Characteristics and outcomes of methicillin-resistant staphylococcus aureus bloodstream infections in patients with cancer treated with vancomycin: 9-year experience at a comprehensive cancer center.
BACKGROUND
Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSIs) can cause significant morbidity and mortality in patients with cancer. However, data on outcomes of patients treated with vancomycin are lacking.


METHODS
We identified 223 patients with cancer who developed MRSA BSIs between January 2001 and June 2009 and were treated with vancomycin. Treatment failure was defined as death within 60 days of infection, persistent bacteremia ≥5 days, fever ≥4 days, recurrence or relapse, and secondary MRSA infection.


RESULTS
The treatment failure rate was 52% (116 of 223 patients). These patients were more likely to have been hospitalized, been treated with steroids within the previous 3 months, developed acute respiratory distress syndrome, required mechanical ventilation, required intensive care unit care, and community-onset infections (all p < .05). Risk factors for MRSA-associated mortality (27 of 223 patients; 12%) included hematologic malignancy and hematopoietic stem cell transplantation, community-onset infection, secondary BSI, MRSA with minimum inhibitory concentration (MIC) ≥2.0 μg/mL, mechanical ventilation, and a late switch to an alternative therapy (≥4 days after treatment failure; all p < .05). On multivariate analysis, mechanical ventilation and recent hospitalization were identified as independent predictors of vancomycin failure, and community-onset infection, secondary BSIs, and MIC ≥2 μg/mL were identified as significant predictors of MRSA-associated mortality.


CONCLUSIONS
We found a high treatment failure rate for vancomycin in patients with cancer and MRSA BSIs, as well as a higher mortality. A vancomycin MIC ≥2 μg/mL was an independent predictor of MRSA-associated mortality. An early switch to an alternative therapy at the earliest sign of failure may improve outcome.
Department of Infectious Diseases, Infection Control and Employee Health, Unit 1460, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, Texas 77030, USA.
Sminil N
SN
Mahajan
Jharna N
JN
Shah
Ray
R
Hachem
Frank
F
Tverdek
Javier A
JA
Adachi
Victor
V
Mulanovich
Kenneth V
KV
Rolston
Issam I
II
Raad
Roy F
RF
Chemaly
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood / Q000382:microbiology*; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology*; D016896:Treatment Outcome; D014640:Vancomycin / Q000627:therapeutic use*
D000900:Anti-Bacterial Agents; D014640:Vancomycin