Predictors of persistent methicillin-resistant Staphylococcus aureus bacteraemia in patients treated with vancomycin.
OBJECTIVE
The high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) coupled with an increase in vancomycin use have induced vancomycin tolerance in MRSA, adversely affecting the outcome of MRSA bacteraemia. This study aimed to identify predictors of persistent MRSA bacteraemia (PMRSAB) in patients treated with vancomycin.


METHODS
A retrospective, case-control study was performed at a university hospital in Korea from January 2006 to February 2009. Subjects included 96 patients who had MRSA bacteraemia and received vancomycin under therapeutic drug monitoring. We compared the clinical characteristics, management and outcomes of cases with PMRSAB (>or=7 days, n = 31) with controls with non-PMRSAB (<or=3 days, n = 32). Vancomycin MICs were determined by the Vitek 2 system.


RESULTS
Of 96 patients with MRSA bacteraemia, MRSA isolates from 21 patients (21.9%) showed a vancomycin MIC of 2 mg/L. Independent predictors of PMRSAB were: retention of implicated medical devices [odds ratio (OR), 10.35; 95% confidence interval (CI), 1.03-104.55]; MRSA infection of at least two sites (OR, 10.24; 95% CI, 1.72-61.01); and vancomycin MIC of 2 mg/L (OR, 6.34; 95% CI, 1.21-33.09). The frequency of side effects and mean trough serum vancomycin concentrations were not significantly different between the two groups. Sixteen patients with PMRSAB subsequently received teicoplanin +/- arbekacin, linezolid or quinupristin/dalfopristin, due to vancomycin failure or intolerance.


CONCLUSIONS
To minimize the risk of PMRSAB, early removal of implicated devices and evaluation for metastatic infections should be encouraged. Alternative antibiotic therapy is warranted for infections due to isolates with elevated vancomycin MICs, as well as for the high rates of side effects.
Yoon
Young Kyung
YK
Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
Kim
Jeong Yeon
JY
Park
Dae Won
DW
Sohn
Jang Wook
JW
Kim
Min Ja
MJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology*; D016022:Case-Control Studies; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007723:Korea; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000382:microbiology*; D016896:Treatment Outcome; D014640:Vancomycin / Q000627:therapeutic use*
D000900:Anti-Bacterial Agents; D014640:Vancomycin