International journal of antimicrobial agents
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Int. J. Antimicrob. Agents · Nov 2013
High vancomycin minimum inhibitory concentrations with heteroresistant vancomycin-intermediate Staphylococcus aureus in meticillin-resistant S. aureus bacteraemia patients.
Patients with high vancomycin minimum inhibitory concentrations (MICs) and heteroresistant vancomycin-intermediate Staphylococcus aureus (hVISA) infection are associated with treatment failure and poor outcomes. The main purpose of this study was to investigate the effect of hVISA on patient outcome, considering both the high vancomycin MIC and the existence of heteroresistant phenotypes. From January 2005 to December 2009, consecutive meticillin-resistant S. aureus (MRSA) isolates from 284 cases of MRSA bacteraemia receiving glycopeptide therapy were collected for further MIC and hVISA testing. ⋯ The high MIC with hVISA phenotype was not associated with higher mortality but was independently associated with persistent MRSA bacteraemia (OR=5.996, 95% CI 1.438-25.005). To summarise, although hVISA is correlated with persistent bacteraemia, higher mortality in high vancomycin MIC infections could not be explained by the existing hVISA phenotype. Facing persistent bacteraemia under glycopeptide therapy for 7 days, clinicians should consider shifting to an alternative class of antibiotics to treat hVISA infection.
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Int. J. Antimicrob. Agents · Nov 2013
Can changes in renal function predict variations in β-lactam concentrations in septic patients?
This study investigated whether variations in creatinine clearance (CLCr) are correlated with changes in β-lactam concentrations or pharmacokinetics in septic patients. Data for 56 adult patients admitted to the ICU in whom routine therapeutic drug monitoring (TDM) of broad-spectrum β-lactams (ceftazidime, cefepime, piperacillin or meropenem) was performed were reviewed. Patients were included if they had at least two TDM during their ICU stay for the same antibiotic and were not concomitantly treated with any extracorporeal replacement therapy. ⋯ The proportion of patients with insufficient β-lactam concentrations at the first and second TDM were 39% and 30%, respectively, and increased proportionally to CLCr. Although CLCr was significantly correlated with concentrations and clearance of broad-spectrum β-lactams, changes in CLCr did not reliably predict variations in drug pharmacokinetics/pharmacodynamics. Routine TDM should be considered to adapt β-lactam doses in this setting.