The physicochemical properties and potential hemostatic application of Wenchang kaolin and Maoming kaolin were inspected and evaluated. Chemical composition analysis, Fourier transform infrared (FTIR) spectroscopy, surface area determination, X-ray diffraction, particle size, scanning electron microscopy (SEM) observations, and zeta potential analysis were performed to quantify the physical and chemical properties of the two kaolins. The results showed that both kaolins have typical FTIR bands of kaolinite with a weight fraction for kaolinite over 90 wt%. Larger conglobate aggregates of Maoming kaolin demonstrated wider particle size distributions with two peaks at 3.17 and 35.57 μm, while the book-like Wenchang kaolin had narrow particle size distribution, with a frequent size of 5.64 μm. Furthermore, thrombelastography, the whole blood clotting tests (WBCT), plasma recalcification time (PRT) measurement, and MTT assay were performed to measure the clotting activities and biocompatibility of the two kaolins. The results showed that both kaolins could promote blood coagulation with good cytocompatibility, while Wenchang kaolin had a better procoagulant activity than Maoming kaolin. These findings demonstrated Wenchang kaolin to be a more suitable local source material for application as a hemostatic agent.

Cronobacter sakazakii 505108 was isolated from a sputum specimen of a neonate with severe pneumonia. C. sakazakii 505108 co-harbors 3 resistance plasmids of the IncHI2, IncX3, and IncFIB incomparability groups, respectively. These 3 plasmids have acquired several accessory modules, which carry an extremely large number of resistance genes, especially including those involved in resistance to carbapenems, aminoglycoside, tetracyclines, and phenicols and sulphonamide/trimethoprim. These plasmid-borne antibiotic resistance genes were associated with insertion sequences, integrons, and transposons, indicating that the assembly and mobilization of the corresponding accessory modules with complex chimera structures are facilitated by transposition and/or homologous recombination. This is the first report of fully sequence plasmids in clinical Cronobacter, which provides a deeper insight into plasmid-mediated multi-drug resistance in Cronobacter from hospital settings.

The international journal of Aerosol and Air Quality Research (AAQR) covers all aspects of aerosol science and technology, atmospheric science and air quality related issues.

This study aimed to genetically characterize two fully-sequenced novel IncFII-type multidrug resistant (MDR) plasmids, p0716-KPC and p12181-KPC, recovered from two different clinical Klebsiella pneumoniae isolates. p0716-KPC and p12181-KPC had a very similar genomic content. The backbones of p0716-KPC/p12181-KPC contained two different replicons (belonging to a novel IncFII subtype and the Rep_3 family), the IncFII_K and IncFII_Y maintenance regions, and conjugal transfer gene sets from IncFII_K-type plasmids and unknown origins. p0716-KPC and p12181-KPC carried similar three accessory resistance regions, namely ΔTn6209, a MDR region, and the bla_KPC-2 region. Resistance genes bla_KPC-2, mph(A), strAB, aacC2, qacEΔ1, sul1, sul2, and dfrA25, which are associated with transposons, integrons, and insertion sequence-based mobile units, were located in these accessory regions. p0716-KPC carried two additional resistance genes: aphA1a and bla_TEM-1. Together, our analyses showed that p0716-KPC and p12181-KPC belong to a novel IncFII subtype and display a complex chimeric nature, and that the carbapenem resistance gene bla_KPC-2 coexists with a lot of additional resistance genes on these two plasmids.

Salmonella can cause global foodborne illnesses in humans and many animals. The current diagnostic gold standard used for detecting Salmonella infection is microbiological culture followed by serological confirmation tests. However, these methods are complicated and time-consuming. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis offers some advantages in rapid identification, for example, simple and fast sample preparation, fast and automated measurement, and robust and reliable identification up to genus and species levels, possibly even to the strain level. In this study, we established a reference database for species identification using whole-cell MALDI-TOF MS; the database consisted of 12 obtained main spectra of the Salmonella culture collection strains belonged to seven serotypes. Eighty-two clinical isolates of Salmonella were identified using established database, and partial 16S rDNA gene sequencing and serological method were used as comparison. We found that MALDI-TOF mass spectrometry provided high accuracy in identification of Salmonella at species level but was limited to type or subtype Salmonella serovars. We also tried to find serovar-specific biomarkers and failed. Our study demonstrated that (a) MALDI-TOF MS was suitable for identification of Salmonella at species level with high accuracy and (b) that MALDI-TOF MS method presented in this study was not useful for serovar assignment of Salmonella currently, because of its low matching with serological method and (c) MALDI-TOF MS method presented in this study was not suitable to subtype S. typhimurium because of its low discriminatory ability.

Epsilon-toxin (ETX) is produced by types B and D strains of Clostridium perfringens, which cause fatal enterotoxaemia in sheep, goats and cattle. Previous studies showed that only a restricted number of cell lines are sensitive to ETX and ETX-induced hemolysis has not previously been reported. In this study, the hemolytic ability of ETX was examined using erythrocytes from 10 species including murine, rabbit, sheep, monkey and human. We found that ETX caused hemolysis in human erythrocytes (HC₅₀ = 0.2 μM) but not erythrocytes from the other test species. Moreover, the mechanism of ETX-induced hemolysis was further explored. Recent studies showed that some bacterial toxins induce hemolysis through purinergic receptor (P2) activation. Hence, the function of purinergic receptors in ETX-induced hemolysis was tested, and we found that the non-selective P2 receptor antagonists PPADS inhibited ETX-induced lysis of human erythrocytes in a concentration-dependent manner, indicating that ETX-induced hemolysis requires activation of purinergic receptors. P2 receptors comprise seven P2X (P2X1–7) and eight P2Y (P2Y1, P2Y2, P2Y4, P2Y6, and P2Y11–P2Y14) receptor subtypes. The pattern of responsiveness to more selective P2-antagonists implies that both P2Y13 and P2X7 receptors are involved in ETX-induced hemolysis in human species. Furthermore, we demonstrated that extracellular ATP is likely not involved in ETX-induced hemolysis and the activation of P2 receptors. These findings clarified the mechanism of ETX-induced hemolysis and provided new insight into the activities and ETX mode of action.