Alterations of gut microbiota in cirrhotic patients with spontaneous bacterial peritonitis: A distinctive diagnostic feature.

Background: Spontaneous bacterial peritonitis (SBP) is a severe infection in cirrhotic patients that requires early diagnosis to improve the long-term outcome. Alterations in the gut microbiota have been shown to correlate with the development and progression of liver cirrhosis. However, the relationship between SBP and gut microbiota remains unknown. Methods: In this study, we applied 16S rRNA pyrosequencing of feces to ascertain possible links between the gut microbiota and SBP. We recruited 30 SBP patients, 30 decompensated cirrhotic patients without SBP (NSBP) and 30 healthy controls. Metagenomic functional prediction of bacterial taxa was achieved using PICRUSt. Results: The composition of the gut microbiota in the SBP patients differed remarkably from that in the NSBP patients and healthy individuals. The microbial richness was significantly decreased, while the diversity was increased in the SBP patients. Thirty-four bacterial taxa containing 15 species, mainly pathogens such as Klebsiella pneumoniae, Serratia marcescens and Prevotella oris, were dominant in the SBP group, while 42 bacterial taxa containing 16 species, especially beneficial species such as Faecalibacterium prausnitzii, Methanobrevibacter smithii and Lactobacillus reuteri, were enriched in the NSBP group. Notably, we found that 18 gene functions of gut microbiota were different between SBP patients and NSBP patients, which were associated with energy metabolism and functional substance metabolism. Five optimal microbial markers were determined using a random forest model, and the combination of Lactobacillus reuteri, Rothia mucilaginosa, Serratia marcescens, Ruminococcus callidus and Neisseria mucosa achieved an area under the curve (AUC) value of 0.8383 to distinguish SBP from decompensated cirrhosis. Conclusions: We described the obvious dysbiosis of gut microbiota in SBP patients and demonstrated the potential of microbial markers as noninvasive diagnostic tools for SBP at an early stage.

[Fourier transform infrared spectroscopic study of Coprinus comatus].

In the paper, Fourier transform infrared (FTIR) spectroscopy was used to study the fruiting body of wild growing and cultivated Coprinus comatus and the cap of the mushroom before and after deliquescing into inky liquid. The results show that the infrared spectra of Coprinus comatus are mainly composed of the absorption bands of protein and polysaccharide. Remarkable differences are observed in the absorption bands of polysaccharide between the spectra of the wild growing and cultivated mushrooms, by which the wild growing and cultivated Coprinus comatus can be discriminated. It was also found that the absorption bands of polysaccharide become weaker obviously in the black-inky samples of deliquescing cap compared with the un-deliquescing cap, indicating that the polysaccharides in the cap of Coprinus comatus are transformed during the process of cap deliquescing into a black, inky liquid. The spectral results can offer useful information for a further study of Coprinus comatus.