Microbiology 12: Respiratory Tract Infections Flashcards

1
Q

Blood culture from a young women isolates a gram +ve diplococcus, alpha-haemolytic bacteria which is optochin sensitive.

What is the most likely causative organism of her pneumonia?

A

Streptococcus. Pneumoniae

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2
Q

List the 3 most common causative organisms of pneumonia in neonates 0-1 months old ?

A

E.coli
Group B streptococcus (GBS)
Listeria monocytogenes

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3
Q

List the 3 most common causative organisms of pneumonia in children 1-6 months old ?

A

Chlamydia trachomatis
Staphylococcus aureus
RSV

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4
Q

List the 2 most common causative organisms of pneumonia in children 6 months - 5 years old ?

A

Mycoplasma pneumonia

Influenza

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5
Q

List the 2 most common causative organisms of pneumonia in people ages 16-30 years old ?

A

Streptococcus pneumonia

Mycoplasma pneumonia

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6
Q

List the 2 typical organisms causing CAP

A

Streptococcus Pneumoniae

Haemophilus influenza

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7
Q

List the 4 atypical organisms causing CAP

A

Legionella
Mycoplasma
Coxiella burnetii (Q-fever)- exposed to farm animals
Chlamydia psittaci (psittacosis)- exposure to birds, you get a haemolytic anaemia

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8
Q

List 3 organisms that cause cavitation on CXR ?

A

Staph aureus (Swiss cheese type pattern)
Klebsiella pneumonia
TB

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9
Q

Which atypical organism is transmitted by inhalation of infected water droplets e.g from saunas, AC and is grown on buffered charcoal yeast extract ?

A

Legionella Pneumophila

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10
Q

What is the antibiotic treatment for atypical CAP ?

A

Macrolide - Azithromycin/ clarithromycin
+
Doxycycline

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11
Q

An auramine stain and ziehl-Nielsen stain are used to identify which organism ?

A

TB

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12
Q

What are the most common causative organisms of HAP ?

A

Enterobacteriaciae (e.coli, klebsiella pneumonia)
S.aureus
Pseudomonas aeruginosa

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13
Q

Which organisms causes bilateral ground glass shadowing (bat’s wing appearance)?

A

Pneumocystis Jirovecii (PCP)

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14
Q

What is a special physical test to diagnose Pneumocystis jirovecii ?

A

The walk test (attach oxygen saturation and get them to walk) - shows desaturation on exertion

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15
Q

Which organisms causing LRTIs are more common in patients with neutropenia ?

A

Fungi - aspergillus

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16
Q

Which organism typically causes LRTIs in patients with bone marrow failure ?

A

CMV

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17
Q

What is the 1st line antibiotic treatment for HAP ?

A

Ciprofloxacin +- vancomycin

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18
Q

Which atypical organism causes Pneumonia with cold agglutinins And erythema multiforme (target lesion) on palms ?

A

Mycoplasma Pneumonia

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19
Q

Which organism causes a pneumonia with cough, myalgia and rose spots on the abdomen and is commonly seen in ornithologists (bird handlers)?

A

Chlamydia Psittaci

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20
Q

Which organism causes pneumonia with target shaped lesions on the palm ?

A

Mycoplasma pneumonia

21
Q

Which 2 organism commonly Infect people with cystic fibrosis ?

A

Pseudomonas aeruginosa

Burkholderia capacia

22
Q

Which organism when stained with Gomori’s methenamine silver stain shows “Flying saucer” shaped cysts ?

A

Pneumocystis jirovecii

23
Q

Which coccus bacteria arranges in grape-like clusters ?

A

Staphylococcus aureus

24
Q

Which organism causes acute exacerbation of COPD and otitis media in children ?

A

Moraxella Caterrhalis

25
Q

what compromises to respiratory function cause respiratory diseases

A
poor swallow
abnormal ciliary function 
abnormal mucus 
dilated airways 
defects in host immunity
26
Q

features of strep pneumoniae

A

alpha-haemolytic and optochin sensitive
gram positive cocci
severe pneumonia, fever + rigors, lobar consolidation
almost always penicillin sensitive

27
Q

what is the CURB-65 scale

A
risk stratification fro pneumonia patients 
confusion 
urea >7mmol/L 
RR>30 
BP <90 systolic, <60 diastolic 
65+ years 

2 = consider admitting
2-5 manage as severe pneumonia and consider ITU admission

28
Q

what organisms commonly cause bronchitis

A

viruses
strep pneumoniae
hemophilus influenzae
moraxelle catarrhalis

29
Q

features of haemophilus influenzae

A

gram-negative cooco-bacilli
common with pre-exisiting lung disease
may produce beta-lactamase

30
Q

features of legionella pneumophilia

A

spread via inhalation of infected water droplets
grown on buffered charcoal yeast extract
can cause multi-organ failure

31
Q

features of legionella pneumophilia

A
aerosol spread 
environmental outbreaks 
confusion, abdo pain, diarrhoea 
lymphopaenia, hyponatraemia
inv = urinary antigens 
sensitive to macrolides
32
Q

features of coxiella burnetii

A

common in domestic farm animals
transmitted by aerosol or milk
inv = serology
sensitive to macrolides

33
Q

features of chlamydia psittachi

A

spread from birds by inhalation
inv = serology
sensitive to macrolides

34
Q

why are empyemas difficult to treat

A

they have a wall around them and the pus contained is very acidotic which inactivates the antibiotics

35
Q

stains for TB

A

auramine stain

ziehl-neelsen stain (auer rods are the acid-fast bacilli)

36
Q

what is a HAP

A

pneumonia onset >48 hrs in hospital

37
Q

features of pneumocyctic jirovecii

A
protozoan 
insidious onset 
presentation: dry cough, weight loss, SOB, malaise
CXR: bat-wing shadowing 
inv: bronchoalveolar lavage 
tx: co-trimoxazole 

detected by silver stain on cytology

38
Q

features of aspergillus fumigatus

A

ABPA: chronic wheeze, eosinophilia, bronchiectasis
Aspergilloma: fungal ball, often in pre-existing cavities
Invasive aspergillosis: immunocompromised, tx = amphotercin B

39
Q

LRTI in HIV patients

A

PCP
TB
atypical mycobacteria

40
Q

LRTI in neutropaenia

A

fungi (esp aspergillus species)

41
Q

LRTI in BM transplant

A

CMV

42
Q

LRTI in splenectomy

A

encapsulated organisms (S Pneumoniae, H influenzae, malaria)

43
Q

what would you use antigen tests for

A

legionella pneumophilia

strep pneumoniae

44
Q

what would you use antibody tests for

A

chlamydia

legionella

45
Q

what colour are gram +ve and gram -ve bugs

A

gram +ve = blue

gram -ve = prink

46
Q

treatment for mild-moderate CAP

A

amoxicillin

or erythromycin/clarythromycin

47
Q

treatment for moderate-severe CAP

A

co-amoxiclav
and clarythromycin

(allergic - give cefuroxime + clarythromycin)

48
Q

treatment for HAP

A

1st line = ciprofloxacin +/- vancomycin
2nd line = piptazobactam + vancomycin
MRSA = vancomycin
pseudomonas = piptazobactam OR cipro +/- gentamycin

49
Q

how can we prevent pneumonia

A

smoking advice

vaccination - inlfuenza anually, pneumovax every 5 yrs