| Classifying and identifying bacteria | Classifying bacteria means placing bacteria with common characteristics in groups that differ from other groups. | |
| The first step in classifying is determining the gram stain reaction. | ||
| The next step is to determine the cell morphology (shape). | ||
| In this unit, we are going to focus on classification. Identification requires determining unique characteristics of the bacterium within its group. These characteristics involve laboratory tests to determine either usage of a substrate or the production of enzymes by the bacterium. | ||
| First let's look at some medically important Gram positive cocci. Two main groups are Streptococcus and Staphylococcus. Streptococcus pyogenes is the causative agent of Strep throat. Staphylococcus aureus is frequently found in wound infections. | ||
| Bacillus anthracis is a Gram positive bacillus that causes anthrax. This organism has become infamous in the last couple of years due to bioterriorism. Another infamous Gram positive bacillus is Listeria monocytogenes. | ||
| One of the more commonly isolated STDs is gonorrhea. Gonorrhea is caused by the microbe Neisseria gonorrhoeae. This organism is a Gram negative cocci. | ||
| Clinically important Gram negative bacilli include Salmonella enteritidis and Escherichia coli. Salmonella enteritidis commonly causes food poisoning and Escherichia coli is the number one cause of urinary tract infections. |
