Persistent Staphylococcus aureus bacteremia: an analysis of risk factors and outcomes.
BACKGROUND
Persistent Staphylococcus aureus bacteremia (pSAB) is an emerging problem among hospitalized patients. We studied key clinical characteristics and outcomes associated with pSAB to better define the epidemiological features of this increasingly recognized clinical entity.


METHODS
A retrospective case-control study of patients hospitalized with SAB between January 1, 2001, and September 30, 2004, was conducted to compare the clinical characteristics, management, and outcomes of patients with pSAB (> 7 days of bacteremia) with those of a cohort of patients with nonpersistent SAB (< 3 days of bacteremia). Patients with 4 to 6 days of bacteremia were excluded from the analysis. To detect a potential association between reduced susceptibility to vancomycin and persistent methicillin-resistant SAB, vancomycin susceptibilities were confirmed using standard dilution methods.


RESULTS
Eighty-four patients with pSAB and 152 patients with nonpersistent SAB were included in the analysis. Methicillin resistance (odds ratio [OR], 5.22; 95% confidence interval [CI], 2.63-10.38), intravascular catheter or other foreign body use (OR, 2.37; 95% CI, 1.11-3.96), chronic renal failure (OR, 2.08; 95% CI, 1.09-3.96), more than 2 sites of infection (OR, 3.31; 95% CI, 1.17-9.38), and infective endocarditis (OR, 10.30; 95% CI, 2.98-35.64) were independently associated with pSAB. The mean time to device removal was significantly longer in patients with pSAB than in patients with nonpersistent SAB (4.94 vs 1.64 days; P < .01). There was no evidence of reduced vancomycin susceptibility among persistent methicillin-resistant S aureus isolates. Clinical outcomes were significantly worse among patients with pSAB.


CONCLUSIONS
Many hospitalized patients may be at risk for pSAB. Aggressive attempts to minimize the risk of complications and poor outcomes associated with pSAB, such as early device removal, should be encouraged.
Hawkins
Claudia
C
Department of Infectious Diseases, Northwestern University Feinberg School of Medicine, 676 N St Clair, Ste 200, Chicago, IL 60611, USA. c-hawkins@md.northwestern.edu
Huang
Jenny
J
Jin
Nancy
N
Noskin
Gary A
GA
Zembower
Teresa R
TR
Bolon
Maureen
M
D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D016896:Treatment Outcome; D014640:Vancomycin / Q000494:pharmacology
D014640:Vancomycin