Gram Positive Cocci Case Study

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The purpose of the infections caused by gram-positive cocci lab exercise is to utilize different identification and diagnostic techniques to differentiate various groups of bacteria, which cause infection. Our primary goal is first to establish the presence of an infection; then, determine which particular pathogens, or groups of pathogens, are the underlying cause of the infection. In the clinic, infections manifesting from gram-positive cocci are a common and growing problem. Two genera in particular, Staphylococcus and Streptococcus, are responsible for a variety of human infections, hence, it is crucial to learn techniques, which aid in the quick identification of a particular microbe. Applying these techniques in our future careers will …show more content…
From the set of three blood bottles given to us, we incubate several samples of the patient’s blood; if the sample rises to the top chamber, it is an indication that bacteria are present. Positive pressure, established from bacterial metabolic by products, causes the bacteria to rise to the top chamber. Of bottles 1, 2 and 3, samples from bottles 1 and 3 rose to the top chamber. We strike out sample from bottles 1 and 3 onto blood agar plates, and after incubation, observed no clearing thus determining both samples to be gamma hemolytic. We gram stained each sample to confirm them being gram-positive, and then performed a catalase test; a positive result is indicated by the presence of bubbles, O2 gas, being released, and we observed both samples to be catalase positive. Next, we perform a coagulase test because a positive result may mean that the patient is dealing with a Staphylococcus aureus infection, as this species typically produces coagulase. The presence of clumping indicates a positive result as coagulase, an enzyme, attaches itself to bacterial cell walls and acts on fibrinogen. This interaction results in a precipitate leading to bacterial cell clumping. We observe the samples from bottles 1 and 3 to be coagulase negative. In order to treat the patient successfully, we need to determine which antibiotics will possibly clear the infection. Our isolate is susceptible to the following …show more content…
anginosus has increasing status as an emerging pathogen. S. anginosus is a member of the viridians streptococci, which are non-hemolytic and catalase negative. This species is also nonmotile, a facultative anaerobe, and is known to have Lancefield antigens A, C, F or G. Historically, these organisms had been recognized as normal flora of the oral cavity and GI tract. However, more recently discovered is their ability to cause abscesses and systemic infections in the host, separating them from other pathogenic streptococci species. An MRI (to elucidate any abscesses) assists in determining the diagnosis of S. anginosus in particularly severe cases of infection, and the common course of treatment in the clinic for S. anginosus is

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