These techniques are gram staining and metabolic testing. Simple staining is used to study the morphology of all microorganisms Fig 1. When dealing with raw meats we disinfect the sinks, counters and any area that is possibly contaminated. The production of hydrogen sulfide is indicated by the presence of a precipitate that blackens the medium in the butt of the tube. The basis of nitrate reduction test the detection of nitrite and its ability to form a red colored compound when it reacts with reagent A which is sulfanilic acid and to form a complex nitrite-sulfanilic acid which then reacts with Reagent B which is α-naphthylamine to give a red precipitate prontosil. Almost all spiral bacteria and about half of the bacilli are motile, whereas essentially none of the cocci are motile. A positive urease bacteria will turn the broth pink in approximately 24 hours to 6 days for a rapid urease-positive organism and can take up to 8 days for a slow urease-positive organism.
Gram Negative Test Purpose Reagents Observations Results Gram stain To determine gram reaction of the bacterium Crystal violet, Iodine, Alcohol, Safranin Pink rods Gram negative result H2S To see if the bacteria produce enzyme Thiosulfate Reductase None Black color in the tube Positive result Indole To see if the bacteria produces Indole from tryptophan Vumicro. Simmons Citrate Citrate slant 37°C The tube stayed green Negative The bacterium is not able to utilize citrate as its sole carbon source. The other products of the reaction are acetate, Lactic acid, formic acid etc. It is based on mannitol fermentation. A series of biochemical tests were performed based on the results of the Gram stains. These plates were incubated for two days to allow the bacteria to grow. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics.
Color of bacteria in Petri dish is yellowish beige. The results for the Indole test were positive and the medium turned a che rry red color. The needle was flamed and bacteria samples were collected from the streak plate containing the unknown. Fourth, make sure that all utensils and dishes used to cook are cleaned properly. This is why we boil water for sterilization and cook foods to specific temperatures in order to kill the bacteria.
Each test performed identified was used to determine the specifics and identify the unknown bacterium. Below is a table of some pathogenic bacteria and their corresponding diseases. Motility is closely linked with chemotaxis, the ability to orientate along certain chemical gradients. Following incubation, one slant culture is used to determine the cultural characteristics of the unknown bacteria. Zinc powder act as a catalyst and that will favours the reduction of nitrate to nitrite. I incubated all my tubes at 37 degrees Celsius and waited two days to view my results. The antiserum of particular bacteria is produced by injecting killed or attenuated cells of those bacteria say X into a laboratory animal.
There were no problems encountered in finding this conclusion. In presence of the enzyme cytochrome oxidase gram-negative bacteria the N,N-dimethyl-p-phenylenediamine oxalate and α-naphthol react to indophenol blue. Characteristically, this type of hemolysis is seen as a distinct greening of the agar in the hemolytic zone, and thus this group of Streptococci has also been referred to as the viridans group. Robert Koch used nutrient gelatin as an early type of solid growth medium. The present tense is reserved for the conclusions about the results.
Oxidative metabolic tests for oxidase and catalase were also performed using an oxidative reagent and hydrogen peroxide, respectively. The inoculated media are incubated at the required temperatures for the required lengths of time. Please note that due to formatting issues the flow charts had to be removed. Utilization media are highly defined formulations designed to differentiate organisms based on their ability to grown when an essential nutrient is strictly limited Leboffe and Pierce 175. The formation of red color after the addition of Methyl red reagent indicates the accumulation of acidic end products in the medium and is an indicative of positive test Fig 4. Fig 9: Lipid hydrolysis: Left side;positive for lipid hydrolysis;right side;negative for lipid hydrolysis Growth on selective and differential media: Selective media allows only the growth of certain types of organisms, while inhibiting the growth of other organisms.
The two microorganisms were identified; one was a Gram-positive bacteria, the other was a Gram-negative bacteria. Because the purple stain impart its color to all cells. . Motile bacteria will grow along the stab line and will tend to swim out away from the stabbed area. They lack a defined nucleus of the sort found in plant and animal cells. Biochemical tests were started and incubated, after the T-streak results showed no contamination or mixture of organisms, for 24 hours in a hot room of 37 degrees celcius. The pattern of growth is bitted.
The citrate slant was then inoculated by lightly moving the tube in a swivel pattern to help the loop not touch the walls of the container. There were a few sediment on the bottom of the broth. If the organism can release gelatinase enzymes the gelatin is broken down or liquefied. Using the above recorded data For example, see Table 7. Fig 5: Voges prausker test Citrate Utilization Test: This test determines the ability of microorganism to utilize Citrate.