Biosafety Levels (BSLs) have been specified for handling infectious agents within the laboratory. This matches requirements for the laboratory environment and practices with the risk of the transmitting the infectious agent to laboratory workers, the community and the environment.
Methods of transmission:
(1) direct inoculation (autoinoculation)
(2) through skin abrasions or cuts (nonintact skin)
(3) ingestion
(4) mucous membranes (splashes, rubbing of eyes, etc.)
(5) aerosols
(6) across intact skin
(7) unknown
Risks associated with handling different infectious agents:
(1) not known to cause disease in healthy adults
(2) capable of causing moderate to severe disease in susceptible individuals
(3) associated with moderate or severe disease in healthy adults
(4) may cause life-threatening disease
(5) high risk for life-threatening disease
(6) uncertain but possibly high risk
|
Agent |
Transmission |
BSL |
|
not known to cause disease in healthy adults |
autoinoculation, ingestion, mucous membrane exposure, nonintact skin |
1 |
|
associated with moderate or severe disease in healthy adults |
autoinoculation, ingestion, mucous membrane exposure, nonintact skin |
2 |
|
may cause life threatening disease in healthy adults |
autoinoculation, ingestion, mucous membrane exposure, nonintact skin, aerosols |
3 |
|
high risk for life-threatening disease or uncertain but possibly high risk |
autoinoculation, ingestion, mucous membrane exposure, nonintact skin, aerosols, intact skin, unknown |
4 |
after Table 1, page 299, Fleming et al
where:
• A person who is susceptible for infection should avoid working with an agent, or else use a higher level of precautions.
|
BSL |
Practices |
|
1 |
standard microbiological practices oversight by person knowledgable about agents |
|
2 |
standard microbiological practices oversight by person knowledgable about agents limited access biohazard warning signs “sharps precautions” biosafety manual |
|
3 |
standard microbiological practices oversight by person knowledgable about agents controlled access biohazard warning signs “sharps precautions” biosafety manual decontamination of all waste decontamination of laboratory clothing before laundering baseline serum for laboratory workers (for serological testing after exposure |
|
4 |
standard microbiological practices oversight by person knowledgable about agents controlled access biohazard warning signs “sharps precautions” biosafety manual decontamination of all material on exit from facility baseline serum for laboratory workers (for serological testing after exposure) clothing changes before entering showering on exit |
where:
• Standard microbiological practices include:
(1) prohibition of mouth pipetting;
(2) decontamination of work surfaces at least once per day and to handle spills;
(3) minimal generation of splashes and aerosols;
(4) all cultures and regulated wastes decontaminated before disposal;
(5) insect and rodent control program in effect;
(6) handwashing after handling materials and before leaving laboratory;
(7) no eating, drinking, smoking, handling contact lenses or application of cosmetics permitted.
• Sharps precautions includes handling of needles, syringes, and broken glass.
|
BSL |
Safety Equipment and Primary Barriers |
|
1 |
personal protective equipment to include laboratory coat or gowns, gloves if skin broken or rash, protective eyewear if splashes possible |
|
2 |
Class I or II Biosafety Cabinet (BSC) personal protective equipment (PPE) with laboratory garments, gloves and face protection |
|
3 |
Class I or II Biosafety Cabinet (BSC) personal protective equipment (PPE) with laboratory garments, gloves and face protection |
|
4 |
Class III Biosafety Cabinet, OR Class I or II BSC with full body, air supplied, positive pressure protection suit |
|
BSL |
Facilities and Secondary Barriers |
|
1 |
open bench impervious to water and resistant to chemicals and heat top sink for handwashing |
|
2 |
top sink for handwashing autoclave available |
|
3 |
autoclave available physical separation from access corridors self-closing, double door access exhausted air not recirculated negative airflow into laboratory |
|
4 |
autoclave available physical separation from access corridors self-closing, double door access separate building dedicated air supply and exhaust dedicated vacuum systems dedicated decontamination systems |
where:
• Rugs and carpets should not be used within the laboratory since they may difficult to clean and decontaminate.
• Laboratory furniture should be sturdy with nonabsorbant surfaces that can be cleaned and decontaminated.
Specialty: Infectious Diseases
ICD-10: ,
