Gram positive:
First, the bacteria sample is placed on a glass slide and heated only to the point of rendering it innocuous in terms of being infectious to the handler. Next, the bacteria sample is treated with a gentian violet-iodine solution for up to sixty seconds. The slide is then gently rinsed under clean water and the Gram solution is applied, which is a mixture of iodine and potassium iodide diluted in water. This step triggers a reaction to the gentian violet compound.
Initially, the reaction produces a dark blue colour. However, a subsequent rinse with ethyl alcohol leads to the colour in some bacteria samples to bleed out, but not in others. A final dye solution is applied that uses a different colour, usually a variation of red. A sample that accepts this counter stain will appear pink, and is …show more content…
Staphylococcus aureus is an important cause of hospital acquired infection.
Gram negative cocci Neisseria gonorrhoea needs raised carbon dioxide levels to be cultured, bacteria appears in pairs (diplococcic)
Gram negative:
Gram-negative bacteria are bacteria which do not turn purple in the Gram staining process used as a basic step in the identification of bacteria. Most bacteria can be divided into either Gram-positive or Gram-negative bacteria, reflecting key differences in the composition of their cell walls. These differences often have a direct influence on what the bacteria does, with some Gram-negative bacteria being pathogenic in nature.
Gram positive bacilli
Sopre foming bacillus cereus- food poisoning, bacillus anthracis, anthrax, clostridium tetani-tetanus; clostridium botulinum- botulism; Clostridium perfringens- gangrene; Clostridium difficile- colonitis
Non sporing: listeria monocytogenes- food poisoning; corynebecterium diphtheria diplohteria; propionibacterium acne-acne
Gram negative
First, the bacteria sample is placed on a glass slide and heated only to the point of rendering it innocuous in terms of being infectious to the handler. Next, the bacteria sample is treated with a gentian violet-iodine solution for up to sixty seconds. The slide is then gently rinsed under clean water and the Gram solution is applied, which is a mixture of iodine and potassium iodide diluted in water. This step triggers a reaction to the gentian violet compound.
Initially, the reaction produces a dark blue colour. However, a subsequent rinse with ethyl alcohol leads to the colour in some bacteria samples to bleed out, but not in others. A final dye solution is applied that uses a different colour, usually a variation of red. A sample that accepts this counter stain will appear pink, and is …show more content…
Staphylococcus aureus is an important cause of hospital acquired infection.
Gram negative cocci Neisseria gonorrhoea needs raised carbon dioxide levels to be cultured, bacteria appears in pairs (diplococcic)
Gram negative:
Gram-negative bacteria are bacteria which do not turn purple in the Gram staining process used as a basic step in the identification of bacteria. Most bacteria can be divided into either Gram-positive or Gram-negative bacteria, reflecting key differences in the composition of their cell walls. These differences often have a direct influence on what the bacteria does, with some Gram-negative bacteria being pathogenic in nature.
Gram positive bacilli
Sopre foming bacillus cereus- food poisoning, bacillus anthracis, anthrax, clostridium tetani-tetanus; clostridium botulinum- botulism; Clostridium perfringens- gangrene; Clostridium difficile- colonitis
Non sporing: listeria monocytogenes- food poisoning; corynebecterium diphtheria diplohteria; propionibacterium acne-acne
Gram negative