In this prospective, multicentered , diagnostic trial, nasal and fecal specimens will collected from patients with sepsis in two critical care units(ICU) at the enrollment day ,the third, seventh, and fourteen days after enrollment or until ICU discharge (whatever come first). Total DNA from the nasal and fecal specimens will be extracted, amplified, and sequenced to determined the characteristics of gut microbiota and nasal microbiota. Finally, the characteristics of gut microbiota and nasal microbiota combined clinical information will be used to construct a prediction model to predict the prognosis of sepsis.

Background:

Sepsis should be defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, with high morbidity and mortality, and its total mortality is 10% to 52%. In sepsis, it is not clear sufficiently about the relationship between intestinal and nasal microbiota character and the development of the sepsis.The study aim to construct a prediction model to predict the prognosis and development of sepsis.

Purpose:

1. To construct a prediction model using nasal and gut microbiota combined with clinical events to predict the prognosis of patients with sepsis and development of sepsis.
2. Analyze the characteristics of nasal and gut microbiota in patients with sepsis using microbiology.

Methods:

nasal and fecal specimens will collected from patients with sepsis in two critical care units(ICU) at the enrollment day ,the third, seventh, and fourteen days after enrollment or until ICU discharge (whatever come first). Total DNA from the nasal and fecal specimens will be extracted, amplified, and sequenced to determined the characteristics of gut microbiota and nasal microbiota. Meanwhile, some related clinical information also will be collected,including demographic characteristics, comorbidities, infection site, results of the microbiology experiments, vital signs, invasive tubing indwelling at enrollment，combined medication，the requirement of organ function support, laboratory indexing, sequential organ failure assessment score and Acute Physiology and Chronic Health Evaluation score. Finally, the characteristics of gut microbiota and nasal microbiota combined the clinical information will be used to construct a prediction model to predict the prognosis of sepsis. The primary outcome is the 28-day all-cause mortality. The secondary outcomes are the incidence of septic shock, the incidence of persistent inflammation- immunosuppression catabolism syndrome and the 90-day all-cause mortality.

Inclusion Criteria:

1. Meet the 2016 International Sepsis Guidelines diagnostic criteria (sepsis 3.0).
2. Serum procalcitonin≥ 2 ng/mL at enrollment.

Exclusion Criteria:

Patients will be excluded if participants meet any of the following criteria:

1. age<18 years old or > 80 years
2. pregnancy or lactation
3. solid organ or bone marrow transplant
4. advanced pulmonary fibrosis
5. HIV-positive
6. neutropenia;
7. hematological/lymphatic tumors have no remission;
8. limited care (lack of commitment to full and aggressive support);
9. long-term use of immunosuppressive drugs or immunodeficiency;
10. advanced tumors;
11. combined with noninfectious factors leading to death (uncontrolled large bleeding, cerebral hernia, etc.);
12. Combined with autoimmune diseases
13. Paraquat poisoning
14. Combined with Nasopharyngeal carcinoma
15. Combined with chronic nasosinusitis
16. Combined with severe nasal injuries

In this study, patients who met the Sepsis 3.0 diagnostic criteria and with PCT ≥ 2ng/ml and will be recruited.

The datasets generated and analyzed during the study are available from the corresponding author on reasonable request.