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Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
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Humoral immune consequences of Staphylococcus aureus ST239-associated bacteremia
H Ghasemzadeh-Moghaddam1,2, Wjb van Wamel3, A van Belkum3,4
1Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
Summary
Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia patients show unique immune responses to specific antigens. Certain antigens like IsaA, IsdA, IsdH, SdrD, and HlgB elicit consistent responses, suggesting their potential for a novel MRSA vaccine.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of hospital-acquired infections, particularly bacteremia.
- Understanding the host immune response to MRSA infection is crucial for developing effective treatments and vaccines.
- Clonally related MRSA strains, such as Sequence Type 239 (ST239), can dominate outbreaks, necessitating targeted research into their specific antigenic targets.
Purpose of the Study:
- To investigate the humoral immune responses against 46 staphylococcal antigens in patients with MRSA bacteremia caused by ST239 strains.
- To compare immune responses between bacteremia patients and non-infected controls.
- To identify specific staphylococcal antigens that elicit consistent immune responses for potential vaccine development.
Main Methods:
- Humoral immune responses were assessed by measuring antibody levels against 46 staphylococcal antigens in 27 bacteremia patients and 31 non-infected controls.
- MRSA strains were confirmed as ST239 using PCR, spa typing, and multi-locus sequence typing (MLST).
- Antibody levels were compared between patient groups and controls, and over time within the patient group.
Main Results:
- Bacteremia patients exhibited significantly higher antibody levels against several antigens, including HlgB, LukD, LukF, SEA, SEB, SEC, SEQ, IsaA, IsdA, IsdH, SdrD, SdrE, EsxA, and SA0104 compared to controls.
- A subset of antigens (IsaA, IsdA, IsdH, SdrD, HlgB) induced similar immune responses across different individuals.
- Staphylococcal enterotoxin A (SEA) and its specific antibodies appeared critical in ST239 MRSA bacteremia, suggesting SEA-targeted therapy as a potential strategy.
Conclusions:
- The immune response to MRSA ST239 bacteremia is diverse, with unique patterns observed in individual patients.
- Specific antigens like IsaA, IsdA, IsdH, SdrD, and HlgB are consistently recognized, making them promising candidates for a multi-component passive vaccine.
- SEA plays a critical role in ST239 MRSA bacteremia, highlighting the potential therapeutic value of targeting SEA or its antibodies.
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