Review: Tuberculosis

Question 1

Know the following characteristics about each disease studied:
Genus and species name
Gram reaction
Cell shape
Disease name
Transmission
Virulence factors
Clinical symptoms of disease
Treatment

Answer 1

Genus and species name: Mycobacterium tuberculosis
Gram reaction: Gram +
Cell shape: Bacillus
Disease name: Tuberculosis
Transmission: Main route: contaminated air droplets (only 10 bacteria can cause active infection)
Coughing, singing
Highly infectious in crowded conditions

Virulence factors: Lives within MØ and NØ protected by lipid cell walls and resist destruction
Inflammation walls off infection into a Granuloma to halt spread of bacteria infection and a lot of fluid build-up

Clinical symptoms of disease: May take several months before diagnosis
Fever, weight loss
Productive cough (rusty sputum)

Treatment : Rifampin
Isoniazid
6 – 24 months drug therapy

Question 2

Be able to translate the organism’s genus and species name into the English language as

Answer 2

Mycobacterium: Myco = fungus Bacterium= bacteria
tuberculosis: an abnormal condition involving tubercles (the disease that this pathogen causes)

Question 3

Who discovered the bacteria: Mycobacterium tuberculosis?

Answer 3

Discovered by Robert Koch

Question 4

Is this organism acid-fast positive or negative?

Answer 4

Acid-fast +

Question 5

What are tubercules? Are tubercules different than granulomas or the same?

Answer 5

walls off bacteria into one area

they are the same

Question 6

How is tuberculosis diagnosed?

Answer 6

1. Sputum sample: test for acid fast + bacillus
2. Tuberculin skin test:
   inject purified protein derivative (PPD) into skin
   check site in 48 hours
   3.If there is a positive skin test, a chest X-ray is needed to determine how extensive the infection

Question 7

Does tuberculosis produce a dry cough or productive cough?

Answer 7

Productive cough (rusty sputum)

Question 8

What is a productive cough?

Answer 8

mucus breaks up and sputum can be coughed up.

Question 9

What is rusty sputum mean?

Answer 9

blood in the sputum

Question 10

What is Miliary tuberculosis?

Answer 10

If lesion penetrates a blood vessel, bacteria can spread through body: Miliary tuberculosis

Question 11

If a patient has a positive tuberculin skin test, what important follow up diagnostic test does the doctor order?

Answer 11

If there is a positive skin test, a chest X-ray is needed to determine how extensive the infection

Question 12

What is Direct Observed Therapy mean when administering medication?

Answer 12

Health care workers visit patients to watch them take drugs

Question 13

What are reasons for drug resistance strains of Tuberculosis seen today?

Answer 13

Skipping or stopping drug treatment has resulted in drug resistant strains

Question 14

What is Mycobacterium bovis?

Answer 14

a cattle infecting species that has little virulence in humans

Question 15

Why is the BCG vaccine considered an Attenuated vaccine?

Answer 15

A live, weakened strain M.bovis

Attenuated vaccine is created by reducing the virulence of a pathogen, but still keeping it viable (or “live”)

Question 16

Why can’t the BCG vaccine be administered to immunocompromised patients?

Answer 16

Because it is a live (viable) vaccine. If administered it could kill a patient

Question 17

Why does a person test positive for Tuberculosis after receiving the TB vaccine?

Answer 17

Because the vaccine is live. So they loose the ability to be able to use the skin test for early detection.

Question 18

What are the arguments against using the vaccine for tuberculosis in the United States?

Answer 18

Conflicting results on immunity generated

Once vaccine is administered, individuals always test positive for tuberculin skin test (one good screening test)

Question 19

There will be diagnostic questions on this exam. For example:
A 12 year old boy has an inflamed throat, fever of 102oF, swollen lymph nodes under jaw, pus pockets in the back of the throat. Name the potential disease from this unit.

Answer 19

(Streptococcal pharyngitis)