A Lab Report on Microbial Growth

Typical hosts of this species are humans and other warm-blooded animals, where a favorable temperature of ICC is usually maintained in the intestinal tract. S. Epidermis may cause urinary tract infections (Tutsis) and infections associated with intramuscular devices such as prosthetic heart valves, shunts, etc. (Babushka, 2004). The second microorganism that was analyzed during this procedure was Escherichia coli. E. Coli is a gram-negative and bacillus (rod-shaped) bacterium, that thrives in an optimum temperature of 37th commonly found in the intestinal tract of humans and other mammals (Cappuccino and Sherman, 2011).


It sis facultative anaerobe that is not normally pathogenic, but pathogenic strains cause U TLS and bladder infections (SAC, 2013). Another bacteria that was observed, was Protests memorabilia. This microorganism is gram-negative and rod shaped. P. Memorabilia is motile and “swarms” towards nutrients such as maltose (Murphy, 2004). It is a mesosphere, which lives in an optimal temperature of ETC. P. Memorabilia is able to elongate itself and secrete a polysaccharide for motility on items such as medical equipment (Murphy, 2004).

This organism is found in the human gastrointestinal tract, but can cause infections when in contact with the urinary tract, wounds, or lungs (Murphy, The fourth bacterium that was analyzed in this experiment was Pseudonymous fluorescent. This gram-negative rod shaped bacterium has a distinct yellow color that glows under fluorescent light (Monte, 2011). It normally inhabits soil, plants, and water surfaces, but can cause respiratory tract infections, cystic fibrosis, pneumonia, and infections to burn patient wounds (Monte, 2011).

The optimum growth temperature of P. Fluorescent is between 25-ICC (Monte, 2011).

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As stated earlier, selective and differential media were used to further understanding of isolating and identifying microorganisms. Selective media allows microbial growth of target organisms, while preventing or slowing the growth of other microorganisms, based on nutritional content (Wisterias, 2003). Differential media does not retard the growth of any one organism, but the nutritional composition of the media causes certain microorganisms to grow differently (i. . Different colors) than other microorganisms (Wisterias, 2003). Another important way to distinguish the differences between microorganisms, is by analyzing differences and similarities in metabolism. The oxides test is a useful procedure to identify oxides-negative gram-negative enteric bacterial rods from the also gram-negative rods, Pseudonymous and Aeron’s (Wisterias, 2003). The oxides test detects the presence of stockroom c, which is an enzyme that assists an organism with utilizing oxygen through aerobic respiration (Wisterias, 2003).

The catalane test identifies if catalane is present in a bacterial sample. Catalane is an enzyme found in aerobic microbes that catalysts hydrogen peroxide, and a positive test reveals oxygen bubbles forming while a negative results yields no bubbles as the bacteria does not contain catalane Wisterias, 2003). Methods: Selective and Differential Media: Each half lab bench acquired two plates of each agar: Blood Agar (BAA), McCracken Agar (MAC), Imitation Salt Agar (MASS), Heighten Agar (HECK), and Each plate was labeled with a marker. Proper Triplicate Soy Agar (TTS). Septic inoculation technique was used to inoculate each media. An inoculating loop was flamed to redness over a Bunsen burner and then acquired bacterial colonies from a nutrient agar sample, then it was streaked in an “E” shape on one half of the selective and differential plates. The loop was then flamed to redness gain for sterilization. Each selective and differential plate was streaked with these pairings of bacteria: E. Coli and Interrogator arrogates, or E. Coli and S. Epidermis. Each of these plates were then incubated for 24 hours at a temperature of ICC.

The bacteria P. Memorabilia and Microcosmic lutes, were observed on Blood Agar, McCracken Agar, Imitation-Salt Agar and Heighten Enteric Agar, in Dry. Brook’s lab room inside of a fume hood. Results of the incubated plates were then acquired after the allotted time. The oxides test was then conducted on P. Memorabilia and E. Coli. Colonies of ACH species were acquired on provided 24-hour Triplicate Soy Agar plates which were first labeled. A dropper was used to drop a freshly prepared 1% aqueous solution of tetrameters-Para-phenylalanine, on an isolated colony of each species.

Results were then recorded. The catalane test was then conducted on P. Memorabilia and E. Coli. One 48-hour Triplicate Soy Broth culture for each species was labeled on each half of the plate. Each half of the plate was then streaked with each of the two species using the inoculating technique stated earlier in the first section of the methods. The plate was then incubated for 24 hours at a temperature of mm. After the allotted time of incubation, 2 drops of 3% hydrogen peroxide solution was added to an isolated colony of each organism used. The results were then recorded.

Results: Table 1: Selective and differential media bacterial growth Bacterium McCracken Agar Mann ITIL-Salt Agar Heighten Enteric Agar Inoculated Purple Pink/Red Green S. Epidermis No Growth Yellow Minimal Growth, Green E. Coli Pink P. Memorabilia Brown Cream-colored Dark green/black Table 2. Hemolytic reactions of bacteria grown on blood agar Bacterium Type of hemolytic observed Beta Gamma Oxides Test: The P. Fluorescent specimen had a positive reaction which entails a blue coloring. This shows that P. Fluorescent contains the stockroom c enzyme. E. Oil had a negative, no-color change result, thus no presence of stockroom c. Catalane Test: E. Coli displayed a positive result for the catalane test, with visible oxygen gas bubbles. P. Fluorescent also had a positive catalane test result. Discussion: Each selective and differential medium that was used in this procedure has varying characteristics that allow for characterizing each microorganism. Imitation-salt agar was used to distinguish between imitation ferments, which these colonies develop yellow “zone” areas, and imitation nonmembers, which do not show a color change (Wisterias, 2003).

McCracken agar distinguished lactose ferments, which develop a pink/red color, and lactose unfermented bacteria, which do not develop a distinct color (Wisterias, 2003). Heighten enteric agar was used to distinguish ferments and nonmembers of lactose, sucrose, saline, and amino acids that contain sulfur (Wisterias, 2003). Heighten enteric agar contains bile salts which provide each of the substrates sited. Blood agar contains hemoglobin, which distinguished between alpha, beta, and gamma hemolytic reactions (Wisterias, 2003).

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A Lab Report on Microbial Growth
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