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Extraintestinal pathogenic Escherichia coli (ExPEC) is an important zoonotic and foodborne pathogen. Biofilms are specially structured communities for bacteria to survive in different hostile environments and can protect the bacteria from eradication by the host and external factors. In this study, we found that oxygen is definitely required for biofilm formation in ExPEC strain PPECC42. Aerobically growing ExPEC showed a bdar (brown, dry, and rough) morphotype, whereas anaerobically growing ExPEC showed a saw (smooth and white) morphotype. Under anaerobic condition, curli fimbriae did not accumulate and the expression levels of curli biosynthesis-related genes including csgB, csgD, and rpoS decreased significantly; in contrast, the expression level of h- ns, of which the encoding protein is a repressor for csgD transcription, increased significantly. Taken together, the results suggested that oxygen-free condition limited ExPEC strain PPECC42 biofilm formation mainly through preventing curli accumulation by affecting the transcriptional levels of curli biosynthesis-related genes. [ABSTRACT FROM AUTHOR]

Identifying the origin of animal species in manufactured meat products is of considerable economic, religious and sanitary importance. In this study, we developed a multiplex PCR method to simultaneously detect chicken, duck and goose DNA in meat products derived from beef, pork, mutton or quail. The PCR primers were designed based on the sequence of mitochondrial genes of each avian species, and the amplicon sizes were 131, 283 and 387 bp for chicken, duck and goose, respectively. The method had no cross-reaction with DNA isolated from beef, mutton, pork or quail, and generated products at a target DNA content as low as 0.05 ng, or a target meat content of 1% of total meat weight. Moreover, screening of 24 commercial meat samples using this method indicated that six, two and one samples were contaminated with chicken, duck, or both, respectively, suggesting its usefulness for the simultaneous identification of chicken, duck and goose DNA in commercial meat products. [ABSTRACT FROM AUTHOR]

Highlights: [•] Low dose ozone was used and obvious effects were obtained in a full scale A/A/O process. [•] Large amount of carbon and little nutrient were solubilized. The ratios of carbon to nitrogen and carbon to phosphorus in ozonated sludge were much higher than influent. [•] Performance of A/A/O process was improved by low-dose ozonation. [•] Low-dose ozonation didn’t destroy sludge cell walls and had no effect on DO concentration of biological reactors. [Copyright &y& Elsevier]

Aims To assess the co-transmission risk of phenotypic and genetic resistance to cephalosporins, colistin, and fosfomycin in Salmonella strains collected along the whole pork production chain. Methods and Results From a total of 107 Salmonella isolates from samples collected in pig slaughterhouses and markets, 15 ESBL-producing Salmonella strains resistant to cefotaxime were identified by broth microdilution method and clavulanic acid inhibition test, including 14 monophasic Salmonella Typhimurium strains and one Salmonella Derby strain. Whole genome sequence analysis showed that nine monophasic S. Typhimurium strains coresistant to colistin and fosfomycin carried the resistance genes bla CTX-M-14, mcr-1 , and fosA3. Conjugational transfer tests demonstrated that the phenotypic and genetic resistance to cephalosporins, colistin, and fosfomycin could cotransfer back and forth between Salmonella and Escherichia coli via an IncHI2/pSH16G4928-like plasmid. Conclusions This study reports the cotransmission of phenotypic and genetic resistance to cephalosporins, colistin, and fosfomycin via an IncHI2/pSH16G4928-like plasmid in Salmonella strains of animal origin, giving an alarm for the prevention of the development and spread of bacterial multidrug resistance. [ABSTRACT FROM AUTHOR]

Development of cefotaxime-resistance and biofilm formation increase the difficulty to prevent and control the infection and contamination of Salmonella , one of the most important foodborne and zoonotic bacterial pathogen. Our previous study observed that 1/8 minimum inhibitory concentration (MIC) of cefotaxime induced the enhancement of biofilm formation and filamentous morphological change by a monophasic Salmonella Typhimurium strain SH16SP46. This study was designed to explore the role of three penicillin-binding proteins (PBPs) in mediating the induction effect of cefotaxime. Three deletion mutants of the genes mrc A, mrc B, and fts I, encoding the proteins PBP1a, PBP1b, and PBP3, respectively, were constructed using the parental Salmonella strain SH16SP46. Gram staining and scanning electron microscopy showed that these mutants showed normal morphology comparable to the parental strain without cefotaxime treatment. However, under the stress of 1/8 MIC of cefotaxime, the strains WT, Δmrc A, and Δfts I, rather than Δmrc B, exhibited filamentous morphological change. Moreover, cefotaxime treatment significantly enhanced biofilm formation by the strains WT, Δmrc A, and Δfts I, but not by the Δmrc B strain. The complement of mrc B gene in the Δmrc B strain recovered the enhanced biofilm formation and filamentous morphological change induced by cefotaxime. Our results suggest that PBP1b encoded by mrc B gene may be a binding target of cefotaxime for initiating the effect on Salmonella morphology and biofilm formation. The study will contribute to further understanding of the regulatory mechanism of cefotaxime on Salmonella biofilm formation. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of organic pollutants is considered an ideal method to solve the global environmental pollution problem. In this method, photocatalytic materials are regarded as the key factor. As an n‐type photocatalytic material, graphitic carbon nitride (g‐C3N4) has attracted much attention due to its suitable bandgap, nontoxicity, and high photostability. However, g‐C3N4 still has defects such as insufficient visible light absorption, low specific surface area, and easy recombination of photogenerated electron–hole pairs, which lead to the poor photocatalytic performance of g‐C3N4. Herein, to solve the above problems, thiourea, lemon juice, and tin chloride pentahydrate are used as precursors, while carbon quantum dots (CQDs) are used as electron mediators, and the third phase SnS2 is introduced by a hydrothermal and ultrasonic composite method. SnS2/CQDs/g‐C3N4 composites with Z‐type heterojunction are successfully prepared. The results show that the SnS2/CQDs/g‐C3N4 has a 2D0D2D structure, which effectively inhibits the recombination of photogenerated electron–hole pairs, making the material have better photocatalytic degradation activity for Rhodamine B (RhB). When the mass ratio of SnS2 is 15%, the photocatalytic degradation efficiency of RhB by the composite reaches the best, which is 87.8%. After four cycles, the photocatalytic degradation efficiency of the 15% SnS2/CQDs/g‐C3N4 composite still remains at 82.9%. [ABSTRACT FROM AUTHOR]

How to make full and efficient use of solar energy is the driving force leading the development of photocatalytic materials. Photothermal catalysis has attracted great attention of researchers because it can use full- spectrum suniight to stimulate the synergy between luminescence catalysis and thermal catalysis to achieve high utilization efficiency of solar energy. In thls paper, the design, synthesls, performance opiimizaiion and practical application of photo-thermo-catalytic materials are reviewed. The future development trend of photothermocatalytic materials is also prospected here. [ABSTRACT FROM AUTHOR]

Bio-templated porous CdS-g-C 3 N 4 /C composite with controllable morphology and energy band structure was successfully prepared by simple thermal condensation and hydro-thermal method using dicyandiamide and cadmium chloride as precursor, Hollyhock stem as biological template and in-situ carbon dopant. The structure and property of the composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N 2 adsorption-desorption, fluorescence spectroscopy (PL), UV–visible spectroscopy and diffuse reflectance ultraviolet spectroscopy (DRS). The results indicated that, compared with pure g-C 3 N 4 , g-C 3 N 4 /C had a porous structure, higher specific surface area and better photogenerated carrier separation efficiency. In addition, compared with g-C 3 N 4 /C, the light response of the three-phase composite anchored with 2D CdS expanded from ultraviolet to visible and even near infrared regions. The n-n heterojunction formed between CdS and g-C 3 N 4 reduces the energy required for electron transition and makes the photogenerated electron hole pairs easier to be separated. The highest photocatalytic efficiency for RhB of CdS-g-C 3 N 4 /C is 86.96%, which is 3.23 times that of pure g-C 3 N 4. In the photo-catalytic process, the main photocatalytic reactive substance is ·O 2 −, followed by h+. Therefore, the CdS-g-C 3 N 4 /C synthesized by stem induction and multi-phase heterojunction has a more stable microstructure, and the charge separation efficiency is greatly improved, which is suitable for practical photocatalytic environmental protection. [Display omitted] [ABSTRACT FROM AUTHOR]

Salmonella is one of the most important foodborne and zoonotic pathogens, and monophasic S. Typhimurium is ranked among the top-five Salmonella serovars causing animal and human infections worldwide. Resistance to the third- and higher-generation cephalosporins in Salmonella has attracted great attention. Bacteria are frequently exposed to sub-minimal inhibitory concentrations (sub-MICs) of antimicrobials that can trigger diverse adaptive responses such as biofilm formation. Biofilms can promote bacterial defense to external and internal harsh conditions. This study aimed to investigate the effect of sub-MICs of cefotaxime, one of the third-generation cephalosporins, on biofilm formation by non-clinical S. enterica strains. Crystal violet staining demonstrated that cefotaxime at 1/8 MIC enhanced biofilm formation by two monophasic S. Typhimurium strains. Confocal laser scanning microscopy and enzymatic treatment assay revealed that cellulose was the most dominant extracellular matrix component contributing to Salmonella biofilm formation. Scanning electron microscopy demonstrated that cefotaxime treatment led to bacterial incomplete cell division and filamentous morphology during the whole process of biofilm formation. Our study is the first to report the enhancement effect of cefotaxime on non-clinical, monophasic S. Typhimurium by affecting bacterial morphology. The results will contribute to conducting risk assessments of Salmonella in the pork production chain and guiding the rational use of antimicrobial agents to reduce the risk of biofilm formation. [ABSTRACT FROM AUTHOR]

Pig is usually the carrier of Salmonella and Staphylococcus aureus, and can transmit the bacteria along the pork production chain to cause severe public health problems. In this study, we investigated the prevalence of Salmonella and S. aureus in fattening pigs in Hubei Province, China. The overall prevalence of Salmonella in rectal swab among 896 samples from 22 farms was 17.30%, and that of S. aureus in nasal swab among 814 samples from 20 farms was 28.26%. Antimicrobial resistance (AMR) analysis showed that 95.33% of the Salmonella strains exhibited resistance to more than three classes of antimicrobial agents tested. The highest resistance proportions were for chloramphenicol (100%), sulfamethoxazole/trimethoprim (SXT) (100%), and tetracycline (TET) (93.46%), while the lowest proportions were for cefotaxime (37.38%), gentamicin (GEN) (34.58%), and ciprofloxacin (24.30%). On the other hand, 98.42% of the S. aureus strains were resistant to more than three classes of antimicrobial agents tested. The most common resistance among the S. aureus strains was against SXT (100.00%), followed by TET (98.43%), erythromycin (91.34%), and clindamycin (91.34%), while the lowest frequent resistances were against GEN (34.65%) and oxacillin (16.54%). The prevalence and AMR of Salmonella and S. aureus exhibited an obvious diversity among different pig farms. Our results provided the epidemiological data for risk analysis of foodborne bacteria and AMR in pig farms. [ABSTRACT FROM AUTHOR]

Zn‐Fe layered double hydroxide with chloride intercalation (ZFCL) was synthesized by a coprecipitation method at room temperature. ZFCL was characterized by N2 adsorption‐desorption isotherms, X‐ray diffraction, scanning electron microscope, Zeta‐sizer analyzer, X‐ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The results showed that ZFCL had large surface area and layered structure. The maximum adsorption capacity of ZFCL was 150.6 mg/g at 25°C. That was higher than most other adsorbent which were reported. The kinetic data were described better by the pseudo‐second‐order adsorption kinetic rate model. The adsorption isotherm on the adsorbent was described by Langmuir, Freundlich, and Sips models at pH 6 and followed the fitting order: Sips >Freundlich>Langmuir. Thermodynamic analyses indicated that the phosphate adsorption on ZFCL was endothermic and spontaneous in nature. The sequence of coexisting cations and anions competing with phosphate was Ca2+ > Mg2+ > Na+ and SO42− > NO3− > Cl−. ZFCL can be regenerated by the sequential use of NaOH and ZnCl2. The adsorption capacity remained high as 108.6 mg/g after regeneration of 3 times. The results of zeta potential, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy analyses indicated that the phosphate adsorption mechanisms involved ion exchange, Zn3(PO4)2 precipitation, and the formation of inner‐sphere complex via replacement of surface hydroxyl groups by phosphate. [ABSTRACT FROM AUTHOR]

The antimicrobial resistance of Salmonella strains is rapidly increasing worldwide, which poses significant threats to animal and public health. In this study, a total of 249 porcine Salmonella isolates collected in China during 2008-2015 were examined, including 155 clinical isolates from diseased pigs and 94 nonclinical isolates from healthy pigs. Based on the minimum inhibitory concentration of seven antimicrobial agents, 96.4% of the isolates were resistant to at least one of the tested antibiotics and 81.0% of them showed multidrug resistance. The highest antimicrobial resistance was observed for tetracycline (85.9%), and the lowest was found for cefotaxime (13.3%). The isolates from diseased pigs exhibited significantly higher levels of antimicrobial resistance than those from healthy pigs. Twenty-two isolates from healthy pigs were resistant to ciprofloxacin, which may inhibit the curative effectiveness of fluoroquinolones on bacterial food-borne poisoning and infections in humans caused by contaminated food. Moreover, cefotaxime resistance of the strains isolated from diseased pigs during 2013-2015 was significantly higher compared with the strains isolated during 2008-2010. Further study showed that the correlation between phenotypic and genotypic resistance varied among the isolates from different sources, and in many cases, the presence of resistance genes was not consistent with the resistance to the corresponding antimicrobials. These results are very significant for veterinary practice and public health. [ABSTRACT FROM AUTHOR]

Since October 2010, porcine epidemic diarrhea (PED) caused by variant porcine epidemic diarrhea virus (PEDV) has led great economic losses to the global pig industry, especially in China. To study the genetic characteristics of PEDV strains in Chinese mainland, a total of 603 clinical samples from nine provinces/districts of Chinese mainland from January 2014 to December 2015 were collected for RT-PCR detection and 1-1323 bp of S gene of 91 isolates and ORF3 gene of 46 isolates were sequenced. The results showed that the variant PEDV were the dominant pathogens of viral diarrhea diseases in these areas. Six novel variant PEDV strains (FJAX1, FJAX2, HeNPDS1, HeNPDS2, HeNPY3, and HeNPY4) with two amino acids (aa) deletion at the 56–57 aa of S protein were identified. A total of 405 Chinese PEDV strains were subjected to phylogenetic and phylogeographic analysis. The results revealed that the subgroup Va in variant PEDV group were the dominant subgroup and the spread trend of variant PEDV strains seemed to be from the southeast coastal districts to other coastal districts and interior districts. The N-terminal of S gene (1–750 bp), to some extent, could represent S1 or full length S gene for phylogenetic, similarity, antigen index, hydrophilicity plot, and differentiation analyses. The 404–472 bp of S gene contained the three genetic markers, i.e., “TAA” insertion at 404–405 bp, “ACAGGT” deletion at 430–435 bp, and “ATA” deletion at 455–457 bp can be used to differentiate the classical and variant virulent parental/attenuated PEDV strains and help us to learn the infectious and genetic characteristics of PEDV strains more convenient and cheaper. This study has important implication for understanding the infectious, genetic, and evolutionary aspects of PEDV strains in Chinese mainland. [ABSTRACT FROM AUTHOR]

• The stem of Hollyhock is explored to induce g-C 3 N 4 lamellae. • Clear interface is established while CdS is anchored and uniformly distributed on the surface of g-C 3 N 4. • The photocatalytic efficiency of the three phase composite is 3.22 times that of pure g-C 3 N 4. CdS-g-C 3 N 4 /C was prepared with g-C 3 N 4 , CdS and hollyhock stem as the starting materials via biotemplate method. The results showed that the hollyhock stem carbon maintains a rigid skeleton to give substrate support and good electron transfer channel, while the g-C 3 N 4 lamellae was anchored on the stem surface uniformly with fracture of the 3-s-triazine ring without agglomeration to contribute higher specific surface area and numerous reactive sites. The clear interface between CdS and g-C 3 N 4 phases was established successfully to endow the composite good reaction activity. The special microscopic morphology mentioned above give the composite higher photocatalytic efficiency for RhB of 86.96%, which is 3.23 times that of pure g-C 3 N 4. In the photocatalytic process, the main photocatalytic reactive substance is ·O 2 −, followed by h+. [ABSTRACT FROM AUTHOR]

Highlights: [•] The adsorption process was highly pH-dependant. [•] Zwitterions are the most sorbed oxytetracycline species on activated sludge. [•] Different metal ions have different effects on the adsorption process. [•] Surface complexation are the main adsorption mechanism of OTC to activated sludge. [ABSTRACT FROM AUTHOR]

Abstract: Haemophilus parasuis is the causative agent inducing a severe inflammation of the serous membranes in pigs, which contribute to the great economic losses in the pig industry in China in the recent years. In this study, it was demonstrated that H. parasuis could activate the inflammatory transcription factor nuclear factor-kappaB (NF-κB) in a bacteria time- and dose-dependent manner in PK-15 cells, and inactivated H. parasuis significantly reduced the level of NF-κB activation in PK-15 cells compared with the counterpart especially in the later stage. After H. parasuis infection, the degradation of IκBα and phosphorylation of p65 was detected in PK-15 cells. Furthermore, the subcellular localization analyzed using confocal laser microscopy showed that p65-GFP rapidly translocated to the nucleus when PK-15 cells were stimulated with H. parasuis. In addition, real-time RT-PCR showed that the key inflammatory mediators including IL-8, CCL4 and CCL5, regulated by nuclear factor-kappaB (NF-κB) were up-regulated dramatically by the infection of H. parasuis in PK-15 cells. This was the first time to report that H. parasuis infection activated the NF-κB pathway in vitro through IκB degradation. [Copyright &y& Elsevier]

Riemerella anatipestifer is the causative agent of duck septicaemia. Determination of R. anatipestifer virulence mechanisms will help us to effectively control this contagious agent. The differentially expressed gene profile of R. anatipestifer in infected duck livers was therefore identified and compared with in vitro cultures by selective capture of transcribed sequences analysis. A total of 48 genes were identified, of which 43 were genes that encode enzymes for amino acid biosynthesis and metabolism, intermediary metabolism, and energy metabolism, or proteins for regulatory adaptive responses, general microbial stress response, transport proteins and secreted proteinases. Five were unknown, novel genes. Eight genes representing the categories were randomly chosen and verified by real-time reverse transcriptase-polymerase chain reaction analysis. All were upregulated by R. anatipestifer in infected duck livers, with changes ranging from 1.44-fold to 4.62-fold compared with in vitro cultures. The results from the present study revealed a gene expression profile of R. anatipestifer in infected duck livers. The unknown but novel genes may be potential novel virulence factors for R. anatipestifer. In conclusion, the data from this study will provide a molecular basis for further study of R. anatipestifer pathogenesis. [ABSTRACT FROM AUTHOR]