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
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