Identification and analysis of Proteus Vulgaris


            The general purpose of this laboratory report is to focus on the identification of the general unknown 128, through the process of conducting some tests which would ultimately lead to the processes of results’ analysis. Some of the initial tests that got carried out resulted in recognizing of an unknown 128 organism. The tests conducted included the Urea hydrolysis, Indole, Simmon’s Citrate, Coagulase, Catalase, Starch hydrolysis, V-P Test, H2S, and Mannitol Salt Agar tests. The results of the tests were proven to be either negative or positive through a close observation of the changing colors in each test. Change in the colors ranged from close observations within the test tubes incubated. The addition of reagents to the slants would confirm whether a test was either positive or negative. Again, the gram stain was put in use to assist in the identification of whether the unknown bacteria were identified to be gram negative or gram positive.  The sole motive of this experiment was to help in the identification process of the unknown bacteria. The elimination technique of finding and identifying the unknown bacteria became essential throughout the experiment.

Materials and methods

            In the specified experiment, the identification of the general unknown 128 became possible through the exploitation of some test procedures. The initial steps included the preparation of a gram stain or explicitly creating an experiment known as Kirby Bauer. An analysis of color changes in the test tubes as well as a simultaneous identification of agar plates followed up. The general unknown would then take about two weeks to get identified. Within the first week, it was vital to conduct the gram stain and the Kirby Bauer experiments. Inoculation process then followed. Another period of one week became essential for inoculation procedures. Inoculation was essential as studies and observations drawn from it would eventually lead to record keeping and microbiology analysis which would then lead to the identification of the general unknown.


            After the completion of the tests done on the Nutrient Agar plate and the EMB plate, the following observations about the general unknown 128 were subject to identification: the size of the average colony within the EMB plate was comparatively small and could not surpass either one or two millimeters mark. From the EMB plate, it was clear that the colony’s color assumed to be light, and nearly pink. The colony could be described to be opaque, flat smooth, amorphous, and alpha. The median colony size on the NA plate was about one millimeter. A light yellow color could get recorded. Besides, the colony was recorded to be smooth and round. The process of gram staining the general unknown 128 led to the identification of a rod-shaped (bacillus) as well as stained red color which meant that the organism was Gram-negative.

(i). The tabular representation below depicts an illustration of the Kirby Bauer Experiment

Code Name of Antibiotic Inhibition Zone Level of Sensitivity
0470000 Streptomycin 26 millimeters Sensitive (≥15)
0470000 Erythromycin 14 millimeters Resistant (≤13)
0470000 Tetracycline 29 millimeters Sensitive (≥19)
0470000 Nalidixic Acid 25 millimeters Sensitive (≥19)
0470000 Penicillin 16 millimeters Resistant (≤26)

(ii). The tabular representation below depicts an illustration of the results subject to the motility and the physiological tests

Name of Test The Expected Results (Positive/Negative) Explanation of the Observed Result Result Interpretation (Positive/Negative)
sugar fermentation   Positive (+) Color changes to yellow Positive (+)
H2S Positive (+) Black precipitate Positive (+)
Mannitol Salt Agar (MSA) Negative (-) Retains red color Positive (+)
Vogues Proskauer Negative (-) Retains brown color Negative (-)
Indole Positive (+) Floating pink ring Positive (+)
Citrate Negative (-) Remains color green Negative (-)
Starch Hydrolysis Positive (+) Clear zones observed Positive (+)
Urea Hydrolysis Positive (+) Phenol Red color Positive (+)
Catalase Positive (+) Bubbles produced Positive (+)
Coagulase Positive (+) Rabbit plasma clots Positive (+)


            Several tests were done to help in the identification of the general unknown 128; the results deduced assisted in narrowing towards the identity of the organism. The result bound to each test gave an illustration of a possible feature of the unknown. One of the slants utilized was the Citrate; a sterile loop, containing general unknown 128 became zigzagged on the agar. Instead of assuming a blue color, the slant retained a green color hence proving that the general unknown 128 could not utilize the carbon from citrate.

            Liquid broth media helped to conduct other tests (Mannitol, and sugar fermentation). Fermented sugar tests indicated a positive result when the color changed from red to yellow. The red phenol indicator revealed the formation of acid. Sugars not bound to fermentation would retain color red hence producing the same result which the Mannitol test had revealed; negative results got recorded as per the Mannitol test datum. The Urease test was again conducted using the broth media. Such a test would help find out if the unknown organism had urease traces; the test also determined the ability of the organism to utilize urea. The production of ammonia indicated that the organism could synthesize urea. The broth turned pink in the presence of the red phenol indicator hence indicating a positive outcome. Indole production, starch hydrolysis, and coagulase tests were inevitable. Another experiment was the V-P Test that could determine if the general unknown 128 had the 2, 3-butanediol pathway responsible for the production of acetoin. The Catalase test involved the addition of hydrogen peroxide to the test tube containing the general unknown 128. Bubbles were released thus indicating the result was positive and that the general unknown 128 had enzyme catalase.

Upon the completion of all the described tests and critically analyzing their possible outcomes, it became clear that the general unknown 128 was Proteus vulgaris.

Clinical Significance of Proteus vulgaris

            Proteus vulgaris is a facultative type of anaerobic organism whose residence is bound to the colon as well as the urinary tract among humans (Oyedemi et al., 2009).  Scientists also identify Proteus vulgaris organism as being gram negative (NIH 2017). Proteus vulgaris only results to human infections when it leaves the gut. The organism gets associated with sepsis and the transmission of infectious urinary tract diseases. Proteus vulgaris would lead to such infections when it produces urease which then leads to the release of ammonia hence raising the potential of Hydrogen in urine (Hascall et al., 1972). In the process, urine assumes basicity thus increasing the likelihood of stone formation hence interfering with urine’s flow. The urinary tract gets rendered to continuous forms of infections when the urinary epithelia get damaged through the trapping of bacteria (Levinson 2010). Again, Proteus vulgaris’s continuous form of motility increases its chances of affecting the urinary tract (Brooks et al., 2010).

            No vaccinations are available to combat the urinary tract infections that result from Proteus vulgaris. Treatments are available instead (CDC 2017). It is then essential to use trimethoprim-sulfamethoxazole or even ampicillin as the possible treatment options for the mild infections. However, in case of advanced infections, cephalosporin can be used. Preventive measures such as the removal of the urinary catheter would help. Apart from the urinary tract diseases, Proteus vulgaris also causes nosocomial, an infection whose spread results from medicinal equipment (Deetae et al., 2009).


Brooks, G. F., Jawetz, E., Melnick, J. L., & Adelberg, E. A. (2010). Jawetz, Melnick, &                 Adelberg’s medical microbiology. New York: McGraw Hill Medical.

CDC (2017). Public Health Image Library. Retrieved on November 12, 2017, from       

Deetae, P., et al., (2009). The growth and aroma contribution of Microbacterium foliorum,         Proteus vulgaris, and Psychrobacter sp. during ripening in a     cheese model medium.          Applied microbiology and biotechnology, 82(1), 169-177.

Hascall, V. C., et al., (1972). The treatment of bovine nasal cartilage proteoglycan with             chondroitinases from Flavobacterium heparinum and Proteus vulgaris. Journal of         Biological Chemistry, 247(14), 4521-4528.

NIH (2017). Dailymed. Retrieved on November 12, 2017, from        Oyedemi, S. O. et al., (2009). The proposed mechanism of bactericidal action of eugenol, ∝-     terpineol and g-terpinene against Listeria monocytogenes, Streptococcus pyogenes,        Proteus vulgaris and Escherichia coli. African Journal of Biotechnology, 8(7).

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