Straighterline Lab Assignment Microbiology Lab 2

Culturing & Aseptic Technique “Pre-Lab Questions” 1. Proper aseptic technique is crucial to ensuring growth of pure bacterial colonies. What is one experimental way you can test your practices to confirm that you are using proper aseptic technique? You can use proper aseptic technique by making sure the media is cover as soon as possible. Making it less exposed to the air. 2. In a laboratory setting, what are three ways you can properly sterilize culturing equipment? a. Dry heat (flame or electronic sterilizer) b. Wet heat (autoclave) c. UV radiation or chemical solvents 3. For each inoculation tool, give one scenario in which use of that tool would be appropriate. When transferring multiple samples or colonies of microorganisms. Always use a new sterile inoculation tool for each individual transfer unless otherwise directed in the experiement instructions. 4. Why don’t microorganisms in cultures exhibit constant exponential growth? What are some steps you could take to extend the lifespan of a microbial culture? Since cultures are exposed to oxygen and do not have much nutrients or “Lab 2 Culturing & Aseptic Technique room to grow, mircoorganisms can not exhibit exponential growth. You could try to extend lifespan by giving more nutrients to the medium, or moving the bacteria to a bigger new plate. 5. Using a textbook or a reputable online source, describe how lab cultures are maintained in a continual pattern of growth. Focus particularly on those used in biotechnology, such as E. coli, which is used to make human insulin. Continual pattern of growth is maintained by devices like chemostat. The culture is continuously diluted by the addition of the medium and the removal of an equivalent volume culture. 6. Which of these has a constant growth pattern: an open system or a closed system? An open system has a constant growth pattern. 7. A human patient represents what kind of system for bacterial infections? Open system 8. You’re a physician trying to isolate bacterial colonies from the human gut in attempt to diagnose a gastrointestinal infection. You streak your sample on a growth media containing glucose, amino acids, and salts that contain both sulfur and phosphorous with a pH of 7. You incubate the plates in aerobic conditions at 37 ˚C for three days, at which point you can see clear bacterial colonies forming on the plate. Would you feel confident in stating that you had successfully cultured all the bacteria from your gut sample? Why or why not? No I would not feel comfortable treating the patient because I would only be “Lab 2 Culturing & Aseptic Technique seeing the aerobes on the culture. I would not be taking into consideration the anaerobic bacteria since it will not grow in this experiement. “EXPERIMENT 1: Agar Plate Preparation and Bacterial Inoculation Data Tables Table 1: Experiment 1 Colony Growth Plate Number Source Growth (Color, Amount, Shape, etc.) 1 Teeth 2 Fridge handle 3 Bottom of shoe 4 Control 0= no growth Airborne + little growth round colonies (3) 5 0 = no growth += little growth, round colonies ,yellowish white ++= moderate growth, round about 8 colonies white Post-Lab Questions 1. Do some research and try to identify one to three types of microbes cultured on your plates. Using any resources available to you (i.e., a textbook or internet sources such as the CDC website), look up what bacteria are usually found on the areas from which you obtained your samples and the morphological characteristics of their colonies. Describe what morphological traits (i.e., size, shape, arrangement, color, margin, etc.) led to your hypothesized species identification. Be as specific as possible in the microbe type. 1. My fridge sample grew out circular white bacteria.The bacteria was not clustered, there was three circles smaller than a dime spread out along the agar plate. Usually the bacteria that grows on a fridge handle is Micrococcus, Bacillus species, staphylococcus warneri, staphylococcus epidermidis. Regarding my specimen, I feel that Staphylococcus “Lab 2 Culturing & Aseptic Technique epidermidis grew on my agar plate. Since the handle is grabbed by humans daily and skin flora and bacteria transfers to the handle. 2. For the colonies hypothesized in Question 1, specify which plate and source the microbes came from. Are you surprised to find this type of microbe on this surface? I am not surprised to see Staphylococcus epidermidis on the fridge handle. It’s actually very interesting to me because I have heard of staphylococcus but I have not heard of staphylococcus epidermidis. When I researched it more it made complete sense to me that skin cells and bacteria from humans are on the fridge handle.The only thing I was supirsed about was the swab I did on by tooth. I did not see any bacteria grow on that agar plate. But I realized that I may have not gotten a proper specimen. Or maybe I brushed my teeth an hour before the sample was taken which killed bacteria. 3. Looking at your control, did you perform proper aseptic technique or were your plates contaminated? If contamination did occur, list the possible sources and how you can prevent contamination in the future. I did preform proper aseptic technique on my plates. My control was not contaminated. There was no growth on the agar plate. I was able to do the control fast and cover the plate to prevent bacteria. 4. Was there a large risk for airborne contamination of your experimental plates? Based on the colonies that grew on your plates, do you think any of your experiment plates received airborne “Lab 2 Culturing & Aseptic Technique contamination? Yes I do think my plates received airborne contamination. Because my airborne plate did have growth on the plate. Also it’s hard to not have airborne contamination when you are doing a lab in your house rather than a clean lab. Insert a photo of your plates after incubation. Include your name and access code handwritten in the background of your photo. “EXPERIMENT 2: Bacterial Transfer to a Stab Tube and an Agar Plate “Lab 2 Culturing & Aseptic Technique Data Tables Table 2: Initial Reserved Plate Colony Growth Observations Plate Sample Appearance (morphology, etc.) 1 No growth appeared on my teeth sample 2 += little growth, round colonies ,yellowish white, flat 3 ++= moderate growth, round about 8 colonies white,flat Table 3: Final Plate and Stab Tube Growth Observations 1 Plate Yes Same Appearance as Initial Plate (Yes or No) No 1 Stab Tube Yes No 2 Plate Yes No Yes 2 Stab Tube Yes No Yes 3 Plate Yes No Yes 3 Stab Tube Yes No Yes Control Plate Yes Yes Yes Control Stab Tube Yes Yes Yes Sample Form Growth (Yes or No) Successful Transfer? (Yes or No) Yes Yes Post-Lab Questions 1. Were all of your colony transfers successful? Explain what could have been the cause of any unsuccessful transfers. All of my colony transfers were successful. If they weren’t successful it probably is because the student didn’t get a good sample from previous palte. Or they ruined the agar palte with the inoculation loop zig zig transfer, by cutting into the agar. “Lab 2 Culturing & Aseptic Technique 2. Did you have any growth that was different in appearance from the initial plates? What might account for any differences in growth on the transfer plate/tube? My growth on the second plates were better than the first plates. I feel that my growth was better the second time around because I decided to place my plates in the garage for a couple days so the plates could grow in heat. When I grow my plates inside, in the cooler temps my plates do not seem to grow as well. I also was able to get good samples of my previous plates to put on the second plates. 3. Describe why an unsuccessful transfer or growth of the transfer plate/tube differing from the initial plates would be a problem if this experiment were placed in a larger context (i.e., only one step in a longer experiment). If the experiment was in a larger context contamination would show with different microbes. Which would make the experiement not accurate, and the data would not be true. 4. Do some research and describe two or three scenarios in which it would be preferable to use a stab tube vs. a growth plate. (Hint: What do bacteria use to help them move? Can motility be used to help identify many medically important pathogenic bacteria such as the Enterobacteriaceae?) 1.Testing Motility of a microbe would be best with a stab tube when growing bacterial culture. 2. Isolating a single clone or colony agar plates are the best, allows for separation of single genetic clone that can be analyzed further. “Lab 2 Culturing & Aseptic Technique Insert a photo of your plates and stab tubes after incubation. Include your name and access code handwritten in the background of your photo.