Microbiology Flashcards

1
Q

Gram+ organisms stain…

A

Purple

Stain well due to thick peptidoglycan layer

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2
Q

Gram- organisms stain…

A

Pink

Thinner peptidoglycan layer doesn’t retain stain well

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3
Q

Endotoxin is produced by…

A

Gram- organisms
Sugar
Part of the cell wall

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4
Q

Exotoxin is produced by…

A

Gram+ organisms
Exported from the cell
Proteins

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5
Q

Gram+ cocci in chains are?

A

Streptococci

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6
Q

Gram+ cocci in clusters are?

A

Staphylococci

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7
Q

The test to classify different Streptococci spp.?

A

Haemolysis
Alpha (partial) - dark green - Strep. pneumoniae + viridans
Beta (complete) - yellow - Group A (pyogenes) and B Strep.
Gamma (none) - red - Enterococcus sp.

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8
Q

Examples of: Alpha-haemolytic Streptococci?

A

Strep. pneumoniae + “viridans” group

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9
Q

Examples of: Beta-haemolytic Streptococci?

A

Group A Strep. (Strep. pyogenes), Group B Strep.

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10
Q

Examples of: Non-haemolytic Streptococci?

A

Enterococcus sp.

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11
Q

The test to distinguish Staphylococcus aureus from other Staph. spp.?

A

Coagulase test
+ve = Staph. aureus
-ve = other Staph. spp. (common skin commensals)

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12
Q

Treatment of choice for Staph. aureus infection?

A

Flucloxacillin

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13
Q

Examples of gram- cocci in pairs (diplococci)

A

Neisseria meningitidis and Neisseria gonorrhoeae

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14
Q

Some examples of Gram- bacilli

A
H. pylori
H. influenzae
Coliforms
Pseudomonas
Campylobacter
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15
Q

Examples of coliforms that are gut commensals

A

E. coli
Klebsiella sp.
Proteus sp.

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16
Q

Examples of coliforms that are gut pathogens

A

Salmonella sp.
Shigella sp.
E. coli 0157

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17
Q

The name of the toxin produced by E. coli 0157 is…

A

Verotoxin (VTEC)

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18
Q

Treatment of choice for coliform infections?

A

Gentamicin

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19
Q

Examples of strict aerobes (2)

A

Pseudomonas sp. (Gram- bacilli)

Legionella sp. (Gram- bacilli)

20
Q

Examples of strict anaerobes (2)

A

Clostridium spp. (Gram+ bacilli)

Bacteroides spp. (Gram- bacilli)

21
Q

Treatment of choice for anaerobic infections?

A

Metronidazole

22
Q

Genetic variation in bacteria is dangerous because…

A

Resistance to antibiotics may develop.

23
Q

Gene transfer: Transformation

A

DNA from dead bacteria is taken up by living bacteria and incorporated into plasmids/ bacterial chromosome.

24
Q

Gene transfer: Conjugation

A

Sex pilus forms between bacteria to allow transfer of plasmid DNA.

25
Q

Gene transfer: Transduction

A

Viruses can transfer bacterial DNA between cells they infect.

26
Q

The 5 methods of spread of infection are…

A

Inhalation, Ingestion (faecal-oral), Inoculation (blood), mother to Infant, Intercourse (sex)

27
Q

Viruses contain RNA or DNA, never both.

True/ False?

A

True

Size of their capsid (protein coat) limits space

28
Q

Bactericidal antibiotics inhibit cell growth.

True/ False?

A

False

Kill bacteria directly - bacteriostatic inhibits cell growth

29
Q

What do glycopeptides treat?

A

Serious gram positive infections

*vancomycin

30
Q

Vancomycin is part of which family of antibiotics?

A

Glycopeptides

31
Q

Penicillins, cephalosporins and glycopeptides act on the bacterial …

A

Cell wall

32
Q

Penicillins:

  • bactericidal/ bacteriostatic
  • safe/ not safe in pregnancy
  • excreted via kidneys/ urine/ liver
A

Bactericidal, safe in pregnancy, kidneys

33
Q

Flucloxacillin is a ___ spectrum antibiotic.

Which organisms is it effective against?

A

Narrow

Staph and Strep only (1st line for Staph aureus)

34
Q

Beta lactamase destroys which antibiotic?

A

Amoxicillin

  • there are different types of beta lacamases
  • psuedonomas aeruginosa, klebsialla, E. coli, staph. aureus
35
Q

What does co-amoxiclav treat?

A

Treats everything apart from pseudomonas and MRSA

Can be taken orally or IV

36
Q

Cephalosporins

  • are bactericidal/ bacteriostatic
  • safe/ not safe in pregnancy
  • excreted via kidneys/ urine/ liver
A

Bactericidal, safe in pregnancy, kidneys + urine

37
Q

Glycopeptides are only active against Gram _ cell walls.

*such as vancomycin

A

+ve

38
Q

Name the 3 macrolides!

A

Erythromycin, clarythromycin, azythromycin

39
Q

What are aminoglycosides used to treat?

*such as gentamicin

A

Read BNF summary

40
Q

Gentamicin belongs to which class of antibiotics?

A

Aminoglycosides

41
Q

Macrolides:

  • bactericidal/ bacteriostatic
  • safe/ not safe in pregnancy
  • excreted via kidneys/ urine/ liver

*such as erythromycin

A

Bacteriostatic, erythromycin safe in pregnancy, liver

42
Q

Gentamicin [aminoglycoside]:

  • bactericidal/ bacteriostatic
  • safe/ not safe in pregnancy
  • excreted via kidneys/ urine/ liver
A

Both bacteriostatic + bactericidal, not safe in pregnancy, urine

43
Q

Name the antibiotics that act on bacterial DNA!

A

Metronidazole, trimethoprim +/- sulphanimide, fluoroquinolones

44
Q

Metronidazole:

  • bactericidal/ bacteriostatic
  • safe/ not safe in pregnancy
  • treats aerobes/ anaerobes
A

Bactericidal, safe in pregnancy, anaerobes (Clostridium and Bacteroides)

45
Q

Trimethoprim +/- sulphonamide

  • bactericidal/ bacteriostatic
  • can be combined with sulphonamide to form _____
A

Bacteriostatic, co-trimoxazole

46
Q

The 4 antibiotics that most commonly cause C diff infection are…

A

Ciprofloxacin
Co-amoxiclav
Clindamycin
Cephalosporins (ceftriaxone)