Objective: To examine whether presepsin level can serve as a distinguishing marker between G- bacteria and G+ bacteria, fungal infection in sepsis patients. Methods: A prospective observation study was conducted on the consecutive patients with positive bacterial cultures in intensive care unit (ICU) from June 2017 to November 2018. The patients were divided into the G- group, G+ group and fungal group. Blood samples were collected upon admission to measure the levels of presepsin and procalcitonin (PCT). Results: (1) Of the 156 patients met the inclusion criteria. 96 (62% G- rods, 25 (16%) G+ microbes, and 35 (22%) fungi were detected. (2) Presepsin concentrations were significantly higher in the G- group compared with the G+ and fungal groups (P = 0.000). (3) Presepsin level has a higher accuracy in differentiating G- sepsis from Gram+ and fungal sepsis than PCT level [area under the curve (AUC): 0.809 vs 0.712]. The AUC value of a combination of presepsin and PCT level was significantly larger than that of presepsin level alone in differentiating G- sepsis from Gram+ and fungal sepsis (AUC: 0.866 vs 0.809). Conclusions In contrast to PCT, presepsin is a good discriminative biomarker in different infections.

OBJECTIVE：To study the effects of Calpeptin inhibitor Calpeptin on the transformation and stemness markers expression induced by estradiol（E2），and to investigate its mechanism. METHODS ：Taking human mammary epithelial cells MCF-10A as research object ，transformed cells were induced by E 2 treatment. Cells were divided into control group （0.1％DMSO）， E2-transformed group （50 nmol/L），E2-transformed+Calpeptin group （50 nmol/L E 2+1 μmol/L Calpeptin），then continuously treated with corresponding drug-containing culture medium for 15 generations. Then ，MTT assay was used to determine the proliferation rate of cells （24，48 h）；plate colony test was used to detect the Clone formation rate of cells ；the number of sphere-forming cells was measured by suspension spheroidization test ；mRNA expressions of stemness marker （CD44，Nanog，OCT4）and extracellular sigal-regulated kinase （ERK）were detected by RT-qPCR ，and protein expressions of CD 44，Nanog，OCT4 ，ERK and p-ERK were detected by Western blotting assay. Another E 2-transformed cells were divided into control group （0.1％DMSO）and U0126 （ERK inhibitor ）group（10 μmol/L）. Clone formation rate ，the number of sphere-forming ，protein expressions of CD 44，Nanog， OCT4，ERK and p-ERK were determined with above methods ，and to validate the relationship of ERK inhibition with transformed cell behavior and the expression of stemness markers. RESULTS ：Compared with control group ，proliferation rate and clone formation rate of E 2 transformed group were increased significantly （P＜0.01），and the number of sphere-forming was increased significantly（P＜0.01）；mRNA expression levels of CD 44，Nanog，OCT4，ERK and protein expression levels of CD 44，Nanog， OCT4 and p-ERK in cells were increased significantly （P＜0.01）. Compared with E 2-transformed group ，proliferation rate （24，48 h）and clone formation rate of E 2-transformed + Calpeptin group were decreased significantly （P＜0.01），and the number of sphere-forming was decreased significantly （P＜0.05）；mRNA expression levels of CD 44，Nanog，OCT4 ，ERK and protein expression levels of CD 44，Nanog，OCT4，p-ERK in cells were decreased significantly （P＜0.05 or P＜0.01）. After treated with ERK inhibitor U 0126，clone formation rate of E 2-transformed cells ，the number of sphere-forming ，protein expression levels of CD44，Nanog，OCT4 and p-ERK were increased significantly （P＜0.05 or P＜0.01）. CONCLUSIONS ：Calpeptin can inhibit the transformation and the expression of stemness markers of human mammary epithelial cells MCF- 10A，and the mechanism of it may be associated with inhibiting the activation of Calpain-ERK signaling pathway.