Understanding Methicillin-Resistant Staphylococcus aureus
Bacterial cells of Staphylococcus aureus, which is one of the causal agents of mastitis in dairy cows. Its large capsule protects the organism from attack by the cow's immunological defenses.
Courtesy of USDA
MRSA (Methicillin-Resistant Staphylococcus aureus) is a strain of Staphylococcus aureus bacteria that has developed resistance to an entire class of antibiotics (called beta lactams), including methicillin, penicillin, amoxicillin, and oxacillin. In addition, S. aureus is often found to be resistant to antiseptics and disinfectants. Over the past four decades in the US, it has evolved from an easily controlled microbe to a major public health problem.