Laboratory SafetyLaboratory Safety

Prabin Shah

BScMLT, MSc(Biochemistry)

Safety in Microbiology LaboratorySafety in Microbiology Laboratory

Contents Introduction Routes of Infection Classification of infective

organism based on hazards Code of Practice Safe Laboratory Design Biological saftey cabinets Others Saftey Summary

IntroductionIntroduction 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 programmes.

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.

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.

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.

Routes of infectionRoutes of infection

Inoculation:-

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

Ingestion:-

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

InhalationInhalation

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”.

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

disease. Example: Bacillus subtilis, common moulds, Yeasts

Risk Group 2 (moderate individual risk, low community risk) 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.

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 indirectly.

No vaccine & chemotherapy available– Includes all viruses,which are of high risk of Laboratory workers &

community.– Effective treatment and preventive measures are not usually

available. Example: SARS, Ebola, Lassa, Marburg, Variola Major

Code of practice/safety measures/standard Code of practice/safety measures/standard precautionprecaution

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 materials.

Precautions to prevent Transmission of Precautions to prevent Transmission of infection in clinical laboratoryinfection in clinical laboratory

WHO , Laboratory biosafety manual, 3WHO , Laboratory biosafety manual, 3rdrd edition edition20042004

Access The international biohazard warning symbol

and sign must be displayed on the doors of

microbiology lab. 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.

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.

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

in laboratories. 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

clothing.

Procedures

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.

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

regulations.

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

is provided. Personnel should be advised of

special hazards,and required to read

the safety or operations manual and

follow standard practices and procedures.

A copy of the safety or operations

manual should be available in the

laboratory. 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

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:

• Formation of aerosols• Work with large volumes and/or high concentrations of

microorganisms• Overcrowding and too much equipment• Infestation with rodents and arthropods• Unauthorized entrance• Workflow: use of specific samples and reagents.

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 slip-resistant.

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 use.

Additional long-term storage space, conveniently located outside the laboratory working areas, should also be provided.

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

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 drinking-water supplies.

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.

Standard microbiology laboratory design,having all saftey euipments.

Biological safety cabinetBiological safety cabinet

Type of safety cabinets: BSL(Biosafety cabinet level)1 BSL2

BSL3

Fig CLASS I BIOLOGICAL SAFETY CABINET

CLASS II TYPE BIOLOGICAL SAFETY CABINETCLASS II TYPE BIOLOGICAL SAFETY CABINET

                                                                                                                  

    

CLASS III BIOLOGICAL SAFETY CABINET CLASS III BIOLOGICAL SAFETY CABINET

Don`t forget Others Safety…………………

Fire safety Electrical 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 )

Summary Summary • 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 pathogens.

• Proper use of infection control manual and formulation of infection control committee is essential in each hospital, blood transfusion center and laboratory institutions.

References www.osha.org World Health Organisation.Laboratory

biosaftey manual.2004 – 3rd edition www.google.com