16 Questions
Which of the following bacteria is not typically found in the nasal cavity?
Streptococcus bacteria
What is the main function of the mucociliary escalator in the respiratory system?
To trap and remove pathogens
Which of the following is a characteristic of Veillonella spp.?
They are potent lactate fermenters
What is the main difference between the upper and lower respiratory systems in terms of microbiota?
The lower respiratory system has no resident microbiota
Which of the following bacteria requires X Factor and V Factor for growth?
Haemophilus bacteria
What is the main function of alveolar macrophages in the respiratory system?
Not mentioned in the content
Which of the following is not a type of bacteria found in the pharynx?
Haemophilus bacteria
What is the name of the structure that separates the right and left main bronchi?
Carina of trachea
What is the primary cause of 'Strep Throat'?
Streptococcus pyogenes
What is a virulence factor of Streptococcus pyogenes?
Hyaluronic acid capsule
What is a characteristic of Streptococcus pyogenes?
Facultative anaerobe
What is a common symptom of streptococcal pharyngitis?
Pain during swallowing
Which of the following bacteria is normally found in the pharynx and nasal cavity?
Propionibacterium acnes
What is a benefit of the upper respiratory microbiome?
It limits infection
What is a characteristic of Streptococcus pneumoniae?
Alpha-hemolytic
What is a complication of Staphylococcus aureus infection?
All of the above
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
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Haemophilus spp. require X Factor (Hemin) and V Factor (NAD+).
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Haemophilus influenzae is a type of Haemophilus spp.
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Veillonella spp. are Gram-negative, anaerobic, and potent lactate fermenters and nitrate reducers.
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Veillonella parvula is an example of Veillonella spp.
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Staphylococcus aureus can cause various diseases, including pneumonia, meningitis, osteomyelitis, toxic shock syndrome, sepsis, scalded skin syndrome, folliculitis, and pimples.
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Diphtheroids include Corynebacterium diptheriae and Propionibacterium acnes.
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Alpha-hemolytic streptococci do not cause complete hemolysis of red blood cells, unlike beta-hemolytic streptococci.
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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.
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.
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