16S rDNA-based molecular profiles of circulating bacteria in patients with severe acute pancreatitis / 肠外与肠内营养

ABSTRACT

Objective:This study aims to characterize the bacterial profile presenting in peripheral blood of severe acute pancreatitis (SAP) patients and investigate the potential role of circulating microorganisms in the development of systemic infection.Methods:A total of 30 patients with SAP were recruited in this study and divided into three groupsinfected,sepsis and Septic shock (n =10 for each group).The peripheral blood was collected sterilely for extraction of DNA,which was subsequently amplified using the universe primers targeted the V6-V8 region of 16S ribosomal RNA genes.The amplicons were separated by denaturing gradient gel electrophoresis (DGGE),and then the gels were stained and photographed.The bands were cut out and sequenced to determine the closest bacterial relatives.Results:As shown in DGGE profile,multiple DNA bands (3 to 8 bands) were detected in peripheral blood from all (100％) of SAP patients complicated with septic shock.The microorganisms most frequently presenting in the blood of these cases included Escherichia coli,Bacillus coagulans,Pseudomonas putida,Pseudomonas aeruginosa,and Klebsiella pneumonia,with an incidence of 40 ％ or higher.In patients with sepsis,bacterial DNA consisting of 2 to 4 bands was observed in 90％ of the blood samples.The most common bacterial species was Pseudomonas putida (60％),followed by Shigella flexneri (40％),Staphylococcus aureus (30％) and Enterococcusfaecium (20％).By contrast,the positive rate of blood bacterial DNA was relatively lower in infected patients (70 ％).Of them,single bacterial species was commonly found in the blood samples.Conclusions:Our data showed that the bacterial profiles presenting in peripheral blood are distinct among SAP patients with different manifestations.Polymicrobial translocation could contribute to the development of systemic infection,offering novel insights into the pathogenesis of sepsis in SAE The findings are helpful for the prevention and treatment for bacterial infection and complications of SAP.