Results: In order to identify the gram positive isolate in the unknown #260 broth, I observed the bacterium under the microscope, created a stock culture, and conducted a variety of biochemical tests. First, I prepared a gram stain of the mixed culture using aseptic technique, shown in Figure 1, and found two different bacteria. There were too numerous to count purple cocci in clusters, pairs, and some single cells, which I identified as the target isolate. The other bacteria present a pink bacilli in short chains and some single cells. After noting these observations, I inoculated a blood agar plate and a Phenylethyl Alcohol agar plate with the unknown #260 mixed culture broth. The blood agar plate, shown in Figure 2, was inoculated using
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After observation, both agar plates were placed in the refrigerator for 6 days. Due to the disappearance of my Phenylethyl Alcohol agar plate, I had to use the blood agar plate to isolate the bacteria and create a stock culture. In order to create this stock culture of the isolate, I collected approximately half of one of the light gray, circular colonies and used it to inoculate a Tryptic Soy agar slant. The slant was then incubated at 35°C for 24 hours, which allowed the bacteria to grow. This growth, shown in Figure 4, was dull yellow, filiform, and had a gummy texture. After making my observations, I placed the TSA slant in the refrigerator for 6 days until it needed to be used …show more content…
According to Hans Christian Gram in regards to the gram staining technique he developed, purple bacteria present on the slide are gram-positive organisms (1). After inoculation of the blood agar plate and Phenylethyl Alcohol agar plate, I was able to match the bacteria present based on their growth characteristics (Figures 2 and 3). PEA plates are a selective medium for gram positive bacteria, consequently inhibiting growth of gram negative bacteria (2). Unfortunately, my PEA plate was lost, which forced me to use the blood agar plate to create a stock culture of the gram positive isolate (Figure 4). Since the bacteria present on the PEA plate matched the light gray, circular, convex, entire colonies on the blood agar plate, I knew that this was my gram-positive isolate. After collecting a sample from one of the suspected gram positive colonies, I inoculated an agar slant to create the stock culture, which was used for the biochemical tests. Using the unknown separation outline, I determined that a Mannitol and Catalase test were required to identify the gram positive isolate. The Mannitol test in Figure 5 shows a yellow colored medium, which indicates a positive Mannitol test. From this result, the next step on the separation outline was to perform a Catalase test (Figure 6). The vigorous bubbling that resulted from
After observation, both agar plates were placed in the refrigerator for 6 days. Due to the disappearance of my Phenylethyl Alcohol agar plate, I had to use the blood agar plate to isolate the bacteria and create a stock culture. In order to create this stock culture of the isolate, I collected approximately half of one of the light gray, circular colonies and used it to inoculate a Tryptic Soy agar slant. The slant was then incubated at 35°C for 24 hours, which allowed the bacteria to grow. This growth, shown in Figure 4, was dull yellow, filiform, and had a gummy texture. After making my observations, I placed the TSA slant in the refrigerator for 6 days until it needed to be used …show more content…
According to Hans Christian Gram in regards to the gram staining technique he developed, purple bacteria present on the slide are gram-positive organisms (1). After inoculation of the blood agar plate and Phenylethyl Alcohol agar plate, I was able to match the bacteria present based on their growth characteristics (Figures 2 and 3). PEA plates are a selective medium for gram positive bacteria, consequently inhibiting growth of gram negative bacteria (2). Unfortunately, my PEA plate was lost, which forced me to use the blood agar plate to create a stock culture of the gram positive isolate (Figure 4). Since the bacteria present on the PEA plate matched the light gray, circular, convex, entire colonies on the blood agar plate, I knew that this was my gram-positive isolate. After collecting a sample from one of the suspected gram positive colonies, I inoculated an agar slant to create the stock culture, which was used for the biochemical tests. Using the unknown separation outline, I determined that a Mannitol and Catalase test were required to identify the gram positive isolate. The Mannitol test in Figure 5 shows a yellow colored medium, which indicates a positive Mannitol test. From this result, the next step on the separation outline was to perform a Catalase test (Figure 6). The vigorous bubbling that resulted from