30. Bacteria Of The Respiratory Tract

Question 1

What are the 2 epithelial cells that are involved in the mucocilliary clearance?

Answer 1

• goblet cells: secrete mucous (traps dust)
  
  • contains mucin= sticky glycoproteins
  • lysozyme: digests peptidoglycan

-ciliated cells: moves mucous toward epiglottis to be swallowed

Question 2

What is mucin?

Answer 2

-sticky glycoproteins that make up the mucous that the goblet cells secrete

Question 3

What is a lysozyme?

Answer 3

-enzyme that digests peptidoglycan

Question 4

What is Otitis media? Risk factors?

Answer 4

(Middle ear infection)
-Inflammation leads to fluid build-up, pressure, pain, temporary hearing impairment, and
sometimes a ruptured ear drum

-Risk factors: inadequate mucus drainage due to Eustachian (auditory) tube dysfunction from
infection (viral), allergies, scar tissue

Risk group: children (shorter, more horizontal tubes)

Question 5

What are the 3 bacteria responsible for most cases of Otitis Media?

Answer 5

-Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis

Question 6

What is bacterial sinusitis?

Answer 6

• inflammation, pressure, swelling, and pain of the sinuses

- caused by viruses and allergies

Question 7

What are the 3 bacteria responsible for most bacterial sinusitis?

Answer 7

-Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis -(same as otitis media)

Question 8

What is bronchitis?

Answer 8

• when bacteria infect the trachea or bronchi

- symptoms:cough due to inflammation of the trachea and or bronchi =extra mucous, shortness of breath

Question 9

What are the 3 bacteria responsible for bronchitis?

Answer 9

-Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis -(same as otitis media and bacterial sinusitis)

Question 10

What is pneumonia?

Symptoms?

Answer 10

• infection of the alveoli
• inflammation (edema), tissue damage disrupt gas exchange

Symptoms: fever, shortness of breath, fatigue , chest pain

-hospital (nosocomial) and community acquired

Question 11

What are the 3 main bacteria responsible for pneumonia?

Answer 11

• streptococcus pneumoniae
• chlamydophilia pneumoniae
• haemophilus influenzae
• viruses as well

Question 12

Morphology of streptococcus pyogenus

Answer 12

• gram positive cocci

- grows in chains

Question 13

What are the diseases caused by streptococcus pyogenus?

Answer 13

1) Pharyngitus (strep throat)
- inflammation of the throat

2) Scarlet fever
- when streptococcal pyrogenic (SPE) toxins are released into blood

3) non-bullous impetigo
- infection around mouth and nose

4) erysipelas
- infection of the superficial dermis and lymphatics: often shiny, red

5) cellulitis
- infection of the entire dermis and subcutaneous fat and other connective tissues

6) necrotizing fasciitis
- infection causing death of fat cells and destruction of fascia (coverings of muscles/organs)
- aggressive infection
- necrosis disrupts blood vessels
- hinders abx delivery

Question 14

Define debridement

Answer 14

-removal of dead/damaged human tissues

Question 15

What are 2 sequelae of Streptococccus pyogenus?

Answer 15

1) acute glomerulonephritis
- antibody-antigen complexes cause the immune system to attack the nephrons of the kidneys, specifically the glomerulus (physical filter of the kidney)

2) rheumatic fever
- autoantibodies attack the joints and heart
- migrating arthritis and heart valve damage

Question 16

Name the superantigen produced by streptococcus pyogenes.

What infections does it play a role in?

Answer 16

• Streptococcus pyogenes endotoxin (erythrogenis toxins)
  
  • cytokine storm
  • scarlet fever
  • toxic shock syndrome
  • necrotizing fasciitis

Question 17

What are the 8 virulence factors of streptococcus pyogenus?

Answer 17

• SPE
• Adhesin (attachment)
• capsule (avoids phagocytosis)
• streptolysins (disrupts WBC chemotaxis, lyes RBC in culture)
• M proteins (mimic human proteins, deactivate complement proteins)
• enzymes that decrease the viscosity of pus and promote spread in connective tissue
  
  • nucleuses that digest DNA ejected by WBC
  • streptokinase breaks down blood clots (fibrin)
  • hyalauronidase >connective tissues

Question 18

What are autoantibodies?

Answer 18

-autoimmunity; attacks our own bodies with antibodies we make

Question 19

What are the differences during alpha, beta, and gamma hemolysis on blood agar?

Answer 19

• Alpha
  
  • RBCs are damages and the heme portion of the hemoglobin is oxidized
  • ‘appears green’
• beta
  
  • RBCs are completely lyzed
  • ‘clear’
• gamma (non hemolysis)
  
  • no hemolysis
  • no change in the blood agar

Question 20

What is the hemolysis pattern of streptococcus pyogenes?

Answer 20

-beta hemolytic

(left)