Objective: to investigate the prevalence and antimicrobial resistance of Enterococcus species isolated from a university hospital, and explore the mechanisms underlying the antimicrobial resistance, so as to provide clinical evidence for the inappropriate clinical use of antimicrobial agents and the control and prevention of enterococcal infections. Methods: a total of 1,157 enterococcal strains isolated from various clinical specimens from January 2010 to December 2012 in the General Hospital of Ningxia Medical University were identified to species level with a VITEK-2 COMPACT fully automated microbiological system, and the antimicrobial susceptibility of Enterococcus species was determined using the Kirby-Bauer disc diffusion method. The multiple-drug resistant enterococcal isolates were screened from the clinical isolates of Enterococcus species from the burns department. The minimal inhibitory concentration (MIC) of Enterococcus species to the three fluoroquinolones, including ciprofloxacin, gatifloxacin and levofloxacin was determined with the agar dilution method, and the changes in the MIC of Enterococcus species to the three fluoroquinolones following reserpine treatment were evaluated. The β-lactam, aminoglycoside, tetracycline, macrolide, glycopeptide resistance genes and the efflux pump emeA genes were detected in the enterococcal isolates using a polymerase chain reaction (PCR) assay. Results: the 1,157 clinical isolates of Enterococcus species included 679 E. faecium isolates (58.7%), 382 E. faecalis isolates (33%), 26 E. casseliflavus isolates (2.2%), 24 E. avium isolates (2.1%), and 46 isolates of other Enterococcus species (4%). The prevalence of antimicrobial resistance varied significantly between E. faecium and E. faecalis, and ≤1.1% of these two Enterococcus species were found to be resistant to vancomycin, teicoplanin or linezolid. In addition, the Enterococcus species isolated from different departments of the hospital exhibited various resistances to the same antimicrobial agent, while reserpine treatment reduced the resistance of Enterococcus species to ciprofloxacin, gatifloxacin and levofloxacin. The β-lactamase gene TEM, aminoglycoside-modifying-enzyme genes aac(6')-aph(2"), aph(3')-III, ant(6)-I and ant(2")-I, tetracycline resistance gene tetM, erythromycin resistance gene ermB, vancomycin resistance gene vanA and the enterococcal multidrug resistance efflux emeA gene were detected in 77%, 62%, 26%, 13%, 36%, 31%, 66%, 5% and 55% of the 100 multiple-drug resistant enterococcal isolates. Conclusions: similar to previous findings, E. faecium and E. faecalis are predominant conditionally pathogenic bacteria that cause hospital-acquired infections that can cause urinary and respiratory system infections. Multiple and high-level antimicrobial resistance is highly prevalent in the hospital isolates of Enterococcus species. Reserpine treatment inhibits the active efflux of Enterococcus species to ciprofloxacin, gatifloxacin and levofloxacin in vitro and reduces the MIC of Enterococcus species to these three fluoroquinolones. The presence of the enterococcal multidrug resistance efflux emeA gene is associated with the resistance to antibiotics in Enterococcus species. The monitoring of the prevalence and antimicrobial resistance of Enterococcus species is of great significance to guide the control and prevention of enterococcal infections.

MicroRNA 21 (miR-21) has been demonstrated to be significantly elevated in many types of cancers, including the hepatocellular carcinoma (HCC). In the present study, we investigated the role of miR-21 in HCC by identifying its novel targets, as well as its underlying molecular mechanism.

Objective: The purpose of this study was to investigate the clinical distribution and genotyping of Stenotrophomonas maltophilia, its resistance to antimicrobial agents, and the possible mechanisms of this drug resistance. Methods: S. maltophilia isolates were collected from clinical specimens in a university hospital in Northwestern China during the period between 2010 and 2012, and were identified to the species level with a fully automated microbiological system. Antimicrobial susceptibility testing was performed for S. maltophilia with the Kirby-Bauer disc diffusion method. The minimal inhibitory concentrations (MIC_s) of norfloxacin, ofloxacin, chloramphenicol, minocycline, ceftazidime, levofloxacin and ciprofloxacin against S. maltophilia were assessed using the agar dilution method, and changes in the MIC of norfloxacin, ciprofloxacin and ofloxacin were observed after the addition of reserpine, an efflux pump inhibitor. Fluoroquinolone resistance genes were detected in S. maltophilia using a polymerase chain reaction (PCR) assay, and the expression of efflux pump smeD and smeF genes was determined using a quantitative fluorescent (QF)-PCR assay. Pulsed-field gel electrophoresis (PFGE) was employed to genotype identified S. maltophilia isolates. Results: A total of 426 S. maltophilia strains were isolated from the university hospital from 2010 to 2012, consisting of 10.1% of total non-fermentative bacteria. The prevalence of norfloxacin, ciprofloxacin and ofloxacin resistance was 32.4%, 21.9% and 13.2% in the 114 S. maltophilia isolates collected from 2012, respectively. Following reserpine treatment, 19 S. maltophilia isolates positive for efflux pump were identified, and high expression of smeD and smeF genes was detected in two resistant isolates. gyrA, parC, smeD, smeE and smeF genes were detected in all 114 S. maltophilia isolates, while smqnr gene was found in 25.4% of total isolates. Glu-Lys mutation (GAA-AAA) was detected at the 151th amino acid of the gyrA gene, while Gly-Arg mutation (GGC-CGC) was found at the 37th amino acid of the parC gene. However, no significant difference was observed in the prevalence of gyrA or parC mutation between fluoroquinolone-resistant and -susceptible isolates (p> 0.05). The smqnr gene showed 92% to 99% heterogenicity among the 14 S. maltophilia clinical isolates. PFGE of 29 smqnr gene-positive S. maltophilia clinical isolates revealed 25 PFGE genotypes and 28 subgenotypes. Conclusions: Monitoring the clinical distribution and antimicrobial resistance of S. maltophilia is of great significance for the clinical therapy of bacterial infections. Reserpine is effective to inhibit the active efflux of norfloxacin, ciprofloxacin and ofloxacin on S. maltophilia and reduce MIC of fluoroquinolones against the bacteria. The expression of efflux pump smeD and smeF genes correlates with the resistance of S. maltophilia to fluoroquinolones.

Biofilms produced by Candida albicans (C. albicans) are intrinsically resistant to fungicidal agents, which are a main cause of the pathogenesis of catheter infections. Several lines of evidence have demonstrated that calcineurin inhibitor FK506 or cyclosporine A (CsA) can remarkably enhance the antifungal activity of fluconazole (FLC) against biofilm-producing C. albicans strain infections. The aim of present study is thus to interrogate the mechanism underpinning the synergistic effect of FLC and calcineurin inhibitors. Twenty four clinical C. albicans strains isolated from bloodstream showed a distinct capacity of biofilm formation. A combination of calcineurin inhibitor CsA and FLC exhibited a dose-dependent synergistic antifungal effect on the growth and biofilm formation of C. albicans isolates as determined by a XTT assay and fluorescent microscopy assay. The synergistic effect was accompanied with a significantly down-regulated expression of adhesion-related genes ALS3, hypha-related genes HWP1, ABC transporter drug-resistant genes CDR1 and MDR1, and FLC targeting gene, encoding sterol 14alpha-demethylase (ERG11) in clinical C. albicans isolates. Furthermore, an addition of CsA significantly reduced the cellular surface hydrophobicity but increased intracellular calcium concentration as determined by a flow cytometry assay (p < 0.05). The results presented in this report demonstrated that the synergistic effect of CsA and FLC on inhibited C. albicans biofilm formation and enhanced susceptibility to FLC was in part through a mechanism involved in suppressing the expression of biofilm related and drug-resistant genes, and reducing cellular surface hydrophobicity, as well as evoking intracellular calcium concentration.

Cigarette smoke is recognized as a major trigger for individuals with chronic obstructive pulmonary disease (COPD), leading to an amplified inflammatory response. The onset and progression of COPD are affected by multiple environmental and genetic risk factors, such as inflammatory mechanisms, oxidative stress, and an imbalance between proteinase and antiprotease. As a result, conventional drug therapies often have limited effectiveness. This study aimed to investigate the anti-inflammatory effect of sodium butyrate (SB) in COPD and explore its molecular mechanism, thereby deepening our understanding of the potential application of SB in the treatment of COPD. In our study, we observed an increase in the mRNA and protein expressions of inflammatory factors interleukin-1beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), Matrix metallopeptidase 9 (MMP9) and MMP12 in both NR8383 cell and rat models of COPD. However, these expressions were significantly reduced after SB treatment. Meanwhile, SB treatment effectively decreased the phosphorylation levels of nuclear transcription factor-kappa B (NF-κB) p65, c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) and inhibited the nuclear translocation of these proteins in the COPD cells, leading to a reduction in the expression of various inflammatory cytokines. Additionally, SB also inhibited the expression level of the Nod-like receptor pyrin domain 3 (NLRP3) inflammasome, which consists of NLRP3, apoptosis-associated speck-like protein (ASC), and Caspase-1 in the cigeratte smoke extract (CSE)-stimulated cells. Our results showed that CSE down-regulated the mRNA levels of G-protein-coupled receptor 43 (GPR43) and GPR109A, while SB only up-regulated the expression of GPR43 and had no effect on GPR109A. Moreover, additional analysis demonstrated that the knockdown of GPR43 diminishes the anti-inflammatory effects of SB. It is evident that siRNA-mediated knockdown of GPR43 prevented the reduction in mRNA expression of IL-1β, IL-6, TNF-α, MMP9, and MMP12, as well as the expression of phosphorylated proteins NF-κB p65, JNK, and p38 MAPKs with SB treatment. These findings revealed a SB/GPR43 mediated pathway essential for attenuating pulmonary inflammatory responses in COPD, which may offer potential new treatments for COPD.

Indole-3-aldehyde (I3A) is an intestinal microbial metabolite that regulates inflammation in various inflammatory diseases; however, its role in chronic ob