Transcript Biosafety in Microbiologic and Biomedical Laboratories

Biosafety in Microbiologic and
Biomedical Laboratories
The University of Texas at Tyler
IACUC Education and Training
*Note: Content not specific to UT Tyler is from the American
Association for Laboratory Animal Science (AALAS)
Principles of BioSafety
This lesson will define and present information on
methods used to provide biosafety in facilities
where potentially infectious agents are used.
These include:
 Containment
 Biological safety cabinets
 Personal protection equipment
 The facility as barrier
 Secondary barriers
Principles of BioSafety
Containment
 The term containment describes safe methods
for managing infectious materials in the
laboratory environment where they are being
handled or maintained.
 The purpose of containment is to reduce or
eliminate exposure to potentially hazardous
agents.
 Exposure could involve not only laboratory
workers but other individuals working close by
and the outside environment.
Principles of BioSafety
The three elements of containment include:
laboratory practice and technique
safety equipment
facility design
The risk assessment of the work to be done with a
specific agent will determine the appropriate
combination of these elements.
Principles of BioSafety: Primary
Containment

Primary containment is the protection of personnel and the immediate
laboratory environment from exposure to infectious agents.

Primary containment is provided by both good microbiological technique
and the use of appropriate safety equipment.
For example, the use of vaccines may provide an increased level of
personal protection. Personal protective equipment such as gowns,
masks, and gloves and biological safety cabinets offer protection when
used properly in conjunction with good laboratory techniques.

Sharps are a frequent cause of exposure to personnel. View some
recommendations on working with sharps on the AALAS Learning
Library site.
Principles of BioSafety:
Secondary Containment
 Secondary containment is
the protection of the
environment external to the
laboratory from exposure to
infectious materials.
 Secondary containment is
provided by a combination
of facility design and
operational practices.
Ventilation systems,
controlled access, airlocks,
and other facility design
features must be part of any
biosafety program.
Principles of BioSafety:
Biological Safety Cabinets
 Safety equipment includes biological safety
cabinets (BSCs), enclosed containers, and
other engineering controls designed to remove
or minimize exposures to hazardous biological
materials.
 The biological safety cabinet (BSC) is the
principal device used to provide containment of
infectious splashes or aerosols generated by
many procedures
Principles of BioSafety:
Biological Safety Cabinets
 There are three types of
biological safety cabinets
used in microbiological and
biomedical laboratories Class I, Class II, and Class
III.
 Open-fronted Class I and
Class II biological safety
cabinets are primary barriers
which offer significant levels
of protection to laboratory
personnel and to the
environment when used with
good laboratory techniques.
Principles of BioSafety:
Biological Safety Cabinets
 The Class II biological safety cabinet also
provides product protection from external
contamination of the materials (e.g., cell
cultures, microbiological stocks) being
manipulated inside the cabinet.
 The gas-tight Class III biological safety cabinet
provides the highest attainable level of
protection to personnel and the environment.
Principles of Biosafety:
Personal Protection
Safety equipment also includes items for
personal protection, such as gloves,
coats, gowns, shoe covers, boots,
respirators, face shields, safety glasses,
or goggles
Principles of Biosafety: Personal
Protection
Personal protective
equipment (PPE) is often
used in combination with
biological safety cabinets
and other devices that
contain the agents, animals,
or materials being handled.
It may be difficult or
impractical to work in
biological safety cabinets in
some situations; in this
instance, personal protective
equipment may form the
primary barrier between
personnel and the infectious
materials.
Principles of Biosafety: The
Facility as a Barrier
 Facility design and
construction contribute to
the laboratory workers'
protection, provide a
barrier to protect persons
outside the laboratory,
and protect people and
animals in the community
from infectious agents
which may be
accidentally released
from the laboratory.
Principles of Biosafety: The
Facility as a Barrier
 Laboratory management is responsible for
providing facilities that are commensurate with
the laboratory's function and with the
recommended biosafety level for the agents
being manipulated.
 A variety of experts should be part of the design
team for any new facility. These include
biosafety professionals, HVAC engineers and
animal care professionals.
Principles of BioSafety:
Biological Safety Cabinets
 The Biosafety in Microbiological and Biomedical
Laboratories (BMBL) 4th Edition has additional
details about biosafety cabinets.
 Biological safety cabinets should be
performance-tested at least annually to validate
proper function. It is optimal to have such
testing done by an NSF-Accredited Biosafety
Cabinet Field Certifier. More information is
available in the CDC/NIH publication Primary
Containment for Biohazards: Selection,
Installation and Use of Biological Safety
Cabinets, 2nd Edition.
Principles of Biosafety:
Secondary Barriers
 The recommended secondary barrier(s)
will depend on the risk of transmission of
specific agents.
 When the risk of infection by exposure to
an infectious aerosol is present, higher
levels of primary containment and
multiple secondary barriers may become
necessary to prevent infectious agents
from escaping into the environment
Principles of Biosafety:
Secondary Barriers
Such design features
include:
 Specialized ventilation
systems to ensure
directional air flow
 Air treatment systems to
decontaminate or remove
agents from exhaust air
 Controlled access zones
 Airlocks as laboratory
entrances (as shown in
this image)
 Separate buildings or
modules to isolate the
laboratory
Principles of Biosafety: BioSafety
Levels
 Biosafety Level 1

BSL-1 laboratories are used to study
agents not known to consistently cause
disease in healthy adults.

They follow basic safety procedures and
require no special equipment or design
features.
Principles of Biosafety:
BioSafety Levels
 Biosafety Level 2

BSL-2 laboratories are used to study moderate-risk
agents that pose a danger if accidentally inhaled,
swallowed or exposed to the skin.

Safety measures include limited access, biohazard
warning signs, sharps precautions, class I or II
BSCs, the use of PPE such as gloves and eyewear
as well as handwashing sinks and waste
decontamination facilities such as an autoclave.
Principles of Biosafety:
BioSafety Levels
 Biosafety Level 3

BSL-3 laboratories are used to study agents that
can be transmitted through the air and may cause
potentially lethal infection.

Researchers perform lab manipulations in class I or
II BSCs or other enclosure. Other safety features
include clothing decontamination, sealed windows,
double-door access, and specialized ventilation
systems.
Principles of Biosafety:
BioSafety Levels
 Biosafety Level 4

BSL-4 laboratories are used to study agents that pose a
high risk of life-threatening disease, aerosol-transmitted
lab infections, or related agents whose risk is not known.
Lab personnel are required to to shower when exiting
the facility. The labs incorporate all BSL 3 features and
occupy safe, isolated zones within a larger building or a
separate building. Procedures are performed in Class III
BSCs or Class II while wearing a positive pressure fullbody suit.
 The laboratory director is specifically and primarily
responsible for assessing the risks and appropriately
applying the recommended biosafety levels.
Risk Assessment and Recommendations:
Acquiring a Laboratory-Associated Infection
 There are risks for acquiring a
laboratory-associated infection from
job-related activities involving infectious
or potentially infectious material.
Assessing risks and identifying risk
management tools are critical for
assigning the appropriate biosafety level
to an infectious organism and reducing
the worker's and the environment's risk
of exposure to the absolute minimum.
Risk Assessment
Assessing the risk for acquiring a laboratory
associated infection is affected by the following
factors:
 Pathogenicity
 Route of Transmission
 Agent Stability
 Infectious Dose
 Susceptibilty
 Concentration and Volume
 Origin
Risk Assessment
 Pathogenicity

The greater the pathogenicity of the infectious or suspected
infectious agent, the more severe is the potentially acquired
disease, and so the higher is the risk.
 For example:
 Since Staphylococcus aureus rarely causes a severe or life-
threatening disease in a laboratory situation, it is assigned to
BSL-2.
 Ebola, Marburg, and Lassa fever viruses cause diseases with
high mortality rates and have no vaccines or treatment, so BSL4 is the appropriate level to work with those viruse.
 Work with human HIV and hepatitis B virus is done at BSL-2
because they are not transmitted by the aerosol route, even
though potentially lethal disease can result from exposure. For
hepatitis B, there is also an effective vaccine available.
Risk Assessment
 Route of Transmission

Agents transmitted by the aerosol route
have caused the most laboratory
infections, versus agents transmitted
parenterally or by ingestion. When
planning work with an unknown agent with
an uncertain mode of transmission, the
potential for aerosol transmission must be
considered due to the higher risk.
Risk Assessment
 Agent Stability

Desiccation, exposure to sunlight or
ultraviolet light, exposure to chemical
disinfectants and other factors can affect
the agent's stability in the environment.
Risk Assessment
 Infectious Dose

Infectious dose can vary from one to
hundreds of thousands of units.
Risk Assessment
 Susceptibilty

The infectious dose is affected by the individual's
resistance, so a laboratory worker's immune status
is directly related to his/her susceptibility to disease
when working with an infectious agent. Thus,
susceptibility may be greater than in a healthy
person for persons who are pregnant, have
undergone surgery, are receiving immunesuppressent medications (including steroids), or
who have systemic infectious diseases.
Risk Assessment
 Concentration and Volume

The concentration is the number of
infectious organisms per unit volume.
Higher concentrations increase the risks of
working with that agent. Working with large
volumes of concentrated infectious
material also increases the risks, since
additional handling of the materials is often
required.
Risk Assessment
 Origin

Origin may refer to geographic location
(e.g., domestic or foreign); host (e.g.,
infected or uninfected human or animal); or
nature of source (potential zoonotic or
associated with a disease outbreak).