Microbiological diagnostic performance of metagenomic next-generation sequencing compared with conventional culture for patients with community-acquired pneumonia.

Background: Community-acquired pneumonia (CAP) is an extraordinarily heterogeneous illness, both in the range of responsible pathogens and the host response. Metagenomic next-generation sequencing (mNGS) is a promising technology for pathogen detection. However, the clinical application of mNGS for pathogen detection remains challenging. Methods: A total of 205 patients with CAP admitted to the intensive care unit were recruited, and broncho alveolar lavage fluids (BALFs) from 83 patients, sputum samples from 33 cases, and blood from 89 cases were collected for pathogen detection by mNGS. At the same time, multiple samples of each patient were tested by culture. The diagnostic performance was compared between mNGS and culture for pathogen detection. Results: The positive rate of pathogen detection by mNGS in BALF and sputum samples was 89.2% and 97.0%, which was significantly higher (P < 0.001) than that (67.4%) of blood samples. The positive rate of mNGS was significantly higher than that of culture (81.0% vs. 56.1%, P = 1.052e-07). A group of pathogens including Mycobacterium abscessus, Chlamydia psittaci, Pneumocystis jirovecii, Orientia tsutsugamushi, and all viruses were only detected by mNGS. Based on mNGS results, Escherichia coli was the most common pathogen (15/61, 24.59%) of non-severe patients with CAP, and Mycobacterium tuberculosis was the most common pathogen (21/144, 14.58%) leading to severe pneumonia. Pneumocystis jirovecii was the most common pathogen (26.09%) in severe CAP patients with an immunocompromised status, which was all detected by mNGS only. Conclusion: mNGS has higher overall sensitivity for pathogen detection than culture, BALF, and sputum mNGS are more sensitive than blood mNGS. mNGS is a necessary supplement of conventional microbiological tests for the pathogen detection of pulmonary infection.

Generation behavior of extracellular polymeric substances and its correlation with extraction efficiency of valuable metals and change of process parameters during bioleaching of spent petroleum catalyst.

The vital functions of extracellular polymeric substances (EPS) have been well recognized in bioleaching of sulfide ores. However, no report is available about the role of EPS in bioleaching of spent catalyst. To completely and deeply understand the functions of EPS in bioleaching of spent catalyst, the generation behavior of EPS at various pulp densities during bioleaching was characterized by three-dimensional excitation-emission matrix (3DEEM), and its relevance with bioleaching performance and process parameters were analyzed using mathematical means. The results showed that the EPS contain humus-like substances as main component (>70%) and protein-like substances as minor component (<30%). Both total EPS and humus-like substances mainly keep growing over the whole duration of bioleaching at low pulp density of 5.0% or lower; whereas total EPS and humus-like fraction keep declining at high pulp density of 7.5% or higher. Among the total EPS and its components, humus-like substances only have a positive significant correlation with bioleaching efficiencies of both Co and Mo and affect bioleaching process more greatly due to greater correlation coefficient. Biofilm appears at the spent catalyst surface under 2.5% of pulp density mediated by EPS while no biofilm occurs at 10% of pulp density due to shortage of EPS, accounting for the great difference in bioleaching efficiencies between high and low pulp densities which are 48.3% for Mo and 50.0% for Co at 10% of pulp density as well as 75.9% for Mo and 78.8% for Co at 2.5% of pulp density, respectively.

Optimization of Melanin Extraction from the Wood Ear Medicinal Mushroom, Auricularia auricula-judae (Agaricomycetes), by Response Surface Methodology and Its Antioxidant Activities In Vitro.

The optimal conditions for melanin extraction from Auricularia auricula-judae (Hei 29) fruiting bodies was determined on the basis of the extract yield of melanin, calculated by using a single-factor experiment and response surface methodology. Its antioxidant activities were also studied in vitro. Various optimal process conditions for melanin extraction were determined by using Design-Expert software: incubation temperature, 69.11°C; incubation time, 58.66 minutes; and incubation pH, 12.81. Under these conditions, the melanin yield was 2.59%. We found that the antioxidant activities of A. auricula-judae melanin in vitro were strong against DPPH radicals and superoxide anions. The rate of DPPH radical scavenging was 63.04% when the A. auricula-judae melanin concentration was 0.36 mg/mL; the rate of superoxide anion scavenging reached 39.79% when the concentration was 0.375 mg/mL. However, the antioxidant activity against hydroxyl radicals was somewhat weak; the rate of scavenging reached only 7.47% when the A. auricula-judae melanin concentration was 0.06 mg/mL.

Identification of a New Fungal Pathogen Causing White Villous Disease on the Fruiting Body of the Culinary-Medicinal Mushroom Auricularia auricula-judae (Agaricomycetes) in China.

Auricularia auricula-judae is an edible and medicinal fungus ranking fourth in production among the edible fungi cultivated worldwide. White villous disease is rampant in Northeast China; it infects the fruiting bodies of A. auricula-judae by forming a white mycelial layer on its ventral side. The disease not only causes an unacceptable morphological appearance and a poor-quality product, but it also significantly reduces the yield. In this study, based on fungal morphology, ribosomal DNA internal transcribed spacer sequences, identification of species-specific primers, and the pathogenicity of the mycelia and spores, 2 fungal pathogens were isolated and identified as Fusarium equiseti and F. sporotrichioides.

[Effects of Fructus Psoralea and Brucea javanica on the level of IL-2 and NK cell in rats infected with Pneumocystis carinii].

SD rat model of PCP was established by subcutaneous injection with dexamethasone. The treatment groups received Fructus Psoralea (FP, 10.0 mg/kg), Brucea javanica (BJ, 1.2 mg/kg) and a mixture of the two Chinese herbs(FP 5mg/kg, BJ 0.6 mg/kg) respectively. By means of detecting the level of IL-2 in sera and NK cells in spleens, the effect of FP and BJ on the level of IL-2 and NK cells in rats with Pneumocystis carinii pneumonia (PCP) was observed, with SMZco treatment group (TMP 50 mg/kg, SMZ 250 mg/kg) and groups of infected and normal rats as controls. Compared with the infected group, the level of IL-2(526.1 +/- 5.5) pg/ml and NK cells (27.1% +/- 0.8%) significantly increased in the FP group (P < 0.01), followed by the FP/BJ combination group [(314.7 +/- 6.7) pg/ml, 22.9% +/- 0.9%) (P < 0.05)], and BJ group [(285.4 +/- 6.1) pg/ml, 20.7% +/- l.0%) (P < 0.05)]. Chinese herbs Fructus Psoralea and Brucea javanica show an immune regulatory action on the PCP rats.

[Electron microscopical observation on rats with Pneumocystis carinii pneumonia treated with Brucea javanica and Fructus Psoraleae].

Rats with Pneumocystis carinii pneumonia (PCP) were established by hypodermic injection of dexamethasone and treated by Brucea javanica combined with Fructus Psoraleae 2 ml (Brucea javanica 0.12 mg and Fructus Psoraleae 1.0 mg) per rat per day for 7 days or 14 days. The effect of cyst-killing and the pathological change were observed under transmission electron microscope. Lung damage was alleviated or repaired, and a significant reduction of cysts was shown in the treatment group. The results show that a combination of Brucea javanica and Fructus Psoraleae played a significant restraining and killing effect on cysts, and helped repair the impairment of pneumonia.