Prevalence and antimicrobial resistance profile of bacterial pathogens isolated from poultry in Jiangxi Province, China from 2020 to 2022.

Poultry is one of the most commonly farmed species and the most widespread meat industries. However, numerous poultry flocks have been long threatened by pathogenic bacterial infections, especially antimicrobial resistant pathogens. Here the prevalence and the antimicrobial resistance (AMR) profiles of bacterial pathogens isolated from poultry in Jiangxi Province, China were investigated. From 2020 to 2022, 283 tissue and liquid samples were collected from clinically diseased poultry, including duck, chicken, and goose, with an overall positive isolation rate of 62.90%. Among all the 219 bacterial isolates, 29 strains were gram-positive and 190 strains were gram-negative. Major bacteria species involved were avian pathogenic Escherichia coli (APEC; 57.53%; 126/219), followed by Salmonella spp. (11.87%, 26/219), Pasteurella multocida (6.39%, 14/219), and Staphylococcus spp. (1.22%, 11/219). Antimicrobial susceptibility testing showed the APEC isolates displayed considerably higher levels of AMR than the Salmonella and P. multocida isolates. The APEC isolates showed high resistance rate to amoxicillin (89.68%), ampicillin (89.68%), and florfenicol (83.33%), followed by streptomycin (75.40%), cefradine (65.87%), and enrofloxacin (64.29%). Multidrug-resistant isolates were observed in APEC (99.21%), Salmonella spp. (96.16%), and P. multocida (85.71%), and nearly 3 quarters of the APEC strains were resistant to 7 or more categories of antimicrobial drugs. Moreover, blaNDM genes associated with carbapenemase resistance and mcr-1 associated with colisitin resistance were detected in the APEC isolates. Our findings could provide evidence-based guidance for veterinarians to prevent and control bacterial diseases, and be helpful for monitoring the emerging and development of AMR in poultry bacterial pathogens.

Exogenous glycogen utilization effects the transcriptome and pathogenicity of Streptococcus suis serotype 2.

Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen that causes severe infections in humans and the swine industry. Acquisition and utilization of available carbon sources from challenging host environments is necessary for bacterial pathogens to ensure growth and proliferation. Glycogen is abundant in mammalian body and may support the growth of SS2 during infection in hosts. However, limited information is known about the mechanism between the glycogen utilization and host adaptation of SS2. Here, the pleiotropic effects of exogenous glycogen on SS2 were investigated through transcriptome sequencing. Analysis of transcriptome data showed that the main basic metabolic pathways, especially the core carbon metabolism pathways and virulence-associated factors, of SS2 responded actively to glycogen induction. Glycogen induction led to the perturbation of the glycolysis pathway and citrate cycle, but promoted the pentose phosphate pathway and carbohydrate transport systems. Extracellular glycogen utilization also promoted the mixed-acid fermentation in SS2 rather than homolactic fermentation. Subsequently, apuA, a gene encoding the unique bifunctional amylopullulanase for glycogen degradation, was deleted from the wild type and generated the mutant strain ΔapuA. The pathogenicity details of the wild type and ΔapuA cultured in glucose and glycogen were investigated and compared. Results revealed that the capsule synthesis or bacterial morphology were not affected by glycogen incubation or apuA deletion. However, extracellular glycogen utilization significantly enhanced the hemolytic activity, adhesion and invasion ability, and lethality of SS2. The deletion of apuA also impaired the pathogenicity of bacteria cultured in glucose, indicating that ApuA is indeed an important virulence factor. Our results revealed that exogenous glycogen utilization extensively influenced the expression profile of the S. suis genome. Based on the transcriptome response, exogenous glycogen utilization promoted the carbon adaption and pathogenicity of SS2.

Whole-genome analysis reveals possible sources of ALV-J infection in an anyi tile-like gray chicken flock.

Avian leukosis virus (ALV) induces multiple tumors in chicken and is still prevalent in a lot of local flocks in China. In this study, we analyzed the ALV infection status in an Anyi tile-like gray chicken flock by DF1-cells isolation, virus identification, and genome sequencing. Results showed a 29% (29/100) ALV positive rate in this flock. Homology analysis based on env genes illustrated that all these stains belong to subgroup J (92-100% identities) and can be further divided into 5 batches, suggesting a higher diversity of ALV-J within the same flock. The whole-genome analysis of representative stains from each batch confirmed the close relationship between these isolated strains with previously reported strains from different regions (Guangxi, Shandong, and Heilongjiang), revealing the enrichment of different strains in Anyi tile-like grey chickens. This study provides the epidemiological data of ALV-J in a special chicken flock and a reference for the further eradication of ALV in China.

A ß1/2 adrenergic receptor-sensitive intracellular signaling pathway modulates CCL2 production in cultured spinal astrocytes.

The phosphorylation of c-jun N-terminal kinase (JNK) and the subsequent production of C-C chemokine CCL2 (monocyte chemoattractant protein; MCP-1) in spinal astrocytes contribute to the initiation of neurological disorders including chronic pain. Astrocytes express neurotransmitter receptors which could be targeted to ameliorate neurological disorders. In the current study, the involvement of the ß-adrenergic system in the regulation of JNK activity and CCL2 production after stimulation with tumor necrosis factor (TNF)-α, one of many initiators of neuroinflammation, was elucidated. Treatment of cultured spinal astrocytes with isoproterenol (a ß-adrenergic receptor agonist; 1 µM) reduced both TNF-α-induced JNK1 phosphorylation, as observed by Western blotting, and the subsequent increase of both CCL2 mRNA expression and CCL2 production, which were measured by real time-PCR and ELISA, respectively. The effects of isoproterenol were completely blocked by pretreatment with either propranolol (a ß-adrenoceptor antagonist) or H89 (a protein kinase A [PKA] inhibitor). The current study revealed that the regulation of glycogen synthase kinase-3ß (GSK-3ß) activity is a crucial factor in the inhibitory action of isoproterenol. The TNF-α-induced JNK1 phosphorylation was significantly blocked by treatment with GSK-3ß inhibitors (either LiCl or TWS119), and stimulation of ß-adrenergic receptors induced the inhibition of GSK-3ß through the phosphorylation of Ser(9) . Moreover, treatment with isoproterenol markedly suppressed the TNF-α-induced increase of CCL2 mRNA expression and CCL2 production through a ß-adrenergic receptor-PKA pathway mediated by GSK-3ß regulation. Thus, activation of ß1/2 adrenergic receptors expressed in spinal astrocytes could be a novel method of moderating neurological disorders with endogenous catecholamines or selective agonists.

Effects of CO(2) enrichment on growth and development of Impatiens hawkeri.

The effects of CO(2) enrichment on growth and development of Impatiens hawkeri, an important greenhouse flower, were investigated for the purpose of providing scientific basis for CO(2) enrichment to this species in greenhouse. The plants were grown in CO(2)-controlled growth chambers with 380 (the control) and 760 (CO(2) enrichment) µmol · mol(-1), respectively. The changes in morphology, physiology, biochemistry, and leaf ultrastructure of Impatiens were examined. Results showed that CO(2) enrichment increased flower number and relative leaf area compared with the control. In addition, CO(2) enrichment significantly enhanced photosynthetic rate, contents of soluble sugars and starch, activities of peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX), but reduced chlorophyll content and malondialdehyde (MDA) content. Furthermore, significant changes in chloroplast ultrastructure were observed at CO(2) enrichment: an increased number of starch grains with an expanded size, and an increased ratio of stroma thylakoid to grana thylakoid. These results suggest that CO(2) enrichment had positive effects on Impatiens, that is, it can improve the visual value, promote growth and development, and enhance antioxidant capacity.