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Hazards of Working with Biological Organisms and
Material
http://upload.wikimedia.org/wikipedia/commons/e/ee/Reconstructed_Spanish_Flu_Virus.jpg
Reconstructed Spanish flu
Working with Fungi
• Fungi and molds everywhere – Mycosis
• disease caused by infection
– Toxicity• from mycotoxins
– Allergies• airborne spores
http://en.wikipedia.org/wiki/File:Four_3-day_old_Aspergillus_colonies_on_a_Petri_dish.png
Photo: Adrian J. Hunter
Hazards of Working with Viruses
• Integration of viral genome
http://www.edidik.com/wp-content/uploads/2010/09/hiv_biology.gif
Calculating Risk Level
• Viruses differ in infectiousness
http://en.wikipedia.org/wiki/File:Hepatitis-B_virions.jpg
Hepatitis B virions
Calculating Risk Level
• Different viruses have different consequences– HBV causes Hepatitis
B– HIV causes AIDS
• Treatment or vaccine?
Viruses and Cancer
• Some viruses are oncogenic
• Moderate risk viruses– Include:
papilloma virus, herpes virus, Epstein-Barr virus, and the Hepatitis B and C viruses http://upload.wikimedia.org/wikipedia/commons/c/c4/
Papilloma_Virus_(HPV)_EM.jpg
HPV
Working with Human Blood Products
“Universal Precautions” – Minimizing use of needles and
sharps and proper disposal of these– Wearing PPE– Decontaminating all work surfaces
frequently– Decontaminating waste– Frequent hand washing– Biohazard sign posting
Working with Tissue Culture
• Tissue culture = in vitro propagation of cells taken from tissue of higher organism
http://ibnul-haithemsciences.com/Images/Cell_Culture_Mgt.jpg
http://www.sydneygenetics.com/Portals/4/fibroblasts%20phase%20contrast.JPG
Primary Cell Culture– Newly isolated cells
from tissue or blood– Can be infectious
http://usm.maine.edu/toxicology/images/nmcl8.jpg
Note cells migrating from piece of tissue
Established cell lines
– Many generations in culture– Less likely to pose unknown
threat
http://upload.wikimedia.org/wikipedia/commons/6/6c/HeLa_cells_stained_with_Hoechst_33258.jpg
Cultured HeLa cells
Disposal of Biohazardous Waste
Biohazard waste– Discarded cultures of bacteria or cell
culture– Out of date stock cultures– Human and animal waste– Used culture dishes and tubes– Biologically contaminated sharps
Disposal– Place in labeled, closable, leak-proof bags– Place bags in secondary containers to
prevent punctures– Usually decontaminate by autoclaving
Routine Clean-up: Disinfection
• Removal of all or almost all pathogens on a surface
http://www.tristel.com/images/duo_laboratory_surface_disinfectant_sml.jpg
Disinfectant Characteristics
Chemicals that kill pathogenic microorganisms and other hazardous particles Ideal:– Broad spectrum– Water-soluble– Low toxicity– Inexpensive
No ideal disinfectants
Factors affecting the effectiveness of
disinfectants– Type of organism
• Least resistant: viruses like HIV, Herpes and Hepatitis B
• Then Bacteria• Then Fungi• Then small
viruses like polio and rhinoviruses
• Most resistant are bacterial spores
http://today.uchc.edu/images/features/photo_spore.jpg
Bacterial spore
Disinfectants
• Effectiveness also affected by– Level of contamination– Chemical composition and
concentration of disinfectant– Length of exposure to disinfectant– Texture of surface to be disinfected
Choosing disinfectants• Low—
– gets rid of most bacteria and SOME viruses and fungi
– used for routine clean-up and decontamination
• Intermediate—– gets rid of most bacteria, viruses and fungi– Not spores– includes phenolics and 500 ppm chlorine bleach– used for clean-up of bodily fluids
http://upload.wikimedia.org/wikipedia/commons/9/93/Agar_plate_with_colonies.jpg
http://upload.wikimedia.org/wikipedia/commons/2/24/Red_White_Blood_cells.jpg
Choosing disinfectants
• High—– gets rid of all microorganisms except
large number of bacterial spores– included H2O2 and 1000 ppm chlorine
bleach– used for instruments that can not be
autoclaved
• http://upload.wikimedia.org/wikipedia/commons/1/12/Bacillus_anthracis.png
Bacillus anthracis containing spores (anthrax)
Sanitization• General
reduction of number of microbes on surface– antiseptic
http://www.tradenote.net/images/users/000/360/463/products_images/Antibacterial_Hand_Soap.jpg
Sterilization
• Killing of all organisms on a surface
http://upload.wikimedia.org/wikipedia/commons/4/44/ExampleAutoclave.jpg
Autoclave
Biohazard spillsFor personal contamination
– Remove all contaminated clothing and soak lab coats in bleach prior to washing
– Wash skin areas vigorously for at least 10 minutes
– Use an antiseptic if available– Inform supervisor immediately
Biohazard Spills• For a small spill with a
BSL-1 or BSL-2 organism– Wear protective clothing– Soak up spill with
absorbent towels soaked in disinfectant (ie 10% bleach)
– Dispose of towels in biohazard waste
– Clean spill area with fresh towels and disinfectant
http://www.enware.com.au/Images/UserUploadedImages/102/ZEO-BZ001%20-%2072dpi%20800px.jpg
Biohazard spillsFor a BSL-2 organism:
– First evacuate for 10 min. to let aerosols settle
– Cover main spill area with towels soaked in disinfectant. Then flood secondary area with disinfectant.
– Place all waste in biohazard bags.– Put additional disinfectant over
spill area and let sit for at least 20 minutes for decontamination.