Microbiology of Upper Respiratory Tract

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Questions and Answers

Which of the following bacteria is not typically found in the nasal cavity?

Staphylococcus bacteria

Haemophilus bacteria

Veillonella bacteria

Streptococcus bacteria (correct)

What is the main function of the mucociliary escalator in the respiratory system?

To produce mucus

To warm and humidify the air

To trap and remove pathogens (correct)

To filter out air pollutants

Which of the following is a characteristic of Veillonella spp.?

They are potent lactate fermenters (correct)

They are Gram-positive bacteria

They require X Factor for growth

They are aerobic bacteria

What is the main difference between the upper and lower respiratory systems in terms of microbiota?

The lower respiratory system has no resident microbiota Signup and view all the answers

Which of the following bacteria requires X Factor and V Factor for growth?

Haemophilus bacteria Signup and view all the answers

What is the main function of alveolar macrophages in the respiratory system?

Not mentioned in the content Signup and view all the answers

Which of the following is not a type of bacteria found in the pharynx?

Haemophilus bacteria Signup and view all the answers

What is the name of the structure that separates the right and left main bronchi?

Carina of trachea Signup and view all the answers

What is the primary cause of 'Strep Throat'?

Streptococcus pyogenes Signup and view all the answers

What is a virulence factor of Streptococcus pyogenes?

Hyaluronic acid capsule Signup and view all the answers

What is a characteristic of Streptococcus pyogenes?

Facultative anaerobe Signup and view all the answers

What is a common symptom of streptococcal pharyngitis?

Pain during swallowing Signup and view all the answers

Which of the following bacteria is normally found in the pharynx and nasal cavity?

Propionibacterium acnes Signup and view all the answers

What is a benefit of the upper respiratory microbiome?

It limits infection Signup and view all the answers

What is a characteristic of Streptococcus pneumoniae?

Alpha-hemolytic Signup and view all the answers

What is a complication of Staphylococcus aureus infection?

All of the above Signup and view all the answers

Study Notes

Microbiology of Upper Respiratory Tract

Upper respiratory system has a diverse microbiome, while lower respiratory system is free of resident microbiota.
Nasal cavity microbiome consists of Haemophilus bacteria, Veillonella bacteria, and diphtheroid.
Pharynx microbiome consists of Staphylococcus bacteria, Streptococcus bacteria, and diphtheroid.

Normal Microbiome of Pharynx and Nasal Cavity

Haemophilus spp. require X Factor (Hemin) and V Factor (NAD+).
Haemophilus influenzae is a type of Haemophilus spp.
Veillonella spp. are Gram-negative, anaerobic, and potent lactate fermenters and nitrate reducers.
Veillonella parvula is an example of Veillonella spp.
Staphylococcus aureus can cause various diseases, including pneumonia, meningitis, osteomyelitis, toxic shock syndrome, sepsis, scalded skin syndrome, folliculitis, and pimples.
Diphtheroids include Corynebacterium diptheriae and Propionibacterium acnes.
Alpha-hemolytic streptococci do not cause complete hemolysis of red blood cells, unlike beta-hemolytic streptococci.
Streptococcus pneumoniae and Streptococcus pyogenes are examples of alpha-hemolytic streptococci.

Pros and Cons of Upper Respiratory Microbiome

The upper respiratory microbiome limits infection, but it also provides opportunities for opportunistic pathogens to thrive.

Bacterial Pharyngitis

Streptococcal pharyngitis, also known as 'strep throat', is characterized by symptoms such as pain during swallowing, bad breath, fever, malaise, and headache.

Causative Agent: Streptococcus pyogenes

Streptococcus pyogenes is a Gram-positive, facultative anaerobe, and a Lancefield Group A Streptococcus.
It is beta-hemolytic, meaning it causes complete hemolysis of red blood cells.

Streptococcus pyogenes: Virulence Factors

M protein is a C3b inhibitor, which helps the bacteria evade the immune system.
Hyaluronic acid capsule and streptokinases are virulence factors that contribute to the bacteria's ability to cause disease.
C5a peptidase and pyrogenic (erythrogenic) toxins are also virulence factors of Streptococcus pyogenes.
Streptolysin O is a hemolysin that causes hemolysis of red blood cells.

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Description

Explore the microbiome of the upper respiratory tract, including normal microbiota, bacterial pharyngitis, and viral diseases. Review respiratory anatomy and understand the significance of the nasal cavity, oral cavity, pharynx, and larynx.