Relationship between hVISA and outcomes among patients with MRSA bloodstream infections treated with vancomycin

Abstract number: P1461

Patel N., Graffunder E., Evans A., Helmecke M., Stellrecht K., Lodise T.P.

Objectives: To examine the relationship between MRSA strains express heterogenous resistance to vancomycin (hVISA) and outcomes among patients with MRSA bloodstream infections treated with vancomycin.

Methods: Study period: 1/05–4/07. Inclusion criteria: (1) leqslant R: less-than-or-eq, slant18 yrs, (2) MRSA bacteraemia (met CDC criteria), (3) received vancomycin therapy within 48 hours of index MRSA blood culture, and (4) survived >24 hours after start of therapy. Demographics, co-morbid conditions, microbiology, and treatment data were collected. MRSA strains with an MIC value geqslant R: gt-or-equal, slanted6 mg/L on high inoculum brain heart infusion agar plates were considered hVISA (method of Walsh et al). Failure was defined as in-hospital mortality, bacteraemia leqslant R: less-than-or-eq, slant7 days on vancomycin therapy, or recurrence of MRSA bacteraemia within 60 days of vancomycin discontinuation. Length of stay (LOS) after start of vancomycin was also compared between groups. Parameters associated with failure by bivariate analysis (P < 0.2) were included a multivariate analysis and a stepwise approach was used to identify independent predictors.

Results: During the study period, 92 patients met the inclusion criteria. Of the 92 patients, 17 (18.5%) were hVISA positive. Comparison of outcomes between hVISA and non-hVISA patient groups are provided in the table. In the multivariate analysis, the parameters independently associated with failure were hVISA (Adjusted odds ratio (AOR), 4.3; 95% CI: 1.3–14.5, p-value=0.02), APACHE-II score leqslant R: less-than-or-eq, slant22 (AOR, 16.9; 95% CI: 1.9–80.2, p-value=0.01), and dialysis (AOR, 3.9; 95% CI: 1.3–11.8, p-value= 0.02.

Bivariate analysis of outcomes between hVISA patient groups

Conclusions: The data strongly suggest that patients with hVISA MRSA bloodstream infections respond poorly to vancomycin. Alternative anti-MRSA therapies should be considered for these patients.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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