Background
Adipokines, secreted from adipose tissues, play crucial roles in immune and metabolic processes. Their role in severe bacterial infections, such as Staphylococcus aureus bacteremia (SAB), remains poorly understood.
Objective
To investigate adipokine serum levels during and after bacteremia and their association with disease severity and clinical outcomes.
Methods
Fifty-two patients with bacteremia (71% S. aureus, 29% other pathogens) were matched 1:1 in a prospective case-control study with infection-free controls by age, sex, and comorbidities. Serum levels of adiponectin, resistin, and visfatin were measured during bacteremia, during convalescence, and in controls using ELISA. Disease severity was assessed using Simplified Acute Physiology Score II (SAPS II) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and adipokine serum levels were correlated with disease severity and hospital mortality.
Results
Resistin (median 25.6 ng/mL vs. 13.8 ng/mL, p  < 0.001) and visfatin (median 19.3 ng/mL vs. 10.3 ng/mL, p = 0.004) were significantly elevated in patients with bacteremia compared to controls. Adiponectin during bacteremia was similar to that in controls, but significantly lower than during convalescence (median 3.5 μg/mL vs. 5.4 μg/mL, p  < 0.001). S. aureus bacteremia showed a trend towards lower adiponectin levels compared to other pathogens. A combined adipokine score using partial least squares (PLS) regression demonstrated superior correlation with disease severity (SAPS II; ρ = 0.430, p = 0.001) compared to individual adipokines. Exploratory logistic regression showed that including adipokines in a model based on clinical variables may improve mortality prediction (area under the receiver operating characteristic curve [AUC] increase from 0.784 to 0.944).
Conclusions
Adipokines show distinct patterns during bacteremia, with higher levels of proinflammatory resistin and visfatin in bacteremia and higher levels of anti-inflammatory adiponectin in convalescence. While individual adipokines have modest prognostic value, combined scores are associated with disease severity and mortality in severe infections.