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Thermostable strains isolated from intestine of catfish were screened for their antagonism activity against Edwardsiella ictaluri, the causative agent of enteric septicemia of catfish (ESC) and red head disease. Four thermostable strains were selected, and their antagonistic activity against E. ictaluri was compared. Adhesion to zebrafish larvae was determined as CFU/larva after exposure for 30min. The isolate Yab4 was found to be highly adhesive and was identified as Bacillus altitudinis based on a phylogenetic tree constructed using 16S rDNA and gyrB sequences. After 28d of feed supplementation with B. altitudinis Yab4, the growth performance of the treatment group is better than that of the control group, with a statistically significant difference observed between the two groups. Moreover, the innate immune indexes including alkaline phosphatase, lysozyme, and total proteins in serum increased significantly, and the expression levels of immune genes including IL-1β, TNF-α, and NF-κB p65 elevated significantly as well. Most importantly, the survival rate of the yellow catfish fed with B. altitudinis Yab4 supplementation reached 60%, marking a 35% increase compared to the control group when challenged with E. ictaluri HSN-1 infected intraperitoneally. This demonstrates that the potential of B. altitudinis Yab4 as a novel Bacillus probiotic to defend against E. ictaluri in catfish aquaculture through feed supplementation. [ABSTRACT FROM AUTHOR]

The type III secretion system effector EseJ plays a regulatory role inside bacteria. It suppresses the adherence of Edwardsiella piscicida (E. piscicida) to host epithelial cells by down regulating type 1 fimbriae. In this study, we observed that more macrophages infected with ΔeseJ strain of E. piscicida detached as compared with those infected with the wild‐type (WT) strain. Terminal deoxynucleotidyl transferase dUTP nick‐end labelling (TUNEL) staining and cleaved caspase‐3 examination revealed that the detachment is due to increased apoptosis, suggesting that EseJ suppresses macrophage apoptosis. However, apoptosis inhibition by EseJ is not relative to a type III secretion system (T3SS) and is not related to EseJ's translocation. Since EseJ negatively regulates type 1 fimbriae, murine J774A.1 cells were infected with ΔeseJΔfimA or ΔeseJΔfimH strains. It was demonstrated that ΔeseJ stimulates macrophage apoptosis through type 1 fimbriae. Moreover, we found that infecting J774A.1 cells with the ΔeseJ strain increased levels of cleaved caspase‐8, caspase‐9, and caspase‐3, demonstrating that EseJ inhibits apoptosis through either an extrinsic or a combination of extrinsic and intrinsic pathways. Pre‐treatment of macrophages with caspase‐8 inhibitor prior to infection with the ΔeseJ strain decreased the levels of cleaved caspase‐8, caspase‐9, and caspase‐3, indicating that the ΔeseJ strain stimulates apoptosis, mainly through an extrinsic pathway by up regulating type 1 fimbriae. Zebrafish larvae or blue gourami fish infected with the ΔeseJ strain consistently exhibited higher apoptosis than those infected with the E. piscicida WT strain or ΔeseJΔfimA strain. Taken together, we revealed that the T3SS protein EseJ of E. piscicida inhibits host apoptosis, mainly through an extrinsic pathway by down regulating type 1 fimbriae. [ABSTRACT FROM AUTHOR]

Context/objective: The 13-item Patient Activation Measure (PAM-13) is the most widely used generic patient activation measure, but spinal cord injury (SCI) related psychometric evaluation of PAM-13 has not been explored globally. This study aimed to assess the validity of the Chinese version of the PAM-13 (PAM-13-C) for individuals with chronic spinal cord injury (CSCI)., Design: Cross-sectional study., Setting: Shanghai Sunshine Rehabilitation Center, and some participants were recruited in a WeChat group (the most commonly used social media platform in China)., Participants: 284 individuals with spinal cord injury who had lived with the injury for ≥0.5 year., Interventions: NA., Outcome Measures: The PAM-13-C, global QoL, seven-item generalized anxiety disorder scale (GAD-7) and nine-item patient health questionnaire (PHQ-9), and General Self-Efficacy Scale (GSES) were used., Results: The mean (SD) PAM-13-C score was 57.4 (16.5). The highest percentage of NA could be observed in item 9 (12.0%). Floor and ceiling effects of the total scores of PAM-13-C were small (0.7% and 6.7%), but a ceiling effect could be observed among all items. Exploratory Factor Analysis supported a one-factor model of the PAM-13-C (CFI = 0.97; RMSEA = 0.07). Construct validity was established through correlation analysis among the PAM-13-C, GAD-7/PHQ-9, global QoL, and GSES. The PAM-13-C demonstrated excellent internal consistency (Cronbach's α  = 0.95) and acceptable test-retest reliability., Conclusion: The PAM-13-C is a reliable and valid measure of patient activation for individuals with CSCI in China.

Type 1 fimbria, the short hair-like appendage assembled on the bacterial surface, plays a pivotal role in adhesion and invasion in Edwardsiella piscicida . The type III secretion system (T3SS), another bacterial surface appendage, facilitates E. piscicida 's replication in vivo by delivering effectors into host cells. Our previous research demonstrated that E. piscicida T3SS protein EseJ inhibits adhesion and invasion of E. piscicida by suppressing type 1 fimbria. However, how EseJ suppresses type 1 fimbria remains elusive. In this study, a lacI -like operator (nt -245 to -1 of fimA ) upstream of type 1 fimbrial operon in E. piscicida was identified, and EseJ inhibits type 1 fimbria through the lacI -like operator. Moreover, through DNA pull-down and electrophoretic mobility shift assay, an AraC-type T3SS regulator, EsrC, was screened and verified to bind to nt -145 to -126 and nt -50 to -1 of fimA , suppressing type 1 fimbria. EseJ is almost abolished upon the depletion of EsrC. EsrC and EseJ impede type 1 fimbria expression. Intriguingly, nutrition and microbiota-derived indole activate type 1 fimbria through downregulating T3SS, alleviating EsrC or EseJ's inhibitory effect on lacI -like operator of type 1 fimbrial operon. By this study, it is revealed that upon entering the gastrointestinal tract, rich nutrients and indole downregulate T3SS and thereof upregulate type 1 fimbria, stimulating efficient adhesion and invasion; upon being internalized into epithelium, the limit in indole and nutrition switches on T3SS and thereof switches off type 1 fimbria, facilitating effector delivery to guarantee E. piscicida 's survival/replication in vivo .IMPORTANCEIn this work, we identified the lacI -like operator of type 1 fimbrial operon in E. piscicida , which was suppressed by the repressors-T3SS protein EseJ and EsrC. We unveiled that E. piscicida upregulates type 1 fimbria upon sensing rich nutrition and the microbiota-derived indole, thereof promoting the adhesion of E. piscicida . The increase of indole and nutrition promotes type 1 fimbria by downregulating T3SS. The decrease in EseJ and EsrC alleviates their suppression on type 1 fimbria, and vice versa ., Competing Interests: The authors declare no conflict of interest.

The type III secretion system (T3SS) of Edwardsiella tarda is crucial for its intracellular survival and pathogenesis in fish. The orf13 gene (escE) of E. tarda is located 84 nucleotides (nt) upstream of esrC in the T3SS gene cluster. We found that EscE is secreted and translocated in a T3SS-dependent manner and that amino acids 2 to 15 in the N terminus were required for a completely functional T3SS in E. tarda. Deletion of escE abolished the secretion of T3SS translocators, as well as the secretion and translocation of T3SS effectors, but did not influence their intracellular protein levels in E. tarda. Complementation of the escE mutant with a secretion-incompetent EscE derivative restored the secretion of translocators and effectors. Interestingly, the effectors that were secreted and translocated were positively correlated with the EscE protein level in E. tarda. The escE mutant was attenuated in the blue gourami fish infection model, as its 50% lethal dose (LD50) increased to 4 times that of the wild type. The survival rate of the escE mutant-strain-infected fish was 69%, which was much higher than that of the fish infected with the wild-type bacteria (6%). Overall, EscE represents a secreted T3SS regulator that controls effector injection and translocator secretion, thus contributing to E. tarda pathogenesis in fish. The homology of EscE within the T3SSs of other bacterial species suggests that the mechanism of secretion and translocation control used by E. tarda may be commonly used by other bacterial pathogens., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)