Serum capacity to neutralize superantigens does not affect the outcome of Staphylococcus aureus bacteremia

• Published in: European journal of clinical microbiology & infectious diseases 2012-08, Vol.31 (8), p.2061-2068
• Main Authors: Yi, J., Park, J. S., Hong, K.-H., Lee, S.-H., Kim, E.-C.
• Format: Article
• Language: English
• Subjects: Antibiotics; Antigens; Bacteremia; Bacterial diseases; Bacterial sepsis; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Blood; Catheters; Cell culture; Cell growth; Cell proliferation; Fatalities; Hospitals; Human bacterial diseases; Infection; Infectious diseases; Internal Medicine; Lymphocytes; Lymphocytes T; Medical instruments; Medical Microbiology; Medical prognosis; Medical sciences; Medicine; Mortality; Multivariate analysis; Nosocomial infections; Patients; Physiology; Polymerase chain reaction; Sepsis; Staphylococcal infections, streptococcal infections, pneumococcal infections; Staphylococcus aureus; Staphylococcus infections; Statistics; Superantigens; T cell receptors
• ISSN: 0934-9723; 1435-4373
• DOI: 10.1007/s10096-011-1541-2

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.