This presentation gives an overview of different classes of Biosafety Cabinets and different Biosafety levels in Diagnostic Microbiology Laboratory.

1. BIOSAFETY IN MICROBIOLOGY LABORATORY
Dr. Sohini Banerjee
Second year Post Graduate Trainee
Department of Microbiology
Burdwan Medical College & Hospital

2. Biosafety-
 Biosafety is the application of safety precautions that reduce
a laboratorian’s risk of exposure to a potentially infectious
microbe and limit contamination of the work environment
and ultimately the community.
(CDC)

3.  Standard Precautions-
(Guidelines to be followed in Microbiology Laboratory for safe work
practices)-
 Blood and body fluids from every patient to be treated as
potentially infectious.
 Do not eat, drink, smoke or apply cosmetics.
 Do not insert, remove contact lenses.
 Do not mouth pipette.
 Limit access of trained personnel only to the laboratory.

4.  Standard Precautions-
(Guidelines to be followed in Microbiology Laboratory for safe work
practices)-
 Use of appropriate barrier to prevent skin, mucous
membrane exposure including gloves, masks, gowns, aprons.
 Thoroughly wash hands and other skin surfaces after any
contamination.
 Take special care to prevent injuries with sharp objects.
 Storage of food and drinks must be ensured in separate
place from work area.
 Proper disposal of waste.

5.  Biosafety cabinets-
 It is a device that encloses a workspace to protect workers
from aerosol exposure of infectious agents.
 It provides personnel, environmental and product protection.
 Air containing infectious agents sterilized by heat, UV light or
by passage through HEPA filter.
 These cabinets are designated as class I to III according to
containment.

6. Biosafety Cabinet-Class-I
• Allows to pass room air to pass
into the cabinet, around the
material.
• Only sterilizes the air to be
exhausted.(HEPA filter)
• Have negative pressure.
• Draws air at a velocity 75fpm.
• Operated with an open front.
• Provides personnel and
environment protection but no
product protection.
• Used in BSL 2,3.

7. Biosafety Cabinet-Class-II
• Sterilizes the air that passes over the materials and as well as the
air that to be exhausted.
• Air flow as sheets, that acts as barrier to the particles from
outside the cabinet and direct flow of contaminated air through
the filter.
• Provides personnel, product and environmental protection.
• Front opening with continuous inward air flow.
• These are classified as type A(A1 & A2) and B(B1 & B2),
according to air flow velocity and percent of air HEPA filtered
and recirculated.

8.  Biosafety cabinet Class-II

9.  Biosafety Cabinet-Class-II

10.  Biosafety Cabinet-Class III
 Totally enclosed with recirculating air.
 Most protection to the worker.
 Air coming into and going out of the
cabinet is sterilized.(HEPA filter)
 Infectious material within is handled
with rubber gloves attached with the
cabinet.
 Samples are passed into the box
through an interlock.
 Negative pressure cabinet.

11.  Biosafety Levels-

12.  Biosafety Level-1
• Class of agents- Not known to cause disease consistently in heathy
adults.
Well defined and characterized.
• Agents- Bacillus subtilis, Saccharomyces cerevisiae.
• Practices- Standard Microbiological practices followed.
Open bench work.
Controlled access, hand washing sink, PPE (Lab coat,
gloves, face protection).
• Primary Barriers - Not required.
• Secondary Barriers- Open bench top sink.

13.  Biosafety level-2
• Class of agents-
I. Commonly found in diagnostic laboratory.
II. Moderate risk infectious agents. Associated with human
diseases.
III. Effective Treatment is available.
• Agents- Staphylococcus aureus, Escherichia coli, Klebsiella sp.,
Proteus sp., Streptococcus pyogenes, Vibrio cholerae.

14.  Biosafety level-2
• Practices-
 Standard Microbiologic practices.
 Controlled access.
 Biohazard warning. Proper waste and sharp disposal. Proper
Biosafety manual must be provided.
• Safety Equipment (Primary Barriers) –
 Biosafety Cabinet Class I or II.
 PPE. (Lab coats, face protection, gloves)
o Facilities(Secondary Barriers)-. Open bench top sink.
Autoclave.

16.  Biosafety Level-3
• Class of Agents-
 Indigenous or exotic agents with potential aerosol
transmission.
 Diseases may have serious or lethal consequences.
 There is effective treatment available.
• Agents- Mycobacterium tuberculosis, SARS, MERS, Yellow
fever virus etc.

17.  Biosafety Level-3
• Practices-
 Controlled access.
 Decontamination of all waste.
 Decontamination of all lab clothing.
 Those working in BSL-3 lab should have baseline sera
specimens stored for comparison with acute sera in the event
of unexplained illness.
o Safety Equipment (Primary Barrier)-
 Biosafety Cabinet- Class I or II.
 PPEs.

18.  Biosafety Level-3
o Facilities (Secondary Barriers)-
 All BSL-2 practices.
 Physical separation from access corridors.
 Self closing double door access.
 Negative airflow in the laboratory.
 Exhausted air not to be recirculated. Exhaust HEPA filter.
 Biohazard warning.

19.  Biosafety Level-4
• Class of Agents-
 Life threatening exotic infectious agents.
 No known treatment or vaccines are available.
• Agents- Marburg virus, Ebola virus, Crimean Congo
hemorrhagic virus.

20.  Biosafety Level-4
• Practices-
 All BSL-3 practices.
 Clothing change on entering.
 Shower on exit.
 All material decontaminated after exit.
o Safety Equipment (Primary Barriers)-
 BSC II or III.
 Full body, air supplied, positive pressure personnel suit.

21.  Biosafety Level-4
• Facilities (Secondary Barriers)-
 Isolated zone.
 Supply and exhaust HEPA Filter.
 Chemical shower out.
 Personal shower out.
 Vacuum line and decontamination system.

23.  Exposure Control Panel-
 Employee Education And Orientation- Appropriate user manual should
be followed to reduce the Hospital acquired infections.
 Disposal of Hazardous elements-
o Proper disposal of patient samples, culture media, slides, sharp
instruments etc.
o Mechanical shredding and compacting waste with chemical like sodium
hypochlorite.

24.  Exposure Control Panel-
 Collection, Transport and Reception of specimens-
o Avoid unnecessary contamination, spillage, splashing.
o Reception staff must wear gown, gloves. In case of leakage senior staff must
decide whether to discard or not, sample should be handled in biosafety
cabinet.
 Spillage-
o Class 2 agents- Disinfect and clean up.
o Class 3 agents- Fumigate.
o Disinfect work benches with 70% isopropyl alcohol.
 All mishaps should be reported and recorded.

25.  References-
 Koneman’s Color Atlas And Diagnostic Microbiology- Laboratory Safety.
 Baily & Scott’s Diagnostic Microbiology- Biosafety.
 Mackie & McCartney Practical Medical Microbiology.
 Biosafety in Microbiological and Biomedical Laboratories- CDC.

26. THANK YOU.