Abstract： Objective:To establish a rat model of severe sepsis induced by postburn Staphylococcus aureus infection.Methods:Male Wistar rats inflicted with 20% total body surface area fullthickness (Ⅲ degree TBSA) scald followed by Staphylococcus aureus challenge(8×1012 CFU/L rat).Results:It was found that following the postburn Staphylococcus aureus challenge,plasma tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ) and nitric oxide(NO) levels markedly elevated (P<0.05 or P<0.01).Meanwhile,serum alanine aminotransferase(ALT),aspartate transferase(AST),creatinine(Cr),isoenzyme of creatine kinase(CK-MB) levels and pulmonary myeloperoxidase (MPO) activities significantly increased at 24 hours postburn,and the multiple organ dysfunction was aggravated by Staphylococcus aureus challenge.Moreover,it was found that staphylococcal enterotoxin B(SEB) levels in heart,liver and kidneys were significantly positively correlated with CK-MB,ALT and Cr (r1=0.789,P=0.011;r2=0.846,P=0.004 and r3=0.670,P=0.048,respectively),together with a negative correlation between plasma SEB content and intestinal diamine oxidase(DAO)(r4=0.440,P=0.017).Conclusions:Thermal injury combined with Staphylococcus aureus challenge could induce excessive production of inflammatory cytokines accompanying with multiple organ damage,which appears to be in line with the criteria and features of severe sepsis.