Pathogens and drug resistance in active surveillance of foodborne diseases from 2017 to 2019 in Chenzhou City

ObjectiveTo provide a scientific basis for the prevention and control of foodborne diseases in Chenzhou， the etiological characteristics and epidemiological patterns of foodborne diseases were analyzed.MethodsThe Case information and stool and anal swab samples were collected from two sentinel hospitals in Chenzhou in 2017 and 2019. According to the methods described in “National Manual of Foodborne Disease Surveillance”， the samples were tested for pathogens， pathogen typing， and drug sensitivity.ResultsA total of 825 samples of diarrhea cases were collected， and the total detection rate of pathogens was 30.18% （249/825）， including 16.24% （134/825） Salmonella， 11.76% （97/825） Norovirus， 3.52% （29/825） diarrheal Escherichia coli， 0.73% （6/825） Vibrio parahaemolyticus， and 0.12% （1/825） Shigella. Bacterial detection rates were higher in the second and third quarters than in other quarters， and viral detection rates were higher in the first and fourth quarters than in other quarters. The highest pathogen detection rate was 40.79% （31/76） in the 2-6-year-old group. Milk and dairy products， grains and their products， and fruits and their products were suspected foods. The highest detection rate in Salmonella was in Salmonella enterica subsp.（74.63%， 100/134）， the highest detection rate in diarrheal Escherichia coli was in intestinal adhesion type and enterotoxin type （34.48%， 10/29）， and the norovirus was mainly GII type （85.57%， 83/97）. The highest resistance rate of Salmonella to tetracycline was 88.71% （110/124）， and the multidrug resistance rate of Salmonella was 85.48% （106/124）. The resistance rate of diarrheal Escherichia coli to ampicillin was significant （79.31%， 23/29）， and the multidrug resistance rate of diarrheal Escherichia coli was 62.07% （18/29）.ConclusionThe main pathogens of diarrheal cases of foodborne diseases were Salmonella and Norovirus in Chenzhou. Salmonella and diarrheal Escherichia coli are highly resistant to antibiotics. Therefore， it is necessary to conduct targeted food safety supervision， strengthen antibiotic resistance monitoring， and strictly prevent antibiotic abuse

Molecular Ecology of Pyrethroid Knockdown Resistance in Culex pipiens pallens Mosquitoes

Pyrethroid insecticides have been extensively used in China and worldwide for public health pest control. Accurate resistance monitoring is essential to guide the rational use of insecticides and resistance management. Here we examined the nucleotide diversity of the para-sodium channel gene, which confers knockdown resistance (kdr) in Culex pipiens pallens mosquitoes in China. The sequence analysis of the para-sodium channel gene identified L1014F and L1014S mutations. We developed and validated allele-specific PCR and the real-time TaqMan methods for resistance diagnosis. The real-time TaqMan method is more superior to the allele-specific PCR method as evidenced by higher amplification rate and better sensitivity and specificity. Significant positive correlation between kdr allele frequency and bioassay-based resistance phenotype demonstrates that the frequency of L1014F and L1014S mutations in the kdr gene can be used as a molecular marker for deltamethrin resistance monitoring in natural Cx. pipiens pallens populations in the East China region. The laboratory selection experiment found that L1014F mutation frequency, but not L1014S mutation, responded to deltamethrin selection, suggesting that the L1014F mutation is the key mutation conferring resistance to deltamethrin. High L1014F mutation frequency detected in six populations of Cx. pipens pallens suggests high prevalence of pyrethroid resistance in Eastern China, calling for further surveys to map the resistance in China and for investigating alternative mosquito control strategies

Dissolved hydrolyzed amino acids in precipitation in suburban Guiyang, southwestern China: Seasonal variations and potential atmospheric processes

Proteinaceous compounds are particularly interesting because of their ubiquity and importance in many atmospheric processes. We investigated hydrolyzed amino acid (HAA), dissolved organic nitrogen (DON), nitrate (NO3-) and ammonium (NH4+) concentrations in precipitation samples collected in a suburban site in Guiyang over a 12 month period. Annually averaged total HAA, DON, NO3- and NH4+ concentrations were 3.7 mu mol L-1, 151.1 mu mol L-1, 68.9 mu mol L-1 and 117.3 mu mol L-1, respectively. Regarding the HAAs in precipitation, glutamic acid, glycine and proline were present in relatively high concentrations, followed by aspartic acid and alanine. The concentrations of total HAAs in precipitation showed a clear seasonal cycle, with a minimum level in winter and a maximum level in spring. Based on seasonal variations of total HAAs together with back-trajectory analysis, the air mass origins did not significantly impact the precipitation HAA levels. The NO3- concentrations recorded a better positive correlation (P < 0.01) with both the DON and total HAA concentrations than the NH4+ concentrations, possibly revealing that the sources for precipitation amino acids in suburban Guiyang were more linked with NO3- sources (from biomass burning, microbial activities and agricultural activities) than with NH4+ sources (from biomass burning and agricultural activities). In particular, in some specific periods, such as spring, abundant pollen releases may have been responsible for the relatively high precipitation amino acid concentrations. The average air temperature and the highest air temperature showed a positive correlation with the total HAA levels in precipitation. Clearly, the increase in precipitation total HAAs with higher air temperatures may indicate the enhanced temperature-induced degradation of high molecular weight atmospheric proteinaceous matter. Moreover, the volume-weighted precipitation glycine and total HAA levels were positively correlated with the product of atmospheric ozone and nitrogen dioxide, indicating that atmospheric proteinaceous matter may be inextricably bound up with both ozone- and nitrogen dioxide-related atmospheric processes. In conclusion, this study improves current knowledge on the origins and atmospheric processes of atmospheric proteinaceous compounds

<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Production and characterization of scorpine by MBP fusion technology in <i style="mso-bidi-font-style:normal">Escherichia coli</i></span>

69-74<span style="font-size: 11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">Scorpine, a small cationic peptide isolated from venom glands of Pandinus imperator, has the anti-bacterial and anti-plasmodial activities, and shows potential important applications in the pharmaceutical industries. Its N-terminal amino acid sequence is similar to cecropins, whereas its C-terminal region has several disulfide bridges, similar to the structure of defensins. Here, we report the expression and purification of recombinant scorpine in Escherichia coli, using maltose-binding protein (MBP) fusion partner. The fusion protein was expressed in soluble form in E. coli, and verified by SDS-PAGE and Western blotting analysis. The fusion protein was purified to 90% purity by amylose resin, which binds to MBP. After the MBP-scorpine fusion protein was cleaved by the Factor Xa protease to remove the MBP tag, the cleaved sample was loaded to a Ni2+-NTA affinity chromatography column. Tricine/SDS-PAGE gel results indicated that scorpine had been purified successfully to more than 95% purity. The recombinantly expressed scorpine showed anti-bacterial activity against two bacteria, Staphylococcus aureus ATCC 29213 and Acinetobacter baumannii ATCC 19606.<span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:advttr;mso-bidi-font-family:="" advttr;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB"> It also produced 100% reduction in Plasmodium falciparum parasitemia in vitro. Thus, the expression strategy presented in this study allows efficient and easy purification of recombinant scorpine for pharmaceutical applications in the future.</span

Correlation of Stacking Fault Energy with Deformation Mechanism in Cu-(2, 20)Zn Alloys

Copper-zinc alloys with different zinc contents contain different stacking fault energies (SFE). The influence of SFE on the deformation mechanism during surface mechanical attrition treatment was studied in this work. Research results indicate that the deformation mechanism directly correlated with the SFE in Cu-Zn alloys. Deformation twinning plays a paramount role during original deformation in Cu-20Zn (19 mJ/m2). However, for Cu-2Zn alloy with low-medium SFE (38 mJ/m2), the deformation mechanism is dominated by the dislocation slipping. Microbands are the predominant microstructural features in large strain and high strain rate regions for both Cu-Zn alloys in the present study. They are likely to be formed by the splitting of the high-density dislocation walls

Research and Development of Self-Waterproofing Concrete for Tunnel Lining Structure and Its Impermeability and Crack Resistance Characteristics

This research paper systematically investigates the combined influence of fly ash, cementitious capillary crystalline waterproofing (CCCW) materials, and polypropylene fibers on the mechanical properties and impermeability of concrete through comprehensive orthogonal tests. Microscopic morphological changes in the concrete induced by different composite materials are examined via scanning electron microscopy (SEM) and X-ray diffraction (XRD) testing. The objective is to facilitate a beneficial synergetic interaction among these materials to develop highly permeable, crack-resistant concrete. Key findings of this study are: (1) The study unveils the impact of the concentration of three additive materials on the concrete’s compressive strength, tensile strength, and penetration height, thereby outlining their significant influence on the mechanical properties and impermeability of the concrete; (2) An integrated scoring method determined the optimal composite dosage of three materials: 15% fly ash, 2% CCCW, and polypropylene fibers at 1.5 kg/m3. This combination increased the concrete’s compressive strength by 12.5%, tensile strength by 48.4%, and decreased the average permeability height by 63.6%; (3) The collective introduction of these three materials notably augments the hydration reaction of the cement, resulting in denser concrete microstructure, enhanced bonding between fibers and matrix, and improved concrete strength and durability

The effect of dietary supplementation with Clostridium butyricum on the growth performance, immunity, intestinal microbiota and disease resistance of tilapia (Oreochromis niloticus).

This study was conducted to assess the effects of dietary Clostridium butyricum on the growth, immunity, intestinal microbiota and disease resistance of tilapia (Oreochromis niloticus). Three hundreds of tilapia (56.21 ± 0.81 g) were divided into 5 groups and fed a diet supplemented with C. butyricum at 0, 1 x 104, 1 x 105, 1 x 106 or 1 x 107 CFU g-1 diet (denoted as CG, CB1, CB2, CB3 and CB4, respectively) for 56 days. Then 45 fish from each group were intraperitoneally injected with Streptococcus agalactiae, and the mortality was recorded for 14 days. The results showed that dietary C. butyricum significantly improved the specific growth rate (SGR) and feed intake in the CB2 group and decreased the cumulative mortality post-challenge with S. agalactiae in the CB2, CB3 and CB4 groups. The serum total antioxidant capacity and intestinal interleukin receptor-associated kinase-4 gene expression were significantly increased, and serum malondialdehyde content and diamine oxidase activity were significantly decreased in the CB1, CB2, CB3 and CB4 groups. Serum complement 3 and complement 4 concentrations and intestinal gene expression of tumour necrosis factor α, interleukin 8, and myeloid differentiation factor 88 were significantly higher in the CB2, CB3 and CB4 groups. Intestinal toll-like receptor 2 gene expression was significantly upregulated in the CB3 and CB4 groups. Dietary C. butyricum increased the diversity of the intestinal microbiota and the relative abundance of beneficial bacteria (such as Bacillus), and decreased the relative abundance of opportunistic pathogenic bacteria (such as Aeromonas) in the CB2 group. These results revealed that dietary C. butyricum at a suitable dose enhanced growth performance, elevated humoral and intestinal immunity, regulated the intestinal microbial components, and improved disease resistance in tilapia. The optimal dose was 1 x 105 CFU g-1 diet

Genetic diversity and population structure of Plasmodium vivax in Central China.

BACKGROUND: In Central China the declining incidence of Plasmodium vivax has been interrupted by epidemic expansions and imported cases. The impact of these changes on the local parasite population, and concurrent risks of future resurgence, was assessed. METHODS: Plasmodium vivax isolates collected from Anhui and Jiangsu provinces, Central China between 2007 and 2010 were genotyped using capillary electrophoresis at seven polymorphic short tandem repeat markers. Spatial and temporal analyses of within-host and population diversity, population structure, and relatedness were conducted on these isolates. RESULTS: Polyclonal infections were infrequent in the 94 isolates from Anhui (4%) and 25 from Jiangsu (12%), with a trend for increasing frequency from 2008 to 2010 (2 to 19%) when combined. Population diversity was high in both provinces and across the years tested (H(E) = 0.8 - 0.85). Differentiation between Anhui and Jiangsu was modest (F'(ST) = 0.1). Several clusters of isolates with identical multi-locus haplotypes were observed across both Anhui and Jiangsu. Linkage disequilibrium was strong in both populations and in each year tested (I(A)(S) = 0.2 - 0.4), but declined two- to four-fold when identical haplotypes were accounted for, indicative of occasional epidemic transmission dynamics. None of five imported isolates shared identical haplotypes to any of the central Chinese isolates. CONCLUSIONS: The population genetic structure of P. vivax in Central China highlights unstable transmission, with limited barriers to gene flow between the central provinces. Despite low endemicity, population diversity remained high, but the reservoirs sustaining this diversity remain unclear. The challenge of imported cases and risks of resurgence emphasize the need for continued surveillance to detect early warning signals. Although parasite genotyping has potential to inform the management of outbreaks, further studies are required to identify suitable marker panels for resolving local from imported P. vivax isolates