Biosafety
Chapter 1,Classification of infective
microorganisms by risk group (WHO
Risk Groups 1,2,3 and 4) for laboratory
work
Risk Group 1 (no or low individual and
community risk),A microorganism that is
unlikely to cause human or animal disease.
Risk Group 2 (moderate individual risk,low
community risk),A pathogen that can cause
human or animal disease but is unlikely to be
a serious hazard to laboratory workers,the
community,livestock or the environment,
Laboratory exposures may cause serious
infection,but effective treatment and
preventive measures are available and the
risk of spread of infection is limited.
Risk Group 3 (high individual risk,low
community risk),A pathogen that usually
causes serious human or animal disease but
does not ordinarily spread from one infected
individual to another,Effective treatment and
preventive measures are available.
Risk Group 4 (high individual and
community risk),A pathogen that usually
causes serious human or animal disease and
that can be readily transmitted from one
individual to another,directly or indirectly,
Effective treatment and preventive measures
are not usually available.
Laboratory facilities are designated as basic
– Biosafety Level 1,basic – Biosafety Level 2,
containment – Biosafety Level 3,and
maximum containment – Biosafety Level 4,
Biosafety level designations are based on a
composite of the design features,
construction,containment facilities,
equipment,practices and operational
procedures required for working with agents
from the various risk groups,
气溶胶
GMT:微生物学操作技术规范
Countries (regions) should draw up a
national (regional) classification of
microorganisms,by risk group,taking into
account:
1,Pathogenicity of the organism.
2,Mode of transmission and host range of
the organism,These may be influenced by
existing levels of immunity in the local
population,density and movement of the host
population,presence of appropriate vectors带菌者,and standards of environmental hygiene.
3,Local availability of effective preventive
measures,These may include,prophylaxis预防 by
immunization or administration of antisera抗血清
(passive immunization); sanitary measures,e.g,
food and water hygiene; control of animal
reservoirs or arthropod节肢动物 vectors.
4,Local availability of effective treatment,This
includes passive immunization,postexposure
vaccination and use of antimicrobials,antivirals
and chemotherapeutic agents,and should take into
consideration the possibility of the emergence of
drug-resistant strains.
The assignment of an agent to a biosafety level for
laboratory work must be based on a risk assessment,
Such an assessment will take the risk group as well as
other factors into consideration in establishing the
appropriate biosafety level,
For example,an agent that is assigned to Risk Group
2 may generally require Biosafety Level 2 facilities,
equipment,practices and procedures for safe conduct
of work,However,if particular experiments require
the generation of high-concentration aerosols,then
Biosafety Level 3 may be more appropriate to provide
the necessary degree of safety,since itensures superior
containment of aerosols in the laboratory workplace.
Therefore,
The biosafety level assigned for the specific
work to be done is driven by professional
judgement based on a risk assessment,rather
than by automatic assignment of a laboratory
biosafety level according to the particular risk
group designation of the pathogenic agent to
be used.
a Environmental and functional isolation from
general traffic.
b Dependent on location of exhaust.
c Dependent on agent(s) used in the laboratory.
d For example,window,closed-circuit television,
two-way communication.
Thus,the assignment of a biosafety level takes
into consideration the organism (pathogenic agent)
used,the facilities available,and the equipment
practices and procedures required to conduct work
safely in the laboratory.
Chapter 2,Microbiological
risk assessment
2.1 Features
The backbone of the practice of biosafety is risk
assessment,
While there are many tools available to assist in
the assessment of risk for a given procedure or
experiment,the most important component is
professional judgement available,
Risk assessments should be performed by the
individuals most familiar with:
the specific characteristics of the organisms
being considered for use,
the equipment and procedures to be employed,
animal models that may be used,and
the containment equipment and facilities
The laboratory director or principal investigator
is responsible for ensuring that adequate and
timely risk assessments are performed,and for
working closely with the institution’s safety
committee and biosafety personnel to ensure that
appropriate equipment and facilities are available
to support the work being considered,
Once performed,
risk assessments should be reviewed routinely and
revised when necessary,taking into consideration
the acquisition of new data having a bearing on the
degree of risk and other relevant new information
from the scientific literature.
One of the most helpful tools available for
performing a microbiological risk assessment is the
listing of risk groups for microbiological agents,
However,simple reference to the risk grouping for
a particular agent is insufficient in the conduct of a
risk assessment,There are other factors that
should be considered:
1,Pathogenicity of the agent and infectious dose
2,Potential outcome of exposure
3,Natural route of infection
4,Other routes of infection,resulting from
laboratory manipulations (parenteral非肠道的,
airborne,ingestion)
5,Stability of the agent in the environment
6,Concentration of the agent and volume of
concentrated material to be manipulated
7,Presence of a suitable host (human or animal)
8,Information available from animal studies and
reports of laboratory-acquired infections or clinical
reports
9,Laboratory activity planned (sonication声波降解,
aerosolization,centrifugation,etc.)
10,Any genetic manipulation of the organism that
may extend the host range of the agent or alter the
agent’s sensitivity to known,effective treatment
regimens
11,Local availability of effective prophylaxis预防 or
therapeutic interventions.
On the basis of the information ascertained during
the risk assessment,a biosafety level can be
assigned to the planned work,appropriate personal
protective equipment selected,and standard
operating procedures (SOPs) incorporating other
safety interventions developed to ensure the safest
possible conduct of the work.
Q,what consequences excessive safety measures
will bring about?
2.2 Specimens for which there is limited
information
The risk assessment procedure described above
works well when there is adequate information
available,
However,there are situations when the information
is insufficient to perform an appropriate risk
assessment,for example,with clinical specimens or
epidemiological samples collected in the field,In
these cases,it is prudent to take a cautious
approach to specimen manipulation.
2.2 Specimens for which there is limited
information
A,Standard precautions (2) should always be
followed,and barrier protections applied (gloves,
gowns,eye protection),whenever samples are
obtained from patients.
B,Basic containment – Biosafety Level 2 practices
and procedures should be the minimum
requirement for handling specimens.
C,Transport of specimens should follow national
and/or international rules and regulations.
In the case of outbreaks of disease of unknown
etiology病源学,appropriate ad hoc guidelines may
be generated and posted by national competent
authorities and/or WHO on the World Wide Web
(as was the case during the 2003 emergence of the
severe acute respiratory syndrome (SARS)) to
indicate how specimens should be consigned for
shipment and the biosafety level at which they
should be analysed.
ad hoc made or happening only for a particular purpose or
need,not planned in advance,e.g,an ad hoc committee
We deal with problems on an ad hoc basis (= as they happen),
The Latin term "Ad hoc " means,in a UK legal context,
"for this purpose."
Chapter 3,Basic laboratories –Biosafety Levels 1
& 2
3.1 Code of practice
This code is a listing of the most essential
laboratory practices and procedures that are basic
to GMT,In many laboratories and national
laboratory programmes,this code may be used to
develop written practices and procedures for safe
laboratory operations.
Each laboratory should adopt a safety or
operations manual that identifies known and
potential hazards,and specifies practices and
procedures to eliminate or minimize such hazards,
GMT are fundamental to laboratory safety,
Specialized laboratory equipment is a supplement
to but can never replace appropriate procedures,
The most important concepts are listed below.
3.1.1 Access
a,The international biohazard warning symbol and
sign (next slide) must be displayed on the doors of
the rooms where microorganisms of Risk Group 2
or higher risk groups are handled.
b,Only authorized persons should be allowed to
enter the laboratory working areas.
c,Laboratory doors should be kept closed.
d,Children should not be authorized or allowed to
enter laboratory working areas.
e,Access to animal houses should be specially
authorized.
f,No animals should be admitted other than those
involved in the work of the laboratory.
Biohazard
warning sign for
laboratory doors
贴于实验室门上的生物危害警告标志
3.1.2 Personal protection 连体衣、隔离服或工作服
a,Laboratory coveralls,gowns or uniforms must
be worn at all times for work in the laboratory.
b,Appropriate gloves must be worn for all
procedures that may involve direct or
accidental contact with blood,body fluids and
other potentially infectious materials or infected
animals,After use,gloves should be removed
aseptically and hands must then be washed.
c,Personnel must wash their hands after handling
infectious materials and animals,and before
they leave the laboratory working areas.
d,Safety glasses,face shields (visors) or other
protective devices must be worn when it is
necessary to protect the eyes and face from
splashes,impacting objects and sources of
artificial ultraviolet radiation.
e,It is prohibited to wear protective laboratory
clothing outside the laboratory,e.g,in canteens,
coffee rooms,offices,libraries,staff rooms and
toilets.
f,Open-toed footwear must not be worn in
laboratories.
g,Eating,drinking,smoking,applying cosmetics
and handling contact lenses is prohibited in the
laboratory working areas.
h,Storing human foods or drinks anywhere in the
laboratory working areas is prohibited.
i,Protective laboratory clothing that has been used
in the laboratory must not be stored in the same
lockers or cupboards as street clothing.
3.1.3,Procedures
1),Pipetting by mouth must be strictly forbidden.
2 ),Materials must not be placed in the mouth,
Labels must not be licked舔,
3 ),All technical procedures should be performed
in a way that minimizes the formation of aerosols
and droplets.
4 ),The use of hypodermic needles and syringes
should be limited,They must not be used as
substitutes for pipetting devices or for any purpose
other than parenteral injection or aspiration of
fluids from laboratory animals.
5 ),All spills,accidents and overt or potential
exposures to infectious materials must be reported
to the laboratory supervisor,A written record of
such accidents and incidents should be maintained.
6 ),A written procedure for the clean-up of all
spills must be developed and followed.
7 ),Contaminated liquids must be decontaminated
(chemically or physically) before discharge to the
sanitary sewer下水道,An effluent treatment system
may be required,depending on the risk assessment
for the agent(s) being handled.
8 ),Written documents that are expected to be
removed from the laboratory need to be protected
from contamination while in the laboratory.
3.1.4,Laboratory working areas
1 ),The laboratory should be kept neat,clean and
free of materials that are not pertinent to the work.
2 ),Work surfaces must be decontaminated after
any spill of potentially dangerous material and at
the end of the working day.
3 ),All contaminated materials,specimens and
cultures must be decontaminated before disposal or
cleaning for reuse.
4 ),Packing and transportation must follow
applicable national and/or international regulations.
5 ),When windows can be opened,they should be
fitted with arthropod-proof screens.
节肢动物
3.1.5,Biosafety management
1 ),It is the responsibility of the laboratory director
(the person who has immediate responsibility for
the laboratory) to ensure the development and
adoption of a biosafety management plan and a
safety or operations manual.
2 ),The laboratory supervisor (reporting to the
laboratory director) should ensure that regular
training in laboratory safety is provided.
3),Personnel should be advised of special hazards,
and required to read the safety or operations
manual and follow standard practices and
procedures,The laboratory supervisor should
make sure that all personnel understand these,A
copy of the safety or operations manual should be
available in the laboratory.
4 ),There should be an arthropod and rodent
control programme,
5 ),Appropriate medical evaluation,surveillance
and treatment should be provided for all personnel
in case of need,and adequate medical records
should be maintained.
3.1.6,Laboratory design and facilities
In designing a laboratory and assigning certain
types of work to it,special attention should be paid
to conditions that are known to pose safety
problems,These include:
1),Formation of aerosols
2),Work with large volumes and/or high
concentrations of microorganisms
3),Overcrowding and too much equipment
4),Infestation with rodents and arthropods
5),Unauthorized entrance
6),Workflow,use of specific samples and reagents.
Laboratory design
for Biosafety Level 1
Laboratory design
for Biosafety Level 2
3.1.7,Design features
1),Ample space must be provided for the safe
conduct of laboratory work and for cleaning and
maintenance.
2),Walls,ceilings and floors should be smooth,easy
to clean,impermeable to liquids and resistant to
the chemicals and disinfectants normally used in
the laboratory,Floors should be slip-resistant.
3),Bench tops should be impervious to water and
resistant to disinfectants,acids,alkalis,organic
solvents and moderate heat.
4),Illumination should be adequate for all activities,
Undesirable reflections and glare should be
avoided.
5),Laboratory furniture should be sturdy,Open
spaces between and under benches,cabinets and
equipment should be accessible for cleaning.
6),Storage space must be adequate to hold supplies
for immediate use and thus prevent clutter on
bench tops and in aisles,Additional long-term
storage space,conveniently located outside the
laboratory working areas,should also be provided.
7),Space and facilities should be provided for the
safe handling and storage of solvents,radioactive
materials,and compressed and liquefied gases.
8),Facilities for storing outer garments and
personal items should be provided outside the
laboratory working areas.
9),Facilities for eating and drinking and for rest
should be provided outside the laboratory working
areas.
10),Hand-washing basins,with running water if
possible,should be provided in each laboratory
room,preferably near the exit door.
11),Doors should have vision panels,appropriate
fire ratings,and preferably be self-closing.
12),At Biosafety Level 2,an autoclave or other
means of decontamination should be available in
appropriate proximity to the laboratory.
13),Safety systems should cover fire,electrical
emergencies,emergency shower and eyewash
facilities.
14),First-aid areas or rooms suitably equipped and
readily accessible should be available.
15),In the planning of new facilities,consideration
should be given to the provision of mechanical
ventilation systems that provide an inward flow of
air without recirculation,If there is no mechanical
ventilation,windows should be able to be opened
and should be fitted with arthropod-proof screens.
16),A dependable supply of good quality water is
essential,There should be no cross-connections
between sources of laboratory and drinking-water
supplies,An anti-backflow device should be fitted
to protect the public water system.
17),There should be a reliable and adequate
electricity supply and emergency lighting to permit
safe exit,A stand-by generator is desirable for the
support of essential equipment,such as incubators,
biological safety cabinets,freezers,etc.,and for the
ventilation of animal cages.
18.There should be a reliable and adequate supply
of gas,Good maintenance of the installation is
mandatory.
19.Laboratories and animal houses are occasionally
the targets of vandals,Physical and fire security
must be considered,Strong doors,screened
windows and restricted issue of keys are
compulsory,Other measures should be considered
and applied,as appropriate,to augment security.
3.1.8,Laboratory equipment
Together with good procedures and practices,the
use of safety equipment will help to reduce risks
when dealing with biosafety hazards,This section
deals with basic principles related to equipment
suitable for laboratories of all biosafety levels,
Requirements for laboratory equipment pertinent
to higher biosafety levels are dealt with in the
relevant chapters.
The laboratory director should,after
consultation with the biosafety officer and safety
committee (if designated),ensure that adequate
equipment is provided and that it is used properly,
Equipment should be selected to take account of
certain general principles,i.e,it should be:
1,Designed to prevent or limit contact between
the operator and the infectious material
2,Constructed of materials that are impermeable
to liquids,resistant to corrosion and meet
structural requirements
3,Fabricated to be free of burrs,sharp edges and
unguarded moving parts
4,Designed,constructed and installed to
facilitate simple operation and provide for ease of
maintenance,cleaning,decontamination and
certification testing; glassware and other breakable
materials should be avoided,whenever possible.
Detailed performance and construction
specifications may need to be consulted to ensure
that the equipment possesses the necessary safety
features.
3.1.9,Essential biosafety equipment
1),Pipetting aids – to avoid mouth pipetting,Many
different designs are available.
2),Biological safety cabinets,to be used whenever:
infectious materials are handled; such materials
may be centrifuged in the open laboratory if sealed
centrifuge safety cups are used and if they are loaded
and unloaded in a biological safety cabinet
there is an increased risk of airborne infection
procedures with a high potential for producing
aerosols are used; these may include centrifugation,
grinding,blending,vigorous shaking or mixing,sonic
disruption,opening of containers of infectious
materials whose internal pressure may be different
from the ambient pressure,intranasal inoculation of
animals,and harvesting of infectious tissues from
animals and eggs.
3),Plastic disposable transfer loops,Alternatively,
electric transfer loop incinerators焚化炉 may be used
inside the biological safety cabinet to reduce
aerosol production.
4),Screw-capped tubes and bottles.
5),Autoclaves or other appropriate means to
decontaminate infectious materials.
6),Plastic disposable Pasteur pipettes,whenever
available,to avoid glass.
7),Equipment such as autoclaves and biological
safety cabinets must be validated with
appropriate methods before being taken into use,
Recertification should take place
at regular intervals,according to the
manufacturer’s instructions.
