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Staphylococcus aureus
Staphylococcus aureus
Gram Positivecocci
Description
S. aureus is a gram-positive, round bacterium that is a common member of skin flora. It can cause a range of illnesses from minor skin infections to life-threatening diseases such as pneumonia and sepsis. MRSA strains are resistant to many antibiotics.
Membrane Composition
Key Properties
Peptidoglycan:20-80 nm (thick)
Lipopolysaccharide:Absent
Teichoic Acid:Present
Outer Membrane:Absent
Membrane Components
- •Cytoplasmic membrane
- •Thick peptidoglycan layer (30-100 layers)
- •Teichoic acids
- •Lipoteichoic acids
Understanding Gram Classification
Gram-positive bacteria retain the crystal violet stain due to their thick peptidoglycan layer (20-80 nm). This thick layer traps the dye-iodine complex during the gram staining process.
The cell wall structure consists of a cytoplasmic membrane surrounded by a thick peptidoglycan layer containing teichoic acids. There is no outer membrane, making the cell wall more permeable to certain antibiotics like penicillin.