Transcript Laboratory Biosafety Levels - UNC Center for Public Health

Laboratory Biosafety Levels
Goals
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Define barriers and procedures used by
laboratories to protect workers and others
from infection
Describe the four biosafety levels and the
protective measures used by each type of
laboratory when handling infectious materials
Provide examples of the types of biological
agents handled in each type of laboratory
Describe typical places where each type of
laboratory can be found in the US
Why is Biosafety Important?
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Laboratorians recognize hazards of
processing infectious agents
Guidelines developed to protect workers
in microbiological and medical labs
through engineering controls,
management policies, work practices
Biosafety Levels
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Precautions so people researching or trying to
identify organisms do not become infected
While handling or testing clinical specimens,
workers could accidentally infect themselves
or coworkers
Labs must adhere to very specific safety
regulations to work with organisms that pose
a threat to human health
Biosafety Levels
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Regulations outline precautions, special
practices, decontamination procedures
Labs divided into 4 biosafety levels; protective
practices increase with each
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Biosafety Level 1 labs - work with least dangerous
agents, require fewest precautions
Biosafety Level 4 labs - have strictest methods
because dealing with agents that are most
dangerous to human health
About this Information…
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Information summarized here should not be
used to establish laboratory safety protocols
Complete information and recommendations
can be found in Biosafety in Microbiological
and Biomedical Laboratories 5th Edition at
http://www.cdc.gov/od/ohs/biosfty/bmbl4/
bmbl4s6.htm
Barriers
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Primary barriers: physical barriers or personal
protective equipment between lab worker and
pathogen
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Gloves, masks, special breathing apparatuses
Secondary barriers: structural aspects of the
laboratory that make working environment
safer against infection
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Sinks for handwashing, special containment areas,
special air ventilation patterns
Universal Precautions
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Universal precautions developed to protect health
professionals
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Most often apply in a clinical setting
May also be important for field epidemiology practices
during an outbreak investigation (e.g., collecting lab
specimens)
Include hand hygiene, gloves, gown, masks, eye
protection, face shields, safe injection practices
Require that all equipment or contaminated items are
handled to prevent transmission of infectious agents
Special circumstances may require additional
precautions
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Protective clothing, special site decontamination
Biosafety Level 1 (BSL-1)
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Agents not known to cause disease in
healthy adults
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Some organisms may cause disease in
immunocompromised individuals
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Agents include Bacillus subtilis,
Naegleria gruberi, infectious
canine hepatitis virus, nonpathogenic E. coli species
(transmission electron micrograph of E. coli)
Biosafety Level 1 (BSL-1)
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Standard practices required:
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frequent handwashing
door that can be kept closed when working;
limits on access to the lab space when working;
no smoking, eating, drinking, storage of food in
laboratory;
care to minimize splashes and actions that may
create aerosols (tiny droplets);
decontamination of work surfaces after every use
after any spills;
(continued on next slide)
Biosafety Level 1 (BSL-1)
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Standard practices (continued):
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decontamination of laboratory wastes;
use of mechanical pipettes only (no mouth
pipetting);
"sharps" precautions, including special containers
for disposing of needles and other sharp objects;
maintenance of insect/rodent control program;
use of personal protective equipment (lab coats,
latex gloves, eye protection or face shields)
Open bench top sink for hand washing
Biosafety Level 2 (BSL-2)
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Agents associated with human disease
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Generally required for any human-derived
blood, bodily fluids, tissues in which
infectious agent may be unknown
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Agents include measles virus,
Salmonella species, pathogenic
Toxoplasma, Clostridium
botulinum, hepatitis B virus
(transmission electron micrograph of hepatitis B virus)
Biosafety Level 2 (BSL-2)
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Primary hazards:
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Agents do not cause lethal infections, are not
transmissible via airborne route
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accidental needle sticks
exposure to eyes and nose (mucous membranes)
ingestion of infectious materials
(do not cause infection if tiny droplets become airborne and
are inhaled, which might occur if the material were
spattered)
Agents are pathogens for which immunization or
antibiotic treatment is available
Extreme care should be taken with contaminated
needles and sharp lab instruments
Biosafety Level 2 (BSL-2)
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Standard practices include BSL-1 plus:
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policies to restrict access to lab;
biohazard warning signs posted outside lab;
surveillance of laboratory personnel with
appropriate immunizations offered;
biosafety manual with definitions of needed waste
decontamination or medical surveillance policies;
supervisory staff who have experience working
with infectious agents and specific training for
laboratory personnel in handling these agents
Biosafety Level 2 (BSL-2)
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Primary barriers: biosafety cabinets or other
approved containment devices
Personal protective equipment: lab coats,
gloves, face protection as needed
Protective clothing removed when personnel
leave laboratory area
Cabinets thoroughly decontaminated daily
and monitored for radiation for personal
protection
Secondary barriers: BSL-1 barriers plus
autoclave for glassware
Biosafety Level 2 (BSL-2)
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Example of
biosafety sign
posted outside lab
working with
infectious agents
Lab’s biosafety level
Infectious agents under
study
Contact information for
responsible person and
2 emergency contacts
Biosafety Level 3 (BSL-3)
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Agents with potential for respiratory
transmission, may cause serious and
potentially lethal infection
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May be studied at BSL-2 for diagnosis
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Agents include Mycobacterium
tuberculosis, St. Louis encephalitis
virus, Francisella tularensis,
Coxiella burnetii
(F. tularensis under direct fluorescent antibody stain)
Biosafety Level 3 (BSL-3)
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Primary hazards: needle sticks, ingestion,
exposure to infectious aerosols
For example:
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Public health surveillance for West Nile virus
includes testing birds
In August 2002, state laboratory worker cut finger
while dissecting bird; 4 days later, had symptoms
of fever, myalgia, recurring sweats, hot flashes
Worker and bird both diagnosed with West Nile
2 other lab-acquired cases in 2002
Biosafety Level 3 (BSL-3)
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Tularemia common source of
laboratory-acquired infection
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infections occur while handling infected
animals or experimenting with cultures
Laboratory-acquired infections known to
occur but not reportable before 9/11/2001
Tularemia now classified as potential
biological weapon
Biosafety Level 3 (BSL-3)
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Standard practices include BSL-2 plus:
 strictly controlled access to the lab;
 specific training for lab personnel in
handling potentially lethal agents;
 decontaminating all waste;
 changing contaminated protective lab
clothing, decontaminating lab clothing
before laundering;
 institutional policies regarding specimen
collection and storage from workers to
establish exposure
Biosafety Level 3 (BSL-3)
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Primary barriers:
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Similar to BSL-2 personal protective equipment
Respiratory equipment if risk of infection through
inhalation
Secondary barriers:
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All BSL-2 barriers
Corridors separated from direct access to lab
Access through self-closing double doors
Air handling systems to ensure negative air flow
(air flows into the lab)
Air pumped into lab not re-circulated in
building
Biosafety Level 4 (BSL-4)
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Dangerous and exotic agents with high risk of
life-threatening disease, aerosol-transmitted
Related agents with unknown risk of
transmission
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Agents (all viruses) include
Marburg virus, Ebola virus, viruses
that cause Congo-Crimean
hemorrhagic fever, Lassa fever
(transmission electron micrograph of Ebola virus)
Biosafety Level 4 (BSL-4)
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Primary hazards:
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respiratory exposure to infectious aerosols
mucous membrane exposure to infectious droplets
accidental sticks with needles or other sharp
objects contaminated with infectious material
For example
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In late 1960s, 25 laboratory-acquired Marburg
infections, including 5 deaths
Workers studying infected monkeys from Uganda
First documented naturally-occurring human case
occurred in 1975
Biosafety Level 4 (BSL-4)
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Personnel must receive specialized training in
handling extremely dangerous infectious
agents, containment equipment and functions
Access to lab is restricted:
immunocompromised persons are never
allowed to enter the lab
Standard practices include BSL-3 plus:
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strictly controlled access to the laboratory;
changing clothing before entering and exiting lab
(showering upon exiting recommended);
decontaminating all material exiting facility
Biosafety Level 4 (BSL-4)
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Primary barriers:
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Biosafety cabinets used at other biosafety levels
Full-body, air-supplied, positive pressure personnel
suit
Secondary barriers:
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All physical barriers at BSL-3
isolated zone or a separate building;
dedicated supply and exhaust, vacuum,
decontamination systems;
a recommended absence of windows
(or sealed and resistant to breakage)
Laboratory Locations
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BSL-1: high schools, community colleges, municipal
drinking water treatment facilities
BSL-2: local health departments, universities, state
laboratories, private laboratories (hospitals, health
care systems), industrial laboratories (clinical
diagnostic companies)
BSL-3: state health departments, universities, private
companies, industry, federal government (NIH, CDC)
BSL-4: only 15 facilities in the US
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9 federal (CDC, NIH), 4 university (Georgia State University,
University of Texas Medical Branch), 1 state, 1 private
Renovations underway at several labs, new facilities
proposed at additional sites
Summary
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Laboratorians have long recognized hazards of
processing infectious agents
Biosafety guidelines developed to protect workers in
microbiological and medical labs through a
combination of safeguards including engineering
controls, management policies and work practices.
Issue described differences between biosafety levels
Help you understand process labs may have to
undertake to identify microorganism, why every lab
cannot test for every organism
References
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US Department of Health and Human Services, Centers for Disease
Control and Prevention and National Institutes of Health. Biosafety in
Microbiological and Biomedical Laboratories. 5th ed. Washington, DC:
US Government Printing Office; 2007. http://www.cdc.gov/od/ohs/
biosfty/bmbl5/bmbl5toc.htm. Accessed February 6, 2008.
Clemson University Environmental Health and Safety. Biological Safety
[online training]. http://ehs.clemson.edu/training/biosafety/index.html.
Accessed February 6, 2008.
Centers for Disease Control and Prevention. Laboratory-Acquired West
Nile Virus Infections — United States, 2002. MMWR Morb Mort Wkly
Rep. 2002; 51:1133-1135. http://www.cdc.gov/mmwr/preview/
mmwrhtml/mm5150a2.htm. Accessed February 6, 2008.
United States Government Accountability Office. High-Containment
Biosafety Laboratories: Preliminary Observations on the Oversight of
the Proliferation of BSL-3 and BSL-4 Laboratories in the United States.
Publication GAO-08-108T. http://www.gao.gov/docsearch/
abstract.php?rptno=GAO-08-108T. Published October 4, 2007.