The mycotoxin deoxynivalenol (DON) contamination in animal feed has been reported to reduce the growth performance of animals and compromise their immune system, especially pigs. Bacterial detoxification is considered a promising strategy to mitigate its harmful effects. We previously identified a bacterial isolate ( Bacillus sp. LS100) from the chicken gut with the ability to detoxify DON. To explore its potential application in swine production, the current study was focused on in vitro characterization of Bacillus sp. LS100 with regard to its capacity to detoxify DON. The bacterium was stable in keeping its activity to fully detoxify DON when subcultured for 12 passages under anaerobic conditions. The bacterial culture was successfully scaled up and stored for at least 1 month without losing any activity to detoxify DON. In addition, it was able to fully detoxify DON in mouldy corn with a diluted medium in an anaerobic atmosphere. While the bacterium exhibited a certain degree of tolerance to oxygen, it was sensitive to low pH and bile salts, including pig gastric fluid. In the presence of digesta from the pig jejunum or ileum, the bacteria retained near-full or full detoxification activity of DON after 24 or 48 h incubation under anaerobic conditions. To protect Bacillus sp. LS100 from the detrimental effects of gastric acid and bile salt, the bacterium was encapsulated anaerobically. The encapsulated bacteria stored in wet beads at 22 °C exhibited greater stability and retained detoxification activity longer than those stored in dry beads. After exposure to simulated gastric fluid for 2 h, the bacterium in the wet beads retained the DON detoxification activity. The current study suggests that, when adequately protected, Bacillus sp. LS100 holds promise as a viable strategy for DON removal in the pig gut.
Inorganic phosphate (Pi) limitation is a pervasive environmental constraint that shapes microbial behaviour in soil and plant-associated niches. To determine how Pi scarcity influences the pathogenic potential of rice-infecting Burkholderia species, we performed comparative proteomic and lipidomic analyses of Burkholderia glumae and Burkholderia plantarii grown under Pi-replete and Pi-deplete conditions. Pi starvation triggered strong activation of the Pho regulon in both organisms, including induction of alkaline phosphatases, phosphonate transporters and the high-affinity PstSABC uptake system. Beyond classical phosphate-stress responses, Pi limitation markedly enriched proteins associated with virulence, secretion systems, toxins, chemotaxis and cell envelope modification. Both species also activated PlcP/Agt-mediated lipid remodelling pathways and synthesized phosphorus-free glycolipids exclusively during Pi depletion, indicating substantial membrane lipid restructuring. These results demonstrate that Pi limitation acts as a major environmental cue coordinating nutrient acquisition with multiple virulence-related functions. Our findings provide new insight into how phosphate scarcity shapes the environmental fitness and pathogenic capacity of Burkholderia phytopathogens and highlight nutrient limitation as an important driver of plant disease emergence.
Carbapenem resistance in Enterobacteriaceae poses a major threat to public health because of the limited therapeutic options. The dissemination of the bla KPC gene, which encodes KPC carbapenemases, typically occurs through Tn 4401 transposons and plasmids that facilitate its transmission. In this study, we analysed 802 genomes of ESKAPE pathogens and other Enterobacteriaceae from Ecuador, including both clinical and non-clinical isolates, to determine the prevalence and genetic context of bla KPC-2 and bla KPC-3 and their associated mobile genetic elements. Whole-genome analysis revealed several isolates carrying bla KPC , with bla KPC-3 restricted to Klebsiella pneumoniae . While most isolates harboured the Tn 4401a transposon, we identified a novel variant, Tn 4401l , in two K. pneumoniae isolates collected between 2020 and 2021. Additionally, two putative plasmids carrying Tn 4401a were reconstructed: pECU0072020, a mosaic multidrug-resistant plasmid with a unique genetic organization, and pECU0062021, a more compact structure carrying only bla KPC-2 . The findings demonstrate the wide distribution of bla KPC within diverse bacterial hosts across multiple regions of Ecuador, the emergence of a novel Tn 4401l variant and the presence of putative plasmids that could potentially accelerate multidrug resistance dissemination. This study highlights the need for continuous genomic surveillance and coordinated strategies and practices regarding the use of antibiotics to mitigate the risk of outbreaks and interspecies transmission of carbapenem resistance.
