Charpter 9,
Laboratory biosecurity concepts
The Laboratory biosafety manual has in the past
focused on traditional biosafety guidance for
laboratories,
The manual emphasizes the use of good
microbiological work practices,appropriate
containment equipment,proper facility design,
operation and maintenance,and administrative
considerations to minimize the risk of worker
injury or illness.
In following these recommendations,the risk to the
environment and surrounding community-at-large
is also minimized,
It has now become necessary to expand this
traditional approach to biosafety through the
introduction of laboratory biosecurity measures,
Global events in the recent past have highlighted
the need to protect laboratories and the materials
they contain from being intentionally
compromised in ways that may harm people,
livestock,agriculture or the environment.
Before the laboratory biosecurity needs of a facility
can be defined,however,it is important to
understand the distinction between,laboratory
biosafety” and,laboratory biosecurity”.
“Laboratory biosafety” is the term used to describe
the containment principles,technologies and
practices that are implemented to prevent
unintentional exposure to pathogens and toxins,or
their accidental release.,Laboratory biosecurity”
refers to institutional and personal security
measures designed to prevent the loss,theft,misuse,
diversion转移 or intentional release of pathogens
and toxins.
Effective biosafety practices are the very
foundation of laboratory biosecurity activities,
Through risk assessments,performed as an
integral part of an institution’s biosafety
programme,information is gathered regarding the
type of organisms available,their physical location,
the personnel who require access to them,and the
identification of those responsible for them,
This information can be used to assess whether an
institution possesses biological materials that are
attractive to those who may wish to use them
improperly,National standards should be
developed that recognize and address the ongoing
responsibility of countries and institutions to
protect specimens,pathogens and toxins from
misuse.
A specific laboratory biosecurity programme must
be prepared and implemented for each facility
according to the requirements of the facility,the
type of laboratory work conducted,and the local
conditions,
Consequently,laboratory biosecurity activities
should be representative of the institution’s various
needs and should include input from scientific
directors,principal investigators,biosafety officers,
laboratory scientific staff,maintenance staff,
administrators,information technology staff,and
law enforcement agencies and security staff if
appropriate.
Laboratory biosecurity measures should be based
on a comprehensive programme of accountability
for pathogens and toxins that includes an updated
inventory with storage location,identification of
personnel with access,description of use,
documentation of internal and external transfers
within and between facilities,and any inactivation
and/or disposal of the materials,
Likewise,an institutional laboratory biosecurity
protocol should be established for identifying,
reporting,investigating and remediating补救
breaches in laboratory biosecurity,including
discrepancies in inventory清查 results,
The involvement and roles and responsibilities of
public health and security authorities in the event
of a security infraction must be clearly defined.
Laboratory biosecurity training,distinct from
laboratory biosafety training,should be provided
to all personnel,
Such training should help personnel understand
the need for protection of such materials and the
rationale基本原理 for the specific biosecurity
measures,and should include a review of relevant
national standards and institution- specific
procedures,
Procedures describing the security roles and
responsibilities of personnel in the event of a
security infraction should also be presented during
training,
The professional and ethical suitability for working
with dangerous pathogens of all personnel who
have regular authorized access to sensitive
materials is also central to effective laboratory
biosecurity activities.
In summary,security precautions should become a
routine part of laboratory work,just as have
aseptic无菌的 techniques and other safe
microbiological practices,
Laboratory biosecurity measures should not hinder
the efficient sharing of reference materials,clinical
and epidemiological specimens and related
information necessary for clinical or public health
investigations,
Competent security management should not
unduly interfere with the day-to-day activities of
scientific personnel or be an impediment to
conducting research,
Legitimate合法的 access to important research and
clinical materials must be preserved,
Assessment of the suitability of personnel,security-
specific training and rigorous adherence to
pathogen protection procedures are reasonable
means of enhancing laboratory biosecurity.
All such efforts must be established and maintained
through regular risk and threat assessments,and
regular review and updating of procedures,
Checks for compliance with these procedures,with
clear instructions on roles,responsibilities and
remedial补救的 actions,should be integral to
laboratory biosecurity programmes and national
standards for laboratory biosecurity,
Chapter 10,Biological safety cabinets
Biological safety cabinets (BSCs) are designed to
protect the operator,the laboratory environment
and work materials from exposure to infectious
aerosols and splashes that may be generated when
manipulating materials containing infectious agents,
such as primary cultures,stocks and diagnostic
specimens,
Aerosol particles are created by any activity that
imparts传授 energy into a liquid or semiliquid
material,such as shaking,pouring,stirring or
dropping liquid onto a surface or into another
liquid,
Other laboratory activities,such as streaking划线
agar plates,inoculating cell culture flasks with a
pipette,using a multichannel pipette to dispense分配
liquid suspensions of infectious agents into
microculture plates,homogenizing and vortexing旋涡 infectious materials,and centrifugation of
infectious liquids,or working with animals,can
generate infectious aerosols,
Aerosol particles of less than 5 μm in diameter
and small droplets of 5–100 μm in diameter are
not visible to the naked eye,The laboratory worker
is generally not aware that such particles are being
generated and may be inhaled or may cross-
contaminate work surface materials.
BSCs,when properly used,have been shown to
be highly effective in reducing laboratory-acquired
infections and cross-contaminations of cultures due
to aerosol exposures,BSCs also protect the
environment,
Over the years the basic design of BSCs has
undergone several modifications,A major change
was the addition of a high-efficiency particulate air
(HEPA) filter to the exhaust system,The HEPA
filter traps 99.97% of particles of 0.3 μm in
diameter and 99.99% of particles of greater or
smaller size.
This enables the HEPA filter to effectively trap
all known infectious agents and ensure that only
microbe-free exhaust air is discharged from the
cabinet.
A second design modification was to direct
HEPA-filtered air over the work surface,providing
protection of work surface materials from
contamination,
This feature is often referred to as product
protection,These basic design concepts have led to
the evolution of three classes of BSCs,The type of
protection provided by each is set out in Table 8.
Note,Horizontal and vertical outflow cabinets
(“clean-air work stations”) are not biological safety
cabinets and should not be used as such,
Laminar 薄片状的
Class I biological safety cabinet
Figure 6 provides a schematic diagram of a Class
I BSC,
Room air is drawn in through the front opening
at a minimum velocity of 0.38m/s,it passes over the
work surface and is discharged from the cabinet
through the exhaust duct,
The directional flow of air whisks aerosol
particles that may be generated on the work
surface away from the laboratory worker and into
the exhaust duct,
The front opening allows the operator’s arms to
reach the work surface inside the cabinet while he
or she observes the work surface through a glass
window,The window can also be fully raised to
provide access to the work surface for cleaning or
other purposes.
The air from the cabinet is exhausted through a
HEPA filter,
(a) into the laboratory and then to the outside of
the building through the building exhaust;
(b) to the outside through the building exhaust; or
(c) directly to the outside,The HEPA filter may be
located in the exhaust plenum of the BSC or in
the building exhaust,
Some Class I BSCs are equipped with an integral
exhaust fan,whereas others rely on the exhaust
fan in the building exhaust system.
The Class I BSC was the first recognized BSC
and,because of its simple design,is still in wide use
throughout the world,
It has the advantage of providing personnel and
environmental protection and can also be used for
work with radionuclides and volatile toxic
chemicals,
Because unsterilized room air is drawn over the
work surface through the front opening,it is not
considered to provide consistently reliable product
protection.
Class II biological safety cabinets
As the use of cell and tissue cultures for the
propagation of viruses and other purposes grew,it
was no longer considered satisfactory for
unsterilized room air to pass over the work surface,
The Class II BSC was designed not only to
provide personnel protection but also to protect
work surface materials from contaminated room
air.
Class II BSCs,of which there are four types (A1,
A2,B1 and B2),differ from Class I BSCs by
allowing only air from a HEPA-filtered (sterile)
supply to flow over the work surface,
The Class II BSC can be used for working with
infectious agents in Risk Groups2 and 3,Class II
BSCs can be used for working with infectious
agents in Risk Group 4 when positive-pressure
suits are used.
Class II type A1 biological safety cabinet
The Class II type A1 BSC is shown in Figure 7,
An internal fan draws room air (supply air) into
the cabinet through the front opening and into the
front intake grill烤架 /铁篦子,barbecue
The inflow velocity of this air should be at least
0.38m/s at the face of the front opening,
The supply air then passes through a supply
HEPA filter before flowing downwards over the
work surface,
As the air flows downwards it,splits” about 6–
18cm from the work surface,one half of the
downwards flowing air passing through the front
exhaust grill,and the other half passing through
the rear exhaust grill,
Any aerosol particles generated at the work
surface are immediately captured in this
downward airflow and passed through the front or
rear exhaust grills,thereby providing the highest
level of product protection,
The air is then discharged through the rear
plenum into the space between the supply and
exhaust filters located at the top of the cabinet,
Owing to the relative size of these filters,about
70% of the air recirculates through the supply
HEPA filter back into the work zone; the
remaining 30% passes through the exhaust filter
into the room or to the outside,
Air from the Class IIA1 BSC exhaust can be
recirculated to the room or discharged to the
outside of the building through a thimble套环
connection to a dedicated duct or through the
building exhaust system,
Recirculating the exhaust air to the room has the
advantage of lowering building fuel costs because
heated and/or cooled air is not being passed to the
outside environment,
A connection to a ducted exhaust system also
allows some BSCs to be used for work with volatile
易变的 radionuclides and volatile挥发性的 toxic
chemicals (Table8).
Note,Horizontal and vertical outflow cabinets
(“clean-air work stations”) are not biological safety
cabinets and should not be used as such,
Laminar 薄片状的
Class II type A2 vented to the outside,B1 and B2
biological safety cabinets
Class IIA2 vented to the outside,IIB1 (Figure8)
and IIB2 BSCs are variations of the type IIA1,
Their characteristics,along with those of Class I
and Class III BSCs,are indicated in Table 9,
Each variation allows the BSC to be used for
specialized purposes(see Table8),
These BSCs differ from one another in several aspects,
the air intake velocity through the front opening;
the amount of air recirculated over the work surface and
exhausted from the cabinet;
the exhaust system,which determines whether air from
the cabinet is exhausted to the room,or to the outside,
through a dedicated exhaust system or through the
building exhaust; and
the pressure arrangements (whether cabinets have
biologically contaminated ducts and plenums under
negative pressure,or have biological contaminated ducts
and plenums surrounded by negative-pressure ducts and
plenums),
Laboratory biosecurity concepts
The Laboratory biosafety manual has in the past
focused on traditional biosafety guidance for
laboratories,
The manual emphasizes the use of good
microbiological work practices,appropriate
containment equipment,proper facility design,
operation and maintenance,and administrative
considerations to minimize the risk of worker
injury or illness.
In following these recommendations,the risk to the
environment and surrounding community-at-large
is also minimized,
It has now become necessary to expand this
traditional approach to biosafety through the
introduction of laboratory biosecurity measures,
Global events in the recent past have highlighted
the need to protect laboratories and the materials
they contain from being intentionally
compromised in ways that may harm people,
livestock,agriculture or the environment.
Before the laboratory biosecurity needs of a facility
can be defined,however,it is important to
understand the distinction between,laboratory
biosafety” and,laboratory biosecurity”.
“Laboratory biosafety” is the term used to describe
the containment principles,technologies and
practices that are implemented to prevent
unintentional exposure to pathogens and toxins,or
their accidental release.,Laboratory biosecurity”
refers to institutional and personal security
measures designed to prevent the loss,theft,misuse,
diversion转移 or intentional release of pathogens
and toxins.
Effective biosafety practices are the very
foundation of laboratory biosecurity activities,
Through risk assessments,performed as an
integral part of an institution’s biosafety
programme,information is gathered regarding the
type of organisms available,their physical location,
the personnel who require access to them,and the
identification of those responsible for them,
This information can be used to assess whether an
institution possesses biological materials that are
attractive to those who may wish to use them
improperly,National standards should be
developed that recognize and address the ongoing
responsibility of countries and institutions to
protect specimens,pathogens and toxins from
misuse.
A specific laboratory biosecurity programme must
be prepared and implemented for each facility
according to the requirements of the facility,the
type of laboratory work conducted,and the local
conditions,
Consequently,laboratory biosecurity activities
should be representative of the institution’s various
needs and should include input from scientific
directors,principal investigators,biosafety officers,
laboratory scientific staff,maintenance staff,
administrators,information technology staff,and
law enforcement agencies and security staff if
appropriate.
Laboratory biosecurity measures should be based
on a comprehensive programme of accountability
for pathogens and toxins that includes an updated
inventory with storage location,identification of
personnel with access,description of use,
documentation of internal and external transfers
within and between facilities,and any inactivation
and/or disposal of the materials,
Likewise,an institutional laboratory biosecurity
protocol should be established for identifying,
reporting,investigating and remediating补救
breaches in laboratory biosecurity,including
discrepancies in inventory清查 results,
The involvement and roles and responsibilities of
public health and security authorities in the event
of a security infraction must be clearly defined.
Laboratory biosecurity training,distinct from
laboratory biosafety training,should be provided
to all personnel,
Such training should help personnel understand
the need for protection of such materials and the
rationale基本原理 for the specific biosecurity
measures,and should include a review of relevant
national standards and institution- specific
procedures,
Procedures describing the security roles and
responsibilities of personnel in the event of a
security infraction should also be presented during
training,
The professional and ethical suitability for working
with dangerous pathogens of all personnel who
have regular authorized access to sensitive
materials is also central to effective laboratory
biosecurity activities.
In summary,security precautions should become a
routine part of laboratory work,just as have
aseptic无菌的 techniques and other safe
microbiological practices,
Laboratory biosecurity measures should not hinder
the efficient sharing of reference materials,clinical
and epidemiological specimens and related
information necessary for clinical or public health
investigations,
Competent security management should not
unduly interfere with the day-to-day activities of
scientific personnel or be an impediment to
conducting research,
Legitimate合法的 access to important research and
clinical materials must be preserved,
Assessment of the suitability of personnel,security-
specific training and rigorous adherence to
pathogen protection procedures are reasonable
means of enhancing laboratory biosecurity.
All such efforts must be established and maintained
through regular risk and threat assessments,and
regular review and updating of procedures,
Checks for compliance with these procedures,with
clear instructions on roles,responsibilities and
remedial补救的 actions,should be integral to
laboratory biosecurity programmes and national
standards for laboratory biosecurity,
Chapter 10,Biological safety cabinets
Biological safety cabinets (BSCs) are designed to
protect the operator,the laboratory environment
and work materials from exposure to infectious
aerosols and splashes that may be generated when
manipulating materials containing infectious agents,
such as primary cultures,stocks and diagnostic
specimens,
Aerosol particles are created by any activity that
imparts传授 energy into a liquid or semiliquid
material,such as shaking,pouring,stirring or
dropping liquid onto a surface or into another
liquid,
Other laboratory activities,such as streaking划线
agar plates,inoculating cell culture flasks with a
pipette,using a multichannel pipette to dispense分配
liquid suspensions of infectious agents into
microculture plates,homogenizing and vortexing旋涡 infectious materials,and centrifugation of
infectious liquids,or working with animals,can
generate infectious aerosols,
Aerosol particles of less than 5 μm in diameter
and small droplets of 5–100 μm in diameter are
not visible to the naked eye,The laboratory worker
is generally not aware that such particles are being
generated and may be inhaled or may cross-
contaminate work surface materials.
BSCs,when properly used,have been shown to
be highly effective in reducing laboratory-acquired
infections and cross-contaminations of cultures due
to aerosol exposures,BSCs also protect the
environment,
Over the years the basic design of BSCs has
undergone several modifications,A major change
was the addition of a high-efficiency particulate air
(HEPA) filter to the exhaust system,The HEPA
filter traps 99.97% of particles of 0.3 μm in
diameter and 99.99% of particles of greater or
smaller size.
This enables the HEPA filter to effectively trap
all known infectious agents and ensure that only
microbe-free exhaust air is discharged from the
cabinet.
A second design modification was to direct
HEPA-filtered air over the work surface,providing
protection of work surface materials from
contamination,
This feature is often referred to as product
protection,These basic design concepts have led to
the evolution of three classes of BSCs,The type of
protection provided by each is set out in Table 8.
Note,Horizontal and vertical outflow cabinets
(“clean-air work stations”) are not biological safety
cabinets and should not be used as such,
Laminar 薄片状的
Class I biological safety cabinet
Figure 6 provides a schematic diagram of a Class
I BSC,
Room air is drawn in through the front opening
at a minimum velocity of 0.38m/s,it passes over the
work surface and is discharged from the cabinet
through the exhaust duct,
The directional flow of air whisks aerosol
particles that may be generated on the work
surface away from the laboratory worker and into
the exhaust duct,
The front opening allows the operator’s arms to
reach the work surface inside the cabinet while he
or she observes the work surface through a glass
window,The window can also be fully raised to
provide access to the work surface for cleaning or
other purposes.
The air from the cabinet is exhausted through a
HEPA filter,
(a) into the laboratory and then to the outside of
the building through the building exhaust;
(b) to the outside through the building exhaust; or
(c) directly to the outside,The HEPA filter may be
located in the exhaust plenum of the BSC or in
the building exhaust,
Some Class I BSCs are equipped with an integral
exhaust fan,whereas others rely on the exhaust
fan in the building exhaust system.
The Class I BSC was the first recognized BSC
and,because of its simple design,is still in wide use
throughout the world,
It has the advantage of providing personnel and
environmental protection and can also be used for
work with radionuclides and volatile toxic
chemicals,
Because unsterilized room air is drawn over the
work surface through the front opening,it is not
considered to provide consistently reliable product
protection.
Class II biological safety cabinets
As the use of cell and tissue cultures for the
propagation of viruses and other purposes grew,it
was no longer considered satisfactory for
unsterilized room air to pass over the work surface,
The Class II BSC was designed not only to
provide personnel protection but also to protect
work surface materials from contaminated room
air.
Class II BSCs,of which there are four types (A1,
A2,B1 and B2),differ from Class I BSCs by
allowing only air from a HEPA-filtered (sterile)
supply to flow over the work surface,
The Class II BSC can be used for working with
infectious agents in Risk Groups2 and 3,Class II
BSCs can be used for working with infectious
agents in Risk Group 4 when positive-pressure
suits are used.
Class II type A1 biological safety cabinet
The Class II type A1 BSC is shown in Figure 7,
An internal fan draws room air (supply air) into
the cabinet through the front opening and into the
front intake grill烤架 /铁篦子,barbecue
The inflow velocity of this air should be at least
0.38m/s at the face of the front opening,
The supply air then passes through a supply
HEPA filter before flowing downwards over the
work surface,
As the air flows downwards it,splits” about 6–
18cm from the work surface,one half of the
downwards flowing air passing through the front
exhaust grill,and the other half passing through
the rear exhaust grill,
Any aerosol particles generated at the work
surface are immediately captured in this
downward airflow and passed through the front or
rear exhaust grills,thereby providing the highest
level of product protection,
The air is then discharged through the rear
plenum into the space between the supply and
exhaust filters located at the top of the cabinet,
Owing to the relative size of these filters,about
70% of the air recirculates through the supply
HEPA filter back into the work zone; the
remaining 30% passes through the exhaust filter
into the room or to the outside,
Air from the Class IIA1 BSC exhaust can be
recirculated to the room or discharged to the
outside of the building through a thimble套环
connection to a dedicated duct or through the
building exhaust system,
Recirculating the exhaust air to the room has the
advantage of lowering building fuel costs because
heated and/or cooled air is not being passed to the
outside environment,
A connection to a ducted exhaust system also
allows some BSCs to be used for work with volatile
易变的 radionuclides and volatile挥发性的 toxic
chemicals (Table8).
Note,Horizontal and vertical outflow cabinets
(“clean-air work stations”) are not biological safety
cabinets and should not be used as such,
Laminar 薄片状的
Class II type A2 vented to the outside,B1 and B2
biological safety cabinets
Class IIA2 vented to the outside,IIB1 (Figure8)
and IIB2 BSCs are variations of the type IIA1,
Their characteristics,along with those of Class I
and Class III BSCs,are indicated in Table 9,
Each variation allows the BSC to be used for
specialized purposes(see Table8),
These BSCs differ from one another in several aspects,
the air intake velocity through the front opening;
the amount of air recirculated over the work surface and
exhausted from the cabinet;
the exhaust system,which determines whether air from
the cabinet is exhausted to the room,or to the outside,
through a dedicated exhaust system or through the
building exhaust; and
the pressure arrangements (whether cabinets have
biologically contaminated ducts and plenums under
negative pressure,or have biological contaminated ducts
and plenums surrounded by negative-pressure ducts and
plenums),
