Microbiology of Respiratory Tract Infections

Question 1

What are the host defences of the URT?

Answer 1

oropharynx (saliva, sloughing, cough)

nasopharynx (nasal hairs, ciliated epithelium, IgA)

Question 2

What are the host defences of the LRT?

Answer 2

trachea

bronchus (mucociliary escalator, cough, AMP, cellular + humoral immunity)

Question 3

What bacteria is a URT coloniser - and hence normal to appear on a swab?

Answer 3

Gram +ve = strep pneumoniae and strep pyogenes, staphylococcus aureus
Gram –ve = haemophilus influenza, Moraxella catarrhalis

Question 4

Describe whooping cough?

Answer 4

Acute trachea-bronchitis
­cold like symptoms for two weeks
­paroxysmal coughing (2 weeks)
­repeated violent exhalations with severe inspiratory “whoop”
vomiting common
­residual cough for month or more

Question 5

What are the pathogens responsible for whooping cough?

Answer 5

Bordetella pertussis

­Gram negative coccobacillus

Question 6

What pathogens are responsible for COPD?

Answer 6

Haemophilus influenzae
Moraxella catarrhalis
Streptococcus pneumoniae
Gram-negatives

Question 7

Is Acute Bronchitis mainly bacterial or viral?

Answer 7

90% viral

Question 8

What are some of the pathogens that cause cystic fibrosis?

Answer 8

Staph aureus
Haemophilus influenzae
Strep pneumoniae
Pseudomonas aeruginosa
Burkholderia cepacia

Question 9

Name a typical pathogen to cause pneumonia?

Answer 9

Streptococcus pneumoniae

Question 10

Name an atypical pathogen to cause pneumonia?

Answer 10

Mycoplasma pneumoniae
Legionella pneumonia
Chlamydophila pneumonia
Chlamydia psitacci
viruses

Question 11

What is Legionellosis caused by?

Answer 11

Legionella pneumophila

Question 12

What is the treatments for Legionella pneumophila?

Answer 12

Clarythromycin

Erythromycin