Safety Guidelines in a Microbiology Laboratory. Universal Precautions

Safety guidelines in microbiology laboratories are required to protect personnel, and the environment, and to prevent the spread of infection. The following are safety guidelines to be followed in the microbiology laboratories.

• 1. Personal Protective Equipment (PPE): Wear proper PPE to protect eyes, skin, and clothes from the microorganism. PPE includes a laboratory coat, gloves, and safety goggles or face shields.

• 2. Hand hygiene: Wash hands thoroughly before entering the laboratory, after handling microorganisms, and before leaving the microbiology laboratory. Use proper soap and water or hand sanitizers to prevent the spread of microorganisms.

• 3. Laboratory design and Layout: Design of the laboratory should have a proper ventilation system. I prevent the accumulation of airborne contamination inside the laboratory. Its design should prevent cross-contamination.

• 4. Work area preparation: Disinfect work area surfaces and equipment before and after use. This prevents contamination and the spread of infection.

• 5. Labeling and storage: Label all containers properly with the name of the microorganism, date, and person working. Store cultures, samples, and reagents at the proper temperature.

• 6. Aseptic techniques: Use aseptic techniques to handle microorganisms and prevent contamination.

• 7. Handling biohazardous materials: Infectious materials are considered biohazardous materials. Proper biological safety cabinets or fume hoods are used if working with aerosol-producing procedures.

• 8. Disposal of materials: Contaminated materials such as used cultures, pipettes, gloves, etc are biohazards. Dispose of them observing laboratory rules and regulations.

• 9. Emergency Procedures: Be familiar with emergency procedures, emergency exists, eyewash solutions, safety showers, fire extinguishers, etc.

• 10. Training and education: Ensure training of all personnel on laboratory safety.

• 11. Personal behavior: Avoid eating, drinking, applying cosmetics, and touching faces in the laboratory. This prevents accidental ingestion or exposure to pathogens.

• 12. Reporting incidents: Report accidents or exposure to supervisor or any responsible person. This helps to take quick action and medical attention.

Biosafety cabinets Principle

Biosafety cabinets are specialized laboratory equipment to control the environment for working with hazardous microorganisms. Biosafety cabinets create a physical barrier to prevent the spread of hazardous materials and microorganisms. It protects the personnel from infection working inside the laboratory.

Biosafety cabinet works on the following principles: Biosafety cabinets use directed air flow, HEPA filtration, and physical barriers to provide a safe working space for the operator. It protects operators from bio-hazardous materials and infection. 

• 1. Protection: Biosafety cabinets provide protection to both personnel and the environment. Biosafety cabinets have a HEPA filter system (High Efficiency Particulate Air). HEPA filter stops entry of airborne particles and microorganisms into Biosafety cabinets. This helps to prevent the entry of hazardous materials into the laboratory environment.

• 2. Airflow and ventilation: Biosafety cabinets have a controlled airflow pattern. Air from the laboratory enters the Biosafety cabinets through a HEPA filter. Thus Biosafety cabinets shall be free from microorganisms. Air enters into Biosafety cabinets and develops a positive pressure. This will not allow entry of microorganisms into Biosafety cabinets. There are three zones of protection that control airflow and ventilation.

  • · Work zone: The operator works with materials in the work zone. The direction of airflow prevents contamination.

  • · Contaminated zone: This area surrounds the work zone. It is in between the work zone and the external environment. Air from the contaminated zone enters into work zone through a HEPA filter.

  • · Clean zone: This area is at the rear part of the biosafety cabinet. Filtered air from the biosafety cabinet enters the laboratory through ventilation.

• 3. Sealed work area: Biosafety cabinets allow to work inside it with a physical barrier to protect the operator from infection. The opening part of the biosafety cabinet has a transparent panel to close or open the biosafety cabinet.

• 4. Use PPE: The operator must wear PPE while working with the biosafety cabinet.

Types of bio-safety cabinets and their applications

There are mainly three types of bio-safety cabinets depending upon their airflow pattern.

• 1. Class I Biosafety cabinet: Airflow is directed from the laboratory into the biosafety cabinet. Then exhausted to the outside environment through a HEPA filter. This airflow pattern protects the operator but does not provide a sterile area inside the biosafety cabinet.

  • Application: It is suitable to work with low to moderate-risk materials. Operator protection is the main concern. They are used to handle chemicals, powders, and non-volatile toxic substances. They are not suitable for volatile or infectious materials that require a sterile environment.

• 2. Class II Biosafety cabinets: It is further divided into four subtypes based on the airflow pattern and other features.

  • · Type A1

  • Airflow: It has inward airflow. 70% of the air is for recirculation through a HEPA filter. 30% air exhausted to the outside cabinet.

  • Application/ Usage: It can handle low to moderate-risk materials and volatile chemicals. It protects both the operator and the environment.

  • · Type A2

  • Airflow: Similar to type A1. However, it maintains a higher level of protection by maintaining constant airflow velocity across the work surface.

  • Application/ Usage: It is commonly used in microbiology research, cell culture, and other applications that handle moderate-risk materials. It provides personnel, environmental, and sample protection.

  • · Type B1

  • Airflow: It maintains constant inward flow. Approximately 70% of air recirculation is through a HEPA filter. 30% exhausted through the exhaust system.

  • Application: It is suitable for handling hazardous volatile chemicals and radioisotopes.

  • · Type B2

  • · Airflow: It maintains constant inward airflow. But all exhausted air is filtered through a HEPA filter and returned to the laboratory environment.

  • · Application: It is used for high-risk microbiological work. It provides personnel and environmental protection. It also maintains a sterile work environment.

• 3. Class III Biosafety cabinets:

  • Airflow: It is enclosed and gas-tight. Air is exhausted through the HEPA filter from the cabinet. It has used gloves and a double-door pass-through system.

  • Application: It is used for most hazardous operations. The operator works through the attached gloves system. It provides maximum protection to the operator.

Dr Pramila Singh.