Journal
JOURNAL OF CLINICAL MICROBIOLOGY
Volume 42, Issue 6, Pages 2398-2402Publisher
AMER SOC MICROBIOLOGY
DOI: 10.1128/JCM.42.6.2398-2402.2004
Keywords
-
Categories
Funding
- NIAID NIH HHS [AI-46919-01A2, AI-523213-01] Funding Source: Medline
Ask authors/readers for more resources
We attempted to find a relationship between the microbiological properties of bloodstream isolates of methicillin-resistant Staphylococcus aureus (MRSA) and the efficacy of vancomycin in the treatment of bacteremia. Vancomycin susceptibility testing was performed, and bactericidal activity was determined for 30 isolates from 30 different patients with MRSA bacteremia for whom clinical and microbiological outcome data were available. The majority of these patients had been previously enrolled in multicenter prospective studies of MRSA bacteremia refractory to conventional vancomycin therapy. Logistic regression found a statistically significant relationship between treatment success with vancomycin and decreases in both vancomycin MICs (less than or equal to50.5 mug/ml versus 1.0 to 2.0 mug/ml; P = 0.02) and degree of killing (reduction in log(10) CFU/milliliter) by vancomycin over 72 h of incubation in vitro (P = 0.03). For MRSA isolates with vancomycin MICs less than or equal to 0.5 mug/ml, vancomycin was 55.6% successful in the treatment of bacteremia whereas vancomycin was only 9.5% effective in cases in which vancomycin MICs for MRSA were 1 to 2 mug/ml. Patients with MRSA that was more effectively killed at 72 It by vancomycin in vitro had a higher clinical success rate with vancomycin therapy in the treatment of bacteremia (log(10) < 4.71 [n = 9], 0%; log(10) 4.71 to 6.26 [n = 13], 23.1%; log(10) > 6.27 [n = 8], 50%). We conclude that a significant risk for vancomycin treatment failure in MRSA bacteremia begins to emerge with increasing vancomycin MICs well within the susceptible range. Elucidating the mechanisms involved in intermediate-level glycopeptide resistance in S. aureus should begin by examining bacteria that begin to show changes in vancomycin susceptibility before the development of obvious resistance. Prognostic information for vancomycin treatment outcome in MRSA bacteremia may also be obtained by testing the in vitro bactericidal potency of vancomycin.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available