Dense (Alicia, 2007). Material & Methods The tests performed on the unknown bacteria cultures were all used to determine the identity of the bacteria. Each of the tests performed provided some key information about the bacteria in question and how it functions. Not all of the tests were performed on every culture, however, as some of the tests were used only for gram (+) or gram (-) bacteria, while others were even more specific and used only for Cisco bacteria. The tests performed and what constitutes a positive and negative test are as follows.
Gram staining was used to determine whether the cells were gram positive or ram negative based on the color they appear at the end. The Gram stain utilizes four basic steps: apply a primary stain (crystal violet), fix it with Gram’s iodine (which fixes the primary dye inside the cell), decolonize with 95% ethyl alcohol to wash out the crystal violet-iodine (CIVIC) complex, and apply a countersink, Safaris. Gram positive cells have a thick pedagogical layer that is external and has a higher degree of cross-thinking that traps the CIVIC complex better than gram negative cells.
Therefore, they are less susceptible to decentralization by alcohol making them appear purple in color. Gram negative cells have a thinner pedagogical layer and a lipid membrane external to the cell wall which makes them susceptible to decentralization thus allowing them to be countersigned with Safaris making them appear red in color (Alicia, 2007). The catalane test was performed only on gram (+) bacteria, as this test would not help in differentiating the gram (-) bacteria because all of the possible unknown gram (-) bacteria were catalane positive.
This test is used to detect the presence of catalane, which helps to breakdown toxic hydrogen peroxide produced from the transport of high-energy electrons directly to oxygen. Catalane is tested for by adding hydrogen peroxide to the culture, and looking for the production of gas bubbles. If gas bubbles appear immediately, the culture is catalane positive. However, if no bubbles are observed, the culture is negative for catalane (Alicia, 2007). Amanita Salt Agar (MASS) is both a selective and differential media used for gram (+) Cisco.
A selective medium contains components that inhibits the growth of undesirable organisms and favors the desirable one. On the other hand, a differential medium seeks to show differences between different organisms growing in a medium. MASS is selective for salt tolerance and differential for imitation sugar fermentation. It also contains phenol red, which acts as a pH indicator, turning yellow under acidic conditions. Therefore, staphylococci that metabolize imitation (Staphylococcus erasures) turn the medium color yellow while those that do not ferment imitation (Staphylococcus epidermises) do not produce acid and the color indicator remains red.
In some cases, as with Staphylococcus saprophytic, MASS color may be redder due to the production of alkaline amines as by-products of protein degradation (Alicia, 2007). Blood Agar is a differential enriched-type medium that contains general nutrients and 5% sheep blood. It is useful for cultivating fastidious organisms and for determining the hemolytic capabilities of an organism. Some bacteria produce zonetimes that else red blood cells and degrade hemoglobin; these are called homologies. Bacteria can produce different types of homologies.
Beta-hemolytic breaks down the red blood cells and hemoglobin completely, showing a clear zone of hemolytic around the bacterial growth. Alpha-hemolytic partially breaks down the red blood cells and leaves a greenish color behind. The greenish color s caused by the presence of blinders, which is a by-product of the breakdown of hemoglobin. If the organism does not produce homologies and does not break down the blood cells, no clearing will occur. This is called non-hemolytic, gamma hemolytic (Alicia, 2007).
Invoicing was used to test the susceptibility profile of a staphylococcus to the antibiotic invoicing. A invoicing disk was placed in the middle of a heavily streaked area on the blood agar plate to obtain a good lawn of growth. After 24 hours of incubation, strains susceptible to the antibiotic will have inhibition zone greater than 18 mm in diameter. In fact, S. Uses and S. Epidermises are susceptible to invoicing, and S. Saprophytic are resistant to invoicing (Alicia, 2007). The coagulate test was performed again only on the gram (+) Cisco to try to identify S. Erasures.
This test was used to identify bacteria that produce a coagulate enzyme. The unknown bacteria culture was added to rabbit plasma in an offender tube. The coagulation, or solidification, of the plasma within 24 hours indicates a positive test result. If the plasma does not coagulate, the test is considered negative (Alicia, 2007). The Dense test was used only for gram (+) Cisco, but more specifically to differentiate S. Epidermis from S. Rues. Gram (+) bacteria cultures were grown on a Dense test agar plate with methyl green to determine if the unknown produced this enzyme.
A positive test results in a clearing around the growth. A negative result shows no change in the agar around the growth, remains green (Alicia, 2007). Results Table 1: Results for all of the tests performed on Unknown #17. Gram stain Catalane MASS Hemolytic Invoicing Coagulate Dense Unknown #17 + (purple) + (bubbles)- (pinkish yellow) None (no clearing)R (15 mm) – (cloudy) – (blue-green) Flow Chart for Identifying Staphylococci. Unknown #17 was determined to be Staphylococcus saprophytic. Discussion The identification and determination of unknown #17 was quite durable.
Once the unknown had been identified as a gram (+) Cisco using a gram stain, and catalane positive, a couple more tests were used to narrow it down to Staphylococcus saprophytic. Of all the possible gram (+) bacteria only S. Erasures were positive for both Coagulate and Dense. Based on the results, the bacteria is negative for both Coagulate and Dense test, so we can eliminate S. Erasures. Looking at the yellowish-brown colony pigments on the ABA, we kind of get an idea that the bacteria could be S. Saprophytic. Due to the resistant to antibiotic torture in the Invoicing test, the unknown culture #17 was highly suspected to be S. Prosthetics, because of the three bacteria only S. Saprophytic is resistant to invoicing. As for the MASS test, the result should be red or dark red instead of pinkish-yellow. This could be due to the contamination when transferring the organism to the media during the experiment. Staphylococcus saprophytic is a bacteria that is most commonly identified in urinary tract infections (Tutsis) in women. Although S. Saprophytic is found in the genital region, it’s not supposed to be in the urinary tract. However, the bacteria can ravel through the urethra and enter the bladder, causing cystitis.