What clinical signs and symptoms indicate Methicillin-resistant Staphylococcus aureus (MRSA) infection?

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Last updated: June 9, 2025View editorial policy

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From the Guidelines

Methicillin-resistant Staphylococcus aureus (MRSA) infection typically presents with skin and soft tissue manifestations, including painful red bumps, boils, or abscesses, and can be indicated by clinical signs and symptoms such as cellulitis, fever, chills, fatigue, muscle aches, headache, and general malaise. These lesions often contain pus, feel warm to the touch, and may be surrounded by areas of redness, swelling, and tenderness 1. Patients may develop cellulitis (spreading skin infection) with warmth, redness, and swelling. More severe MRSA infections can cause pneumonia (with cough, chest pain, and difficulty breathing), bloodstream infections (with high fever and low blood pressure), surgical site infections, urinary tract infections, or bone and joint infections (with localized pain, swelling, and limited mobility) 1. MRSA can also cause life-threatening conditions like sepsis, toxic shock syndrome, and necrotizing fasciitis. Some key clinical signs and symptoms that may indicate MRSA infection include:

  • Painful red bumps, boils, or abscesses that may resemble spider bites
  • Cellulitis (spreading skin infection) with warmth, redness, and swelling
  • Fever, chills, fatigue, muscle aches, headache, and general malaise
  • Pus-filled lesions that feel warm to the touch and are surrounded by areas of redness, swelling, and tenderness
  • Systemic signs of infection, such as fever, tachycardia, and hypotension
  • Severe local infection or signs of systemic illness, such as sepsis or toxic shock syndrome 1. It is essential to note that MRSA infections can be difficult to diagnose and treat, and a high index of suspicion is necessary to promptly identify and manage these infections effectively 1.

From the Research

Clinical Signs and Symptoms of MRSA

The clinical signs and symptoms that may indicate Methicillin-resistant Staphylococcus aureus (MRSA) infection include:

  • Recurrent skin and soft tissue infections (SSTI), such as folliculitis, furunculosis, and abscesses 2
  • Severe SSTI due to necrotising fasciitis and purpura fulminans 2
  • Complicated skin and soft tissue infections (cSSTIs), which can present a challenge to healthcare providers 3
  • Toxin-producing community-acquired MRSA (CA-MRSA) strains, which are increasing in prevalence and can cause infections in previously healthy individuals 3

Presentation of MRSA Infections

MRSA infections can present in various ways, including:

  • Skin and soft tissue infections, such as abscesses, cellulitis, and wound infections 4, 5
  • Community-acquired MRSA (CA-MRSA) infections, which can present as skin and soft tissue infections in previously healthy individuals 5
  • Hospital-acquired MRSA (HA-MRSA) infections, which can present as more severe infections, such as pneumonia, bacteremia, and endocarditis 3

Diagnostic Evaluation of MRSA

The diagnostic evaluation of MRSA infections can include:

  • Wound culture results, which can confirm the presence of MRSA 6
  • MRSA nares swab PCR testing, which can identify patients with MRSA nasal carriage and predict the risk of MRSA wound infection 6
  • Clinical risk factors, such as previous MRSA infection, recent hospitalization, and antibiotic use, which can increase the risk of MRSA infection 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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