Clostridium perfringens is a Gram-positive bacterium, meaning it will stain purple/blue with the Gram stain procedure due to its thick peptidoglycan layer.
If iodine is not applied, both the gram-positive and gram-negative stains will appear to be gram-negative. The iodine acts as a mordant that helps to fix the crystal violet stain in the gram-positive bacteria, making them appear purple. Without iodine, the crystal violet stain can be easily washed out of both gram-positive and gram-negative bacteria, resulting in a pink or red color.
Anthrax is a gram-positive bacterium, meaning it retains the crystal violet stain in the Gram staining procedure.
The Gram stain for anthrax shows large, Gram-positive bacilli that appear as long chains of cells. Anthrax bacteria stain blue or purple because of their thick peptidoglycan cell wall, which retains the crystal violet dye used in the Gram staining procedure.
Gram-negative on a Serratia marcescens gram stain means that the bacterium has a cell wall that does not retain the crystal violet stain used in the gram staining procedure. This indicates that Serratia marcescens has a thin peptidoglycan cell wall, and the outer membrane contains lipopolysaccharides.
Lyme Disease is caused by Borrelia burgdorferi. This is a spirochete bacterium with a gram negative cell wall structure. These organisms are best viewed by dark-field microscopy.
Yogurt contains mostly lactic acid bacteria, which are Gram-positive bacteria. This means they will stain purple under a Gram stain.
Gram positive
The answer to whether HIV gram-stain positive or negative is that HIV gram-stain is negative. They retain the light red or pink color after the stain.
Gram Positive.
gram positive
gram positive Exactly. When doing a gram stain on B. subtilis, this bacterium resists decolorization (keping the first stain and NOT taking on the color of the secondary stain). Therefore, this bacterium is gram (+).
Clostridium perfringens is a Gram-positive bacterium, meaning it will stain purple/blue with the Gram stain procedure due to its thick peptidoglycan layer.
Contamination
Mad Cow Disease cannot be identified by a gram stain. Mad Cow Disease is caused by prions, incorrectly folded proteins. Gram staining is a way to separate bacteria into two groups - positive and negative - and cannot be used to identify prions, since prions are not bacteria.
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.
Which pathogens can't you use the gram stain on? Some pathogens are gram negative such as Tuberculosis. Others are gram positive. Those you can stain with the gram stain. The differences have to do with the structure of the outer membrane. Not all pathogens are gram negatives. Staph and strep are gram positive. People die from Strep infections.