Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP), a type of Klebsiella pneumoniae (KP) that exhibits hypervirulence and carbapenem resistance phenotypes, can cause severe infections, both hospital- and community-acquired infections. CR-hvKP has brought great challenges to global public health and is associated with significant morbidity and mortality. There are many mechanisms responsible for the evolution of the hypervirulence and carbapenem resistance phenotypes, such as the horizontal transfer of the plasmid carrying the carbapenem resistance gene to hypervirulent Klebsiella pneumoniae (hvKP) or carbapenemase-producing Klebsiella pneumoniae (CRKP) acquiring a hypervirulence plasmid carrying a virulence-encoding gene. Notably, KP can evolve into CR-hvKP by acquiring a hybrid plasmid carrying both the carbapenem resistance and hypervirulence genes. In this review, we summarize the evolutionary mechanisms of resistance and plasmid-borne virulence as well as the prevalence of CR-hvKP.

Objective To assess the accuracy of pleural fluid homocysteine for discriminating malignant pleural effusion (MPE) and benign pleural effusion (BPE). Methods A total of 194 patients from two cohorts (Hohhot and Changshu) with undiagnosed pleural effusion were prospectively enrolled. Their pleural homocysteine was measured, and its diagnostic accuracy and net benefit for MPE were analyzed by receiver operating characteristic (ROC) curve analysis and decision curve analysis, respectively. Results In the Hohhot cohort ( n = 136) and the Changshu cohort ( n = 58), MPE patients had significantly higher homocysteine levels than BPE patients. The areas under the ROC curves of homocysteine for the diagnosis of MPE were 0.61 ( p = 0.027) and 0.59 ( p = 0.247), respectively. The decision curves of homocysteine were close to the reference line in both the Hohhot cohort and the Changshu cohort. Conclusion The diagnostic accuracy of pleural fluid homocysteine for MPE was low.

Background: Tumor-associated macrophages (TAMs) affects the outcomes of non-small cell lung cancer (NSCLC). NSCLC cells released exosomes to suppress the antitumor activity of TAMs. MiR-146a is a critical regulator in TAM polarization. We hypothesized that NSCLC cells released exosomal miR-146a to regulate TAM polarization and thus affected its antitumor activity. Methods:We used H1299 cells-derived exosomes to stimulate THP-1 cells that was pretreated with phorbol 12-myristate 13-acetate (M0 macrophage). Flow cytometry and reverse transcription-quantitative polymerase chain reaction (PCR) were used to determine the polarization of macrophages. The conditioned medium of exosome-treated M0 cells was used to culture H1299 cells, and the Cell Counting Kit-8, Ki67, transwell and scratch wound assays were used to determine the biological behavior of H1299 cells. To investigate whether exosomal miR-146a regulates TAM macrophages through targeting tumor necrosis factor receptor-associated factor 6 (TRAF-6) and interleukin-1 receptor-associated kinase 1 (IRAK-1), we used small interfering RNA to knockdown the expressions of them.Results: Upregulation of miR-146a inhibited M1 polarization and thus impaired the antitumor activity of TAMs. Exosomes released by H1299 cells can be taken by M0 macrophage, and they upregulated the expression of miR-146a in M0 macrophage. The exosome suppresses M1 polarization by exosomal miR-146a. TRAF-6 and IRAK-1 mediated the inhibitive effects of exosomal miR-146a on M1 polarization.Conclusions: NSCLC cells released exosomal miR-146a to inhibit the expressions of TRAF-6 and IRAK-1 in TAMs, resulting in the impaired antitumor activity of TAMs. NSCLC cell-derived exosomal miR-146a represents a novel therapeutic target for NSCLC treatment.

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Pleural effusion (PE) is a common sign caused by various disorders. Microbiology, histology and cytology are reference standards for these disorders. However, these diagnostic tools have limitations, including invasiveness, high cost, long turnaround time, and observer-dependent. Soluble biomarkers in pleural fluid (PF) are promising diagnostic tools because they are mininvasive, economical, and objective. Recent studies have revealed that some cell-free nucleic acids (e.g., DNA, mRNA, microRNA, and lncRNA) in PF are potential diagnostic markers for many disorders. Here, we review the performance of PF cell-free nucleic acids for differentiating and stratification of PE.