Submitted by: Submitted by tsimpson
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Category: Science and Technology
Date Submitted: 11/04/2013 03:52 PM
What are advantages and disadvantages of the differential staining techniques discussed in Chapter 3 that are used to study microorganisms? Focus your response in terms of the following parameters:
o Ease and cost of sample preparation
o Why you would use it (i.e. what information is imparted)
o Specificity of identification
o Chance of false positives or negatives
When using a light microscope, the staining process can be a lot easier and cheaper compared to an electron microscope. Although the resolution is better, the sample for an electron microscope must be fixed and dehydrated making it impossible to observe living things, whereas, with a light microscope you can view live specimens. The sample preparation for an electron microscope can be lengthy and more complicated. It is often necessary to coat the specimen with a thin layer of metal, such as gold to reflect the electrons.
Simple staining provides a quick and easy way to determine cell shape, size, and arrangement. Simple stains are used to give color to microorganisms for better viewing. A simple stain uses only a single dye and does not distinguish between different types of microorganisms.
A differential stain uses more than one dye and stains different microorganisms different colors. the chemical composition of microorganisms can be found by using differential stains.
• The Gram stain - Gram staining is one of the most useful staining procedures used in medical microbiology. It can classify bacteria into two groups, gram negative and gram positive providing valuable information for treating diseases. It is the first step to determine what type of bacteria is growing and what the best antibiotic is to treat it. If a gram stain is positive it means the bacteria can be killed with penicillin’s and cephalosporins. Gram negative staining means the bacteria is more resistant making them difficult to treat with antibiotics. Resistance among both groups is usually due to bacterial...