Mycobacteriaceae – Part I General Characteristics & Safety

1. 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

2. 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

3. 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

4. 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 = 35-37°C • Some species prefer 30°C • Prefer CO2 for growth

5. 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.

6. Safety –Administrative Controls • Patient screening and risk assessment • Prompt isolation and appropriate therapy

7. Safety – Monitor Personnel • Purified protein derivative (PPD) skin test • Quantiferon-TB® Gold test

8. 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

9. Safety – Monitor Personnel • Quantiferon-TB® Gold test • This test is performed on blood collected from the patient • Measures the amount of interferon-gamma (INF-γ) 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

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