Week 7: Respiratory system (upper and lower)

Question 1

Streptococcal pharyngitis bacteria

Answer 1

S. pyogenes

Question 2

Streptococcal pharyngitis symptoms (4)

Answer 2

Fever, headache, tonsillitis, otitis media

Question 3

Scarlet fever bacteria

Answer 3

S. pyogenes

Question 4

Scarlet fever host (1)

Answer 4

Humans only

Question 5

Scarlet fever rash cause

Answer 5

Erythrogenic toxin of s.pyogenes

Question 6

Corynebacterium diptheriae location

Answer 6

Throat of asymptomatic carrier

Question 7

Corynebacterium diptheriae transmission

Answer 7

Airborne

Question 8

Does Corynebacterium diptheriae form spores?

Answer 8

Nope

Question 9

Corynebacterium diptheriae shape

Answer 9

Club

Question 10

C. diptheria disease symptoms (4)

Answer 10

Sore throat, neck swelling, leather formation in throat, skin infection (cutaneous diptheria)

Question 11

In diptheria, describe the term ‘leather’

Answer 11

Formation of grey membrane in throat from fibrin, bacterial cells and dead tissue cells

Question 12

What causes damage in diphtheria

Answer 12

Exotoxin which circulates in blood and damages heart and kidneys

Question 13

Diphtheria treatment and prevention

Answer 13

Penicillin and erythromycin in conjunction with antitoxin, immunisation with diphtheria toxoid

Question 14

Otitis media

Answer 14

Infection of middle ear
Inflammation -> Pus increases pressure against eardrum -> pain

Question 15

Otitis media causes (highest to lowest- 6)

Answer 15

S. pneumoniae (35%)
Non-encapsulated H. influenzae (20-30%)
Moraxella catarrhalis (10-15%)
S. pyogenes (8-10%)
Others (bacteria/non-bacterial cause) (3-5%)
S. aureus (1-2%)

Question 16

Viral causes of common cold (2)

Answer 16

Rhinoviruses and coronaviruses

Question 17

Which antibody contributes to immunity against viral colds?

Answer 17

IgA

Question 18

In influenza, what component of the virus contributes to its pathogenicity? What are the names of these components (2)

Answer 18

Spike proteins (neuraminidase and haemagglutinin)

Question 19

Define antigenic shift in relation to viruses

Answer 19

Spike proteins change so that antibodies against the spike proteins become ineffective

Question 20

Gram status, oxygen use and shape of Bordella pertussis

Answer 20

Gram negative, obligate aerobe, cocco-bacillus

Question 21

How does Bordetella pertussis capsule contribute to its pathogenicity

Answer 21

Capsule allows it to attach to ciliated cells in trachea, impeding their action and destroying them

Question 22

Causative agent of pertussis (whooping cough)

Answer 22

Bordetella pertussis

Question 23

Does bordetella pertussis produce toxins?

Answer 23

Yes

Question 24

Pertussis treatment

Answer 24

Erythromycin and airway protection (postural drainage, keep head and face down, high humidity)

Question 25

Name and describe the three stages of pertussis

Answer 25

Catarrhal stage: resembles common cold (2-3 weeks incubation) Paroxysmal stage: prolonged sieges of coughing (mucous accumulation) (physiological damage) Convalescence stage: lasts few months, recovery

Question 26

Describe the gram status of mycobacterium tuberculosis

Answer 26

Neither gram positive nor gram negative due to lipid cell wall, acid fast

Question 27

How does M. tuberculosis cause disease

Answer 27

Bacteria are inhaled and reach alveolar macrophages, phagocytosed but survive. As they multiply, more macrophages are attracted forming a tubercle. Macrophages die, releasing bacteria and forming a caseous centre in the tubercle. The tubercle ruptures, spilling bacteria into the rest of the body.

Question 28

Tuberculosis treatment

Answer 28

Streptomycin Multiple therapy: isoniazid, rifampin, pyrazinamide Drug resistant cases: ethambutol or streptomycin

Question 29

Explain the mechanism of the tuberculin skin test

Answer 29

Proteins from tuberculosis are injected into the skin. If the person has been previously infected, memory T cells react with the antigen leading to hardening and reddening of the area.

Question 30

Diagnosis of tuberculosis

Answer 30

Isolation, acid fast staining, cultivation on loweinstein agar, production of CO2 in broth containing palmitic acid, DNA probes, PCR and rRNA

Question 31

Tuberculosis vaccine

Answer 31

Live attenuated strain of avirulent strain M. bovis (BCG vaccine)

Question 32

What is a potential issue of the tuberculin skin test?

Answer 32

VAccinated individuals will have a positive reaction

Question 33

What is a potential issue of the BCG vaccine for tuberculosis?

Answer 33

Live strain so may be dangerous in the immunocompromised

Question 34

Bacterial pneumonia causes (2)

Answer 34

Strep pneumoniae (typical), other microorganisms (atypical)

Question 35

S. pneumoniae characteristics (gram, shape, capsule?)

Answer 35

Positive, ovoid, diplococcus, has capsule

Question 36

S. pneumoniae treatment + prevention

Answer 36

Penicillin, vaccine of purified capsular material

Question 37

Diagnosis of S. pneumoniae (lab)

Answer 37

alpha haemolytic susceptible to optichin

Question 38

H. influenza (atypical pneumonia) gram status

Answer 38

Gram negative

Question 39

H. influenza (atypical pneumonia) treatment

Answer 39

Beta lactamase resistant second generation cephalosporins

Question 40

Mycoplasma pneumonia (atypical pneumonia) characteristics

Answer 40

Lacks cell wall Forms small fried egg like colonies in medium with horse serum and yeast extract

Question 41

M. pneumoniae pneumonia diagnosis (3)

Answer 41

Serology PCR Complement fixation to detect IgM and IgG

Question 42

Legionnaire's is a type of what disease caused by which bacteria?

Answer 42

Pneumonia, Legionella pneumoniae

Question 43

Legionella pneumoniae (atypical pneumonia) characteristics

Answer 43

Gram negative, aerobic rod

Question 44

Chlamydia psittaci and Chlamydia pneumoniae characteristics

Answer 44

Gram negative, obligate intracellular From bird droppings vs person to person contact

Question 45

Q fever (atypical pneumonia) cause

Answer 45

Coxiella burnetti

Question 46

Meliodosis (atypical pneumonia) cause

Answer 46

Burkholderia pseudomallei

Question 47

Viral diseases of lower RT (4)

Answer 47

Severe acute respiratory syndrome (SARS) Viral pneumonia Respiratory syncytial virus Influenza

Question 48

Fungal diseases of lower respiratory tract (3)

Answer 48

Histoplasmosis casued by Histoplasma capsulatum: airborne spores from soil -> human Pneumocystis pneumonia (P. jiroveci formerly P. carini) Coccidioidomycosis caused by Coccidioides imitis

Question 49

How do fungal diseases of the LRT occur?

Answer 49

Production of spores in immunocompromised patients

Question 50

Describe the disease cycle of coccidiodomycosis (6)

Answer 50

Soil 1. Arthrospore germinates into tubular hypha 2. Hypha segmant into arthrospores and separate from hypha. Some become airborne and some return to the soil. 3. Airborne arthrospore is inhaled Human 4. Inhaled arthrospore enlarges and begins to develop into spherule 5. Endospores develop in spherule 6. Spherule releases endospores which spread in tissue and develop into new spherules

Question 51

Coccidioidomycosis is an example of a _ disease of the lower RT

Answer 51

Fungal