Organization of a microbiological laboratory

Classification and specialization

All microbiological laboratories are classified according to two main criteria: the objects of study (microbe groups) and the methods applied.

According to the spectrum of tasks to be solved, several types of institutions are distinguished:

• Clinical diagnostic — operate within the structure of hospitals, outpatient clinics, and dispensaries.
• State Sanitary and Epidemiological Surveillance laboratories — have a sanitary and epidemiological profile.
• Research — problem-oriented, university, and sectoral institutes.
• Industrial — perform quality control directly at enterprises.
• Specialized — designed to work with agents of particularly dangerous infections.

Depending on the object of study, facilities can be bacteriological, virological, mycological (working with fungi), and protozoological (studying protozoa). There is also a narrow specialization in specific taxa, for example, rickettsial, chlamydial, or tuberculosis centers. Depending on equipment, laboratories use classical culture methods, immunological methods (serological reactions), or molecular genetic tests (PCR).

Pathogenicity groups of microorganisms

The degree of danger posed by a microbe is assessed by its pathogenicity, infectious dose, transmission mechanisms, host range, and availability of treatment. All laboratory work is strictly regulated depending on which group of pathogens is to be handled. The Russian Federation uses a system of four pathogenicity groups (numbering is inverse to the WHO classification, where group 1 is the least dangerous).

1. Group 1 (particularly dangerous infections): Pose a high individual and public risk. Cause severe diseases with easy human-to-human transmission. Examples: plague, yellow fever, smallpox.
2. Group 2: High individual but low public risk. Causative agents of severe diseases for which effective drugs are available, and the risk of transmission is limited. Examples: anthrax, glanders, tularemia.
3. Group 3: Moderate risk. Cause diseases, but laboratory-acquired infections are rare. Examples: typhoid fever, dysentery, gonorrhea, diphtheria, tuberculosis.
4. Group 4: Low risk. These are opportunistic microorganisms that normally do not cause disease in healthy individuals. Examples: Escherichia, Staphylococcus, Enterococcus.

Engineering solutions and biosafety

The key objective in laboratory design is to prevent the spread of infectious material beyond the work area. To achieve this, strict access control is applied, and an isolating perimeter is created.

Premises must meet strict requirements:

• Walls, ceilings, and floors must be smooth, waterproof, and resistant to disinfectants, acids, and alkalis.
• Floors must have a non-slip coating, and surface joints must be completely airtight.
• Laboratory furniture is designed so that the space beneath it is easy to clean, and work surfaces are chemically resistant.

Engineering utilities include specialized sewage systems, water supply, and ventilation (exhaust air release into the atmosphere is permitted only after filtration through bacterial filters). An autoclave for waste disposal and biological safety cabinets are mandatory.

Personnel working rules

To prevent infections in the researcher and other staff, strict organizational rules are in effect. Only instructed personnel who have undergone necessary vaccination are allowed to work.

Main safety requirements:

• Use of PPE: Wearing lab coats and gloves is mandatory. Going outside the laboratory work zone in special clothing is strictly prohibited. All clothing is disinfected before being sent to the laundry.
• Hygiene and daily routine: Drinking, eating, smoking, storing food, and applying cosmetics are strictly prohibited in the rooms. Hands must be washed after contact with biological material and before each exit.
• Handling biological material: Unpacking containers is carried out on trays after wiping the packaging with a disinfectant. During manipulations, laboratory doors must be closed to prevent the spread of microbial aerosols.
• Liquid manipulations: Mouth pipetting is prohibited (dispensers are used). Transferring must be performed strictly over a vessel containing a disinfectant solution.
• Open flame: Working with cultures is carried out near a lit burner. Bacteriological loops, spreaders, and test tube edges must be flamed. The burner must not be carried while lit, and it should be extinguished only with its cap.

Class and exam questions

What else to study on this topic

• Detailed criteria for assessing microorganism hazard (infectious dose, host range)
• Architectural and planning features of maximum containment laboratories
• Mechanisms of microbial aerosol formation and methods for its control
• Algorithm for targeted sanitary processing of personnel when exiting the work zone
• Systems for disposal and hardware decontamination of liquid and solid waste

Other topics in the section "Microbiological diagnostics"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.