Risk factors for hospital-acquired Staphylococcus aureus bacteremia.
BACKGROUND
Staphylococcus aureus bacteremia (SAB) acquired in hospitals continues to be a frequent and serious complication to hospitalization, and no previous case-control studies dealing with risk factors of this severe disease are available.


METHODS
Based on a 1-year prospective analysis, the data from all patients with hospital-acquired SAB admitted to 4 hospitals in Copenhagen County, Denmark, from May 1, 1994, through April 30, 1995, were evaluated. Eighty-five patients with hospital-acquired SAB were matched to 85 control patients with a similar primary diagnosis at admission (matched controls). Of these, 62 patients with hospital-acquired SAB were compared with 118 other patients with a similar time of admission, who were randomly selected with no clinical evidence of SAB (unmatched controls).


RESULTS
The incidence of hospital-acquired SAB was 0.71 per 1000 hospital admissions. The presence of a central venous catheter (odds ratio, 6.9; 95% confidence interval [CI], 2.8-17.0), anemia (odds ratio, 3.3; 95% CI, 1.4-7.6), and hyponatremia (odds ratio, 3.3; 95% CI, 1.5-7.0) was significantly associated with hospital-acquired SAB in a conditional and a usual logistic regression analysis. Nasal carriage was not an independent risk factor, but nasal carriers among patients in surgery (odds ratio, 4.0; 95% CI, 1.3-13.0) had a significantly higher risk for hospital-acquired SAB compared with matched and unmatched controls. The presence of hospital-acquired SAB increased the mortality rate 2.4-fold (95% CI, 1.1-5.2).


CONCLUSIONS
The presence of a central venous catheter is an important risk factor, and hyponatremia and anemia are associated with the development of hospital-acquired SAB. Furthermore, hospital-acquired SAB in itself increases mortality.
Jensen
A G
AG
Sector for Microbiology, Statens Serum Institut, Copenhagen, Denmark.
Wachmann
C H
CH
Poulsen
K B
KB
Espersen
F
F
Scheibel
J
J
Skinhøj
P
P
Frimodt-Møller
N
N
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000009:adverse effects; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000150:complications; D000900:Anti-Bacterial Agents / Q000009:adverse effects; D016470:Bacteremia / Q000453:epidemiology* / Q000209:etiology* / Q000382:microbiology; D016022:Case-Control Studies; D002405:Catheterization, Central Venous / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology* / Q000209:etiology* / Q000382:microbiology; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006764:Hospitals, Community; D006801:Humans; D007010:Hyponatremia / Q000150:complications; D016867:Immunocompromised Host; D007223:Infant; D007262:Infusions, Intravenous / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000382:microbiology; D016017:Odds Ratio; D011446:Prospective Studies; D012044:Regression Analysis; D006435:Renal Dialysis / Q000009:adverse effects; D012307:Risk Factors; D012737:Sex Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000209:etiology* / Q000382:microbiology; D013211:Staphylococcus aureus; D013514:Surgical Procedures, Operative / Q000009:adverse effects; D016019:Survival Analysis; D065227:Transfusion Reaction
D000305:Adrenal Cortex Hormones; D000900:Anti-Bacterial Agents