Bacterial Respiratory Infections

Question 1

Function of upper respiratory system

Answer 1

Collects air, filters contaminants from air, delivers to lower respiratory system

Question 2

Microbiota present in the upper respiratory system

Answer 2

S.aureus and S.epidermis

Question 3

Lower respiratory system function

Answer 3

Allows gas exchange to take place. No microorganisms are present in the lower RS, and if they infiltrate it then it could be life threatening.

Question 4

Difference between professional invaders and secondary invaders

Answer 4

Professional invaders successfully infect the respiratory tract of healthy individuals.

Secondary invaders only cause disease when the host immune defence is already impaired.

Question 5

Streptococcal RTIs

Symptoms, pathogen, virulence, transmission, treatment

Answer 5

Upper RTI

Symptoms: sore throat, may progress to scarlet or rheumatic fever
Pathogen: Strep A (S.pyogenes)
Virulence: M proteins (bind to serum factor H and destroy C3 convertase), hyaluronic acid capsule, C5a peptidase, streptolysin (exotoxin)
Transmission: droplets
Treatment: penicillin

Question 6

Diphtheria

Symptoms, pathogen, virulence, transmission, diagnosis, treatment

Answer 6

Upper RTI

Symptoms: sore throat, oozing fluid that hardens into a pseudomembrane that can obstruct airways
Pathogen: Corynebacterium diptheriae (Gram+ bacillus)
Virulence: toxin which prevents polypeptide synthesis and causes cell death
Transmission: droplets and skin contact
Diagnosis: presence of pseudomembrane
Treatment: antitoxin and antibiotics

Question 7

Pneumococcal pneumonia

Symptoms, pathogen, virulence, transmission, treatment

Answer 7

Lower RTI

Symptoms: fever, chills, cough, chest pain, rapid breathing
Pathogen: streptococcus pneumoniae (Gram+)
Virulence: adhesins, capsule
Transmission: inhalation of bacteria/droplets
Treatment: penicillin

Question 8

Primary Atypical (Mycoplasmal) pneumonia

Symptoms, pathogen, virulence, transmission, treatment

Answer 8

Lower RTI

Symptoms: fever, malaise, sore throat, excessive sweating
Pathogen: Mycoplasma pneumoniae (Gram-)
Virulence: adhesion protein
Transmission: nasal secretions/droplets
Treatment: tetracycline/erythromycin

Question 9

Pertussis (Whooping Cough)

Answer 9

Lower RTI

Symptoms: cold like symptoms, then characteristic cough develops
Pathogen: Bordetella pertussis (Gram-)
Virulence: toxins
Transmission: droplets
Treatment: primarily supportive treatment