title: Serum capacity to neutralize superantigens does not affect the outcome of Staphylococcus aureus bacteremia.
abstract: Staphylococcal superantigens (SAg) could play an important role in sepsis by activating numerous T cells. We investigated whether serum capacity to neutralize SAgs can be a prognostic factor in Staphylococcus aureus bacteremia (SAB). In a university hospital, 105 consecutive SAB patients were enrolled during a 12-month period. The earliest serum samples prior to SAB onset were stored for a later T cell proliferation assay. Multiplex polymerase chain reaction (PCR) for 19 SAg genes was performed for S. aureus blood isolates. To determine the serum capacity to neutralize SAgs, T cell proliferation by the culture supernatant of each S. aureus isolate was measured in the presence and absence of the corresponding patient's serum. Twenty-six (24.8%) patients died within 4 weeks from SAB onset. Vascular catheter-related infection was associated with survival for ≥4 weeks. Unknown primary focus, Simplified Acute Physiology Score-II (SAPS-II), and specific SAg genes (tst, sec, sel, or sep) were associated with the 4-week mortality. No variables related to T cell proliferation assay showed statistical significance. In the multivariate analysis, SAPS-II ≥33 and tst were independently associated with the 4-week mortality. Serum capacity to neutralize SAg does not significantly affect SAB outcome. SAPS-II ≥33 and tst are independent predictors of the 4-week mortality.
authors.affiliation: Department of Laboratory Medicine, Pusan National University School of Medicine, Yangsan, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Yi
authors.forename: J S
authors.initials: JS
authors.lastname: Park
authors.forename: K-H
authors.initials: KH
authors.lastname: Hong
authors.forename: S-H
authors.initials: SH
authors.lastname: Lee
authors.forename: E-C
authors.initials: EC
authors.lastname: Kim