Mycobacteriaceae

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Mycobacteriaceae Part IGeneral Characteristics
Safety

• Created by Michele L. Jurgensmeier MT(ASCP)
• Edited by Kathy Talmon MT(ASCP)SM
• Voice over lecturer Carol Larson MSEd, MT(ASCP)
• Clinical Laboratory Science Program

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General Characteristics

• Found in water, soil and animals
• Aerobic, non spore formers
• Slow growing
• Gram stain beaded gram-positive rod
• High lipid content difficult to pick up aniline
  dyes

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General Characteristics

• Acid fast
• Resist decolorization by acid alcohol
• Distinguishes Mycobacteria from other genera

Photo courtesy of CDC public image library
Content provider Dr. George P. Kubica
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Growth Requirements

• Mycobacteria are slow growers
• High lipid content
• Hydrophobic cells clump, nutrients slow into cell
• Slow replication rate
• Range 2 days to 8 weeks
• Optimal temp 35-37C
• Some species prefer 30C
• Prefer CO2 for growth

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Safety

• Is critical!
• WHY ?
• Serious nature of mycobacterial disease,
  particularly tuberculosis
• Health care workers are at risk for contracting
  tuberculosis
• Minimal chance of infections when proper
  precautions used.

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Safety Administrative Controls

• Patient screening and risk assessment
• Prompt isolation and appropriate therapy

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Safety Monitor Personnel

• Purified protein derivative (PPD) skin test
• Quantiferon-TB Gold test

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Safety Monitor Personnel

• Purified protein derivative (PPD) skin test
• In vivo
• Administer PPD test (Mantoux) upon employment
• Negative - Screen regularly
• Positive - Counseled regularly, report changes in
  health status

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Safety Monitor Personnel

• Quantiferon-TB Gold test
• This test is performed on blood collected from
  the patient
• Measures the amount of interferon-gamma (INF-?)
  secreted by a patient's lymphocytes in whole
  blood in response to simulated mycobacterial
  antigens in vitro.
• Detection and quantification of interferon-gamma
  is the basis of test

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References

1. Mahon, C.R. Manuselis, G., Textbook of
   Diagnostic Microbiology, 2nd Ed., W.B. Saunders,
   2000
2. Forbes, B.A., Sahm, D. F., Weissfeld, A.S.,
   Bailey and Scotts Diagnostic Microbiology, 11th
   Ed., Mosby, 2002.
3. Koneman, Color Atlas and Textbook of Diagnostic
   Microbiology, 5th Ed., J.B. Lippincott Co., 1997
4. Murray PK, et al., Manual of Clinical
   Microbiology, 7th ed., ASM Publishing, Washington
   DC, 1999.
5. Center for disease control and prevention/
   National institute of Health, Biosafety in
   Microbiological and Biomedical Laboratories, 4th
   ed., U.S. Government Printing Office, 1999.
6. www.ehs.cornell.edu/bio/cabinets.htm
7. www.medicinenet.com
8. www.cdc.gov