Cocci Bacteria Lab Report
Coccus is a term used to describe a type of morphology that helps us distinguish different kinds of bacteria. The cell’s morphology is only one of the many ways we can differentiate the different species. Looking at these bacterium underneath the microscope is an important step to determine which kind of species it is. All cocci bacteria are not gram positive, but this lab will examine only this kind because of their influence in human health. Staphylococcus Aureus is a gram-positive coccus bacterium found in humans. It is frequently found on the mucus membrane in the nasal cavity and on the skin. It also infects many people in the hospital, also called a nosocomial infection. S. aureus has a large association with clinically significant infections and
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foodborne diseases and has been broadly investigated which has lead the discovery of large species diversity, (Zhang, D., Zhi, X., Zhang, J., Paoli, G. C., Cui, Y., etc.). Staphylococcus aureus is the most commonly occurring bacterial pathogen among the patients in the hospital, (Naber 2009). It was also the second most frequently occurring pathogen among clinical isolates from outpatients (Naber 2009). Staphylococcus aureus also plays a major role in blood infections, being the most common pathogen to cause nosocomial bacteremia in North America and Latin America (Naber 2009). The increase in prevalence in the occurrence of bacteremia induced by gram-positive S. aureus can be contributed to the increase in frequency of invasive procedures that prevents it from entering the body, higher occurrence of immunocompromised patients, and an increase in antibiotic resistant strains, (Naber 2009). S. aureus has gained extra attention from the medical, scientific, and pathological realms because it has become increasingly antibiotic resistant, with the presence of methicillin-resistant S. aureus strands becoming a serious threat to human health (Naber 2009). The development of extensive antibiotic resistant pathogens such as gram-positive S. aureus has led to further research and understanding of the overuse of antibiotics on bacteria and the resulting causes of antibiotic resistance. Not only is the prevalence of normal Staphylococcus aureus infections cause for concern, the introduction of an antibiotic resistance factor further increases alarm and need for medical and microbiological research. Staphylococcus aureus’s presence in dangerous blood infections and increasing antibiotic resistant has presented it as a serious pathological threat to human healthcare.
Materials and Methods: Five different tests will be done to six different known species and one unknown species. We can differentiate them by the cell’s grouping, by their gram-stain, and by the certain enzyme they carry Through these tests we will be able to determine which species is closest to the unknown sample by comparing each test results to each other. The species we will be using are Enterococcus faecalis, Micrococcus luteus, Moraxella catarrhalis, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes which are all gram-positive cocci.
Gram Stain: A Gram stain was observed underneath a microscope to determine the species’ morphology and whether it was a gram-positive or gram-negative bacterium.
In this procedure we used crystal violet, the primary stain to dye the bacteria purple, gram’s iodine, which will cause the crystal violet color to bind more tightly with the cell, ethanol, which removes the purple color from gram-negative bacteria, and then safranin, a pink dye, (Caldas, Herron, La Mota-Peynado, Wong, and Trowbridge, 2017). After heat fixing a slide with a smear of a bacterium species, we wash the slide first with crystal violet and let it sit for one minute and rinsed will distilled water. We repeated this same procedure with gram’s iodine. Before we add the safranin however, ethanol, is applied and only sitting on the smear for about 20 seconds. Next safranin is applied and goes through the same producer as before. Gram positive bacteria have a thick peptidoglycan layer cell wall which holds the purple dye of crystal violet even after the ethanol is applied. While gram negative bacteria is changed pink after it is decolorized with ethanol and recolored with safranin. This is the distinguishing factor between gram positive and gram
negative.
foodborne diseases and has been broadly investigated which has lead the discovery of large species diversity, (Zhang, D., Zhi, X., Zhang, J., Paoli, G. C., Cui, Y., etc.). Staphylococcus aureus is the most commonly occurring bacterial pathogen among the patients in the hospital, (Naber 2009). It was also the second most frequently occurring pathogen among clinical isolates from outpatients (Naber 2009). Staphylococcus aureus also plays a major role in blood infections, being the most common pathogen to cause nosocomial bacteremia in North America and Latin America (Naber 2009). The increase in prevalence in the occurrence of bacteremia induced by gram-positive S. aureus can be contributed to the increase in frequency of invasive procedures that prevents it from entering the body, higher occurrence of immunocompromised patients, and an increase in antibiotic resistant strains, (Naber 2009). S. aureus has gained extra attention from the medical, scientific, and pathological realms because it has become increasingly antibiotic resistant, with the presence of methicillin-resistant S. aureus strands becoming a serious threat to human health (Naber 2009). The development of extensive antibiotic resistant pathogens such as gram-positive S. aureus has led to further research and understanding of the overuse of antibiotics on bacteria and the resulting causes of antibiotic resistance. Not only is the prevalence of normal Staphylococcus aureus infections cause for concern, the introduction of an antibiotic resistance factor further increases alarm and need for medical and microbiological research. Staphylococcus aureus’s presence in dangerous blood infections and increasing antibiotic resistant has presented it as a serious pathological threat to human healthcare.
Materials and Methods: Five different tests will be done to six different known species and one unknown species. We can differentiate them by the cell’s grouping, by their gram-stain, and by the certain enzyme they carry Through these tests we will be able to determine which species is closest to the unknown sample by comparing each test results to each other. The species we will be using are Enterococcus faecalis, Micrococcus luteus, Moraxella catarrhalis, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes which are all gram-positive cocci.
Gram Stain: A Gram stain was observed underneath a microscope to determine the species’ morphology and whether it was a gram-positive or gram-negative bacterium.
In this procedure we used crystal violet, the primary stain to dye the bacteria purple, gram’s iodine, which will cause the crystal violet color to bind more tightly with the cell, ethanol, which removes the purple color from gram-negative bacteria, and then safranin, a pink dye, (Caldas, Herron, La Mota-Peynado, Wong, and Trowbridge, 2017). After heat fixing a slide with a smear of a bacterium species, we wash the slide first with crystal violet and let it sit for one minute and rinsed will distilled water. We repeated this same procedure with gram’s iodine. Before we add the safranin however, ethanol, is applied and only sitting on the smear for about 20 seconds. Next safranin is applied and goes through the same producer as before. Gram positive bacteria have a thick peptidoglycan layer cell wall which holds the purple dye of crystal violet even after the ethanol is applied. While gram negative bacteria is changed pink after it is decolorized with ethanol and recolored with safranin. This is the distinguishing factor between gram positive and gram
negative.