In a clinical setting signs and symptoms can lead a care taker down a treatment path, but if a bacterial infection is suspected, a definitive answer from the “lab” is needed before prescribing medications. In this instance a yellow sputum was produced by the patient, which will be taken to the lab an analyzed under a microscope.There are three suspect bacteria, which are Bacillus, Mycoplasma, and Escherichia. A discussion of staining procedures, as well as anatomical differences will be discussed for each specimen.
Bacillus are Prokaryotic cells, that are rod shaped bacteria and can from long chains. Bacillus are also spore forming. When gram staining a Bacillus sample, they are found to be gram positive. However, there are some Bacillus that are gram negative. Escherichia are similar to Bacillus, in that they are rod shaped, but they are non spore forming. The significance in this is that Bacillus spores can infect up to hundreds if not thousands of years after they were produced, as they are harbored in soil. Most Escherichia are motile by flagella and are gram negative Mycoplasma are the smallest known bacteria. They are so small that they will pass through filters that most bacteria could not pass through.
Mycoplasma does not have a cell wall, which allows for it to take many different shapes. The lipids in the plasma membrane in the cell creates sterols, which protect it from rupture. The peptioglyan proteins are a target for antimicrobial activity. It disrupts the final linking of the peptidoglycan rows, which leads to it’s destruction due to rupture (Tortora, 2010, pg 85). Mycoplasma are gram positive when stained. To prepare the sample for staining and stain the sample the following steps would be taken: Take a small sample of sputum and smear it on a slide.
This is then tempered by heat on to the slide, which will prevent washing it off with the stains. Crystal violet, a primary stain, is placed on the slide and allowed to set for a short time. It is then washed off. A mordant, such as iodine, is added to the slide. When it is washed off both gram negative and positive samples will appear purple. Next the slide is washed with a decolorizing agent, which removed color from gram negative cells. Finally, the slide is washed again and stained with a counterstain, such as safranin. The counterstain will dye the gram negative cell and will not effect the gram positive cell.
It is known that Mycoplasma pneumonia causes pneumonia. Escherichia coli causes diseases such as urinary tract infections and gastro-intestinal problems from diarrhea to dysentery-like conditions (Madigan). Finally, Bacillus is known for Bacillus cereus, commonly known as food poisoning.
After gram staining the sample, Escherichia could be ruled out as it is gram negative. The next step would be to explore the shape and cell structure of the two remaining bacteria types. Bacillus shaped like a rod and divides to form a chain. It also has a endospore layer, located internal to the cell membrane. Mycoplasma are very small and have variable shapes, due to not having a cell wall. At this point it should be apparent that Bacillus would be eliminated, due to the presence of a cell wall, endospore layer, and larger size. I can be surmised that the bacterial culprit in the sputum sample is Mycoplasma pneumonia. In conclusion, it is evident that gram staining led to the ability to easily identify types of bacteria, which in turn has lead to the quick recognition and treatment of disease.