MRSA: antibiotic resistant bacteria. Coloured transmission electron micrograph of a section through a methicillin-resistant Staphylococcus aureus (MRSA) bacterium. This bacterium is resis- tant to most antibiotic drugs, though some strains yield to vancomycin. Staphylococcus aureus is a Gram-positive spherical (coccus) bacteria with a cell wall (red) and capsule (blue) surrounding it. S. aureus can cause boils, abscesses and wound infections. MRSA is of serious concern in hospitals and has been the cause of dangerous outbreaks, particularly in geriatric wards. Its spread may be very difficult to control. Magnification: x77,000 at 6x7cm size. x250,000 at 8x9"~LANDSCAPE"