Basic Bacterial Morphology Bacteria and fungus (mold and yeast) grow in a variety of shapes, sizes and colors. Although it is difficult to make a definite identification of cultures growing in broth or solid media many have distinguishing characteristics that give us clues to identification. Many Microbiologist can make a tentative identifications by growth characteristics but definitive id requires further testing (ie Gram stain, chemical testing, etc). The palm of a hand print print done on TSA agar. There is a mix of different textured and colored colonies on the plate some bacterial some yeast. By looking at color, texture, growth times and various growth temperatures you can get an idea as to what is on the plate. Ex: the orange colonies are yeast and tend to grow better at room temperature or refrigerated temperatures where the large colony on the left ( Bacillus spp) and the white colonies ( Staphylococcus ) grows wel...
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Oxygen Requirements: Fluid Thioglycolate Media A B C D E Organisms grown in Fluid Thioglycollate Media, a reducing media that uses sodium thioglycolate to chemically combine with dissolved oxygen to deplete the oxygen in the media. The top portion of the tube contains oxygen while the bottom of the tube is lacking molecular oxygen. All organism except for Neisseria sicca were grown for 48 hour...
Staining Procedures For Identification Organisms can be tentatively identified by growing them on media and looking at morphology or growth characteristics. This gives the researcher a tentative idea as to what the bacteria might be but further test need to need be done to positively identify organism and many times bacterial cultures can look similar to yeast. The next step to identifying an organism is staining and t here are a variety of stain used in Microbiology, many time based on morphology, all with the purpose of helping to identify an organism. Some stains, like wet mounts and the simple stains, give limited information while others (Gram Stain, Acid Fast Stain, Spore Stain) give the user more detailed information. Unknown Yeast contaminant on TSA agar after 3 weeks refrigerated temperatures. The colony appeared mucoid colony with lobate edges, was white in the center of the colony and yellow on the edges. The agar surrounding the colon...
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