Evaluation of Commercial Products for Colistin and Polymyxin B Susceptibility Testing for mcr-Positive and Negative Escherichia coli and Klebsiella pneumoniae in China.

Purpose: To evaluate the performance of five widespread commercial products for colistin and polymyxin B susceptibility testing in China for mcr-positive and -negative Escherichia coli and Klebsiella pneumoniae. Methods: A total of 132 E. coli and 83 K. pneumoniae strains (including 68 mcr-1-positive E. coli and 28 mcr-8-positive K. pneumoniae) were collected. We analysed the performance of colistin susceptibility (with Vitek 2 and Phoenix M50) and the performance of polymyxin B susceptibility (with DL-96II, MA120, and a Polymyxin B Susceptibility Test strip; POL E-strip). Broth microdilution was used as the gold standard. Categorical agreement (CA), essential agreement (EA), major error (ME), and very major error (VME) were calculated for comparisons. Results: For E. coli, the total CA, EA, ME, and VME to colistin were as follows: Vitek 2, 98.5%/98.5%/0%/2.9%; and Phoenix M50, 98.5%/97.7%/0%/2.9%. The total CA, EA, ME, and VME to polymyxin B were as follows: POL E-strip, 99.2%/63.6%/1.6%/0%; MA120, 70.0%/-/0%/58.8%; and DL-96II, 80.2%/-/1.6%/36.8%. Only Vitek 2 and Phoenix M50 presented satisfactory performances for mcr-1-positive E. coli. For K. pneumoniae, the total CA, EA, ME, and VME to colistin were as follows: Vitek 2, 73.2%/72.0%/0%/61.6%; and Phoenix M50, 74.7%/74.7%/0%/58.3%. The total CA, EA, ME, and VME to polymyxin B were as follows: POL E-strip, 91.6%/74.7%/2.1%/16.7%; MA120, 92.8%/-/2.1%/13.9%; and DL-96II, 92.2%/-/2.1%/8.3%. All systems were unsatisfactory for mcr-8-positive K. pneumoniae. When the susceptibility of mcr-negative strains was tested, all systems presented excellent performance. Conclusion: Vitek 2 and Phoenix M50 with colistin for E. coli showed acceptable performance regardless of mcr-1 expression, while DL-96II, MA120, and the POL E-strip performed worse for mcr-1-positive strains. Furthermore, mcr-8 greatly affected the performance of all systems with both colistin and polymyxin B for K. pneumoniae isolates.

Prevalence and Genetic Diversity of Clostridium perfringens Isolates in Hospitalized Diarrheal Patients from Central China.

OBJECTIVE: This study aimed to investigate the prevalence, genetic diversity and clinical characteristics of Clostridium perfringens isolates from hospitalized clinical diarrheal patients. METHODS: A prospective study was conducted on 1108 patients with diarrhea during hospitalization. Stool samples were cultured for C. perfringens, and the toxin genes were detected by PCR. The available clinical data of 112 patients were analyzed to study the clinical features of various isolates. Multi-locus sequence typing (MLST) was performed to assess phylogenetic relationship between different isolates. RESULTS: A total of 153 (13.8%) isolates were obtained from patients' stools. C. perfringens type F (49.0%) was the major toxin type in the isolates, followed by type A (n = 59, 38.6%) and type C (n = 14, 9.2%). Patients older than 50 years and those with underlying diseases of cancer, hepatobiliary system, and ulcerative colitis (UC) were more predisposed to C. perfringens type F and type A infection than to type C. The patients infected with type C experienced more severe clinical symptoms compared to those with type A infection. There was a significant association between type FC and foodborne gastrointestinal (GI) diseases (p = 0.018), between type FP and antibiotic-associated diarrhea (AAD) (p < 0.001), and between type A and sporadic diarrhea (SD) (p < 0.001). Phylogenetic analysis indicated that type F isolates carrying a chromosomal cpe gene mainly belonged to ST77 (6/15 isolates). Type F isolates with cpe gene on a plasmid exhibited high genetic diversity. CONCLUSION: High prevalence and considerable genetic diversity of C. perfringens type F were found in clinical diarrheal patients. Elderly people and patients with cancer, hepatobiliary diseases or UC, or suspected of having food poisoning (FP) may be targeted for routine testing of C. perfringens toxin genes and may benefit from early detection of C. perfringens type C isolates that cause more severe clinical symptoms.

Arborinine, a potential LSD1 inhibitor, inhibits epithelial-mesenchymal transition of SGC-7901 cells and adriamycin-resistant gastric cancer SGC-7901/ADR cells.

Arborinine is a natural product isolated from G. parva leaf extracts, which displays potentially antiproliferative activity against human cervical cancer cells. In contrast, its anticancer effects against gastric cancer cells and drug-resistant gastric cancer cells remain unknown. In this work, arborinine was evaluated as a broad-spectrum antiproliferative agent, and it exhibited potently inhibitory activity against NCI-N87 (IC50 = 5.67 µM), BGC-823 (IC50 = 7.26 µM), MGC803 (IC50 = 4.75 µM), SGC-7901 (IC50 = 1.96 µM), HGC-27 (IC50 = 5.70 µM), SGC-7901/ADR (IC50 = 0.24 µM), SGC-7901/VCR (IC50 = 1.09 µM), and MGC803/PTX (IC50 = 1.32 µM) cell lines. Subsequent target verification experiments demonstrated that arborinine selectively and reversibly inhibited LSD1 in a time-dependent manner. Furthermore, it was found that arborinine suppressed the epithelial-mesenchymal transition of gastric cancer cell line SGC-7901 and adriamycin-resistant gastric cancer cell line SGC-7901/ADR in a dose-dependent manner. The in vivo antitumor study further indicated that arborinine can significantly reduce the growth of tumors both in SGC-7901 and SGC-7901/ADR xenograft mouse models. Overall, we demonstrated the potential of arborinine as an effective treatment for gastric cancer and adriamycin-resistant gastric cancer.

IGFBP5 modulates lipid metabolism and insulin sensitivity through activating AMPK pathway in non-alcoholic fatty liver disease.

AIMS: Non-alcoholic fatty liver disease (NAFLD) characterized by excessive hepatic fat deposition is an increasing public health issue worldwide. Insulin resistance is a pivotal factor in NAFLD progression. Studies have found that IGFBP5 was related to insulin sensitivity. Nevertheless, the role of IGFBP5 in NAFLD remains unclear. MATERIALS AND METHODS: NAFLD models were established in vitro and in vivo by treating HepG2 cells with free fatty acids (FFA) and feeding mice with high-fat diet (HFD), respectively. IGFBP5 expression was then analyzed in these models. The effects and mechanism of IGFBP5 on lipid lipogenesis, fatty acid ß-oxidation, and insulin resistance were investigated following IGFBP5 overexpression. Additionally, AMPK inhibitor compound C was used to treat HepG2 cells to confirm whether IGFBP5 functioned via activating AMPK pathway. KEY FINDINGS: IGFBP5 expression was decreased in both NAFLD models. IGFBP5 overexpression reduced levels of lipogenesis-associated proteins (SREBP-1c, FAS and ACC1), elevated expression of fatty acid ß-oxidation-related genes (PPARα, CPT1A and ACOX1), decreased intracellular lipid droplets, promoted glucose uptake and glycogenesis, and activated IRS1/Akt and AMPK pathways. Administration of IGFBP5 vectors also decreased body weight and relieved liver damage in HFD-treated mice. In contrast, compound C abrogated the influences of IGFBP5 overexpression on cell models. SIGNIFICANCE: IGFBP5 dampened hepatic lipid accumulation and insulin resistance in NAFLD development via activating AMPK pathway. This study indicates that IGFBP5 may be a novel therapeutic agent for NAFLD.

Adsorption of lambda-cyhalothrin and cypermethrin on two typical Chinese soils as affected by copper.

BACKGROUND, AIM, AND SCOPE: Pesticides and heavy metals pollution in soil environment has become a serious problem in many countries including China. Repeated applications of bordeaux mixture (a blend of copper sulfate and calcium hydroxide) and pyrethroid (Pys) insecticides have led to elevated copper (Cu) and Pys concentrations in vineyard surface soils. However, few studies focused on the interaction of Pys and heavy metals in the soil environment. Our previous studies had indicated the combined effect of cypermethrin (CPM) and Cu on soil catalase activity. Also, we had suggested that the addition of Cu could catalyze photo-degradation of CPM and lambda-cyhalothrin (lambda-CHT) in aqueous solution and restrain their degradation in soil. To better understand the potential influence of Cu on the fate of Pys in the soil environment, the aim of the present work was to examine the effect of Cu on the adsorption of lambda-CHT and CPM on two typical Chinese soils with different soil characteristics, which was one of the key processes controlling the fate of Pys, and to provide more information about the potential ecological risk of chemicals on the soil ecosystem. Fourier transform infrared and point charges analysis using the MOPAC program of the Gaussian system were also used to reveal the probable adsorption mechanism of lambda-CHT and CPM on soils. MATERIALS AND METHODS: Two vineyard soils with different properties were chosen as experimental samples. They were sampled from 0 to 10 cm, dried, and sieved to 2 mm. Each soil was spiked with copper sulfate solution to obtain the following total soil Cu concentrations: 100, 200, 400, 800, and 1,600 mg.kg(-1). The treated soils were incubated for 2 weeks and then dried at 20 degrees C. For each soil sample and at each soil Cu concentration, the adsorption of lambda-CHT and CPM was measured using a batch equilibrium method. The concentration of lambda-CHT was determined by HPLC, and the amount of lambda-CHT and CPM adsorbed by the soil sample at equilibrium was determined by the difference between the initial and equilibrium concentrations in solution corrected by the blank adsorption measurement. RESULTS: Without the addition of Cu, the adsorption of lambda-CHT and CPM on Black soil is greater than that on Red soil, while the adsorption of lambda-CHT on both soils is significantly stronger than that of CPM. As the soil Cu concentration increased from 19 (or 18; background) to 1,600 mg.kg(-1), the adsorption coefficient (K (d)) of lambda-CHT decreased from 12.2 to 5.9 L.kg(-1) for Red soil, and from 26.1 to 16.8 L.kg(-1) for Black soil, whereas the CPM adsorption coefficient in both soils decreased nearly by 100% (K (d) decreased from 9.4 to 0.2 L.kg(-1) for Red soil and from 16.2 to 0.5 L.kg(-1) for Black soil). DISCUSSION: Pys adsorption is a surface phenomenon which depends on the surface area and the organic matter content. Thus, the Black soil, having higher organic matter and greater surface area than that of the Red soil, show greater adsorption affinity to lambda-CHT and CPM. In our study, the different adsorption affinity of the two Pys was obtained, which was probably attributed to differences with respect to their physical-chemical properties. Further comparison upon the two Pys was conducted. The point charges of halogen atoms in the lambda-CHT and CPM were calculated, the differences of which probably lead to the fact that lambda-CHT has a stronger binding capacity to soils than CPM. Also, FTIR spectra show that competitive adsorption occurs between CPM and Cu for the same adsorption sites, which is responsible for the obtained suppression of CPM adsorption affected by Cu. CONCLUSIONS: Lambda-cyhalothrin shows a significantly stronger adsorption than cypermethrin on both soils. This phenomenon may be due to several reasons: (1) lambda-CHT has lower solubility and a higher octanol-water partition coefficient value than CPM; (2) lambda-CHT consists of specific isomers, whereas CPM is mixtures of eight different isomers; (3) the chlorine and fluorine atoms in the lambda-CHT have a negative point charge, whereas the chlorine atoms in the CPM have a positive point charge. As the soil Cu concentrations increased from 19 (or 18) mg.kg(-1) to 1,600 mg.kg(-1), the adsorption coefficient of lambda-CHT and CPM decreased on both soils. This is mainly due to a competition between Cu and Pys for occupying the adsorption sites on soils. The information from this study have important implications for vineyard and orchard soils, which often contain elevated levels of Cu and Pys. These results are also useful in assessing the environmental fate and health effect of lambda-CHT and CPM. RECOMMENDATIONS AND PERSPECTIVES: It is important for environmental scientists and engineers to get a better understanding of soil-metal-organic contaminant interactions. However, pesticide adsorption involves complex processes, and shortcomings in understanding them still restrict the ability to predict the fate and behavior of pesticide. Therefore, considerable research should be carried out to understand the mechanism of interaction between Pys and heavy metal on soils clearly.