Low serum trough concentrations and high vancomycin MIC in methicillin-sensitive Staphylococcus aureus from hemodialysis patients in Brazil

• Published in: Therapeutic drug monitoring
• Main Authors: Penedo da Vitória, Michel, Alvarenga, Cristiane Gomes de Sousa, Vasconcellos Filho, Lauro Monteiro, Birro, Jéssica de Cássia Teixeira, Barbosa, Maralisi Coutinho, Ferreira, Mariana Abou Mourad, Schuenck, Ricardo Pinto, Ferreira Nunes, Ana Paula, Santos, Kênia Valéria Dos
• Format: Journal Article
• Language: English
• Published: United States 04.12.2018
• ISSN: 1536-3694

The empiric antimicrobial therapy for bacteremia of long-term hemodialysis (HD) outpatients is currently based on the combination of vancomycin and gentamicin because of the high frequency of isolated Staphylococcus species. The vancomycin trough level range from 15 to 20 µg/mL is expected for therapeutic success against methicillin-resistant S. aureus with vancomycin MIC ≥ 1.0 µg/mL. Despite the availability of clinical practice guidelines for vancomycin therapeutic drug monitoring (TDM), these target serum concentrations are not reached in many patients. In this study the authors investigated the vancomycin trough levels in 20 HD-patients with S. aureus bacteremia, as well as the antimicrobial susceptibility pattern of 45 S. aureus strains isolated from 45 HD-patients. The vancomycin serum concentration was determined by chemiluminescent assay. The MIC was determined by broth microdilution method. None of the HD-patients included in this study had vancomycin trough concentrations within the therapeutic range. Also, the vancomycin MIC for most methicillin-sensitive S. aureus (MSSA) isolated from bacteremia was ≥ 1.0 µg/mL. The therapeutic range of vancomycin was not achieved, and vancomycin MIC was surprisingly high in MSSA.