Empirical Anti-MRSA vs Standard Antibiotic Therapy and Risk of 30-Day Mortality
A recent article published in JAMA Internal Medicine questioned the utility of empiric anti-MRSA pneumonia therapy.  It was a retrospective multicenter cohort study conducted in the Veteran’s Health Administration healthcare system that looked at 88,605 patients with community-onset pneumonia. They compared 30-day mortality of patients hospitalized for pneumonia receiving empirical anti-MRSA therapy plus standard therapy against standard therapy alone. Secondary outcomes analyzed development of kidney injury and secondary infections with C. difficile, VRE, or gram-negative rods. They also analyzed subgroups: ICU admission, MRSA risk factors, positive MRSA surveillance test, and positive MRSA culture on admission.

 

Anti-MRSA Therapy: Vancomycin (98%), Linezolid (2%)

Standard Therapy: Beta-lactam + macrolide/tetracycline, or respiratory fluoroquinolone

 

Outcomes
Mortality: aRR=1.4 [95% CI, 1.3-1.5]
Kidney Injury: aRR=1.4 [95% CI, 1.3-1.5]
Secondary C. difficile: aRR=1.6 [95% CI, 1.3-1.9]
Secondary VRE: aRR=1.6 [95% CI, 1.0-2.3]
Secondary gram-negative rods: aRR=1.5 [95% CI, 1.2-1.8]

 

Mortality in Subgroups

ICU: aRR=1.3 [95% CI, 1.2-1.5]

MRSA Risk Factors*: aRR=1.2 [95% CI, 1.1-1.4]

Positive MRSA Surveillance: aRR=1.6 [95% CI, 1.3-1.9]

MRSA Detected on Culture: aRR=1.1 [95% CI, 0.8-1.4]

 

*MRSA Risk Factors
-History of MRSA infection/colonization within the past year
-Or 2 of the following: previous hospitalization, nursing home residence, and previous intravenous antibiotic therapy

 

Take-Home Point

Empirical anti-MRSA therapy did not decrease mortality for any groups of patients hospitalized for pneumonia. Given that healthcare-associated pneumonia is no longer a definition supported by the IDSA/ATS, be judicious in your use of anti-MRSA therapy in community-onset pneumonia and reserve for those patients at higher risk for MRSA, such as those with post-influenza pneumonia.

References

Jones BE, Ying J, Stevens V, et al. Empitical anti-MRSA vs standard antibiotic therapy and risk of 30-day mortality in patients hospitalized for pneumonia [published online ahead of print, February 17, 2020]. JAMA Intern Med. doi: 10.1001/jamainternmed.2019.7495.

Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Resp Crit Care. 2019;200:e45-e67.

Smith C. Is Empiric Anti-MRSA Pnumonia Therapy Harmful? https://journalfeed.org/article-a-day/2020/is-empiric-anti-mrsa-pneumonia-therapy-harmful. March 4, 2020. Accessed March 6, 2020.