2. Safety in Microbiology LaboratorySafety in Microbiology Laboratory
Routes of Infection
Classification of infective
organism based on hazards
Code of Practice
Safe Laboratory Design
Biological saftey cabinets
Clinical laboratory personnel including support
employees are prone to risk of
infection,chemicals,radiations etc. Such risks can be
prevented or minimized by a laboratory safety
The attitude “What you don’t know can’t hurt you’’ is
common among laboratory employee, in the beginning
of 1980, this relax attitude toward safety among lab
personnel changed dramatically due to HIV.
5. Many laboratory workers, researchers & scientists
suffered & also lose their life such as the scientists
like Ricketts and Karls Urbani died while doing
research on finding the cause of Rocky mountain
fever and the cause of Severe acute respiratory
syndrome (SARS) respectively. They might have
breach the necessary safety guidelines while working
or doing research.
The routes by which infections are acquired in the
laboratory may be different from natural infection.
6. The varieties and concentrations of microorganisms
found in a microbiology laboratory are such that
special precautions must be taken for the safety of
the staff/student and those around him or her.
With passage of time the concepts of laboratory
safety expanded to include chemical, radioactive,
electrical & fire hazard protection.
7. Routes of infectionRoutes of infection
Literally inoculation means the introduction of material into
an ‘eye’, but it covers deliberate or accidental introduction
of infection into body by splashing or by rubbing with
contaminated fingers ,injection through skin,by needle
stick injury or bite of ectoparasite, Incision by sharp
instrument, broken glass
By oral route sucking or accidental swallowing of
infective materials eg. Mouth pipetting of cultures or
infected fluids, contamination of fingers during
eating , drinking or smoking in the laboratory
Infection by breathing in of infected aerosol or dust.
An aerosol is a cloud of small droplets of liquid in
air. It usually contain many droplets of liquid in air;
Droplets smaller than 0.1 mm diameter dry rapidly,
become solid residues called “droplet nuclei”.
10. Classification of infective microorganisms
based on Hazards
Risk Group 1 (no or low individual and community risk)
A microorganism that is unlikely to cause human
Example: Bacillus subtilis, common moulds, Yeasts
Risk Group 2 (moderate individual risk, low community
A pathogen that can cause human disease and may
be a hazard to lab workers; effective treatment and
preventive measures are available.
Example: Staphylococcus, Streptococcus, Shigella,
Vibrio, Poliovirus, Hepatitis virus etc.
11. Risk Group 3 (high individual risk, low community risk)
A pathogen that usually causes serious human disease and
present a serious hazard to the laboratory workers
• May pose a risk of spread in the community
• Effective treatment and preventive measures are available.
Example: Bacillus anthracis, Mycobacterium tuberculosis,
Brucella, Histoplasma, Rickettsia.
• Risk Group 4 (high individual and community risk)
A pathogen that usually causes serious human disease and that can
be readily transmitted from one individual to another, directly or
No vaccine & chemotherapy available
– Includes all viruses,which are of high risk of Laboratory workers &
– Effective treatment and preventive measures are not usually
available. Example: SARS, Ebola, Lassa, Marburg, Variola Major
12. Code of practice/safety measures/standardCode of practice/safety measures/standard
In Britain (1978) ‘Howie code’ documented ‘Code of
practice’ or in general term laboratory practice.
In 1987,the CDC published guidelines known as
“Universal precautions to reduce the risk of HBV
transmission in clinical lab& blood bank.”
In 1996 ,CDC & OSHA (US occupational safety &
health administration) jointly published ‘’Standard
precautions’’ which simply stated , blood & body
fluids from all patients be treated as infectious
13. Precautions to prevent Transmission ofPrecautions to prevent Transmission of
infection in clinical laboratoryinfection in clinical laboratory
WHO , Laboratory biosafety manual, 3WHO , Laboratory biosafety manual, 3rdrd
The international biohazard warning symbol
and sign must be displayed on the doors of
Only authorized persons should be allowed
to enter the laboratory working areas.
Laboratory doors should be kept closed.
Children and pet animal should not be
allowed to enter laboratory working areas.
No animals should be admitted other than those
Involved in the work of the laboratory.
14. Personal protection
Laboratory coveralls, gowns or uniforms
must be worn at all times for work
in the laboratory.
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.
Personnel must wash their hands after
handling infectious materials and
animals and before they leave the
laboratory working areas.
15. Safety glasses, face shields or other
protective devices must be worn .
It is prohibited to wear protective
laboratory clothing outside the lab.
Open-toed footwear must not be worn
Eating, drinking, smoking, applying cosmetics
and handling contact lenses is prohibited
in the laboratory working areas.
Protective laboratory clothing that has been
used in the laboratory must not be stored in
the same lockers or cupboards as street
Pipetting by mouth must be strictly forbidden.
Materials must not be placed in the mouth.
Labels must not be licked.
All technical procedures should be performed
in a way that minimizes the formation
of aerosols and droplets.
The use of hypodermic needles and
syringes should be limited.
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.
17. Laboratory working areas
The laboratory should be kept neat, clean
and free of materials that are not pertinent
to the work.
Work surfaces must be decontaminated
after any spill of potentially dangerous
material and at the end of the working day.
All contaminated materials, specimens
and cultures must be decontaminated
before disposal or cleaning for reuse.
Packing and transportation must follow
applicable national and/or international
18. Biosafety management
The laboratory supervisor should ensure
the development and adoption of a
biosafety management plan and a safety
or operations manual.
The laboratory supervisor should ensure
that regular training in laboratory safety
Personnel should be advised of
special hazards,and required to read
the safety or operations manual and
follow standard practices and procedures.
19. A copy of the safety or operations
manual should be available in the
There should be an arthropod and
rodent control programme
Appropriate medical evaluation,
surveillance and treatment
should be provided for all
personnel in case of need,
and adequate medical records
should be maintained
20. 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.
• Formation of aerosols
• Work with large volumes and/or high concentrations of
• Overcrowding and too much equipment
• Infestation with rodents and arthropods
• Unauthorized entrance
• Workflow: use of specific samples and reagents.
21. Design features
Ample space must be provided for the safe conduct of laboratory
work and cleaning
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
Bench tops should be impervious to water and resistant to
disinfectants, acids and alkalis etc
Open spaces between and under benches, cabinets and
equipment should be accessible for cleaning.
Storage space must be adequate to hold supplies for immediate
Additional long-term storage space, conveniently located
outside the laboratory working areas, should also be provided.
22. Space and facilities should be provided for the safe
handling and storage of solvents, radioactive materials,
and compressed and liquefied gases.
Separate room storage of personal belongings and for
fooding and rest
Hand-washing basins, with running water if possible,
should be provided in each laboratory room, preferably
near the exit door.
Doors should have vision panels, appropriate fire ratings,
and preferably be selfclosing.
Safety systems should cover fire, electrical emergencies,
emergency shower and eyewash facilities.
First-aid areas or rooms suitably equipped and readily
accessible should be available
23. mechanical ventilation systems that provide an inward flow
of air without recirculation.
Good quality water is essential. There should be no
crossconnections between sources of laboratory and
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.
There should be a reliable and adequate supply of gas.
Good maintenance of the installation is mandatory.
29. Don`t forget Others Safety…………………
Chemicals and radioactive substances safety
Engineering control & equipments eg fume hood,
closed centrifuge,Biosafety cabinets.
Safety programs also involve disaster preparedness
plans that outline steps to take in an emergency (In
areas of the country prone to natural disasters like
earthquake, hurricanes, snowstorms )
• Proper collection, treatment and disposal of infectious waste
reduce the rate of infection, prevent aerosol formation and
protects environmental pollution.
• All infectious and non-infectious waste materials must be
collected separately and disposed properly.
• Use of red, yellow and blue color-coded bag is useful for
proper disposal of waste.
• Autoclaving, incineration and disinfection are useful means for
disposal of infectious waste.
• Now sophisticated biosafety systems & improved training
methods are necessary to cope with the increased challenges
raised by the emergence & reemergence of significant
• Proper use of infection control manual and formulation of
infection control committee is essential in each hospital, blood
transfusion center and laboratory institutions.