In vitro Antimicrobial Activity of Fosfomycin, Rifampin, Vancomycin, Daptomycin Alone and in Combination Against Vancomycin-Resistant Enterococci.

PURPOSE: The emergence of vancomycin resistant Enterococci (VRE) is shortening the choices for clinical anti-infective therapy. The aim of this study was to investigate the mechanism of vancomycin resistance and evaluate the effect of fosfomycin (FM), rifampin (RIF), vancomycin (VAN), linezolid (LNZ), daptomycin (DAP) alone or in combination against VRE. METHODS: Eight VRE isolates were collected. A total of 18 antibiotics susceptibility tests were further done for VRE. Whole genome sequencing and bioinformatics analysis were performed. The effect of FM, RIF, VNA, LNZ, DAP alone or in combination was determined using anti-biofilm testing and the time-kill assay. RESULTS: All isolates were susceptible to LNZ and DPA. The high-level resistance determinant of VAN in these strains was due to VanA-type cassette. MLST revealed two different STs for vancomycin-resistant Enterococcus faecium (VREm) and four different STs for vancomycin-resistant E. faecalis (VREs). Virulence genes in VREs were more than VREm, especially for 4942 isolated from blood. Gene acm and uppS were only identified in VREm, while virulence genes related to cytolysin were only found in E. faecalis. Further in vitro studies indicated FM (83 mg/L) combined with DAP (20.6 mg/L) and DAP monotherapy (47.1 mg/L) had bactericidal effect against VRE isolates at 24h. CONCLUSION: High-level resistance determinant of VAN in tested isolates was due to VanA-type cassette. FM combined with DAP is a potential therapeutic option for VRE infections.

Inhibiting RRM2 to enhance the anticancer activity of chemotherapy.

RRM2, the small subunit of ribonucleotide reductase, is identified as a tumor promotor and therapeutic target. It is common to see the overexpression of RRM2 in chemo-resistant cancer cells and patients. RRM2 mediates the resistance of many chemotherapeutic drugs and could become the predictor for chemosensitivity and prognosis. Therefore, inhibition of RRM2 may be an effective means to enhance the anticancer activity of chemotherapy. This review tries to discuss the mechanisms of RRM2 overexpression and the role of RRM2 in resistance to chemotherapy. Additionally, we compile the studies on small interfering RNA targets RRM2, RRM2 inhibitors, kinase inhibitors, and other ways that could overcome the resistance of chemotherapy or exert synergistic anticancer activity with chemotherapy through the expression inhibition or the enzyme inactivation of RRM2.

Accuracy of circulating microRNAs in diagnosis of sepsis: a systematic review and meta-analysis.

OBJECTIVES: The aim of this study was to systematically assess the accuracy of circulating microRNAs (miRNAs) as a promising biomarker for sepsis via a meta-analysis. METHODS: PubMed, Cochrane Library, Embase, Web of Science, Scopus, and Ovid databases were searched up to April 3, 2020. The Quality in Prognostic Studies (QUADAS-2) tool was used to assess methodological quality. The pooled sensitivity (Sen), specificity (Spe), positive or negative likelihood ratios (PLR or NLR), diagnostic odds ratio (DOR), curve, and area under the curve (AUC) were calculated with 95% confidence interval (95% CI). The overall accuracy (OA) of miRNAs, procalcitonin (PCT), and C-reactive protein (CRP) was analyzed by the chi-square test. RESULTS: A total of 22 records were eligible for systematic review, including 2210 sepsis, 426 systemic inflammatory response syndrome (SIRS), and 1076 healthy controls (HC). The pooled Sen, Spe, and DOR of miRNAs were 0.80 (95% CI 0.75-0.83), 0.85 (95% CI 0.80-0.89), and 22 (15-32), respectively. The DOR of PCT and CRP were 17 (95% CI 4-68) and 7 (95% CI 1-48), respectively. The OA value of miRNAs (79.02%) and PCT (76.95%) were higher than CRP (61.22%) (P < 0.000). The subgroup analysis indicated that miRNAs in adults, serum type, downregulation of miRNA expression, criteria of Sepsis-3, internal reference of non-U6, and dysregulation expression of miR-223 had superior diagnostic accuracy. In addition, there was no significant publication bias among the included studies. Fagan's nomogram showed valuable clinical utility. CONCLUSIONS: Our meta-analysis indicated that the level of circulating miRNAs, particularly the miR-223, could be used as an indicator for sepsis.

In Vitro Antimicrobial Activity of Fosfomycin, Vancomycin and Daptomycin Alone, and in Combination, Against Linezolid-Resistant Enterococcus faecalis.

INTRODUCTION: Enterococcus faecalis is a significant cause of nosocomial infections and is difficult to treat because of intrinsic and acquired resistance to many antibiotics. In addition, the emergence of linezolid-resistant E. faecalis (LZR-Efa) is reducing the choices available for anti-infective therapy. The aim of this study was to examine the in vitro antibacterial effects of fosfomycin (FM), vancomycin (VAN) and daptomycin (DAP), alone and in combination, against LZR-Efa. METHODS: Five LZR-Efa strains and E. faecalis ATCC 29212 were studied. The antibacterial effects of FM, and of FM, VAN and DAP, were assessed using the time-kill assay. Biofilm formation and elimination were evaluated by crystal violet staining. RESULTS: When used at concentrations greater than 0.5 × MIC, FM did not produce dose-dependent effects against LZR-Efa isolates. The use of DAP (47.1 mg/L) alone, and FM (83 mg/L) combined with DAP (20.6 mg/L), produced a persistent inhibitory effect against both planktonic LZR-Efa isolates and those forming biofilms. In addition, FM and VAN combined with glucose-6-phosphate produced visible eradication effects against biofilms grown for 24 h, while DAP alone or combined with FM resulted in the best eradication activity against biofilms grown for 72 h prior to exposure. CONCLUSION: The use of FM combined with DAP provided the best potential therapeutic option for treating LZR-Efa infections out of those tested. In addition, the optimum treatment for biofilm elimination depended on the stage of biofilm formation.

Identification of osalmid metabolic profile and active metabolites with anti-tumor activity in human hepatocellular carcinoma cells.

BACKGROUNDS: Ribonucleotide reductase (RR) catalyzes the essential step in the formation of all four deoxynucleotides. Upregulated activity of RR plays an active role in tumor progression. As the regulatory subunit of RR, ribonucleotide reductase subunit M2 (RRM2) is regarded as one of the effective therapeutic targets for DNA replication-dependent diseases, such as cancers. Recent studies have revealed that osalmid significantly inhibits the activity of RRM2, but the metabolic profile of osalmid remains unknown. OBJECTIVE: The aim of this study was to clarify the metabolic profile including metabolites, isoenzymes and metabolic pathways of osalmid. The anti-human hepatocellular carcinoma activity and mechanism of metabolites were further investigated. MATERIALS AND METHODS: Ultra high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was used for identifying metabolites and for characterizing phase I and phase II metabolic pathways with recombinant enzymes or in human liver microsomes of osalmid. The eHiTS docking system was used for potential RRM2 inhibitor screening among metabolites. Cytotoxicity assays were performed for evaluating cell proliferation inhibitory activity of metabolites. Cell cycle assays and cell apoptosis assays were assessed by flow cytometry. Western blotting analysis of RRM2, cyclin D1, p21, p53, phosphorylated p53, Bcl-2 and Bax was performed to explore the anti-hepatocellular carcinoma mechanism of the active metabolites. RESULTS: Ten metabolites of osalmid were identified, and none of them have been reported previously. Hydroxylation, glucuronidation, sulfonation, acetylation and degradation were recognized as the main metabolic processes of osalmid. Isozymes of CYP1A2, CYP2C9, UGT1A1, UGT1A6, UGT1A9, UGT2B7 and UGT2B15 were involved in phase I and phase II metabolism of osalmid. Metabolites M7, M8 and M10 showed higher binding affinities with the RRM2 active site than osalmid. Metabolite M7 exhibited potent inhibitory activity to hepatocellular carcinoma cell lines by both competitive inhibition and down-regulation of RRM2. Moreover, M7 significantly induced cell cycle arrest and apoptosis by activating p53-related pathways. CONCLUSIONS: The metabolic profile of osalmid was identified. M7 significantly inhibited human hepatocellular carcinoma progression by inhibiting RRM2 activity. Furthermore, M7 induced cell cycle arrest and apoptosis by activating p53-related signaling pathways.