Methicillin-resistant Staphylococcus aureus (MRSA)

Last reviewed: 25 Aug 2022
Last updated: 01 Sep 2022

Summary

Definition

History and exam

Key diagnostic factors

  • erythematous skin lesions or pustules, in single or multiple forms
  • irritation or pain at indwelling catheter site
  • heart murmur and other signs of endocarditis
More key diagnostic factors

Other diagnostic factors

  • infection unresponsive to penicillins
  • history of a presumed spider bite
  • abscess formation
  • fever
  • fatigue
  • tachycardia and hypotension
  • shortness of breath and cough
  • painful urination, hematuria, or urinary retention
  • night sweats or chills
  • altered mental status
  • signs of pulmonary consolidation
  • abdominal pain or flank pain
  • joint pain
  • joint swelling
Other diagnostic factors

Risk factors

  • age >50 years (healthcare-associated)
  • children and younger adults <35 years (community-associated)
  • Native Americans and Pacific islanders (community-associated)
  • men who have sex with men (community-associated)
  • intravenous drug users (community-associated)
  • indwelling device or current wound (healthcare-associated)
  • hospitalization within the last year (healthcare-associated)
  • chronic illness requiring healthcare visits (healthcare-associated)
  • crowded conditions/semi-closed communities (healthcare-associated and community-associated)
  • previous history of MRSA (healthcare-associated and community-associated)
  • exposure to an MRSA-positive person (healthcare-associated and community-associated)
  • nasal colonization with MRSA (healthcare-associated and community-associated)
  • prior antibiotic use (healthcare-associated and community-associated)
  • HIV infection (community-associated and healthcare-associated)
More risk factors

Diagnostic investigations

1st investigations to order

  • CBC
  • blood culture
  • urine culture
  • tissue culture
  • sputum culture
  • echocardiogram
  • CXR
  • arthrocentesis fluid culture
  • indwelling vascular catheter tip culture
More 1st investigations to order

Investigations to consider

  • polymerase chain reaction (PCR)
More investigations to consider

Treatment algorithm

ACUTE

skin and soft-tissue infection: community-associated

skin and soft-tissue infection: healthcare-associated

bacteremia

pneumonia

visceral abscess

endocarditis

septic arthritis

urinary tract infection (UTI)

osteomyelitis

ONGOING

recurrent skin and soft-tissue MRSA infections in colonized patients

Contributors

Authors

Kyle J. Popovich, MD MS

Associate Professor of Medicine

Rush University Medical Centre

Chicago

IL

Disclosures

KJP declares that he has no competing interests.

Acknowledgements

Dr Kyle J. Popovich would like to gratefully acknowledge Dr Dara Grennan, Dr Paul F. Roberts, and Dr R. John Presutti, the previous contributors to this topic.

Disclosures

DG, PFR, and RJP declare that they have no competing interests.

Peer reviewers

Chad M. Hivnor, Major, USAF, MC, FS

Chief

Outpatient & Pediatric Dermatology

59th Medical Wing/ SGOMD

Lackland Air Force Base

San Antonio

TX

Disclosures

CMH declares that he has no competing interests.

Linda Kalilani, MBBS, MPhil, PhD

Epidemiologist

College of Medicine

University of Malawi

Zomba

Malawi

Disclosures

LK declares that she has no competing interests.

Christine Radojicic, MD

Professor

Cleveland Clinic Foundation

Cleveland

OH

Disclosures

CR declares that she has no competing interests.

Alistair Leanord, BSc, MBChB, MD, DTM&H, FRCPath

Consultant Microbiologist

Microbiology Department

Southern General Hospital

Glasgow

UK

Disclosures

AL declares that he has no competing interests.

  • Methicillin-resistant Staphylococcus aureus (MRSA) images
  • Differentials

    • Insect or spider bite
    • Cellulitis
    • Folliculitis
    More Differentials
  • Guidelines

    • Infection prevention and control in paediatric office settings
    • 2018 WSES/SIS-E consensus conference: recommendations for the management of skin and soft-tissue infections
    More Guidelines
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