Y4 - Microbiology Tutorial Flashcards

1
Q

What is the incubation period of the influenza virus?

A

1-4 days

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

What is the transmission of influenza?

A

Droplet

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

How does droplet transmission differ from aerosol?

A

Droplet involves larger particle sizes (>5microns) Aerosol is smaller particles (can travel further as they are smaller and more infective)

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

What sorts of patients would you give antivirals to if they had flu?

A

Immunocompromised, elderly, really young, pregnant, heart/lung/other chronic disease

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

If you want to use antivirals to treat the flu, and there is high resistance to oseltamivir, what antiviral should you use?

A

Zanamivir

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

How do you treat uncomplicated flu?

A

Fluid, rest, analgesia etc.

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

What is the incubation period of norovirus?

A

72 hours

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

What is the advice you should give to a healthcare worker who has norovirus?

A

Don’t come back to work until you are >48h symptom free

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

What is the transmission of norovirus?

A

Faecal-oral, contact, droplet (swallowing droplets)

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

What is the treatment of norovirus?

A

Supportive If elderly/immunocompromised can get into kidney failure (dehydration)

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

Define incubation period

A

Period of time between contracting the pathogen and displaying overt symptoms

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

True or false: When there is an outbreak of norovirus, hand gel is sufficient to kill the bacteria

A

False Must wash hands with soap and water as norovirus is a non-enveloped virus so alcohol gel doesn’t work

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

What is the difference between gram negative and positive bacteria?

A

Structure of their cell wall: Gram positive: single thick peptidoglycan layer Gram negative: thin peptidoglycan layer & outer cell membrane with lipopolysaccharide layer

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

Describe the process of gram staining

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

What bacteria tend to cause eye infections?

A

Staph aureus

Nessieria gonorrhoea

Chlamydia trachomatis

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

What infections tend to cause sinusitis?

A

Strep pneumoniae

H. influenzae

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

What bacteria tend to cause URTIs?

A

Strep pyogenes

H. influenzae

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

What infections tend to cause gastritis?

A

H. pylori

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

What bacteria can cause food poisoning?

A

Campylobacter jejuni

Salmonella

Shigella

Clostridium

Staphylococcus aureus

E. coli

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

What bacteria tend to cause UTIs?

A

E. coli

Other enterococci

Staphylococcus saprophyticus

Pseudomonas aeruginosa

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

What bacteria cause STIs?

A

Chlamydia trachomatis

Neisseria gonorrhoea

Treponema pallidium

Ureplasma urealyticum

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

What bacteria commonly cause skin infections?

A

Staph aureus

Strep pyogenes

Pseudomonas aeruginosa

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

What bacteria tend to cause community acquired pneumonias?

A

Strep pneumoniae

H. influenzae

Staph aureus

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

What bacteria cause atypical pneumonia?

A

Mycoplasma pneumoniae

Chlamydia pneumoniae

Legionella pneumophila

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What bacteria causes TB?

A

Mycobacterium tuberculosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What bacteria causes otitis media?

A

Strep pneumoniae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What bacteria commonly cause meningitis?

A

Strep pneunmoniae

Neisseria meningitidis

H. influenzae

Strep agaetiae

Listeria monocytogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is strep pyogenes also known as?

A

Group A strep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the clinical signifiance of group B strep?

A

Importance cause of neonatal sepsis

Tested for in pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does group C strep tend to cause?

A

Skin and soft tissue infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What can strep pyogenes cause?

A

Tonsilitis, necrotising fasciitis, scarlett fever etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Give examples of gram negative rods

A

Enteric bacteria:

  • E. coli
  • Salmonella
  • Shigella
  • Yersinia
  • Pseudomonas
  • Proteus
  • Vibrio cholerae
  • Klebsiella pneumoniae

Other gram -ve rods:

  • Bodetella pertussis
  • H. influenzae
  • Campylobacter jejuni
  • H. pylori
  • Legionella pneumophilia

Anaerobes:

  • Bacteriodes fragilies
  • Fusobacterium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the main thing that proteus bacteria cause?

A

UTIs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What main things does pseudomonas cause?

A

Chronic lung infection in those with CF

Seen in a lot of ulcers too

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Do we culture bordetella pertussis?

A

No takes too long

Can do PCR (from throat/nasal swab) in first 2 weeks of infection

After 2 weeks can do bordetella serology

36
Q

What does bacteriodes fragilis cause? How do you treat it?

A

Abscesses

Rx: metronidazole (used for anaerobes!)

37
Q

What infections do fusobacterium cause?

A

Sore throat and tonsilitis that doesn’t seem to get better. Seen more in young fit people and can cause jugular vein thrombosis

38
Q

Give examples of gram negative cocci?

A

Neisseria gonorrhoea (gonoccocus)

Nesseria meningitidis (meningococcus)

nb these are both gram -ve intracellular diplococci

39
Q

What are the gram positive cocci?

A

Staphylococci

Streptococci

40
Q

Which of the gram positive cocci are catalase positive?

A

Staphylococci

41
Q

What is the apearance of staphylcocci?

A

Gram positive cocci in clusters

42
Q

What bacteria are staphylococci?

A

Staphylococcus aureus

Staph. epidermis and other CNS

43
Q

How do you tell the difference between staph aureus and staph epidermis?

A

Staph aureus is coagulase positive, other staph are coagulase negative (CNS)

44
Q

What are the streptococci?

A

Strep pyogenes

Strep pneumoniae

Viridians type strep

Enterococci faecalis

NB: chains of strep tend to be group A/B/C strep, diplococci of strep tend to be strep pneumoniae

45
Q

Staph aureus/epidermis is usually significant when found in blood culture.

A

Staph aureus

Staph epidermis usually a contaminant

46
Q

What are the gram positive rods?

A

Clostridia

  • Anaerobes
  • C. perfringens
  • C. tetani
  • C. botulinum
  • C. difficle

Bacillis cereus (aerobe)

Listeria monocytogenes (facultative anaerobe)

47
Q

What can C. perfringens cause?

A

Gas gangrene

48
Q

What can listeria cause?

A

Meningitis in neonates, immunocompromised, pregnant

49
Q

Where is listeria contracted from?

A

Usually soft cheese, pate etc.

50
Q

What types of bacteria are not gram-stainable?

A

Unusual gram positives

Spirochaetes

51
Q

What are the unusual gram positives?

A

Mycobacteria (M. tuberculosis, M. avium)

May be weakly positive/unstained on gram stain

52
Q

What stain must you use for mycobacteria?

A

Ziehl-Neelsen stain

(as they are acid-fast bacilli)

53
Q

What is the appearance of spirochaetes?

A

Thin spiral bacteria

54
Q

How do you visualise spirochaetes?

A

Phase-contrast microscopy/silver stain

55
Q

Give examples of spirochaetes

A

Treponema pallidium

Borrelia burgdorferi

56
Q

What causes lyme disease?

A

Borrelia burgdorferi

57
Q

What vectors carry lyme disease?

A

Lxodes ricnus complex hard ticks (sheep ticks)

58
Q

What is the classic rash associted with lyme disease?

A

Erythema migrans

59
Q

What can happen if lyme disease is left untreated?

A

Dissemination to CNS, joints and heart

60
Q

How do you treat suspected lyme disease?

A

Doxycyline 100mg BD for 3 weeks

61
Q

What is staph aureus bacteraemia?

A

Cause of serious healthcare associated blood stream infection

62
Q

What is the mortality rate associated with staph aureus bacteriaemia?

A

20-40%

63
Q

True or false:

Staph areus can colonise patients

A

TRUE
Can live on people’s skin and mucosa (nose) without causing infection

It can cause infection if it enters the body through broken skin or medical procedure

64
Q

What infections can staph aureus bacteraemia come from?

A

Wounds

Cellulitis

Pneumonia

Joint infection

Bacteraemia

Endocarditis

65
Q

Once in the bloodstream, staph aureus can release toxins - name these.

A

Enterotoxins, toxic shock syndrome toxin 1, epidermolytic toxins

66
Q

What are the complications associated with staph aureus bacteraemia?

A

Metastatic infections, e.g. endocarditis, vertebral osteomyelitis, discitis

High mortality

67
Q

How do you prevent staph aureus bacteraemia?

A

Hand hygiene, aseptic technique doing invasive procedures

68
Q

What examination findings may help point to a cause in staph aureus bacteraemia?

A

Murmurs, skin and bone and joint tenderness (e.g. SA/discitis), urinary catheters, prostheses (prosthetic joints/valves)

69
Q

How do you investigate staph aureus bacteraemia?

A

CT/MTI (discitis), joint aspiration, TTE, CXR, repeat blood cultures

70
Q

How do you treat staph aureus bacteraemia?

A

Methicillin sensitive - IV flucloxacillin 2g 4-6hrly assuming normal renal function

TREAT FOR AT LEAST 14 DAYS IV (longer for deep seated infection such as endocarditis)

71
Q

Define endocarditis

A

Infection of endocardial surface of the heart

72
Q

What is the mortality associated with endocarditis?

A

20%

73
Q

What valves are most commonly affected by endocarditis?

A

Mitral and aortic alone (left side more common due to pressure difference)

IVDA more commonly get the right side of the heart and are also more likely to get lung abscess

74
Q

What is the pathogenesis of endocarditis?

A

Requires simultaneous occurence of many events

Altered valve surface-bacterial attachment and colonisation

Platelet-fibrin deposition

Bacteria adhesion-colonisation-invasion

75
Q

What organisms can cause endocarditis?

A

Staph (most common)

Strep

Enterococci

Gram -ve and fungi v. rare

Culture negative causes may incl. prev course of antibiotics, Q fever (coxiella burnetti)

76
Q

What are the clinical features of endocarditis?

A

Fever

Heart murmur

New murmur

Others: chill, weakness, SoB, anorexia, weight loss, stroke

Osler nodes

Janeway lesions

Roth spots

Glomerulonephritis (haematuria)

Septic emboli to brain/lungs/spleen

77
Q

Describe janeway lesions

A

Non-tender, microabscesses

Tend to be on palms/soles

78
Q

Describe Roth spots

A

Retinal lesions surrounded by haemorrhage and usually located near the optic disc

79
Q

Describe Osler’s nodes

A

Non-specific, tender, immunological sign

80
Q

What investigations should you do for endocarditis?

A

Hx, Ex

ESR, CRP, WCC, dipstick for haematuria

Blood cultures - 3 sets

Serology for blood culture negative endocarditis

Echo (TOE more sensitive than TTE, but use TTE first)

81
Q

What criteria is used for assessing endocarditis?

A

Duke criteria

Endocarditis: 2 major or 1 major and 3 minor or 5 minor

82
Q

What are the major duke criteria?

A
  • Positive blood cultures for IE (e.g. staph/strep/enterococci)
  • Evidence of endocardial involvement - +ve echo with mass on valve, new valvular regurgitation
83
Q

What are the minor duke criteria?

A
  • Predisposition - valve abnormality, IVDU
  • Fever
  • Vascular-arterial emboli, septic pulmonary infarct, Janeway lesions
  • Immunological: Osler’s nodes, Roth spots
  • Microbiological phenomena: positive blood culture but not met major criteria
  • Echo findings: consistent with endo but not met major criteria
84
Q

What is the management of endocarditis?

A

Antibiotics dependent on organism and sensitivity

E.g. flucloxacillin 2g IV 4-6hrly for 4 weeks for flucloxacillin sensitive staph aureus native valve endocarditis

For PVE due to MSSA use combination of flucloxacillin, rifampicin and gentamicin for 6 weeks

85
Q

What are the indications for surgical management of endocarditis?

A
  • Heart failure - refractory pulmonary oedema or cardiogenic shock esp in prosthetic heart endocarditis
  • Perivalvular infection with abscess
  • Failure of medical Rx-persistent fever and positive blood culture >10 days after appropriate antimicrobial therapy
  • Septic emboli especially from AV or MV with large vegetation >10mm