Methicillin-resistant Staphylococcus aureus (MRSA) Bacteria. Scanning electron micrograph of methicillin-resistant Staphylococcus aureus (MRSA, brown) surrounded by cellular debris. MRSA resists treatment with many antibiotics. Credit: NIAID. Source: https://commons.wikimedia.org/wiki/File:Methicillin-resistant_Staphylococcus_aureus_(MRSA)_Bacteria.jpg