Antibiotic choice may not explain poorer outcomes in patients with Staphylococcus aureus bacteremia and high vancomycin minimum inhibitory concentrations
- PMID: 21742831
- DOI: 10.1093/infdis/jir270
Antibiotic choice may not explain poorer outcomes in patients with Staphylococcus aureus bacteremia and high vancomycin minimum inhibitory concentrations
Abstract
Background: There are concerns about reduced efficacy of vancomycin in patients with Staphylococcus aureus bacteremia (SAB), especially when the minimum inhibitory concentration (MIC) nears the upper limit of the susceptible range.
Methods: We examined the relationship between antibiotic treatment, 30-day mortality, and microbiologic parameters in a large Australasian cohort of patients with SAB.
Results: We assessed 532 patients with SAB from 8 hospitals. All patients with methicillin-resistant S. aureus (MRSA) bacteremia were treated with vancomycin, and patients with methicillin-susceptible S. aureus (MSSA) bacteremia received either flucloxacillin or vancomycin. Increasing vancomycin MIC was associated with increased mortality in vancomycin-treated patients. However, even in patients with MSSA bacteremia treated with flucloxacillin, mortality was also higher if the vancomycin Etest MIC of their isolate was >1.5 μg/mL, compared with those with lower MIC isolates (26.8% vs 12.2%; P < .001). After adjustment in a multivariate model, age, hospital-onset SAB and vancomycin MIC were independently associated with mortality, but methicillin resistance and antibiotic choice were not.
Conclusions: We have confirmed an association between higher vancomycin MIC and increased mortality in patients with SAB, but surprisingly this relationship was not related to the antibiotic treatment received, suggesting that the use of vancomycin per se is not responsible for the poorer outcome.
Comment in
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Vancomycin minimum inhibitory concentration and outcome in patients with Staphylococcus aureus bacteremia: pearl or pellet?J Infect Dis. 2011 Aug 1;204(3):329-31. doi: 10.1093/infdis/jir275. J Infect Dis. 2011. PMID: 21742827 No abstract available.
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Vancomycin minimum inhibitory concentrations and outcome in patients with severe Staphylococcus aureus infection.J Infect Dis. 2012 Mar 1;205(5):864-5; author reply 865-6. doi: 10.1093/infdis/jir848. Epub 2012 Jan 11. J Infect Dis. 2012. PMID: 22238463 No abstract available.
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Role of high vancomycin minimum inhibitory concentration in the outcome of methicillin-susceptible Staphylococcus aureus bacteremia.J Infect Dis. 2012 Mar 15;205(6):1024-5. doi: 10.1093/infdis/jir870. Epub 2012 Jan 18. J Infect Dis. 2012. PMID: 22262793 No abstract available.
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