Describe the Gram stain technique and the effect on Gram-positive and Gram-negative bacteria after each step. Be very specific about what is happening at each step and why it happens. (hint: be sure to fully explain your answer and not just list the steps)
No, acid-fast bacteria do not stain gram-negative when subjected to the gram stain.
Gram stain
The counter or secondary stain used in the Gram stain procedure is safranin.
Yogurt contains mostly lactic acid bacteria, which are Gram-positive bacteria. This means they will stain purple under a Gram stain.
There are two types of stains, the simple stain and the differential stain. A simple stain colors all objects the same while a differential stain is used to spot differences in microorganisms. A gram stain is a differential stain, which is used to tell the difference in gram negative and gram positive bacteria. A simple stain would stain all the organisms the same and this difference would not be noted. You would be able to determine their shape, whether it is a cocci or bacillus (rod), but not the type. I'm not sure why the simple stain would be preferable unless you just wanted a quick answer as to the shape of the bacteria. In some cases, a wet prep can be made of a presumptive gram positive cocci to tell the difference between bacteria or yeast. Otherwise, I would say that the gram stain is the only way to go.
No, acid-fast bacteria do not stain gram-negative when subjected to the gram stain.
Gram stain
Gram Negative
Protists are often stained using a silver stain, not a Gram stain.
pink
The Gram stain is used for bacteria and not for viruses.
Using Congo red instead of safranin in the Gram stain technique would not provide accurate results. Safranin is essential for counterstaining gram-negative bacteria, whereas Congo red would not differentiate between gram-positive and gram-negative cells due to its staining properties. This would lead to incorrect classification of bacteria in the Gram stain.
In a Gram stain of blood or cerebrospinal fluid in a meningococcal case, you would look for Gram-negative diplococci, which are indicative of Neisseria meningitidis. These bacteria are the causative agent of meningococcal disease. Their appearance in the Gram stain can help diagnose the infection.
If a Gram stain had been performed instead of an endospore stain, the slide would show the bacterial cells either as purple (Gram-positive) or pink (Gram-negative) based on their cell wall composition. The endospores, which typically do not retain the Gram stain, would likely appear as clear or colorless structures within the stained cells. Thus, the focus would be on the overall morphology and arrangement of the vegetative cells rather than highlighting the presence of endospores.
Enterobacter cloacae is a Gram-negative bacterium. It will stain pink or red in a Gram stain procedure.
Bacteria stain either gram-positive or gram-negative based on the presence or absence of a cell wall. Viruses do not pick up a gram stain.
The counter or secondary stain used in the Gram stain procedure is safranin.