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Updated: May 31, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)
Published on: February 9, 2011
Pulmonary infections and community associated methicillin resistant Staphylococcus aureus: a dangerous mix?
Natalie Shilo1, Caroline Quach
1Division of Respirology, Department of Pediatrics, The Montreal Children’s Hospital, McGill University Health Center, McGill University, Québec, Canada.
Abstract:
The incidence of complicated pneumonias in children is increasing with a concurrent increase in the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections. CA-MRSA is distinct from hospital associated MRSA [HA-MRSA] in regards to its genotype, epidemiology, and clinical course. Unlike HA-MRSA, CA-MRSA often strikes young, previously healthy children. Pneumonias caused by CA-MRSA have a rather distinct presentation. Because of its pore-forming toxins, namely Panton-Valentine leukocidin (PVL) and alpha-hemolysin, extensive necrotizing disease with corresponding hypoxaemia and hypercarbia is common. Other features include multilobar disease, leucopenia, haemoptysis, and high mortality rates. A previous influenza-like illness or skin and soft tissue infection [SSTI] often precede the development of pneumonia due to CA-MRSA. Vancomycin is recommended as first-line empiric therapy for suspected CA-MRSA infections. However, vancomycin is not an ideal agent for the treatment of pneumonia given its poor concentrating ability in alveolar fluid. Linezolid and clindamycin have also been used in the treatment of CA-MRSA pneumonia and ongoing research is looking for alternative antimicrobials. Recent studies have continued to report a lack of correlation between nasal colonization and active infections due to CA-MRSA. Given that the role of nasal colonization in CA-MRSA infection is not clear, the utility of decolonization treatment has been a point of debate. Finally, patients with cystic fibrosis are becoming increasingly colonized with MRSA as opposed to MSSA. There is some accumulating evidence that patients with MRSA show a more rapid deterioration in their degree of obstructive disease as measured by forced expiratory volume in one second (FEV(1)). However, it still is not clear whether MRSA is a marker for worsening disease or whether it actually is a cause of disease progression in cystic fibrosis. More longitudinal data is needed to understand how MRSA colonization impacts the course of disease in cystic fibrosis.
Insights
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) causes severe childhood pneumonia with high mortality. Current treatments like vancomycin are suboptimal, and the role of nasal colonization remains unclear.
Area of Science:
- Pediatric Infectious Diseases
- Microbiology
- Pulmonology
Background:
- Increasing incidence of complicated pediatric pneumonias linked to community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).
- CA-MRSA differs from hospital-associated MRSA (HA-MRSA) in its distinct genotype, epidemiology, and clinical presentation, often affecting healthy children.
- CA-MRSA pneumonia is characterized by severe necrotizing disease due to toxins like Panton-Valentine leukocidin (PVL), leading to hypoxemia, hypercarbia, and high mortality.
Purpose of the Study:
- To review the distinct clinical presentation and management challenges of CA-MRSA pneumonia in children.
- To discuss current therapeutic recommendations and limitations for CA-MRSA pneumonia.
- To explore the debated role of nasal colonization and the impact of MRSA in cystic fibrosis patients.
Main Methods:
- Literature review and synthesis of current evidence on CA-MRSA epidemiology, clinical features, and treatment.
- Analysis of therapeutic options, including vancomycin, linezolid, and clindamycin, and emerging antimicrobial research.
- Examination of studies investigating the correlation between nasal colonization and active CA-MRSA infections, and MRSA's role in cystic fibrosis.
Main Results:
- CA-MRSA pneumonia presents uniquely with features like multilobar disease, leukopenia, hemoptysis, and significant mortality.
- Vancomycin is recommended but has limitations in treating pneumonia due to poor alveolar penetration; linezolid and clindamycin are alternatives.
- The link between nasal colonization and active CA-MRSA infection is not well-established, impacting decolonization strategies.
- MRSA colonization in cystic fibrosis patients may correlate with faster disease progression, but causality requires further investigation.
Conclusions:
- CA-MRSA poses a significant threat in pediatric pneumonia, necessitating optimized treatment strategies beyond current first-line agents.
- Further research is crucial to clarify the role of nasal colonization in CA-MRSA infections and to identify effective decolonization methods.
- Longitudinal studies are needed to determine if MRSA colonization causes or merely marks disease progression in cystic fibrosis.
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