Hazards of Working with
Biological Organisms and
Material
http://upload.wikimedia.org/wiki
pedia/commons/e/ee/Reconstru
cted_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
Photo: Adrian J. Hunter
http://en.wikipedia.org/wiki/File:Four_3day_old_Aspergillus_colonies_on_a_Petri_dish.png
Hazards of Working
with Viruses
• Integration of viral genome
http://www.edidik.com/wpcontent/uploads/2010/09/hiv_biology.gif
Calculating Risk
Level
• Viruses differ in
infectiousness
Hepatitis B virions
http://en.wikipedia.org/wiki/File:Hepatitis-B_virions.jpg
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
HPV
http://upload.wikimedia.org/wikipedia/commons/c/c4/Papilloma_
C viruses
Virus_(HPV)_EM.jpg
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://ibnulhaithemsciences.com/Images/Cell
_Culture_Mgt.jpg
http://www.sydneyg
enetics.com/Portals
/4/fibroblasts%20ph
ase%20contrast.JP
G
Primary Cell Culture
– Newly isolated cells
from tissue or blood
– Can be infectious
Note cells migrating from piece of tissue
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Established cell lines
– Many generations in culture
– Less likely to pose unknown
threat
Cultured HeLa cells
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mmons/6/6c/HeLa_cells_stained_with_H
oechst_33258.jpg
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– Out of date stock cultures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
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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
Bacterial spore
http://today.uchc.edu/images/features/photo_spore.jpg
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
http://upload.wikimedia.org/
wikipedia/commons/9/93/Ag
ar_plate_with_colonies.jpg
• 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/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
Bacillus anthracis
containing spores
(anthrax)
•
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acillus_ant
hracis.png
Sanitization
• General
reduction of
number of
microbes on
surface
– antiseptic
http://www.tradenote.net/images/users/000/360/463/products_im
ages/Antibacterial_Hand_Soap.jpg
Sterilization
• Killing of all
organisms on
a surface
Autoclave
http://upload.wikimedia.org/wikipedia/commons/4/44/ExampleAut
oclave.jpg
Biohazard spills
For 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/Us
erUploadedImages/102/ZEOBZ001%20-%2072dpi%20800px.jpg
Biohazard spills
For 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.