Antibiotics Flashcards

1
Q

What are the 2 main mechanisms of antimicrobial action

A
  1. Time dependent killing
  2. Concentration dependent killing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where do beta lactams act

A

They act on the cell wall of the bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the mechanism of killing in a betalactam

A

They use time dependent killing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the mechansim of elimination

A

Renal elimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the main adverse effects of beta- lactams

A

Hypersensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the most common resistance method in bacteria against beta lactams

A

Beta- lactamases: These are enzymes that are able to degrade β-lactam antibiotics and it can not be overcome by increasing the conc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the method of resistance in betalactams that can be overcome by increasing the dose

A

Mutations in penicillin binding protein, reducing the ability of β-lactam antibiotics to bind and inhibit their activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do beta lactams work

A

They work by binding to Penicillin-Binding Proteins, these Penicillin-Binding Proteins catalyze the final step in peptidoglycan synthesis and so it weaken or increased the cell wall permeability leading to death of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the microbe classes that are susceptible to beta lactams

A

Gram positive and spirochetes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What types of bacteria are susceptible to penicillin 5

A

Streptococci
Syphilis
Enterococci
Listeria
Actinomyces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are aminopenicillins and what are the 2 main types

A

They are subclass of penicillins within the β-lactam class of antibiotics. They are distinguished by an added amino group (-NH2) on the penicillin structure, which enhances their spectrum of activity against certain Gram-negative bacteria while retaining activity against Gram-positive bacteria. They 2 main types are Ampicillin and Amoxicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the main benefit of Cloxacillin and what bacteria is it used on

A

It is good at working in beta lactamase enviroments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which bactria can cloxacillin and flucloxacillin be used in and what is the difference

A

They are both only able to be used in gram positive patients, the are very simiar flucloxacillin is just better absorbed orally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the 2 main beta-lactamase inhibitors

A

Clavulanate and Tazobactam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the benefit to beta-lactamase inhibitors

A

If used in combination with penicillin they can reverse resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the drug of choice for Resp tract infections

A

Amoxicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the drug of choice for Staph infections

A

Cloxacillin/flucloxacillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 2 types of 1st generation cephalosporins and what are they used for

A

Cefazolin and Cephalexin mainly used for Strep and Staph.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the second generation of cephalosporin

A

Cefuroxime it can be used against Strep, Staph, Haemophilus, community acquired gram negative infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 2 main 3rd generation cephalosporins and what are they effective against

A

Ceftriaxone and Ceftazidime effective against Strep, Staph, CAP gram negatives and Haemophilus as well as spirochetes and typhoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What drug is given as surgical prophylaxis

A

Cefazolin 1g to prevent Staphylococcal infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the main excretion method used by ceftriaxone

A

Bile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the drug of choice in empirical treatment of bacterial meningitis

A

Ceftriaxone because of its good CSF penetration

25
Q

What is the function of a carbapenems

A

These are very broad spectrum antibiotics that cover most types of infection

26
Q

Which antibiotic classes fall into the beta lactam family 4

A

Penicillins, cephalosporins, carbapenems, and monobactams

27
Q

What are the 3 main manifestations of penicillin allergies

A
  1. Maculopapular Rash
  2. Anaphylaxis
    3.Angioedema, Urticaria(hives), and Bronchospasm
28
Q

What is the mechanism of killing used by Glycopeptides

A

Time dependent killing

29
Q

What are the microbes that are killed by glycopeptides

A

Gram positive bacteria

30
Q

What is the MOA of glycopeptides

A

They interfere with the synthesis of the cell wall by binding to specific components of the bacteria peptidoglycan

31
Q

What is the main glycopeptide used and its side effects

A

Vancomycin is the main glycopeptide used and the main side effects is that it is nephro and oto toxic

32
Q

What are aminoglycosides most effective against

A

Aerobic gram negative bacilli

33
Q

What is the MOA of a aminoglycoside

A

They act as bactericidal inhibitors of protein synthesis

34
Q

What is the mechanism of killing of an aminoglycoside

A

They kill by concentration dependent killing

35
Q

What are 2 examples of aminoglycosides

A

Gentamicin and Amikacin

36
Q

What is gentamicin used to treat

A

Pyelonephritis and is often combined with beta lactams for polymicrobial infections or for its synergistic effects

37
Q

What is the mechanism of action of a quinolone

A

It targets gyrase and topoisomerase enzymes used in DNA synthesis

38
Q

What are the signs of toxicity in Quinolones

A
  1. Rashes
  2. CNS disturbances
39
Q

What are examples of 2nd generation quinolones and what is the uses 1

A

Ciprofloxacin, They are used in very serious infections and are the drug of choice in conditions like bacterial dysentery and pyelonephritis

40
Q

What is an example of a 3r generation Quinolone and what is it main use

A

Levofloxin, MDR TB

41
Q

What is the MOA of a macrolide

A

It inhibits the 50s ribosomal component thus inhibiting protein synthesis

42
Q

What are macrolides most effective against

A

The are active against gram positive bacteria. and are also used for S. pneumoniae resistance

43
Q

What is the most common side effect

A

GIT disturbance

44
Q

What are 2 examples of macrolides and what is the benefit of the one over the other

A

Erythromycin and Azithromycin
Macrolides inhibit CYP450 metabolism but azithromycin does not

45
Q

What is the main therapeutic use of macrolides

A

They are used in atypical pneumonias like Legionella, Mycoplasma and Chlamydophila

46
Q

What is the MOA of tetracyclines

A

They function by inhibiting the synthesis of proteins by inhibiting 30s ribosomes

47
Q

What are the 2 main mechanisms of resistance in tetracycline

A
  1. Efflux
  2. Enzymatic breakdown
47
Q

What are the forms of toxicity that occur in doxycycline 3

A
  1. Nausea
  2. Photosensitivity
  3. Teeth discolouration
48
Q

Why should tetracyclines be avoided in children

A

It causes permanent discolouration of the teeth

49
Q

Which infections are treated with tetracyclines

A

Rickettsia
Brucellosis
Acne in low doses

50
Q

What infection can tetracycline be given as prophylaxis

A

Falciparum malaria

51
Q

What are the 2 active components in Cotrimoxazole

A

Sulfamethoxazole and trimethoprim

52
Q

What is the function of Trimethoprim

A

Enzyme that reduces dihydrofolic acid to tetrahydrofolic acid, which is needed for the synthesis of nucleotides and ultimately DNA.

52
Q

What is the function of Sulfamethoxazole

A

It interferes with the folic acid pathway to thus inflencing the DNA synthesis in bacteria

53
Q

What is the main side effect of sulphonamide hypersensitivity

A

Stevens-Johnson Syndrom

54
Q

What is the main use of cotrimoxazole in HIV patients 3

A
  1. Pneumocystis jirovecii pneumonia
  2. Toxoplasmosis
  3. Cystoisospora belli diarrhoea
55
Q

What is the MOA of metronidazole

A

It is toxic to DNA and forms free radicals in anaerobic metablism

56
Q

What is the main side effects of long term metronidazole use

A

Neurotoxic and neutropenia

57
Q

Which protozoans are affected by metronidazole

A
  1. Entamoeba histolytica
  2. Trichomonas vaginalis
  3. Giardia lamblia