Diagnosis of Infected Patient Essay

678 Words May 11th, 2014 3 Pages
M21 Essay: Diagnosis of an Infected Patient Essay

As we know bacteria comes in various classes and are distinguished by their shapes, chemical configuration, source of energy either sunlight or chemicals, nutritional requisites and biochemical actions.
We have a patient that may be infected with an unknown bacterial infection; we’ve collected a sputum sample and will be testing for one of the following genera: Bacillus, Escherichia and Mycoplasma. In order to determine which one of the three may be the source of the infection we have to recognize the characteristics of each one and the staining protocol needed to identify them.
All three of the above mentioned genera are considered to be members of the Prokaryotic cell family
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Let’s begin with Mycoplasma because this genera has a very thin or lacks a cell wall we will consider this a “Gram- positive” bacteria. If mycoplasma retains its structure, size and capsules that’s an indication of the type of bacteria causing the infection in the patient.
Bacillus are part of the prokaryotic cell family containing a thin layer of peptidoglycan; however they are spore forming; this trait helps to identify them as “gram-positive”. Step (1) in the staining process is adding the sputum to the slide, step (2) is applying heat to the sample, step (3) adding crystal-violet dye which turns the cytoplasm cells purple and applying mordant to the specimen, step (4) wash with de-coloring solution (alcohol) which causes the peptidoglycan to become more impermeable crystal –violet and iodine, step (5) counterstain is absorbed and is masked by the primary purple dye that was previously absorbed by the “gram-positive” cells (pg. 86). It’s during this step when the microbes are identified.
While the bacillus is in the aging process some cells die and give the appearance of gram-negative bacteria; these are known as “gram-variable” (Tortora, 2013).
Escherichia (E.coli) these rod shaped microorganisms have a thick outer membrane; however they are non-spore forming; therefore they are considered “gram-negative” cells. The steps in the staining of “gram-negative”