The Effect of Common Bactericidal Agents on Staphylococcus Epidermidis
The Effect of Common Bactericidal Agents on Staphylococcus Epidermidis
Introduction
Staphylococcus epidermidis is a facultative anaerobic bacterium. It is part of the normal human flora and is found on the skin. Colonies of these bacteria can produce a protective slime called a hydrophobic biofilm. Staphylococcus epidermidis is usually not pathogenic unless it enters the human body. One of the most common places for infections are hospitals where people often have weakened immune systems, open wounds or medical devices implanted in their bodies. Staphylococcus epidermidis can be fatal because of the protective biofilm and the bacteria’s resistance to common antibiotics makes the infection difficult to treat. This stresses the importance for hospitals to prevent infection by keeping a sterile environment. There are many chemical agents that can be used to kill bacteria, but a hospital’s choices are limited by availability and cost of the agents. In this experiment the effectiveness of three common bactericidal agents, bleach, hydrogen peroxide, and isopropyl alcohol, were tested. This was done by creating aqueous solutions of staphylococcus epidermidis bacteria and a chemical agent. The solutions were then incubated on an agar petri dish for 24 hours. The quantity of staphylococcus epidermidis bacteria colonies that were grown were used as an indicator of how effective each agent was in killing the bacteria. Each bactericidal agent has its own mechanism for killing bacteria. Both bleach and hydrogen peroxide are strong oxidizing agents, although hydrogen peroxide is a stronger oxidizing agent than hypochlorous acid, the oxidizing agent found in bleach. Oxidizing agents are very reactive compounds that take electrons away from other molecules to obtain a more stable form. When the oxidizing agents react with the bacteria they create free radicals which react with the lipids of the cell membrane. This reaction changes the molecular composition of the cell
Introduction
Staphylococcus epidermidis is a facultative anaerobic bacterium. It is part of the normal human flora and is found on the skin. Colonies of these bacteria can produce a protective slime called a hydrophobic biofilm. Staphylococcus epidermidis is usually not pathogenic unless it enters the human body. One of the most common places for infections are hospitals where people often have weakened immune systems, open wounds or medical devices implanted in their bodies. Staphylococcus epidermidis can be fatal because of the protective biofilm and the bacteria’s resistance to common antibiotics makes the infection difficult to treat. This stresses the importance for hospitals to prevent infection by keeping a sterile environment. There are many chemical agents that can be used to kill bacteria, but a hospital’s choices are limited by availability and cost of the agents. In this experiment the effectiveness of three common bactericidal agents, bleach, hydrogen peroxide, and isopropyl alcohol, were tested. This was done by creating aqueous solutions of staphylococcus epidermidis bacteria and a chemical agent. The solutions were then incubated on an agar petri dish for 24 hours. The quantity of staphylococcus epidermidis bacteria colonies that were grown were used as an indicator of how effective each agent was in killing the bacteria. Each bactericidal agent has its own mechanism for killing bacteria. Both bleach and hydrogen peroxide are strong oxidizing agents, although hydrogen peroxide is a stronger oxidizing agent than hypochlorous acid, the oxidizing agent found in bleach. Oxidizing agents are very reactive compounds that take electrons away from other molecules to obtain a more stable form. When the oxidizing agents react with the bacteria they create free radicals which react with the lipids of the cell membrane. This reaction changes the molecular composition of the cell
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