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Lab Report sample annotated

Lab Report sample annotated - Strains of Staphylococcus...

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Jane Doe 1 Strains of Staphylococcus aureus differ in their susceptibility to a new antibiotic, faekomycin. Introduction Antibiotics were first developed in the late 1920s by Alexander Fleming and have been used extensively since then to treat diseases caused by bacteria (Freeman 2005). Unfortunately, antibiotic resistance, or non-susceptibility of bacteria to antibiotics, is becoming more and more prevalent (Freeman 2005). Antibiotics were originally used in hospitals to fight diseases and prevent infections after surgery. More recently, antibiotics have been used to treat and prevent infections in livestock (Melchior et al. 2006). In addition, many doctors inappropriately prescribe antibiotics for viral diseases, such as the common cold, often after prodding by parents (Nyquist et al 1998). To make matters worse, even when properly prescribed for bacterial diseases, many patients do not finish their prescriptions, but instead stop when the symptoms go away. The combination of these factors is thought to have led to the recent increase in antibiotic resistance (Freeman 2005). Current work needs to focus on what factors allow bacteria to evolve resistance to antibiotics. The most likely candidate is evolution by natural selection. Evolution by natural selection requires variation in a heritable trait that affects an organism’s ability to survive and reproduce (Jensen 2009). Increased use of antibiotics increases general exposure of bacteria to antibiotics, and there is variation among strains of bacteria in antibiotic resistance giving the right conditions for natural selection to favor bacteria that are less susceptible to the antibiotics (Freeman 2005). Antibiotic resistance is known to have a genetic component, often carried in
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Jane Doe 2 plasmids between bacteria (Keller and Lanford 2009). Therefore, antibiotic resistance should be able to evolve by natural selection. Staphylococcus aureus is one such bacterium. S. aureus is a gram positive bacterium that can cause acne, boils, impetigo, and most importantly, toxic shock syndrome if not treated effectively (Freeman 2005). S. aureus grows naturally on our bodies, but some strains can be very harmful (Salyers and Whitt 2005). One example is methicillin resistant S. aureus (MRSA). Originally, MRSA was typically limited to hospitals, but since 1998 “community associated” strains have been found in places like prisons, long term health care facilities, and among athletic teams (Tenover et al. 2006). Most strains of MRSA are not only resistant to methicillin, but all other types of B-lactases, such as penicillin and amoxicillin, as well (Salyers and Whitt 2005). Therefore, new antibiotics are needed to fight S. aureus (Freeman 2005). I am working with a new antibiotic, faekomycin, which is in the same class of antibiotics as daptomycin. This class of antibiotic works by binding to the membrane of the bacteria, causing depolarization of the cell, a loss of membrane potential in the cell, and eventually cell death (Steenbergen et al. 2005). For this study, I wanted to test whether or not common strains of S.
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