Antimicrobials 2 Flashcards

1
Q

Whats is penicillin V a derivative off?

and when can it be used?

A

Benzylpenicillin

used in infectious mononucleosis - when amoxicillin can’t be used

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2
Q

Erysipelas is a skin infection that causes a nasty rash and is associated with S. pyogenes, what would be first line treatment?

A

Benzylpenicillin

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3
Q

What does tazocin cover that co-amoxiclav doesn’t?

A

Pseudomonas

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4
Q

Those with penicillin allergy can be given what other beta lactamase?

and what is the exception to the allergic reaction?

A

Aztreonam
- monobactam

If they had anaphylactic reaction they can’t be given them

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5
Q

Can vancomycin be stored at room temperature?

A

Yes - its extremely stable

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6
Q

What are the two main side effects of vancomycin? and what is the major clinical problem with it?

A

Nephrotoxicity
Red man syndrome

Clinically - underdosing

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7
Q

How does rifampin work?
when is it used?

what interaction can it have with certain drugs?

A

RNA polymerase

TB

P450 enzyme inducer - increases activity of it

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8
Q

How does Sulfamethoxazole work? and what category of antibiotics does it fall under?

A

Dihydropteroate Synthase

Folate inhibitors

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9
Q

What are common side effects of macrolides?

what drug are they contraindicated in?

A

D&V

Prolonged QT

  • simvastatin
  • reduced P450 enzymes
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10
Q

In the presence of a gram positive toxic producing disease, what antibiotic should be added?

A

Clindamycin

due to its excellent toxin producing inhibitory effects.

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11
Q

Whats the main antibiotics associated with C.Diff infection?

A

Co-amoxiclav

Cephalosporin

Ciprofloxacin (all quinolones)

Clindamycin

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12
Q

In upper non complicated UTI infections - which antibiotics should be used?

A

Ciprofloxacin

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13
Q

What are some common side effects of quinolones?

A

QT interval increase

Tendon rupture

Gastrointestinal upset
- can cause C. Diff

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14
Q

What organisms are ciprofloxacin very good against?

A

Gram negative

Atypicals

  • hence their use in UTIs
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15
Q

Name the only bacteriostatic antibiotic used in TB treatment:

A

Ethambutol

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16
Q

List the antibiotics used in TB, and their mechanism of action and side effects:

A

Isoniazid

  • bacterial cidal against fast growing organisms - stops mycolic acid production
  • hepato and neural toxicity
  • *6 months

Rifampin

  • Bacterial cidal against slow growing in nectroci material - RNA polymerase inhibitor
  • liver, bone marrow toxicity
  • *6 months

Pyrazinamide

  • bacterial cidal against mycobacterium intracellularly
  • liver toxicity
  • *2 months

Ethambutol

  • Bacteriostatic - slow growing mycobacterium
  • optic neuritis - colour vision loss
    • 2 months
17
Q

What antibiotic is used in Pneumocystis Jervico?

A

Co-trimoxazole

  • sulfamethoxazole combination.

associated with Steven-johnson syndrome

18
Q

How does metronidazole work?

what bacteria is it good against and what specific one is it not?

A

induces free radicals

Anaerobic bacteria

Actinomyces - it has no effect against.

19
Q

What is first line treatment for UTIs and when is it contraindicated?

A

Trimethoprim

- 1st trimester of pregnancy

20
Q

What is the pathway for UTI management:

A

No treatment - SNAIDs

Uncomplicated/ no pregnancy: Trimethoprim

Complicated UTI/ Pregnant: Ciprofloxacin

Severe UTI: Amoxicillin + gentamicin

21
Q

Which antibiotics are not considered safe during pregnancy?

A

Trimethoprim - 1st trimester

Tetracyclines

Nitrofurantoin - 3rd trimester - haemolytic anaemia

Aminoglycosides
- Ototoxicity

Quinolones
- bone and joint abnormalities

22
Q

Give an example of an inherently resistant antibiotic to a microorganism:

A

Vancomycin to Gram negatives - simply unable to uptake the drug

23
Q

There is vertical and horizontal transmission of genetic information: what are they? and which is the most important towards resistance?

A

Vertical is from parent cell to progeny

Horizontal is the transferring of DNA information via other routes other than traditional parent to progeny.

Horizontal is most important towards the development of resistance.

24
Q

Why are double regimes sometimes given to bacterial infections which are known to have mutations?

A

If resistance develops to one - the other will kill it prior to it being able to spread its resistance genes to progeny - i.e. vertical transmission

25
Q

What the most important mode of horizontal transmission between bacteria, what is transferred, and what bacteria commonly do this?

A

Conjugation

Plasmids

Gram negative

26
Q

Outline some facts about plasmids and common genes they encode for resistance:

A

Can be free within the bacteria or incoperated into the DNA.

most important for horizontal transfer of resistance.

frequently code for lactamases and efflux pumps

27
Q

Where is MecA found and how does it lead to MRSA?

A

Found in the DNA chromosomes

causes resistance by encoding a mutated form of penicillin binding protein - preventing beta lactamases from working

28
Q

MecA is encoded on cassettes of genes, which can vary in sizes - which sizes would you expect to find where?

A

Small cassettes - community

Larger cassettes - hospital

29
Q

When taking a MRSA swap - where do you do it?

A

Nose

Perineum

30
Q

In beta lactamase inhibitors - what are the parts that bind to the beta lactamases, preventing their function?

A

Tazobactam

Clavulanic acid

31
Q

The genes for extended spectrum beta lactamases are often found where?

A

On plasmids

32
Q

What is a gene that codes for carbpenamases?

What is another mode which some bacteria have become resistant to carbapenems?

A

NDM-1

Loss of porins

33
Q

What pathogen can upregulate its efflux pumps in times of stress - such as having antibiotics present?

A

Pseudomonas aeruginosa

34
Q

List some ways that anti-microbial resistance can be reduced through prescribing:

A

Narrow spectrum use - more targeted

Using older antibiotics - we have fewer new ones

Shorter periods of use.

Good infection control

35
Q

Which bacteria frequently produce resistance through the production of beta lactamase production?

A

Coliforms

36
Q

List some appropriate antimicrobial prescribing steps:

A

Establish diagnosis and severity prior to prescribing

microbiology samples
- before prescribing

Document indication for use

Document duration

Check penicillin allergies

Check for known resistance
- MRSA

Contact microbiology

Check specific for patients

37
Q

What are Integrons?

A

These are Cassettes of resistant genes that are organised into genetic elements. They have the ability to increase (integrate) and remove these genes.

this ability makes them important for the spread of resistance

38
Q

Name the most common genetic mutation leading to vancomycin resistance:

A

VanA

  • plasmid
  • chromosomal
39
Q

Define septic Shock:

A

A subset of sepsis where there is profound circulatory, metabolic and cellular deterioration
with Hypotension with <65mmHg MAP despite vasopressors
with a lactate of >18mg/L