Labster Virtual Lab Manual: Aseptic Technique PDF

Virtual Lab Manual Aseptic Technique: Culture your sample without contamination Synopsis This simulation, along with “Fermentation: Optimize bio-ethanol production,” was adapted from learning objectives in the original “Fermentation” si...

Virtual Lab Manual Aseptic Technique: Culture your sample without contamination Synopsis This simulation, along with “Fermentation: Optimize bio-ethanol production,” was adapted from learning objectives in the original “Fermentation” simulation. For more information on this topic, see Labster’s Microbiology simulations. A patient sample has arrived in the microbiology lab. Will you be able to culture it using good aseptic technique? Learn about aseptic technique and what you should pay attention to when preparing a sterile work area, sterilizing equipment and reagents, and decontaminating the work area after you finish your experiment. Preparing a sterile field You will start off by preparing the sterile work area. Use your own microbiology knowledge, the tooltips, and theory pages to ensure you are using good aseptic technique. Don’t worry if you make a mistake and your work area is not quite sterile. In the virtual lab, Dr. One can guide you to repeat some steps without losing several hours like you would in the physical lab. Culturing and cleaning up Next, you will culture your sample and the appropriate control using sterile equipment and reagents. Once you have placed your samples in the incubator: it’s clean up time! Dr. One will again guide you if you accidentally contaminated one of the samples or accidentally set the lab on fire. 1 Copyright Labster ApS 2020 All Rights Reserved Analyzing your results After the incubation, check your samples to see if you have used correct aseptic technique throughout the experiment. Will you be able to create a pure culture that the microbiologist can use to identify an unknown microbe? Techniques in Lab Aseptic technique Culturing Learning Objectives At the end of this simulation, you will be able to… Understand the principles of aseptic technique for the prevention of infection and contamination Create and maintain a sterile work area Use sterile equipment and consumables correctly State potential sources of microbial contamination Assess whether a sample was contaminated Theory Microbiological culture Culturing is the practice of growing microorganisms, such as yeast or bacteria, in the lab. The nutrients the microbes need are provided by the culture medium. Microorganisms can be grown in liquid culture or on media made solid by the addition of agar, which gives culture media a gel-like consistency. When culturing microorganisms, good aseptic technique is required to keep the culture free from external contaminations. Correct aseptic technique also keeps those working in the lab safe, which is particularly important when working with pathogenic organisms. Setting up liquid and solid cultures To create a liquid culture, a colony from an agar plate is added to liquid medium using a culture loop, or a small volume of liquid culture is added using a pipette. To create a solid culture, a colony is streaked across a petri dish containing solid medium (known as an agar plate) using a culture loop or a small volume of liquid culture is added to the plate and spread across the surface using a spreader. All equipment must be sterilized before and after each use. 2 Copyright Labster ApS 2020 All Rights Reserved Controls To ensure good aseptic technique is used, the best negative control is uncultured medium. Since the medium and equipment should be sterile, microbial growth in this control indicates contamination. Everything else should be treated the same across the sample and control. Aseptic technique Sterile technique is used to ensure a "clean" lab environment. It is essential to ensure the reliability of experimental results. Sterile practices are especially important when working with microorganisms. A single spore or tiny bacterium can overgrow your whole medium and destroy your experiment. The following steps are used to keep laboratory work sterile: Keep calm and assess the situation: Laboratory doors and windows are kept closed to prevent air currents, preventing surface microorganisms becoming airborne. The wire loop and glass spreader are sterilized before and after use with a Bunsen burner to prevent the introduction of unwanted microorganisms. Lids from bottles and tubes are held when removed, and not placed on the bench during material transfer from one bottle or tube to another. The neck of a bottle or tube must be immediately heated using the Bunsen burner so that any air movement is outward. The bottle or tube are opened for the minimum time possible, and while open, all work is performed close to the Bunsen burner flame. Media and equipment are sterilized to prevent the growth of unwanted microorganisms. Figures 1: Left- A contaminated petri dish. Various species of fungi have grown in this petri dish. Right- Sterile technique used in material transfer from the bottle. The neck of the bottle is heat-sterilized by the Bunsen burner flame. 3 Copyright Labster ApS 2020 All Rights Reserved