Health and safety in microbiological practices

1. Health and Safety in
Microbiological Practices
Dr. Diganta Dey
Ashok Laboratory Clinical Testing Centre Pvt. Ltd.

2. Risk Group Classification
(WHO Laboratory Biosafety Manual, 3rd Edition, 2004)
 Risk Group 1
no or low individual and community risk
 Risk Group 2
moderate individual risk, low community
risk
 Risk Group 3
high individual risk, low community risk
 Risk Group 4
high individual and community risk

3. Relation of risk groups to biosafety
levels, practices and equipment
Risk
Group
Biosafety
Level
Laboratory
Type
Laboratory
Practice
Safety Equipments
1 Basic- Biosafety
Level-1
Basic teaching,
Research
GMT None, open bench work
2 Basic- Biosafety
Level-2
Primary health
services;
diagnostic
services, research
GMT plus Protective
clothing, biohazard
sign
Open bench plus BSC
for potential aerosols
3 Containment-
Biosafety Level-3
Special diagnostic
services,
Research
As Level-2 plus
special clothing,
controlled access
directional airflow
BSC and or other
primary devices for all
activities
4 Maximum
containment-
Biosafety Level-4
Dangerous
pathogen units
As Level-3 plus airlock
entry, shower exit,
special waste disposal
Class III BSC, or positive
pressure suits in
conjunction with Class II
BSCs, double ended
autoclave, filtered air
BSC, biological safety cabinet; GMT, good microbiological techniques

4. Selection of a Safety Cabinet
through Risk Assessment
Protection Provided
Biological
Risk
Assessed
Personnel Product Environmental BSC Class
BSL 1 – 3 Yes No Yes I
BSL 1 – 3 Yes Yes Yes II (A1, A2, B1,
B2)
BSL – 4 Yes Yes Yes III; II—When
used in suit
room with suit

5. Biosafety Cabinet – Class I
 (A) front opening
 (B) sash
 (C) exhaust HEPA filter
 (D) exhaust plenum
 Does not provide
product protection
HEPA, an air filter must
remove 99.97% of particles
that have a size of 0.3 µm

6. Biosafety Cabinet – Class II
 The Class II, Type A1 BSC
 (A) front opening
 (B) sash;
 (C) exhaust HEPA filter
 (D) supply HEPA filter
 (E) common plenum
 (F) blower
 Class II BSC are of four types:
Type A1 (formerly A), Type A2
(formerly A/B3), Type B1, and
Type B2
 Provides product protection

7. Biosafety Cabinet – Class III
 (A) glove ports with
O-ring for attaching
arm-length gloves to
cabinet
 (B) sash
 (C) exhaust HEPA
filter
 (D) supply HEPA
filter
 (E) double-ended
autoclave or pass-
through box

8. Horizontal
Laminar Flow
Vertical
Laminar Flow

9. Personal Protective
Equipment
 “Specialized clothing or equipment worn by an
employee for protection against infectious
materials” (OSHA)
 Gloves: Protect hands
 Gowns/aprons: Protect skin and/or clothing
 Masks and respirators: Protect mouth/nose
 Respirators: Protect respiratory tract from
airborne infectious agents
 Goggles: Protect eyes
 Face shields: Protect face, mouth, nose and
eyes
 Overshoes

10. Hand Protection: Gloves
 Minimise the risk of
acquiring infections from
patients
 Prevent microbial flora
from being transmitted
from health care providers
to patients
 Glove material - vinyl,
latex, nitrile
 Sterile or non-sterile
 One or two pair
 Single use or reusable

11. Gowns or Aprons
 Cover street clothing
 Control contamination of
clothing
 Material:
◦ Natural or man-made
◦ Reusable or disposable
◦ Resistance to fluid
penetration
 Clean or sterile

12. How to Don Eye and Face
Protection
 Masks - protect nose and mouth
 Place over nose, mouth and chin.
Fit
flexible nose piece over nose
bridge.
Secure on head with ties or
elastic and adjust to fit
 Should fully cover nose and
mouth
and prevent fluid penetration
 Goggles - protect eyes
 Should fit snuggly over and
around eyes
 Personal glasses not a substitute
for goggles

13. Respiratory Protection
 Respirators that filter the air before it is inhaled
should be used for respiratory protection.
 The most commonly used respirators in healthcare
settings are the N95, N99, or N100 particulate
respirators.
 The device has a sub-micron filter capable of
excluding particles that are less than 5 microns in
diameter.
 Respirators are approved by the CDC’s National
Institute for Occupational Safety and Health.
 Like other PPE, the selection of a respirator type
must consider the nature of the exposure and risk
involved. For example, N95 particulate respirators
might be worn by personnel entering the room of a
patient with infectious tuberculosis. However, if a
bronchoscopy is performed on the patient, the
healthcare provider might wear a higher level of
respiratory protection, such as a powered air-
purifying respirator or PAPR.

14. Sequence for Donning PPE
 Gown first
 Mask
 Goggles or face shield
 Gloves

15. Sequence for Removing PPE
 Gloves
 Goggles or face shield
 Gown
 Mask

16. Hand Hygiene

17. Hand Hygiene

18. Procedures for routine hand
wash

19. Needle Stick Injury
 Most common dangers: HIV, HBV, HCV
 Exposure:
◦ Percutaneous- penetrating injury e.g. NSI
(most common)
◦ Mucocutaneous- mucus membrane (eyes,
mouth) e.g. splashes
◦ Cutaneous (skin)- Intact or Broken
 Infectious material: Blood, CSF, sterile
fluid, sputum, vaginal discharge, semen
 Not infectious: Tear, urine, stool, saliva
 Dictum- all material is infectious

20. Needle Stick Injury
Best approach is
prevention
 Vaccination- HBV
 Keep Lab clean
 Good spill
management
 Wipe work benches
with 1% hypochlorite
or 70% alcohol after
work
 Standard precautions
 PPE - gloves, apron,
goggles
 No mouth pipetting
 Apply band-aid over cuts
 No
eating/drinking/cosmetics
 Safe sharp handling
 Safe disposal
 Careful work
 Never recap
 Never break
 Never reuse

21. Post exposure prophylaxis
 First aid
 Inform authority
 Counseling
 PEP
◦ HIV, HBV
◦ BEST WITHIN 2HRS.
◦ Not effective after 72 hrs, so take within 72 hrs.
◦ Baseline tests- HIV (antibody), HBV (HBsAg, antibody), HCV (antibody).
◦ PEP taken for HIV - at least 4 weeks (HAART: zidovudine + lamivudine)
◦ If injured is HIV pos- no PEP
◦ PEP taken for HBV – Intramuscular HBIg (0.6 mIU/mL) within 24 hrs
Dos Don’ts
Wash with soap and water
Wash mouth with NS
Eyes-Lean back on chair and ask
friend to wash with NS/ use eye
washing station
Panic
Put finger in mouth
Squeeze
Apply disinfectant

22. Post exposure prophylaxis
 Follow up: After-2,4 & 6 weeks 3 & 6 months
HIV HBV

23. Management of Laboratory Spillage
 Best approach is to avoid spillage- know the position of all
chemicals, don’t keep bottles at the edge, wear PPE.
 First step is First Aid, alerting everyone and evacuation if
needed.
 Person involved in cleaning must wear PPE.
 Towels and gloves should be disposed of in a yellow clinical
waste bag for an autoclave if in a laboratory.
 Wash hands after the process.
 Keep hypo for 10 mins in case of large spill.
 After microbiological spill treat with 1% hypochlorite, and
autoclave towel before discarding.
 Discard jars must contain-
◦ 1% hypochlorite.
◦ In case of AFB- 2% phenol
 1% Hypochlorite is prepared from commercially available 4%
hypochlorite

24. Management of Laboratory
Spillage

25. Disposal of Biomedical Wastes
 BMW: Waste generated by any health care
facility. Example- gloves, cotton, needles,
syringe, test tubes etc.
 Most of the generated waste is infectious and
can injure or infect workers
 Segregation at site: Puncture proof container,
Yellow, blue, and black plastic bags
 Liquid waste: Pre-treat with 10% hypochlorite
and discharge through drains
 Microbiological waste: Autoclave for 60 mins
and discard in yellow bags

26. Disposal of Biomedical Wastes
Bag Waste Example Destination
Yellow (non-
chlorinated)
Contaminated Human waste,
blood stained
cotton, used
pipette,
microbiological
waste
Incineration
Blue (non-
chlorinated)
Solid, glass Test tube, IV set Disinfection by chemical
treatment/ Autoclaving/
Microwaving followed
by Mutilation/ Shredding
Puncture proof
(1%
hypochlorite
filled 3/4th)
Sharps Needles, scalpel -Do-
Black (non-
chlorinated)
Non infectious Paper, food Disposal in municipal
dump site

27. Disposal of Biomedical Wastes

28. Fire Hazards
 Fire-fighting equipment should be placed near room
doors and at strategic points in corridors and hallways.
 Fire extinguishers should be regularly inspected and
maintained, and their shelf-life kept up to date.
TYPE USE FOR DO NOT USE FOR
Water Paper, wood, fabric Electrical fires,
flammable liquids,
burning metals
Carbon dioxide
(CO2) extinguisher
gases
Flammable liquids
and gases, electrical
fires
Alkali metals, paper
Dry powder Flammable liquids
and gases, alkali
metals, electrical
fires
Reusable equipment
and instruments, as
residues are very
difficult to remove
Foam Flammable liquids Electrical fires
Types and uses of fire extinguishers

29. Thank you…