Microbiology 4 - Respiratory tract infection Flashcards Preview

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Flashcards in Microbiology 4 - Respiratory tract infection Deck (43)
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1
Q

What is the most likely causative organism in a young patient with a lower lobe pneumonia, raised WCC and CRP?

A

Strep pneumoniae

2
Q

Recall the appearance of streptococcus in culture

A

Gram positive cocci in chains

3
Q

Recall how streptococcus is identified in the lab

A

Demonstrates alpha haemolysis

4
Q

What is the most common pathogen implicated in CAP?

A

Streptococcus

5
Q

Is streptococcus gram pos or gram neg?

A

Gram pos

6
Q

Recall the 2 pathogens that can cause typical CAP

A

S. pneumonia

H influenzae

7
Q

Which investigation are indicated in suspected CAP?

A

FBC, U&E, CRP, LFT

Blood cultures, sputum MC&S

8
Q

What severity score can be used to score CAP?

A
CURB-65
Confusion
Urea (>7)
RR (>30)
BP (<90 systolic)
>65 years
Score 2 or above = admit
9
Q

What is bronchitis?

A

Inflammation of medium sized airways

10
Q

How does bronchitis appear on CXR?

A

Normal

11
Q

How do haemophilus influenzae appear under the microscope?

A

Gram neg cocco-bacilli

12
Q

On what sort of agar should H influenzae be cultured?

A

Chocolate agar

13
Q

What colour sputum is produced in Strep pneumoniae?

A

Rusty

14
Q

Which type of atypical pneumonia is associated with hyponatraemia?

A

Legionella

15
Q

What is the special culture required for legionella?

A

Buffered charcoal yeast

16
Q

What extrapulmonary features are likely in atypical pneumonia?

A

Hepatitis

Hyponatraemia

17
Q

Which type of pneumonia is associated with confusion, abdo pain and diarrhoea?

A

Legionella

18
Q

Which type of pneumonia is spread by birds?

A

Chlamydia psittaci

19
Q

What is an empyema?

A

A collection of pus in the pleural cavity, gram-positive, or cultured from the pleural fluid

20
Q

What are the key features of TB pneumonia?

A
Ethnicity
Prolonged prodrome
Fevers
Weight loss
haemoptysis
21
Q

Recall 2 stains that can identify TB

A

Auramine stain

ZN stain

22
Q

How can upper and lower respiratory flora be differentiated?

A

Bronchial lavage

23
Q

Which type of pneumonia is common in the immunosuppressed (eg people who have had TB, HIV)?

A

Pneumocystis jirovecii

24
Q

Recall 4 symptoms of pneumocystis pneumonia

A

Dry cough
Weight loss
SOB
Malaise

25
Q

Recall the typical CXR finding in pneumocystis pneumonia

A

Bat wing

26
Q

What is the most likely cause of pneumonia when there are interstitial changes on CT, neutropaenia and a history of ABx treatment?

A

Aspergillus fumigatus

This is particularly associated with prolonged ABx use - if ABx hasn’t worked it may have a fungal cause

27
Q

Which type of LRTI is more common in people who have had a BM transplant?

A

CMV

28
Q

Which pneumonia pathogens can be tested for in urine?

A

Legionella

S pneumoniae

29
Q

Which type of atypical pneumonia are those who work around farm animals at increased relative risk of?

A

Coxiella burnetti

30
Q

What colour does gram stain appear with gram pos/gram neg bacteria?

A

Gram pos: blue

Gram neg: pink

31
Q

What is the treatment for mild-moderate pneumonia?

A

Amoxicilin

32
Q

What is the first line treatment for HAP?

A

Ciprofloxacin +/- vancomycin

33
Q

What type of an antobiotics is coxiella burnetti penumonia sensitive to?

A

Macrolides

34
Q

How will CXR appear in bronchitis?

A

Normal

35
Q

Which pathogen is the most likely cause of a post-influenza pneumonia?

A

S aureus

36
Q

Which pneumonia-causing pathogen is associated with smoking?

A

M catarrhalis

37
Q

Which pathogen is associated with the cause of pneumonia in the alcohol-dependent and the elderly?

A

Klebsiella

38
Q

Which pathogen is associated with the cause of pneumonia in patients with pre-existing COPD?

A

Haemophilus influenza

39
Q

Which type of pneumonia gives a positive cold agglutinin test?

A

Mycoplasma pneumonia

40
Q

Which type of pneumonia may present with erythema multiforme?

A

Mycoplasma pneumonia

41
Q

Which stain can be used to detect PCP, and what shape would the organisms appear?

A

Silver stain (Gomari’s methamine silver)
Boat-shaped organisms
May also show “flying saucer cysts”

42
Q

How can chlamydia pneumonia be diagnosed?

A

TWAR agent

43
Q

How can PCP be diagnosed in the lab?

A

Silver stain in cytology lab

Shows boat-shaped organisms

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