p.1
Principles of Biosafety
What does biosafety focus on?
Keeping people, animals, and the environment safe from germs and diseases.
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Principles of Biosafety
What is the main difference between biosafety and biosecurity?
Biosafety focuses on health safety, while biosecurity focuses on preventing theft or misuse of dangerous materials.
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Types of Biological Safety Cabinets
What type of air does a Class I Biological Safety Cabinet allow?
Unsterilized air, which can expose samples to contamination.
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Types of Biological Safety Cabinets
What is the primary use of a Class II Biological Safety Cabinet?
To provide protection for the worker, environment, and samples, sterilizing air with a HEPA filter.
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Types of Biological Safety Cabinets
What is the airflow configuration of Class II, Type A2 Biological Safety Cabinet?
70% recirculated and 30% exhausted.
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Types of Biological Safety Cabinets
What is the purpose of a Class II, Type B2 Biological Safety Cabinet?
To process chemicals, radioisotopes, and carcinogens, with exhaust air discharged completely outside.
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Types of Biological Safety Cabinets
What types of agents can Class II Biological Safety Cabinets handle?
BSL-1, BSL-2, and provisions for BSL-3 organisms.
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Types of Biological Safety Cabinets
What is the airflow configuration of a Class III Biological Safety Cabinet?
0% recirculated and 100% exhausted.
p.1
Types of Biological Safety Cabinets
What is the primary purpose of a Biological Safety Cabinet (BSC)?
To protect workers from aerosol exposure and infectious disease agents.
p.2
Types of Biological Safety Cabinets
What is a key feature of a Class III Cabinet?
It has an airtight system that completely separates the worker from the sample.
p.3
Biosafety Levels of Biological Agents
What distinguishes Risk Group 4 pathogens?
Causes serious human or animal disease that can be transmitted from one individual to another, directly or indirectly.
p.9
Direct Microscopic Examination Methods
What is the purpose of a positive acid-fast stain?
To identify acid-fast bacteria, such as Mycobacterium species.
p.3
Specimen Management and Transport
What is the purpose of a triple packaging system in transporting infectious samples?
To limit the risk of exposure and/or release during transportation by using redundant layers of packaging.
What is the primary purpose of pasteurization?
To eliminate organisms responsible for food spoilage.
p.3
Biosafety Levels of Biological Agents
What are examples of Category A agents?
Bacillus anthracis, Clostridium botulinum, Yersinia pestis, and Variola major (smallpox).
p.8
Specimen Management and Transport
What should be maintained at 37°C if there is a delay in processing?
CSF (Cerebrospinal Fluid).
p.2
Biosafety Levels of Biological Agents
What biosafety level is preferred for handling BSL 4 agents?
Class III Biological Safety Cabinet.
p.2
Classification of Infective Microorganisms by Risk Group
What is a characteristic of Risk Group 1 microorganisms?
Unlikely to cause human or animal disease.
p.7
Specimen Collection Techniques
What type of swabs are NOT recommended for viral collection, including SARS-CoV-2 studies?
Calcium alginate swabs or swabs with wooden shafts.
What indicates a potential anaerobic infection in tissue samples?
Necrotic tissue samples with black discoloration.
What is the principle of incineration?
Burning materials into ashes at 300°C to 400°C.
p.6
Chemical Disinfectants and Their Mechanisms
What is the purpose of using AgNO3 in newborns?
It is used for the prophylaxis of ophthalmia neonatorum.
p.2
Types of Biological Safety Cabinets
What is the purpose of the HEPA filter in a Class III Cabinet?
To sterilize the air coming in and going out of the cabinet.
p.2
Biosafety Levels of Biological Agents
What defines Biosafety Level 4 agents?
Cause life-threatening infections; aerosol transmission risk is very high.
p.4
Infection Control Protocols
What is the purpose of droplet precautions?
To prevent the spread of infections through respiratory droplets.
p.7
Specimen Management and Transport
What characteristics should the primary receptacle for infectious substances have?
It should be watertight, leak-proof, and properly labeled.
p.8
Specimen Management and Transport
What type of specimens should be prioritized for processing?
CSF, tissue, blood, and sterile fluids.
p.8
Direct Microscopic Examination Methods
What is the acceptable range of epithelial cells in sputum samples for cultivation?
Less than 10 epithelial cells and more than 25 pus cells per microscopic field.
What temperature and time are required for boiling to destroy vegetative bacteria?
100°C for 10 to 15 minutes.
p.6
Chemical Disinfectants and Their Mechanisms
What is the difference between bactericidal and bacteriostatic agents?
Bactericidal agents kill all bacteria, while bacteriostatic agents inhibit the growth of organisms.
p.9
Infection Control Protocols
What are some examples of select agents that can be detected?
Brucella, Legionella, vancomycin-resistant S. aureus.
p.4
Infection Control Protocols
What are contact precautions designed to prevent?
The spread of infectious agents such as multidrug-resistant organisms.
What is sterilization?
A process that kills all forms of microbial life, including bacterial endospores.
What is the principle behind dry heat sterilization?
It kills microorganisms by denaturing proteins.
p.6
Chemical Disinfectants and Their Mechanisms
What is a disinfectant and give an example?
A substance usually applied to inanimate objects; an example is sodium hypochlorite (NaOCl) in a 1:10 dilution.
What type of filters are used in air filtration for sterilization?
High-efficiency particulate air (HEPA) filters.
What is the effect of desiccation on bacteria?
It disrupts metabolism by removing water, considered bacteriostatic.
p.2
Biosafety Levels of Biological Agents
What defines Biosafety Level 1 agents?
No known potential for infecting healthy people; used for educational training.
p.2
Classification of Infective Microorganisms by Risk Group
What defines Risk Group 2 microorganisms?
Can cause human or animal disease but is unlikely to be a serious hazard.
p.9
Infection Control Protocols
What is the significance of detecting antibiotic-resistant organisms?
To ensure proper infection control and treatment protocols.
p.3
Biosafety Levels of Biological Agents
What is the risk associated with Risk Group 3 pathogens?
Causes serious human or animal disease but does not ordinarily spread from one infected individual to another.
p.4
Infection Control Protocols
What is the ideal air-handling system for a clinical microbiology laboratory?
It should be under negative pressure, and the air should not be recirculated after passing through the laboratory.
p.7
Specimen Management and Transport
What is the preferred anticoagulant for blood culture media?
Sodium polyanetholsulfonate (SPS) in 0.025% to 0.050% concentration.
p.6
Chemical Disinfectants and Their Mechanisms
What is an antiseptic?
A substance applied topically on the skin, such as hexachlorophene or tincture of iodine.
p.3
Biosafety Levels of Biological Agents
What is the risk associated with Category B agents?
Moderate morbidity and low mortality, requiring surveillance and diagnostic assistance.
p.6
Chemical Disinfectants and Their Mechanisms
What is the role of phenol in microbial control?
Phenol destroys plasma membranes and denatures cell proteins; 5% phenol is effective against mycobacteria.
p.6
Specimen Collection Techniques
Why are swabs not recommended for routine specimen collection?
Because they are easily contaminated and dried out.
p.2
Types of Biological Safety Cabinets
What is the pressure condition inside a Class III Cabinet?
The interior is under negative pressure.
p.3
Biosafety Levels of Biological Agents
What are Category A infectious substances?
Biological agents capable of causing permanent disability or life-threatening disease in otherwise healthy humans or animals.
p.3
Biosafety Levels of Biological Agents
What are Category A agents in terms of bioterrorism?
Agents that pose the greatest public health threat, resulting in high mortality rates and potential public panic.
p.7
Specimen Management and Transport
What is a common reason for specimen rejection?
The information on the label does not match the information on the requisition slip.
What is Tyndallization?
A method that destroys vegetative cells and spores after three consecutive days of sterilization.
p.7
Specimen Management and Transport
What is the purpose of triple packaging for infectious substances?
To limit the risk of exposure and/or release during transportation.
p.7
Specimen Management and Transport
What is the function of viral transport media (VTM)?
To preserve samples for viral and bacterial isolation and maintain the viability of organisms.
What is the temperature and time for oven heating in dry heat sterilization?
160°C to 170°C for 1.5 to 2 hours.
p.6
Chemical Disinfectants and Their Mechanisms
What are the mechanisms by which chemical disinfectants destroy microorganisms?
1. Reaction with cytoplasmic membrane components 2. Denaturation of cellular proteins 3. Reaction with thiol groups of enzymes 4. Damage to DNA and RNA.
p.3
Biosafety Levels of Biological Agents
What are Category B infectious substances?
Materials containing biological agents capable of causing infection in humans or animals, but do not meet the criteria for Category A.
p.8
Direct Microscopic Examination Methods
What is the purpose of direct microscopic examination of specimens?
To determine the quality of the specimen and provide early indications of illness.
What biological indicator is used for autoclaving?
Geobacillus stearothermophilus.
p.8
Critical Panic Values in Laboratory Testing
What are critical panic values in laboratory testing?
Positive blood cultures, positive spinal fluid Gram stain or culture, and others indicating severe conditions.
p.2
Biosafety Levels of Biological Agents
What are the characteristics of Biosafety Level 2 agents?
Moderate potential hazard; can be acquired by ingestion or exposure.
p.3
Biosafety Levels of Biological Agents
What characterizes Category C agents?
Emerging pathogens with potential for high morbidity and mortality rates.
What should be done with serum for serological studies?
It should be frozen at -20°C for up to one week.
What temperature and time are required for inspissation?
70°C to 80°C for two hours over three consecutive days.
p.6
Specimen Collection Techniques
What type of swabs should be used for specimen collection from the upper respiratory tract?
Dacron or calcium alginate swabs.
p.2
Types of Biological Safety Cabinets
What level of safety does a Class III Cabinet provide?
The highest level of safety to the laboratory worker.
p.2
Types of Biological Safety Cabinets
What type of gloves are used in a Class III Cabinet?
Rubber gloves that are attached and sealed onto the cabinet.
p.2
Biosafety Levels of Biological Agents
Give an example of a Biosafety Level 1 agent.
Bacillus subtilis or Escherichia coli.
p.2
Biosafety Levels of Biological Agents
Name an example of a Biosafety Level 2 agent.
Human Immunodeficiency Virus (HIV) or Hepatitis B Virus (HBV).
p.2
Biosafety Levels of Biological Agents
Provide an example of a Biosafety Level 3 agent.
Mycobacterium tuberculosis or Francisella tularensis.
p.2
Biosafety Levels of Biological Agents
What is a key feature of Biosafety Level 3 agents?
Potential for aerosol transmission; requires controlled air movement.
