M5: Mycobacterium

Question 1

best way to visualize Mycobacterium tuberculosis

Answer 1

acid-fast stain (due to poor gram stain)

Question 2

Tuberculosis overview

Answer 2

• caused by mycobacterium tuberculosis
• spread person-to person via mucosal emissions
• must be inhaled to be infectious
• primarily a respiratory infection, but can travel through blood to brain/spine/kidneys once lungs are fully colonized
• usually non-infectious outside lungs

Question 3

Primary tuberculosis symptoms (3)

Answer 3

• bad cough for 3 weeks
• pain in chest
• coughing up blood or heavy sputum (mucus)

Question 4

Secondary tuberculosis symptoms (4)

Answer 4

• weakness
• fatigue
• weight loss
• fever/chills

Question 5

Test for tuberculosis

Answer 5

2 options: skin test or blood test

Question 6

TB skin test

Answer 6

• small fluid sample of tuberculin placed under skin of arm
• raised red bump forms at injection site = evidence of previous exposure to TB (antibody reaction)
• if this occurs, will need more tests to determine disease progression

Question 7

TB blood test

Answer 7

• tuberculin added to blood sample to test for antibody reaction

Question 8

tuberculin

Answer 8

• purified protein extract of tubercle bacillus

- used in TB tests to ID presence of antibodies

Question 9

treatment of TB

Answer 9

• combo of isoniazid (INH), rifampin (RIF), ethambutol (EMB), pyrazinamide (PZA)
• lasts 6-9 months
• stopping early/skipping doses can cause re-emergence and/or antibiotic resistance

Question 10

best way to visualize Mycobacterium leprae

Answer 10

acid-fast stain (due to poor gram stain)

Question 11

Leprosy (Hansen’s disease)

Answer 11

• caused by Mycobacterium leprae
• spread person-to-person via airborne fluid droplets
• not as infectious as TB
• infected person can stay asymptomatic for 3-20 years
• left untreated can cause severe nerve damage –> more injuries due to lack of sensation
• completely curable via combo of dapsone, rifampin, clofazimine provided for free by WHO