Microbiology Unknown Lab Report
Lab12-Medical Microbiology- Part1– Differential Media/Biochemical Tests, Sp2012 (Set all of your margins to ½”)
Purpose: The purpose of this lab is to help you become a little familiar with some of the tests that can be typically performed in a clinical or research lab facility. These tests may help in determining a particular pathogen’s growth needs.
There are several sections to this lab. Find each section and complete the “Preparing for Class” sections.
Preparing for class - Day 1
Read in your lab manual about the following agar mediums: Blood Agar (pg 168), EMB Agar (pg 170), Mannitol Salt Agar (MSA)(pg 172) ), MacConkey Agar (pg 174), and PEA Agar (pg 176) to answer the following:
1. What does the blood agar select for? Blood agar allows distinction among bacteria based on their ability to lyse red blood cells (hemolytic activity). 2. What color is the blood agar? Blood red color. 3. What are the 3 types of blood agar results and how can you recognize them? Beta hemolysis, which is the complete lysis of red blood cells and hemoglobin. This results in complete clearing of the blood around the colonies. Alpha hemolysis refers to the partial lysis of red blood cells and hemoglobin. This results in a greenish-grey discoloration of the blood around the colonies. No hemolysis, sometimes called gamma hemolysis results in no change in the medium. 3. What color is the EMB agar? Dark blue colonies with green metallic sheen or pink. 4. What does the EMB agar select for? Gram-negative bacteria. 5. What bacteria can easily be differentiated on EMB agar? Gram-positive. How is it recognized? It contains the dyes eosin and methylene blue, which inhibit the growth of gram-positive bacteria. 6. What color is the Mannitol Salt Agar (MSA)? Yellow color change in surrounding media. 7. What does the MSA agar select for? It contains 7.5% sodium chloride, which selects for organisms that are halotolerant. 8. Which
Purpose: The purpose of this lab is to help you become a little familiar with some of the tests that can be typically performed in a clinical or research lab facility. These tests may help in determining a particular pathogen’s growth needs.
There are several sections to this lab. Find each section and complete the “Preparing for Class” sections.
Preparing for class - Day 1
Read in your lab manual about the following agar mediums: Blood Agar (pg 168), EMB Agar (pg 170), Mannitol Salt Agar (MSA)(pg 172) ), MacConkey Agar (pg 174), and PEA Agar (pg 176) to answer the following:
1. What does the blood agar select for? Blood agar allows distinction among bacteria based on their ability to lyse red blood cells (hemolytic activity). 2. What color is the blood agar? Blood red color. 3. What are the 3 types of blood agar results and how can you recognize them? Beta hemolysis, which is the complete lysis of red blood cells and hemoglobin. This results in complete clearing of the blood around the colonies. Alpha hemolysis refers to the partial lysis of red blood cells and hemoglobin. This results in a greenish-grey discoloration of the blood around the colonies. No hemolysis, sometimes called gamma hemolysis results in no change in the medium. 3. What color is the EMB agar? Dark blue colonies with green metallic sheen or pink. 4. What does the EMB agar select for? Gram-negative bacteria. 5. What bacteria can easily be differentiated on EMB agar? Gram-positive. How is it recognized? It contains the dyes eosin and methylene blue, which inhibit the growth of gram-positive bacteria. 6. What color is the Mannitol Salt Agar (MSA)? Yellow color change in surrounding media. 7. What does the MSA agar select for? It contains 7.5% sodium chloride, which selects for organisms that are halotolerant. 8. Which