1. Digging Deeper into Bacteria
Discuss the mycobacteria and normal flora.
Digging Deeper into Bacteria
Part 3 of 3: Mycobacteria and Normal Flora

2. Normal Flora (a.k.a. indigenous flora)
See table 7-4 in your textbook for a list of normal flora
Term used to describe microbes that commonly live in parts of the human body including:
Respiratory tract
Gastrointestinal tract
Skin
Some are:
Symbiotic
Opportunistic
Neither helpful nor harmful

3. Mycobacterium Basics Easily to identified by the prefix “myco”
Include microbes responsible for leprosy and tuberculosis
All are acid-fast
Will not stain using regular gram techniques
Acid fast is known as the Ziehl-Neelson test
Sputum should be collected every morning for three days to rule out or confirm tuberculosis
All are aerobic

4. Mycobacterium tuberculosis
Aerobic bacillus
Causes tuberculosis (TB)
Tubercles form in the lungs and cause difficulty breathing and hemoptysis
Most known for infecting lungs but may infect nearly any body part including bones and organs
Mummies in both Egypt and Peru have been found with spinal tuberculosis
Tubercle definition:
Hemoptysis definition:

5. M. tuberculosis History
Most strains are multi-drug resistant (MDR)
Extremely drug resistant (XDR) strain is often fatal
TB kills many people worldwide daily
10% of people who become infected with TB become symptomatic (i.e. get active TB)
50% of them will die from TB

6. M. tuberculosis resources
In the U.S., patients with AIDS or other immune diseases are considered high risk
The CDC monitors TB therapy in the U.S.
For more information on TB:
Mountains Beyond Mountains: Healing the World: The Quest of Dr. Paul Farmer by Tracy Kidder
XDR TB video
Tuberculosis, The Silent Killer video
XDRTB.org with TED talk winner video - powerful images
For a local history of TB watch Sanitorium Scenes
XDR TB video:
TB Silent Killer video:
TED Talk video:
Sanitorium Scenes:

7. Chest x-ray shows right upper lobe consolidation caused by TB.
Common for TB to start in the upper portions of the lungs and work its way down. This is uncommon of many other consolidations.
M. tuberculosis

8. M. Tuberculosis Test
PPD shown on the left; results shown on the right

9. Mycoplasma pneumoniae
Pleomorphic
Causes pneumonia
Slow onset
Long duration even with medication treatment
Causes upper and lower respiratory tract infections usually in late summer and early fall
Community acquired
Often presents similarly to Legionnaire‘s

10. Mycobacterium Summary
Tuberculosis is the most important mycobacterium to know though you may see patients with M. pneumoniae more frequently.
Tuberculosis seems scary with its antibiotic resistance
Rarely contracted by non-immune suppressed individuals.
Most hospitals will have you tested for TB every 6-12 months.
Many opportunities for healthcare workers to get involved with the worldwide fight against tuberculosis.

11. Next Steps
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