Methicillin-resistant S. aureus (MRSA)

Definition

Methicillin-resistant S. aureus (MRSA) is a type of Staphylococcus aureus bacterium that is resistant to several widely used antibiotics, making infections difficult to treat. It is particularly notorious for its resistance to methicillin and other beta-lactam antibiotics.

5 Must Know Facts For Your Next Test

1. Methicillin resistance in MRSA is primarily due to the acquisition of the mecA gene, which codes for an altered penicillin-binding protein (PBP2a).
2. MRSA can cause a range of infections from minor skin conditions to severe diseases such as pneumonia and bloodstream infections.
3. Hospital-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) are two types differentiated by their epidemiology and genetic characteristics.
4. Standard treatment options for MRSA include non-beta-lactam antibiotics such as vancomycin, linezolid, and daptomycin.
5. Infection control measures like hand hygiene and contact precautions are critical in preventing the spread of MRSA in healthcare settings.

Review Questions

• What genetic component is primarily responsible for methicillin resistance in MRSA?
• What are the main differences between hospital-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA)?
• Name three non-beta-lactam antibiotics commonly used to treat MRSA infections.

Related terms

Beta-lactam Antibiotics: A class of broad-spectrum antibiotics that includes penicillins, cephalosporins, carbapenems, and monobactams.

Vancomycin:

An antibiotic used as a treatment of choice for serious infections caused by Gram-positive bacteria resistant to other antibiotics.

Penicillin-binding proteins (PBPs): Enzymes found in bacterial cell walls that are targeted by beta-lactam antibiotics to inhibit cell wall synthesis.