MRSA Coverage in Influenza Patients
MRSA coverage should be added to antibiotic therapy in patients with severe influenza-related pneumonia not responding to initial treatment, as Staphylococcus aureus is a significant pathogen in influenza complications. 1
Relationship Between Influenza and MRSA
- Staphylococcus aureus is an uncommon cause of sporadic community-acquired pneumonia but assumes greater importance during influenza pandemics 1
- Recent increases in MRSA in hospitalized patients may result in subsequent readmission with MRSA infection secondary to influenza 1
- MRSA co-infection with influenza can lead to severe, necrotizing pneumonia with high mortality rates 2, 3
When to Consider MRSA Coverage
Initial Empiric Therapy
- For patients with severe pneumonia during periods of high influenza activity, empiric therapy should include consideration for MRSA 3
- Patients with recent hospitalization have a higher chance of carrying MRSA and should receive consideration for MRSA coverage if they develop influenza-related pneumonia 1
Treatment Failure Scenarios
- For patients with severe pneumonia not responding to initial combination antibiotic therapy, adding antibiotics effective against MRSA is recommended 1
- When evaluating treatment failure, microbiological data should be reviewed to exclude S. aureus infection 4
Antibiotic Options for MRSA Coverage
Preferred Therapy for MRSA
- Vancomycin 1g bd IV (with dose monitoring) ± rifampicin 600 mg od or bd PO/IV is the preferred therapy for MRSA pneumonia 1
- For severe cases, vancomycin monotherapy may be insufficient - consider adding a second anti-MRSA antibiotic 5
Alternative Options
- Linezolid has shown advantageous therapeutic effects in post-influenza MRSA pneumonia compared to vancomycin in some studies 2
- Linezolid may attenuate proinflammatory cytokine response and acute lung damage in influenza-MRSA co-infection 6, 2
Duration of Therapy
- For pneumonia caused by S. aureus, extend treatment to 14-21 days 1
- For severe, microbiologically undefined pneumonia, 10 days treatment is proposed 1
Important Considerations and Pitfalls
- MRSA co-infection with influenza can be rapidly fatal if not appropriately treated 7
- Early empirical treatment with beta-lactams plus fluoroquinolones or macrolides may mask bacterial co-infection, leading to under-reporting of MRSA in influenza patients 7
- Bacterial co-infection should be considered in patients with influenza who have high fever, leukopenia, and signs of acute lung injury 5
- Local consultation with microbiology services is essential during influenza outbreaks to guide appropriate antibiotic selection 1