T P Lodise1, G L Drusano2, V Lazariu3, N El-Fawal4, A Evans5, E Graffunder6, K Stellrecht5, R E Mendes7, R N Jones7, L Cosler2, L A McNutt3. 1. Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, NY, USA thomas.lodise@acphs.edu. 2. Institute for Therapeutic Innovation, College of Medicine, University of Florida, 6550 Sanger Road, Lake Nona, FL, USA. 3. University at Albany, State University of New York, Albany, 5 University Place, A217, Rensselaer, NY, USA. 4. Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, NY, USA. 5. Albany Medical Center Hospital, Department of Pathology and Laboratory Medicine, 43 New Scotland Avenue, Albany, NY, USA. 6. Albany Medical Center Hospital, Department of Epidemiology, 43 New Scotland Avenue, Albany, NY, USA. 7. JMI Laboratories, 345 Beaver Kreek Ctr, Ste A, North Liberty, IA, USA.
Abstract
OBJECTIVES: Several phenotypic characteristics of Staphylococcus aureus have been identified as aetiological factors responsible for adverse outcomes among patients receiving vancomycin. However, characterization of the outcomes associated with these reduced vancomycin susceptibility phenotypes (rVSPs) remains largely incomplete and it is unknown if these features contribute to deleterious treatment outcomes alone or in concert. This study described the interrelationship between rVSPs and assessed their individual and combined effects on outcomes among patients who received vancomycin for a methicillin-resistant S. aureus (MRSA) bloodstream infection. METHODS: An observational study of adult, hospitalized patients with MRSA bloodstream infections who were treated with vancomycin between January 2005 and June 2009 was performed. The rVSPs evaluated included the following: (i) Etest MIC; (ii) broth microdilution MIC; (iii) MBC : MIC ratio; and (iv) heteroresistance to vancomycin by the Etest macromethod. Failure was defined as any of the following: (i) 30 day mortality; (ii) bacteraemia ≥ 7 days on therapy; or (iii) recurrence of MRSA bacteraemia within 60 days of therapy discontinuation. RESULTS: During the study period, 184 cases met the study criteria and 41.3% met the failure criteria. There was a clear linear exposure-response relationship between the number of these phenotypic markers and outcomes. As the number of phenotypes escalated, the incidence of overall failure increased incrementally by 10%-18%. CONCLUSIONS: The data suggest that rVSPs contribute to deleterious treatment outcomes in concert.
OBJECTIVES: Several phenotypic characteristics of Staphylococcus aureus have been identified as aetiological factors responsible for adverse outcomes among patients receiving vancomycin. However, characterization of the outcomes associated with these reduced vancomycin susceptibility phenotypes (rVSPs) remains largely incomplete and it is unknown if these features contribute to deleterious treatment outcomes alone or in concert. This study described the interrelationship between rVSPs and assessed their individual and combined effects on outcomes among patients who received vancomycin for a methicillin-resistant S. aureus (MRSA) bloodstream infection. METHODS: An observational study of adult, hospitalized patients with MRSA bloodstream infections who were treated with vancomycin between January 2005 and June 2009 was performed. The rVSPs evaluated included the following: (i) Etest MIC; (ii) broth microdilution MIC; (iii) MBC : MIC ratio; and (iv) heteroresistance to vancomycin by the Etest macromethod. Failure was defined as any of the following: (i) 30 day mortality; (ii) bacteraemia ≥ 7 days on therapy; or (iii) recurrence of MRSA bacteraemia within 60 days of therapy discontinuation. RESULTS: During the study period, 184 cases met the study criteria and 41.3% met the failure criteria. There was a clear linear exposure-response relationship between the number of these phenotypic markers and outcomes. As the number of phenotypes escalated, the incidence of overall failure increased incrementally by 10%-18%. CONCLUSIONS: The data suggest that rVSPs contribute to deleterious treatment outcomes in concert.
Authors: A Capone; V Cafiso; F Campanile; G Parisi; B Mariani; N Petrosillo; S Stefani Journal: Eur J Clin Microbiol Infect Dis Date: 2016-01-27 Impact factor: 3.267