ObjectiveStroke is a leading cause of death and disability worldwide. Neuroprotective approaches have failed in clinical trials, thus warranting therapeutic innovations with alternative targets. The gut microbiota is an important contributor to many risk factors for stroke. However, the bidirectional interactions between stroke and gut microbiota remain largely unknown.DesignWe performed two clinical cohort studies to capture the gut dysbiosis dynamics after stroke and their relationship with stroke prognosis. Then, we used a middle cerebral artery occlusion model to explore gut dysbiosis post-stroke in mice and address the causative relationship between acute ischaemic stroke and gut dysbiosis. Finally, we tested whether aminoguanidine, superoxide dismutase and tungstate can alleviate post-stroke brain infarction by restoring gut dysbiosis.ResultsBrain ischaemia rapidly induced intestinal ischaemia and produced excessive nitrate through free radical reactions, resulting in gut dysbiosis with Enterobacteriaceae expansion. Enterobacteriaceae enrichment exacerbated brain infarction by enhancing systemic inflammation and is an independent risk factor for the primary poor outcome of patients with stroke. Administering aminoguanidine or superoxide dismutase to diminish nitrate generation or administering tungstate to inhibit nitrate respiration all resulted in suppressed Enterobacteriaceae overgrowth, reduced systemic inflammation and alleviated brain infarction. These effects were gut microbiome dependent and indicated the translational value of the brain–gut axis in stroke treatment.ConclusionsThis study reveals a reciprocal relationship between stroke and gut dysbiosis. Ischaemic stroke rapidly triggers gut microbiome dysbiosis with Enterobacteriaceae overgrowth that in turn exacerbates brain infarction.

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The aim of this study was to develop and evaluate a rapid and effective method to detect Vibrio parahaemolyticus, a leading pathogen causing seafood-borne gastroenteritis. A newly designed loop-mediated isothermal amplification (LAMP) assay including a short enrichment period was optimized. This assay correctly detected all the target strains (n 61) but none of the non-target strains (n 34). Very low numbers of V. parahaemolyticus (2 colony forming unit (CFU) per gram of seafood) could be detected within 3 h and the minimum time of the whole assay was only 5 h. Comparative screening of various seafood samples (n 70) indicated that the LAMP assay is superior to polymerase chain reaction (PCR) and conventional culture methods because it is more rapid and less complex. This highly sensitive LAMP assay can be applicable as the method of choice in large-scale and rapid screening of seafood and environmental samples to detect V. parahaemolyticus strains.Key words Vibrio parahaemolyticus; loop-mediated isothermal amplification; rapid detection; enrichment culture; seafood Vibrio parahaemolyticus is one of the most important seafood-borne pathogen causing gastrointestinal disorders to humans. This halophilic Gram-negative bacterium was first identified as a causative agent of human gastroenteritis in Japan in 1950.1) However, V. parahaemolyticus can occur ubiquitously in the brackish coastal environment of most continents and infections associated with seafood contaminated by this pathogen have occurred throughout the world.2-4) Particularly, the worldwide spread of the V. parahaemolyticus O3 : K6 serotype after its emergence in Asia in 1995, it has become very important to identify this pathogenic species in a rapid and sensitive manner.5) At present, the outbreak of V. parahaemolyticus infections is a significant public health concern in many countries including China, Japan and U.S.A. 6,7)Seafood is very popular in many countries, and simple and specific identification of a pathogen from seafood samples is essential for taking preventive and curative measures. Conventional methods for the diagnosis of V. parahaemolyticus include cultivation of bacteria on selective media followed by biochemical tests. However, the traditional phenotypic identification is problematic, it is very time-consuming requiring 3-7 d and not highly specific because several Vibrio species display similar biochemical characteristics, which make it difficult for rapid identification of V. parahaemolyticus. 8) To circumvent this problem, the identification of V. parahaemolyticus by rapid and specific molecular techniques targeting the genes encoding thermostable direct haemolysin (TDH) and TDH-related haemolysin (TRH) were developed.9-11) However, these genes are only found in pathogenic strains and most V. parahaemolyticus isolates from the environment sources do not produce TDH or TRH. 3,12) Besides, there are reports of toxigenic factors other than TDH or TRH, e.g., type III secretion system 2, associated with clinical V. parahaemolyticus stra...

Bacteria of the genus Providencia are opportunistic pathogens of clinical significance due to their association with diarrhea and urinary tract infections. The present study was conducted to examine the prevalence and antimicrobial resistance of Providencia spp. in retail meats sold in Guangzhou, China and Osaka, Japan. Out of 158 meat samples including beef, pork and chicken, 67 Providencia (42%) belonging to four species viz., P. alcalifaciens, P. rustigianii, P. stuartii and P. rettgeri were isolated, and most of them were resistant to tetracycline (91%) followed by ampicillin (69%) and streptomycin (49%). Of 67 isolates, 29 (43%) were MDR, which is defined to be resistant to more than three classes of antimicrobials. No statistically significant differences were observed between Chinese and Japanese retail meat samples regarding contamination rate of Providencia spp. as well as frequency of the antimicrobial resistance of the isolates including MDR. Class 1 and/or class 2 integrons were detected in six of the eight isolates that were resistant to more than 4 antimicrobials, however none of the isolates harbored class 3 integron. A P. rustigianii harboring the blaOXA-10 gene was isolated, which is the first report of Providencia with blaOXA-10 gene of food origin. These data suggest that retail meats in China and Japan are substantially contaminated with Providencia spp., which displayed a high frequency of antimicrobial resistance, and establishing the surveillance of Providencia spp., especially antimicrobial resistant one, in retail meats is imperative.