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Microbiology Laboratory Safety
and Techniques
Microbiology Lab Reviewer 2
Biosafety Levels
Biosafety Level 1
Health Risks: Not known to cause disease in healthy individuals. Primary Barriers: Gloves required. Secondary Barriers: Open benchtops and sinks.
Biosafety Level 2
Health Risks: Can cause disease in healthy people, but organisms are easily contained. Primary Barriers: Gloves, lab coat, eye protection, and face shield. Secondary Barriers: Open benchtops and sinks, access to autoclave.
Biosafety Level 3
Health Risks: Can cause severe disease, especially when inhaled. Primary Barriers: Gloves, lab coat, eye protection, and face shield. Biosafety cabinets used for all manipulations. Secondary Barriers: Open benchtops and sinks, access to autoclave, access to self-closing double doors, negative pressure (air flows into lab from outside, exhausted air not recirculated).
Biosafety Level 4
Health Risks: Highly virulent microbes posing extreme risk to humans, especially when inhaled. Primary Barriers: Gloves, lab coat, eye protection, and face shield. All procedures are conducted in complete isolation BSC's or in class 1 or 2 BSC's along with full body, positive pressure suits with supplied air. Secondary Barriers: Open benchtops and sinks, access to autoclave, access to self-closing double doors, negative pressure (air flows into lab from outside, exhausted air not recirculated), isolated building or lab, isolated laboratory systems (air supply and exhaust, vacuum, decontamination).
Proper Handling and Disposal
Carrying glass test tubes and cultures: Test tubes and cultures in your hand tight and carry cultures bottoms up.
Disposing of materials: Glass test tubes or cultures: As instructed by teacher. Petri dishes: Goes in plastic bag as instructed by teacher. Gloves: Place in plastic bag at the left of the room. Sharps and hard disposable objects (glass pipettes, cotton-tipped swabs, and microscope slides): As instructed by teacher. Cleaning lab bench: Clean once with wipe and wait 30 seconds, then wipe again and throw towels in the trash. Cleaning up a spill: Report to instructor immediately, and they will clean it up. Safety equipment location and purpose: As indicated in the lab.
Microbiology Concepts
Colony: A macroscopic cluster of cells appearing on a solid medium, each arising from the multiplication of a single cell. Cell vs. Colony: Cell: Individual membrane-bound living entity, the smallest unit capable of an independent existence. Colony: Macroscopic cluster of cells appearing on a solid medium, each arising from the multiplication of a single cell. Bacterial species identification properties: Configurations: Round, wrinkled, complex, irregular. Margins: Smooth, wavy, thread-like, ciliate. Elevations: Flat, raised, convex, drop-like, hilly. Pigment: Red, yellow, white, eggshell.
Techniques
Sterilizing and using wire transfer tools: Twist tools through flame until bright orange, go ½ up the tool, then twist back out of the flame and wait 20 seconds for it to cool. Inoculating tubes of media and transferring bacteria: Open tubes with pink of right hand, flame the lip, keep tubes tilted, keep the lid of a Petri dish closed as much as possible, and don't breathe into tubes or Petri Dishes.
Definitions
Aseptic: Methods of handling microbial cultures, patient specimens, and other sources of microbes in a way that prevents infection of the handler and others who may be exposed. Sterile: Completely free of all lifeforms, including spores and viruses. Inoculation: The implantation of microorganisms into or upon culture media. Pathogen: Any agent that causes disease, usually a virus, bacterium, fungus, protozoan, or helminth. Turbid: Cloudy appearance of nutrient solution in a test tube due to growth of microbe population.
