br Introduction Bloodstream infection BSI

Introduction Bloodstream infection (BSI) is a type of common infectious disease in hospitals with poor prognosis, which is caused by pathogens invasion and rapid reproduction in the bloodstream. Its general symptoms are characterized by chills, high fever, and rash, etc. The pathogens include bacteria, fungi, and viruses etc., among which, bacteria takes up a large proportion. The incidence of bacterial BSI is increasing steadily in recent years due to excessive use of antibiotics, unreasonable application of intravascular catheter and a large number of invasive examinations, and the mortality rate has increased to 30%. Thus, it is particularly important to diagnose and treat BSI at an early stage. The blood culture is the gold-standard method for the diagnosis of BSI, but its long culture time and low positive rates make the timely diagnosis and therapy impossible for most of the BSI patients. There are some other molecular diagnosis methods for BSI, such as Real-time PCR, PCR+Sequencing, PNA+FISH, etc., with common problems like complicated operation and time-consuming process. Bacteria stimulate the immune dihydrochloride and promote the production of a variety of cytokines, chemokines and acute phase reaction proteins, such as IL-6, IL-8, IL-10, IL-12p40, IL-12p70, CRP and PCT. CRP and PCT can be used as auxiliary diagnostic indexes but the specificity is poor. IL-6, mainly produced by macrophages, T cells and B cells, has the function of regulating immune response and acute phase response, and plays an important role in the anti-infection immune response. IL-10 is a type of cytokines secreted by Treg cells, and it can mediate immune response with the main biological activity immunosuppression. There are few reports about the expression differences of IL-6 and IL-10 in the BSI caused by different bacterial and about the change trends over time. In this study, the expression levels of IL-6 and IL-10 in serum of mice infected with Staphylococcus areaus, Enterococcus faecalis, Escherichia coli and Klebsiella pneumoniae were detected by The Luminex® xMAP™ System, which aims to investigate the clinical significance of IL-6 and IL-10 in bacterial BSI and provide a basis for early diagnosis and differential diagnosis for BSI caused by different kinds of bacteria.
Materials and methods
Results
Discussion BSI is associated with high morbidity, mortality and hospital costs. There are few early diagnosis methods for BSI. The identification of BSI mostly relies on blood culture conventionally, but cerebral cortex method has low positive rate, and is time-consuming. There are some other molecular methods for BSI diagnosis, such as Real-time PCR, PCR+Sequencing, PNA+FISH, etc., with common drawbacks like complicated operation and time-consuming process. In addition, bacteria DNA extracted from clinical samples are usually influenced by the content of bacteria in the blood of suspected BSI patients and proficiency of operators. Thus, these methods cannot provide an accurate basis for clinical diagnosis at the early stage of BSI. Cytokines and chemokines produced by the stimulation of bacterial play an important role in auxiliary diagnosis for BSI. Corresponding immune response is triggered by the infected body after the stimulation from the bacterial. It is a complicated process and immune reactions caused by different kinds of bacterial can be different. The immune response can be divided into intracellular immunity and extracellular immunity, according to the different parasitic sites of bacterial in the infected bodies. Besides, the immune responses stimulated by G+ bacterial infection and G− bacterial infection are also different. At present, the biomarkers used clinically for diagnosis of infection are CRP, PCT, etc., with an unsatisfactory specificity. In our previous study, mouse models infected with a single type of bacteria were established and evaluated. In order to search for early biomarkers of different bacteria and provide a basis for early diagnosis and therapy for bacterial BSI, the same method was applied to this study for S. areaus, E. faecalis, E. coli and K. pneumoniae infected models.