CP 1 - Intro to Antibacterial Agents Flashcards

1
Q

Definition of antibiotics

A

chemical products of microbes that inhibits or kill organisms

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2
Q

Definition of antimicobial agents

A

Include antibacterial, antifungal, antiviral eg antibiotics, synthetic compounds with similar effects, semi-synthetic (modified from antibiotics)

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3
Q

Definition of bacteristatic

A

inhibition of bacterial growth eg protein synthesis inhibitors

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4
Q

Definition of bactericidal

A

kill bacteria eg cell wall-active agents

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5
Q

Definition of minimum inhibitory concentration - MIC?

A

minimum concentration of antibiotic at which visible growth is inhibited

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6
Q

Definition of synergism

A

activity of 2 antimicrobials given together providing a greater outcome that the sum of the 2 separately

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7
Q

Definition of antagonism

A

one agent diminishes the activity of another

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8
Q

Definition of difference

A

activity unaffected by the addition of another agent

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9
Q

one clinical example of synergism?

A

Beta-lactam & aminoglycoside combination therapy of streptococaal endocarditis

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10
Q

what are the 5 antibiotic targets if it is aimed to inhibit critical process in bacterial cells

A

cell wall, protein synthesis, DNA synthesis, RNA synthesis, plasma membrane

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11
Q

what compound is found in both gram -ve & +ve bacteria?

A

peptidoglycan - major compound of bacterial cell wall, polymer of N-acetyl muramic acid (NAM) & N-acetyl glucosamine (NAG)

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12
Q

what are the 2 cell wall synthesis inhibitors?

A

Beta-lactams & glycopeptides

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13
Q

what does all β-lactam antibiotics contain in their chemical structure?

A

β-lactam ring - structural analogue of D-alanyl-D-alanine (DADA) - competitive inhibitors

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14
Q

what does β-lactam antibiotics interfere present in the bacteria?

A

Interfere with penicillin binding proteins (a transpeptidases involved in peptideoglycan cross-linking)

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15
Q

what are the subclass within the β-lactam antibiotics ?

A

penicillins, cephalosporins, carbapenems, monobactams (Gram -ve only)

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16
Q

how does glycopeptides work?

A

large molecules - bind directly to D-alanyl-D-alanine on NAm pentapeptides so inhibiting binding of transpeptidases and thus peptideoglycan cross-linking

17
Q

what are the target spectrum of glycopeptides?

A

only gram +ve - unable to penetrate gram -ve

18
Q

what are the 4 subclasses for protein synthesis inhibitor?

A

Aminoglycosides, Macrolides, Lincosamides, Streptograms (MLS), Tetracyclines, Oxazolidinones, others (Mupirocin, fusidic acid)

19
Q

Mechanism of action for aminoglycosides?

A

binds to 30s ribsomal subunit

20
Q

common example for aminoglycosides?

A

gentamicin

21
Q

common examples for MLS?

A

erythromycin, clindamycin (binds to 50s ribosomal subunit)

22
Q

common examples for tetracyclines?

A

doxytetracycline (binds to 30s ribosomal subunit & inhibit RNA translation)

23
Q

Common examples for oxazolidinones?

A

linezolid - binds to 50s ribosomal subunits & inhibits initiation of protein synthesis

24
Q

what are the 2 subclasses within DNA synthesis inhibitors?

A

Trimethoprim & suflonamides, Quinolones & fluoroquinolones

25
Q

MOA for trimethoprim & sulfonamides?

A

inhibit folate synthesis (folic acid is a purine synthesis precursor)

26
Q

what is the name of the drug which is combination of trimpethoprim & sulfonamides?

A

co-trimoxazole (trimethoprim-sulfamethoxazole)

27
Q

what are the common examples for quinolones & fluoroquinolones

A

inhibit one or more of 2 related enzyme involving DNA remodelling and replication

28
Q

common examples for quinolones & fluoroquinolones?

A

ciprofloxacin

29
Q

Common example for RNA synthesis inhibitors?

A

Rifampicin

30
Q

MOA of Rifampicin?

A

RNA polymerae inhibitors - prevents synthesis of mRNA

31
Q

what are the 2 agents for the plasmas membrane agents?

A

colistin - gram -ve, daptomycin - gram +ve, cyclic lipopeptides & destory cell membrane

32
Q

what are the common adverse effects for all drugs?

A

nausea, vomiting, headache, skin rashes, infusion reactions, allergic reactions, fungal infection - superficial and invasive candidiasis, C.diff infection

33
Q

what are the adverse effect for aminoglycosides?

A

reversible renal impariment on accumulation, irreversible ototoxicity (ear toxicity)

34
Q

adverse effect for B-lactams?

A

allergic reactions mainly

35
Q

adverse effect for linezolid

A

bone marrow depression

36
Q

what class of antibiotics can be used if patient allergic to B-lactams?

A

cephalosporins & carbapenems for non-severe pencillin allergic, aztreonam for severe allergic reactions (does not include a bicycles nucleus)

37
Q

common precipitating antibiotics for C.diff?

A

4Cs - co-amoxiclav (amoxicilin-clavulanate), cephalosporins, ciprofloxacin, clindamycin