Microbiology of Respiratory Tract Infections II

Question 1

What is present in the nasopharynx to protect agains RTIs?

Answer 1

Nasal hairs
Ciliated epithelia
IgA

Question 2

What is present in the oropharynx to protect against RTIs?

Answer 2

Saliva
sloughing
Cough

Question 3

What type of gram positive bacteria colonise the nasopharynx and oropharynx?

Answer 3

Alpha haemolytic streptococcus and beta-haemolytic strep

Staph aureus

Question 4

What type of gram negative bacteria colonise the nasopharynx and oropharynx?

Answer 4

Haemophilus influenza
Moraxella catharalis
Other

Question 5

What is epiglottis?

Answer 5

Inflammation of the pipiglottis and superior larynx

Question 6

What bacteria causes acute epiglottitis?

Answer 6

Haemophilus influenza type B

Question 7

What clinical presentation does acute epiglottitis have in children?

Answer 7

Sore trhorat
Drooling
Severe stridor
Hight termperature

Question 8

What are the risk factors for eppiglottitis?

Answer 8

Immunocompromised/suppressed

Transmission of capsulated strain to unvaccinated host

Question 9

How is acute epiglottitis treated?

Answer 9

Admit to ICU

Ceftriaxone

Question 10

What does a gram stain of haemophilia influenza show?

Answer 10

Pus cells and gram negative coccobacillus

Question 11

What are the upper respiratory tract defences?

Answer 11

Nasopharynx

Oropharynx

Question 12

What are the conducting airways’ defences?

Answer 12

Trachea and bronchi

Question 13

What normally colonises the conducting airways?

Answer 13

Not usually colonised

Question 14

How do the conducting airways resist infection?

Answer 14

Mucociliary escalator
Cough
AMPs
Cellular and humoral immunity

Question 15

When are acute exacerbation of COPD typical?

Answer 15

Following a viral infection

Winter (temp decrease / humidity increase)

Question 16

What bacteria cause an acute exacerbation of COPD?

Answer 16

Haemophilus Influenza
Moraxella Catarrhalis
Strep pneumonia

Question 17

What is cystic fibrosis?

Answer 17

Congenital disorder that causes abnormally viscous mucous and blockage of many tubular structures including the conducting airways and lungs

Question 18

What are the bacteria that are involved in CF infections due to inefficient clearance and mucous build-up?

Answer 18

Staph aureus 
Haemophilus influenza 
Strep pneumoniae 
Pseudomonas aeruginosa 
Burkholderia capacia 
many others

Question 19

What causes acute bronchitis?

Answer 19

90% viral (others including whooping cough=

Preceeded by URT infection

Question 20

What is pertussis?

Answer 20

Acute tracheobronchitis

“Whooping cough”

Question 21

How is pertussis diagnosed?

Answer 21

Pernasal swab - culture in charcoal blood agar / PCR / serology

Question 22

What are the common causes of community-acquired pneumonia?

Answer 22

Strep pneumoniae
H. influenza
M. carrhalis

Question 23

What are atypical causes of CAP?

Answer 23

Mycoplasma pneumoniae
Legionella pneumophilia
Chlamydophila pneumoniae
Chlamydophila psitacci

Question 24

What are other lung infections besides CAP?

Answer 24

Hospital accrued pneumonia
Immune defects and anatomical abnormalities
TB

Question 25

What is the pathogenesis of legionella Pneumonia?

Answer 25

Invade alveolar macrophages and replicated

Question 26

How is legionella pneumonia transmitted?

Answer 26

Inhalation of contaminated water droplets | No person-person transmission

Question 27

How is legionella pneumonia diagnosed?

Answer 27

Legionella urinary antigen - detect hero group Culture Paired serology - rise in titres PCR from sputum

Question 28

What are risk factors for HAP?

Answer 28

Invasive ventilation Issues with mucociliary escalator (from drugs?) Sedation Immunosuppression

Question 29

What bacteria cause HAP?

Answer 29

60% gram negative: E. coli / Kleb. spp. / Pseudomonas spp | CAP organisms: S. aureus / anaerobes

Question 30

In which patients is pneumocystis pneumonia (PCP) very common?

Answer 30

AIDS patients / immunosuppressed

Question 31

What are the clinical symptoms of PCPß

Answer 31

``` Fever Dry cough Dyspnoea Fatigue Higher fever if non-HIV ```

Question 32

How is PCP diagnosed?

Answer 32

BAL > Sputum > PCR

Question 33

How is PCP treated?

Answer 33

Co-trimoxazole

Question 34

How is legionella pneumonia treated?

Answer 34

Clarithromycin Erythromycin Quinolone (e.g. levofloxacin)

Question 35

Which antibiotic would be used to treat an acute exacerbation of COPD?

Answer 35

Amoxicillin (1st line) | Doxycycline (2nd line)

Question 36

How is pertussis / whopping cough treated?

Answer 36

Antibiotics

Question 37

What is Aspergillus?

Answer 37

Fungal chest infection

Question 38

What usually causes Aspergillus?

Answer 38

Aspergillus fumigatus

Question 39

What does aspergillus cause in immunocompromised/suppressed patients?

Answer 39

Severe pneumonia Pre-existing chest condition Invasive disease

Question 40

What does aspergillus cause in immunocompetent patients?

Answer 40

Localised pulmonary infection | Aspergilloma in pre-existing chest cavities

Question 41

What is an Aspergilloma?

Answer 41

Fungal ball

Question 42

How is aspergillus transmitted?

Answer 42

Inhalation of fungal spores

Question 43

How is Aspergillus diagnosed?

Answer 43

BAL (Broncho-alveolar lavage) - fungal culture / PCR | Tissue histopathology

Question 44

How is Aspergillus treated?

Answer 44

Amphotericin B Voriconazole Surgery

Question 45

What bacterium causes TB?

Answer 45

Mycobacterium tuberculosis (thick waxy coat)

Question 46

What is the pathogenesis of TB?

Answer 46

Engulfed by alveolar macrophages in alveoli - resist killing & multiply Most TB is latent but can be reactivated (10% immediate)

Question 47

What is TB infection associated with?

Answer 47

Travel to high-prevalence areas | Immunocompromised/suppressed

Question 48

How does the Ziehl-neelson stain work?

Answer 48

Red dye added to smear - heated (to allow dye to penetrate waxy coat) - acid/alcohol added - waxy coat retain dye - counter-stain added - mycobacterium appear reed

Question 49

What are the three diagnostic tools for TB?

Answer 49

ZN PCR Culture

Question 50

What are the 3 main routes of transmission?

Answer 50

Contact Airborne Droplet