Inhibition of Metastasis and Invasion of Ovarian Cancer Cells by Crude Polysaccharides from Rosa Roxburghii Tratt in Vitro Rosa roxburghii tratt polysaccharides;ovarian cancer;metastasis;MMP-9; Background: Rosa Roxburghii Tratt is a promising wild fruit crop in Southwest China. Its extracts have been used as traditional Chinese medicine, which benefit immune responses and cure various health disorders. However, whether Rosa Roxburghii Tratt polysaccharides could inhibit metastasis and invasion of ovarian cancer cells remains unknown. Materials and Methods: Effects of crude polysaccharides from Rosa Roxburghii Tratt on the viability of ovarian cancer A2780 cells were detected by MTT assay. Ovarian carcinoma cell migration and invasion after exposure to Rosa Roxburghii Tratt polysaccharides were quantified by wound healing and Transwell assays, respectively. Western blotting was applied to assess protein levels of MMP-9. Results: The results indicated that Rosa Roxburghii Tratt polysaccharides significantly reduced wound closure rate of A2780 cells, inhibited their migration and invasion, and suppressed the expression of MMP-9. Conclusions: Our findings indicated that Rosa Roxburghii Tratt polysaccharides have potential for develop as anti-metastatic cancer drug preparations for ovarian cancer patients.

Tigecycline is one of the few therapeutic options that are available for treating serious clinical infections. However, tigecycline nonsusceptible Enterobacteriaceae has emerged recently in China. In this study, a total of 28 clinical Klebsiella pneumoniae isolates that were not previously exposed to tigecycline were collected and confirmed for tigecycline minimum inhibitory concentrations (MICs) using standard broth microdilution tests. To elucidate the mechanisms underlying molecular resistance to tigecycline, the expression levels of efflux pumps AcrAB and OqxAB and their regulators RamA, MarA, RarA, and SoxS were determined by quantitative polymerase chain reaction. The expression levels of the genes acrB, ramA, marA, and soxS were statistically different in different MIC groups ( p < 0.05). Sequence analysis of the acrR and ramR genes revealed several nonsynonymous mutations in the nine resistance isolates. The values of MIC in these isolated strains with ramR mutations were significantly higher than those without ramR mutation ( p = 0.029). Moreover, mutations in the ramR gene led to the overexpression of RamA. These results indicated that the mutation of the ramR gene through the upregulated expression of RamA contributed to tigecycline resistance and that several of the newly identified types of mutations in ramR and acrR were not previously reported in K. pneumoniae clinical isolates.

Purpose: Antibiotic resistance is a growing health crisis that is further complicated by treatment failures caused by bacteria that exhibit heterogeneous susceptibility to antibiotics. The aim of this study was to describe imipenem (IPM)-heteroresistant strains among multidrug-resistant (MDR) ESBL/AmpC-producing Klebsiella pneumoniae clinical isolates, investigate their molecular phenotypic characteristics, and elucidate the outcome of antibiotic treatment in mice infected with the heteroresistant isolates. Materials and Methods: Antimicrobial susceptibility of K. pneumoniae isolates was determined by the disk diffusion and E-test methods. Heteroresistance to IPM was confirmed by population analysis profile (PAP) assays. PCR and sequencing were employed to detect MDR determinants. Molecular differences between the susceptible and resistant subpopulations were evaluated by sequencing and quantitative real-time reverse transcription PCR (qRT-PCR) analysis. The effect of the carbapenem-heteroresistant strains on antibiotic treatment was assessed using a mouse model of peritonitis with heteroresistant K. pneumoniae and subsequent treatment with IPM. Results: In total, 37 MDR ESBL/AmpC-producing clinical isolates of K. pneumoniae were identified between September 2018 and December 2019. These strains were notably resistant to conventional antimicrobials other than carbapenems. Among the isolates, three strains exhibited heteroresistance to IPM and carried several ESBL and/or AmpC genes. Mice infected with a lethal dose of any of the three heteroresistant isolates were unable to survive in the presence of IPM treatment, as the percentage of the IPM-resistant subpopulation of each strain was increased in the peritoneum of these mice at 24 h after infection. The resistant subpopulation of the strains presented pulsed-field gel electrophoresis (PFGE) profiles that were identical to those of the susceptible subpopulation, but ompK36 porin showed a reduction in gene expression (0.09- to 0.50-fold) in the resistant subpopulation. Conclusion: Carbapenem-heteroresistant strains were present among the MDR K. pneumoniae isolates producing ESBL/AmpC β-lactamases, and these heteroresistant strains failed IPM therapy in experimentally infected mice.

Background: Ventilator-associated pneumonia (VAP) is a common nosocomial infection associated with high morbidity due to multidrug-resistant (MDR) pathogens. The purpose of this study was to determine the occurrence of extended-spectrum β-lactamase (ESBL) genes, especially bla_CTX-M-15, in Klebsiella pneumoniae (K. pneumoniae)-associated VAP and to investigate the antimicrobial resistance patterns and molecular epidemiological characteristics of K. pneumoniae strains. Materials and methods: From January 2013 to December 2015, we retrospectively collected 89 VAP-causing K. pneumoniae isolates from tertiary-care hospitals in China, among which ESBL-producing strains were assessed for antimicrobial susceptibility. Several antibiotic resistance genes of clinical relevance in K. pneumonia isolates producing ESBL were investigated. Polymerase chain reaction (PCR) and DNA sequencing were employed to characterize the genetic contexts of bla_CTX-M-15. Conjugative plasmids carrying bla_CTX-M-15 were obtained by mating and further subjected to replicon typing. The genetic relatedness of isolates was assessed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Results: All of the 30 ESBL-producing isolates identified displayed MDR phenotype, with bla_SHV, bla_CTX-M, bla_OXA, and bla_TEM detected in 21, 21, 1, and 20 isolates, respectively. bla_CTX-M-15 was the most prevalent ESBL gene (19/30, 63.33%), and ISEcp1 was detected 48 bp upstream of 15 bla_CTX-M-15 genes. Based on S1-PFGE analyses, 25 isolates exhibited different plasmid profiles, ranging from ~70 to 320 kb. The bla_CTX-M-15 with bla_TEM and qnr genes and the ISEcp1 element from eight isolates were co-transferrable to recipients via conjugation, with IncFIB, IncFIC, and IncFII being the most prevalent replicons. Twenty different PFGE patterns and 11 sequence types were identified, with ST304 being dominant. Conclusion: This work reports the emergence of bla_CTX-M-15 in K. pneumoniae-induced VAP in China. We showed that IncFIB, IncFIC, and/or IncFII plasmids carrying bla_CTX-M-15 with bla_TEM, qnr resistance genes, and the ISEcp1 element mediate the local prevalence in K. pneumoniae-associated VAP.

Probiotic fermentation can promote the release of more effective components from traditional Chinese medicines (TCMs). Astragalus membranaceus (Fisch.) Bunge (A. membranaceus) and Raphani Semen are TCMs that have gained attention for their immunoenhancing activities. This study aimed to investigate the effects and underlying mechanisms of probiotic-fermented A. membranaceus and Raphani Semen (PROAS) in cyclophosphamide (CTX)-induced immunocompromised mice. Changes in the composition of A. membranaceus and Raphani Semen after fermentation by probiotic strains, including Bifidobacterium longum SD5219, Lactobacillus fermentum NCIMB5221, and Lactobacillus paracasei SD5219, were identified using high-performance liquid chromatography. The immunostimulatory effects and mechanisms of PROAS were evaluated in immunosuppressed mice 3 and 7 days after CTX treatment. Probiotic fermentation of TCMs resulted in changes in major bioactive components. PROAS supplementation effectively restored intestinal integrity in CTX-treated mice by upregulating the mRNA expression of the tight junction proteins. PROAS significantly ameliorated the reduction in the spleen index and number of B lymphocytes caused by CTX treatment and regulated the secretion of cytokines in serum and colon tissues. PROAS administration modulated gut microbial dysbiosis and short-chain fatty acid (SCFA) content in CTX-treated mice. These results suggest that PROAS enhances B lymphocyte function by increasing the regulation of intestinal microbiota to produce high levels of SCFA, repairs the intestinal barrier damage induced by CTX, and promotes intestinal mucosal immunity.