Infection and immunity Flashcards

1
Q

What type of bacteria is staph aureus? What infections is it associated with?

A

Gram positive cocci
Grape shaped

Septic arthritis
Hospital acquired pneumoniaf
Impetigo
Cellulitis

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

What type of bacteria is coagulase negative staph?

What infections is it associated with?

A

Gram positive cocci
Eg staph saprophyticus and staph epidermis

UTI
Prosthetic devices via biofilms

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

What type of bacteria is strep pneumoniae?

What infections is it associated with?

A

Group A strep
Gram positive cocci
Chains

Community acquired pneumonia
Meningitis
ENT infection

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

What type of bacteria is strep pyogenes?

What infections is it associated with?

A

Group A strep
Gram positive cocci

Necrotising fasciitis
Strep throat

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

What type of bacteria is strep viridans?

What infections is it associated with?

A

Gram positive cocci

Endocarditis

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

What type of bacteria is clostridium difficile?

What infections is it associated with?

A

Gram positive bacilli

GI

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

What type of bacteria is TB?

A

Acid fast bacilli

Mycobacterium

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

What type of bacteria is neisseria meningitidis?

What infections is it associated with?

A

Gram negative diplococci

Meningitis

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

What type of bacteria is neisseria gonorrhoea?

What infections is it associated with?

A

Gram negative diplococci

STI
Septic arthritis

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

What type of bacteria is haemophilus influenzae?

What infections is it associated with?

A

Gram negative cocci

Community acquired pneumonia
Bronchiectasis/COPD flare

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

What type of bacteria is Escherichia Coli?

What infections is it associated with?

A

Gram negative bacilli

UTI
Traveller’s diarrhoea
Meningitis (neonates)

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

What type of bacteria are pseudomonas aeruginosa and burkholderia cepacia?
What infections is it associated with?

A

Gram negative bacilli

CF pneumonia

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

Which organisms are most commonly associated with bronchiolitis?

A

Respiratory syncytial virus

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

Which organisms are most commonly associated with community acquired pneumonia?

A

Strep pneumoniae
Haemophilus influenzae
(Staph aureus)

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

Which organisms are most commonly associated with hospital acquired pneumonia?

A

Staph aureus

Pseudomonas aeruginosa

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

Which organisms are most commonly associated with pneumonia in alcoholics?

A

Klebsiella pneumoniae

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

Which organisms are most commonly associated with CF flares?

A
Staph aureus
Haemophilus influenzae
Aspergillus fumigatus
Pseudomonas aeruginosa
Burkholderia cepacia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which organisms are most commonly associated with COPD or bronchiectasis flares?

A

Haemophilus influenzae

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

Which organisms are most commonly associated with endocarditis?

A

Strep viridans
Staph aureus
Coagulase negative staph (on prosthetic valves)

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

Which organisms are most commonly associated with meningitis at various ages?

A

Neonates - E coli and group B strep
Elderly - Listeria monocytogenes
Everyone else - Strep pneumoniae, Neisseria meningitidis, Haemophilus influenzae

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

Which organisms are most commonly associated with septic arthritis?

A

Staph aureus
Strep A
Neisseria Gonorrhoea

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

Which organisms are most commonly associated with necrotising fasciitis?

A

Strep pyogenes

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

Which organisms are most commonly associated with dog bite?

A

Pasturella multocida

Clostridium tetani

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

Which organisms are most commonly associated with UTI?

A

E Coli

Strep saprophyticus

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

Which organisms are most commonly associated with acne?

A

Propioni acnes

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

Which organisms are most commonly associated with impetigo?

A

Staph aureus

27
Q

Which organisms are asplenic patients most susceptible to?

A

Encapsulated eg neisseria meningitidis

Spleen releases complement including opsonins.
Therefore
Decrease in ability to recognise microbes (particularly because no visible pamp without opsonin) and decrease in ability to recruit phagocytes.

28
Q

Which infections do you not give first line amoxicillin/co-amoxiclav?

A

Endocarditis - vancomycin
Meningitis - ceftriaxone
C diff - metronidazole
UTI - trimethoprim

29
Q

What is the triple therapy for h pylori?

A

LAC - 14 days

Lansoprazole
Amoxicillin
Clarithromycin

30
Q

What is the standard treatment for TB?

A

RIPE

Rifampicin
Isoniazid
Pyrazinamide
Ethanbutol

All 4 for 2 months
RI for 4 further months

31
Q

What are the side effects of the TB drugs?

A

Rifampicin - hepatitis, orange secretions, CYP inducer

Isoniazid - peripheral neuropathy, give vit B6, CYP inhibitor

Pyrazinamide - hepatitis, gout

Ethanbutol - optic neuritis - acuity and colour blindness

32
Q

What is the treatment for a CURB 1-2 pneumonia?

A

Amoxicillin or doxycycline

33
Q

What is the treatment for a CURB 3+ pneumonia?

A

Co amoxiclav + clarithromycin
or
Doxycycline + clarithromycin

34
Q

What is the treatment for septic arthritis?

A

Co amoxiclav or clindamycin

35
Q

What is the treatment for centor 3 or 4 tonsillitis?

A

Penicillin V or erythromycin

36
Q

What is the mechanism of action of penicillin?

A

Beta lactam that inhibits the transpeptidase that catalyzes the final step in cell wall biosynthesis, the cross-linking of peptidoglycan

37
Q

What is the mechanism of action of vancomycin?

A

Glycopeptide

Inhibits cell wall synthesis

38
Q

What is the mechanism of action of gentamicin?

A

Aminoglycoside

Inihibits protein synthesis

39
Q

What is the mechanism of action of erythromicin?

A

Macrolide

Inhibits protein synthesis

40
Q

What is the mechanism of action of ciprofloxacin?

A

Quinolone

Inhibits DNA synthesis

41
Q

What is the mechanism of action of trimethoprim?

A

Folic acid antagonist

42
Q

What is the difference between amoxicillin and co amoxiclav?

A

Clavulanic acid to inhibit beta lactamase in penicillin resistant bacteria

43
Q

Which antibiotics are most associated with a risk of c diff?

A

Cephalosporins eg ceftriaxone
Clindamycin
Penicillins

44
Q

What is a hypersensitivity reaction/

A

An antigen specific immune response that is inappropriate or excessive.

45
Q

Describe the Gell and Coombs classification of hypersensitivity reactions

A
I - atopy and anaphylaxis 
II - transfusion reaction, Goodpastures
III - SLE
IV - Contact dermatitis, scabies, TB
V - Grave's disease, myaesthenia gravis
46
Q

Describe the pathophysiology of anaphylaxis

A

Phase 1
Silent 1st exposure, TH2 phenotype of CD4 T cell tells B cell to switch IGm to IGe
This primes the mast cells

Phase 2
Antigen crosslinking on the primed mast cells causes them to release histamine, leukotrienes and prostaglandins

47
Q

What is the treatment for anaphylaxis?

A
0.5mg IM adrenalin (can have several doses)
100mg IV hydrocortisone
oxygen
fluid
monitor airway
48
Q

Describe the pathogenesis of TB

A

Type 4 hypersensitivity reaction (T cell mediated)

Mycobacteria detected and phagocytosed inside macrophage where they multiply and are taken to lymph nodes. In the lymph node this is the Ghon complex.

Either then primary TB (mild)
Or T cells send it latent

Then can have secondary disease (severe)

49
Q

What is miliary TB?

A

Secondary active disease that is disseminated across the body
Usually in immunocompromised

50
Q

What does a negative quantiferon test mean?

A

Never had TB

51
Q

What does a positive quantiferon test mean?

A

Latent or active TB

52
Q

What does a negative mantoux mean?

A

Never vaccinated or exposed to TB

Give BCG

53
Q

What does a positive mantoux mean?

A

Either vaccinated already or exposed to TB in some way

Do not give BCG

54
Q

Describe the histology of TB

A

Caseous necrosis and granulomas (epithelioid histiocytes) with Langhan’s giant cells

55
Q

Describe how TB appears in radiology?

A

Patchy consolidation with cavitating lesions

Hilar lymphadenopathy

56
Q

Describe the HIV stages?

A
Acute phase
1 - asymptomatic
2 - CD4 <500
3 - CD4 <350
4 - CD4 <200
57
Q

At what stage should antiretrovirals be started for HIV?

A

At diagnosis

58
Q

What conditions are commonly seen at CD4 counts <500, <200, <100?

A

<500 - Candidiasis, TB, Herpes zoster, leukoplakia, Kaposi’s sarcoma

<200 - Pneumocystis jirovecii pneumonia (PCP), toxoplasmosis

<100 - Cytomegalovirus, meningitis, oesophageal candidiasis

59
Q

Which type of pneumonia is associated with HIV?

A

Pneumocystis jirovecii pneumonia (PCP)

60
Q

How would the results of hepatitis B serology look in a patient who is immune due to infection?

A

HBsAg (exposure) - positive

antiHBs (immunity) - positive

61
Q

How would the results of hepatitis B serology look in a patient who is immune due to vaccination?

A

HBsAg (exposure) - negative

antiHBs (immunity) - positive over 100

62
Q

How would the results of hepatitis B serology look in a patient who has active disease?

A

HBsAg (exposure) - positive

antiHBs (immunity) - negative
antiHBc - positive IgM

63
Q

How would the results of hepatitis B serology look in a patient who has chronic disease?

A

HBsAg (exposure) - positive

antiHBs (immunity) - negative
antiHBc - positive IgG

64
Q

Which antibiotics can you give in general instead of co-amoxiclav in penicllin allergic patients?

A

Cefuroxime (cephalosporin generally for lung but be careful in severe/proper allergy)
Clindamycin (macrolide generally for MSK)
Doxycycline (tetracycline generally low risk for c diff)