Infectious Diseases (basics) Flashcards

1
Q

Define Eukaryotes?

A

cells containing membrane bound organelles e.g. nucleus, mitochondria or chloroplasts, can be unicellular e.g. fungi, or part of a complex multicellular organism e.g. a human

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2
Q

Define prokaryotes?

A

cells lack any membrane bound organelles – usually unicellular e.g. bacteria and archaea

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3
Q

What are archaea?

A
  • Archaea are a domain of single cell organisms that live at extremes (type of prokaryote)
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4
Q

Describe difference in way DNA is organised in prokaryotes vs eukaryotes?

A
  • DNA in prokaryotes and therefore bacteria is circular including the circular chromosome and plasmids – this is in contrast to eukaryotes where DNA is arranged in a linear fashion e.g. in chromosomes
  • prokaryotes can do co-transcriptional translation (all happening at the same time) because nothing is membrane bound
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5
Q

Proteins are synthesised in the ______

A

ribosome

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6
Q

What is essential for synthesis and regulation of DNA within the bacteria?

A

folic acid

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7
Q

Explain the process of gram staining and what it involves?

A
  • This allows organisms to be classed as gram positive or negative
  • Atypical organisms cannot be classed this way – definition = organisms that cannot be stained or cultured in normal ways
  • Gram staining involves first using a crystal violet stain which will stain gram positive organisms purple, then a counterstain which will stain gram negative organisms pink
  • Gram staining is to do with differences in thickness of peptidoglycan cell walls
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8
Q

Name 6 gram positive rods?

A
  • Propionibacterium
  • Clostridium
  • Lactobacillus
  • Corneybacteria
  • Actinomyces
  • Listeria
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9
Q

2 genus of gram positive cocci? How can you differentiate?

A

streptococci - grow in chains - catalase negative
staphylococci - grow in clusters - catalase positive

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10
Q

2 species of staph that are clinically relevant?

A

aureus and epidermidis

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11
Q

Describe classification of streptococci?

A

Alpha haemolytic – viridans and pneumonia
Beta haemolytic (complete) – Group A and Group B
Gamma haemolytic – Enterococcus

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12
Q

Describe neisseria genus?

A

gram negative cocci in pairs
includes neisseria meningitidis and neisseria gonorrhoea

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13
Q

What are the coliforms? List 3?

A

COLIFORMS- gram negative non spore forming bacilli
E. coli
Klebsiella
Enterobacter

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14
Q

Pseudomonas shape and gram stain?

A

gram negative rod

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15
Q

Moraxella Catarrhalis shape and gram stain?

A

gram negative diplococcus

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16
Q

List 4 gram positive anaerobes?

A

Clostridium, lactobacillus, actinomyces, Propionibacterium

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17
Q

Name a gram negative anaerobe?

A

Bacteroides

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18
Q

Define bacteriostatic vs bacteriacidal?

A
  • Bacteriostatic – stops reproduction and growth of the bacteria
  • Bacteriacidal – kills the bacteria directly
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19
Q

Antibiotics that inhibit cell wall synthesis?

A
  • Antibiotics that inhibit cell wall synthesis can be split into beta lactam and non beta lactam antibiotics
  • Beta lactam – penicillins, carbapenems and cephalosporins
  • Non beta lactam – vancomycin and teicoplanin
20
Q

Antibiotics that inhibit folic acid metabolism?

A
  • Antibiotics that inhibit folic acid metabolism – sulfamethoxazole, trimethoprim, co-trimoxazole (combination of the above 2)
21
Q

Antibiotic that affects nucleic acid synthesis?

A
  • Antibiotic that affects nucleic acid synthesis – metronidazole – this only converts to active form in anaerobic cells so is only effective against anaerobes
22
Q

Antibiotics that affect protein synthesis by targetting the ribosome?

A
  • Inhibition of protein synthesis by targeting the ribosome – macrolides, clindamycin, tetracyclines, gentamicin, chloramphenicol
23
Q

Amoxicillin coverage

A

widely covers gram positive and some gram negative organisms, covers most strep, enterococcus and listeria

24
Q

Co-amoxiclav coverage?

A

widely covers gram positive, gram negative and anaerobes

25
Q

Metronidazole coverage?

A

treats anaerobic infections

26
Q

Gentamicin coverage?

A

mainly gram negative coverage against pseudomonas, E. coli, proteus, klebsiella, Enterobacter, can also treat Staph

27
Q

Vancomycin coverage?

A

coverage for gram positive organisms, oral vancomycin is used for C diff GI infection

28
Q

Doxycycline coverage?

A

broad spectrum covering gram positive, negative and anaerobes and some atypical infections

29
Q

Clindamycin coverage?

A

active against gram positive and anaerobes

30
Q

Clarithromycin coverage?

A

gram positive and atypical organisms

31
Q

Ciprofloxacin coverage?

A

gram negative cover

32
Q

6 antibiotics you could get gram positive cover with?

A

Amoxicillin
Co-amoxiclav
Vancomycin
Doxycycline
Clindamycin
Clarithromycin

33
Q

4 antibiotics you could get gram negative cover with?

A

Gentamicin
Doxycycline
Co-amoxiclav
Ciprofloxacin

34
Q

4 antibiotics you could get good anaerobe cover with?

A

Metronidazole
Doxycycline
Clindamycin
co-amoxiclav

35
Q

Define sepsis?

A
  • Dysregulated host response to infection (overreaction by host to presence of infection)
  • Essentially clinically can view it as NEWS > 5 and signs of infection
36
Q

Define septic shock?

A
  • Septic shock is a subset of sepsis where there is circulatory and cellular/ metabolic dysfunctions associated with high risk of mortality
  • Criteria for septic shock: persistent hypotension requiring vasopressors to maintain MAP greater than or equal to 65, lactate greater than or equal to 2 mmol (despite adequate volume resuscitation)
37
Q

Explain why lactate is measured in sepsis?

A
  • Lactate is measured in sepsis as a high lactate suggests hypoperfusion of tissues (as they are switching to anaerobic respiration)
38
Q

What is the sepsis 6?

A
  • Sepsis 6 needs commenced in 1 hour: take blood cultures, measure urine output, take lactate, give empirical antibiotics, give high flow oxygen, give fluids
39
Q

What type of antibiotic is ceftriaxone? What does it cover? What is it especially good for?

A

cephalosporin
it is broad spectrum covering both gram positive and gram negative
it is good for CNS infections - it reaches a high bacteriacidal titre in the CSF and persists at the site of infection longer than any other beta lactam
(ceftaxime is similar and also good for this)

40
Q

What antibiotic is used to treat C diff infection?

A

ORAL vancomycin

41
Q

As well as bacterial infection what can metronidazole also treat?

A

some parasitic infections

42
Q

What antibiotic can treat some parasitic infections?

A

metronidazole

43
Q

Co-amoxiclav covers gram negative, positive and anaerobes but does not cover?

A

pseudomonas

44
Q

Pseudomonas is sensitive to ?

A

ciprofloxacin

45
Q

Name an antibiotic that cover MRSA?

A

vancomycin

46
Q

C diff treatment?

A

1st line is oral vancomycin
2nd line is for patients who fail to improve after 7 days or worsen on oral treatment - findaxomicin twice daily for 10 days or oral vanc plus Iv met

choose oral vanc plus IV met if life threatening infection