not give in pregnancy - children TEETH
Uses: chlamydiae infections, COPD, acne
Poorly absorbed with antacids

27
Q

Orphans - chloramphenicol

A

Rarely used in U.K. Broad spectrum particularly against +ve

28
Q

Orphans - fusidic acid

A

Related to steroid hormones

Specific activity against staphylococci

29
Q

Orphan - linezolid

A

Valuable anti- staphylococcal agent (good for MRSA and VRE) oral and I.V. Can be toxic over 2 weeks, monitor WBC

30
Q

Orphans- mupirocin -

A

For topical nasal decolonisation of MRSA carriage

31
Q

Orphans - daptomycin

A

Potent I.v. Anti-MRSA (also VRE) agent v cidal good in endocarditis and foreign body infections inc CPK sometimes

32
Q

Orphans - nitrofurantoin

A

Lower UTI (no tissue levels) Adverse effects GI common

33
Q

Orphans - fidaxomicin

A

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

34
Q

Folate antagonists - sulphonamide

A

Widespread resistance only used against strenotrophomonas and as co-trimoxazole for pneumocystis jirovecii

35
Q

Folate antagonists - trimethoprim

A

Cheap, oral heavily used for UTI

Resistance 20-30%

36
Q

Folate antagonists co-trimoxazole

A

Trimethoprim and sulphamethoxazole combined

No advantage in UTI

37
Q

Folate antagonists - metronidazole

A

Active agent almost all anaerobes
Long term use –> peripheral neuropathy
Antabuse effect with alcohol

38
Q

How does trimethoprim work

A

Bacteria have to make there own folic acid where as humans can use folic acid

Trimethoprim has a greater affinity for bacterial DHFR (dihydrofolate reductase) so acts on it preventing its use

39
Q

3 main mechanisms by which resistance is mediated

A

1) inactivation of antibiotic such that it becomes unable to bind to target molecule e.g. Production of beta-lactamases as with penicillins
2) mutation in target molecule: antibiotic cannot bind e.g. Streptomycin
3) altered permeability of cell membrane prevents entry of antibiotic e.g. Tetracyclines