简介：AbstractPurpose:COVID-19 is also referred to as a typical viral septic pulmonary infection by 2019-nCoV. However, little is known regarding its characteristics in terms of systemic inflammation and organ injury, especially compared with classical bacterial sepsis. This article aims to investigate the clinical characteristics and prognosis between COVID-19-associated sepsis and classic bacterial-induced sepsis.Methods:In this retrospective cohort study, septic patients with COVID-19 in the intensive care unit (ICU) of a government-designed therapy center in Shenzhen, China between January 14, 2020 and March 10, 2020, and septic patients induced by carbapenem-resistant klebsiella pneumonia (CrKP) admitted to the ICU of the Second People's Hospital of Shenzhen, China between January 1, 2014 and October 30, 2019 were enrolled. Demographic and clinical parameters including comorbidities, critical illness scores, treatment, and laboratory data, as well as prognosis were compared between the two groups. Risk factors for mortality and survival rate were analyzed using multivariable logistic regression and survival curve, respectively.Results:A total of 107 patients with COVID-19 and 63 patients with CrKP were enrolled. A direct comparison between the two groups demonstrated more serious degrees of primary lung injury following 2019-nCoV infection (indicated by lower PaO2/FiO2), but milder systemic inflammatory response, lower sequential organ failure assessment score and better functions of the organs like heart, liver, kidney, coagulation, and circulation. However, the acquired immunosuppression presented in COVID-19 patients was more severe, which presented as lower lymphocyte counts (0.8×109/L vs. 0.9×109/L). Moreover, the proportion of COVID-19 patients treated with corticosteroid therapy and extracorporeal membrane oxygenation was larger compared with CrKP patients (78.5% vs. 38.1% and 6.5% vs. 0, respectively) who required less invasive mechanical ventilation (31.6% vs. 54.0%). The incidence of hospitalized mortality and length of ICU stay and total hospital stay were also lower or shorter in viral sepsis (12.1% vs. 39.7%, 6.5 days vs. 23.0 days and 21.0 days vs. 33.0 days, respectively) (all p < 0.001). Similar results were obtained after being adjusted by age, gender, comorbidity and PaO2/FiO2. Lymphocytopenia and high acute physiology and chronic health evaluation II scores were common risk factors for in-hospital death. While the death cases of COVID-19 sepsis mostly occurred at the later stages of patients’ hospital stay.Conclusion:Critical COVID-19 shares clinical characteristics with classical bacterial sepsis, but the degree of systemic inflammatory response, secondary organ damage and mortality rate are less severe. However, following 2019-nCoV infection, the level of immunosuppression may be increased and thus induce in more death at the later stage of patients’ hospitalstay.