The results obtained in the experimental test with Mannitol salt agar (MSA), showed that there was microbial growth in the plates inoculated with staphylococcus aureus. However, the colonies of S. aureus were quite different in size and color components. Actually, the colonies of S. aureus were small in size, but there was almost no colony for S. epidermidis. These S. aureus colonies were surrounded by yellow coloring, which acted as a confirmation of their presence. In this connection, the results were consistent with our expectations. The Mannitol salt agar had its color change with S aureus while remaining the same with S. epidermidis. Several reasons might have contributed to the observed results, especially those factors which affect the physiological functions and metabolic processes of an organism (Otto 557).
Even with this kind of knowledge and understanding, the most probable reason for this to happen is intimately related to the organism’s production of acidic substance, which reacts with phenol red indicator in the medium. Based on this kind of thinking, we argue that the species of S. aureus was able to carry out Mannitol substrate fermentation at a higher salt concentration environment than it is with S. epidermidis, a process that ended up with a production of an acidic by-product, and which in turn, reacted with the indicator used in the experiment, changing it from its red color to yellow.
It is established that S. aureus has very strong cell walls; moreover, it has a range of osmoprotectant accumulations responsible for responding to osmotic pressure stresses. What this implies, in general, is that S. Aureus was able to produce all the enzymes needed for the metabolism of Mannitol substrate without obstruction by the high salt concentration, or any other factor in the medium (Pommerville 223)
On the other part of the experiment in which blood agar plates (BAP) were used, the outcomes of the throat swab sample from a patient showed a greenish ring around the colonies. For the case of a surface swab, the results for the blood agar plates showed a clearing, intersecting with a few green zones. We, therefore, see that these results were to a large extent consistent with our expectations that hemolytic processes would have to take place in the test.
In the first case, green surroundings showed that there were microbial pathogens capable of lysing red blood cells without destroying them. The microbial bacteria present in the throat swab produced hemolysins, which partially lyzed the red blood cells in the blood agar, by reducing their hemoglobin to methemoglobin. Based on this observation, we can say that the hemolytic activity of these microbial bacteria was thus in the category of alpha hemolysins (Otto 560).
Looking at the second case in which a clearing intersecting with green zones was formed, we find that the hemolytic process took place as per our hypothetical expectations. Even though we see there was mixing up of the experimental indicators needed for identification of the organisms, the results would not just be discarded, ignored, or be counted trivial in this experiment; however, there was a lot much that could be given within the interpretative section. The combination of clearing and green zones showed that there were two types of enzymatic extracts being released to the medium. This implies that there were two species found in the medium, as each of the organisms produced a specific hemolysin. The lysing of the red blood cells at different degrees showed that both organisms may perhaps be pathogenic.
From this point of view, the one producing a clearing was believed to be the most dangerous due to its high degree of pathogenicity. Well, under the theory of organism’s habitats, S. epidermidis is mostly found on the skin surfaces and nosocomial membranes, while the S. aureus habitats the nasal membranes. The S. epidermidis exists up to 90 % as normal flora on the skin areas, and it’s accounted for as of great benefits to the animal it habitats on. Through its acid production, it protects the animals from other pathogenic attacks. Therefore, it is rarely associated with disease attacks, which means the patient should not be much worried about it, not unless it exceeds the normal flora population percentage (Pommerville 233).
Finally, the techniques employed in this experiment are advantageous in that, the media used would reveal a change in color when a metabolic reaction takes place, and the specific color changes are useful for organism’s identification. For the blood agar plate part, it is very selective and thus, it may be used for medical or clinical purposes in the identification and differentiation of closely related pathogenic and non-pathogenic species.
Works cited
Otto, Michael. Staphylococcus epidermidis-the ‘accidental’ pathogen. Nature Reviews Microbiology, 2009, 7(8), 555-67.
Pommerville, Jeffrey. Alcamo’s Fundamentals of Microbiology. 9th ed. Sudbury: Jones and Bartlett, 2010. Print.