Microorganisms最新文献

Antibiotic feeding in shrimp farming is an optional practice conducted with the aim of preventing and controlling bacterial diseases. However, the administration of antibiotics can disrupt the microbiota of both shrimp and surrounding environment, potentially compromising host health. Given the limited effective antibiotic options in aquaculture, it is crucial to evaluate the effects of florfenicol (FF) on the intestinal health of shrimp and the associated microbial communities. This study first investigated the impact of FF on the intestinal structure of Penaeus vannamei over two feeding durations (5 and 10 days), each followed by a 10-day basal diet recovery period. Simultaneously, variations in microbial communities and antibiotic resistance genes (ARGs) in both the intestine and rearing water were explored. The results showed that intestinal damage was aggravated with the extension of FF duration and gradually recovered after FF withdrawal. Significant changes in microbial composition and β-diversity were observed in both the rearing water and intestine following FF feeding. Extending the FF treatment to 10 days led to a reduced abundance of Rhodobacteraceae and an increased abundance of Flavobacteriaceae and Vibrionaceae in the intestine after 10 days of feeding the basic diet, which may pose a potential risk to shrimp health. Based on correlation analysis of ARGs, microbial communities and pathogenic bacteria, we speculated that rearing water may serve as a reservoir for ARGs dissemination compared to the shrimp intestine. These findings are of great importance for assessing the impact of administration duration under the FF therapeutic dose and highlight the potential risks associated with its overuse in shrimp farming.

Evolutionary history of the host may influence the skeletal morphology of scleractinian corals. However, its effects on the assembly and function of endolithic microbiomes remain unknown. We analyzed bacterial and archaeal microbiomes from the coral skeleton by using 16S rRNA gene sequencing. We collected the samples of seven coral genera distributed among the diverse "Complex" and "Robust" clades. In this study, bacterial α-diversity was significantly higher in the Complex clade relative to the Robust clade. Archaea, on the other hand, remained stable and showed no significant differences between the two host clades, and were most abundantly Nanoarchaeota and Thermoproteota. Analysis of the network topologies showed that network structures were different between the Complex group and the Robust clade. The Robust clade formed a dense and closely knit network among bacteria and archaea. The Com-plex group formed a more modular network structure. Functional predictions further highlighted lineage-specific metabolic strategies. Enrichment was apparent in both nitrification genes (amoB, amoC) and denitrification genes (nirK, nirS) in the Complex clade. This suggests that the coupling of these nitrogen cycles is possible. The opposite was observed for the Robust clade, which had low potential for both types of nitrogen cycling. This reflects the degree of diffusion limitation in the more massive skeleton of this host lineage. Overall, species evolutionary lineage is a pre-eminent driver for the selective filtering of endolithic assembly. It generates discrete skeletal micro-niches on which microbial strategies diverge. In particular, Complex corals favor fast metabolic flux, and Robust corals favor strong network connectivity.

Salmonella is a major foodborne pathogen, and its increasing antimicrobial resistance poses a significant public health challenge. In this study, we conducted a comprehensive genomic epidemiological investigation of Salmonella isolates recovered from meat products across multiple provinces in China. A total of 141 isolates were collected and subjected to antimicrobial susceptibility testing and whole-genome sequencing. Core genome MLST and hierarchical clustering (HierCC) were performed using EnteroBase, while SNP phylogeny and phylodynamic analyses were conducted to characterize the evolutionary dynamics of Salmonella populations. The predominant serovars were Enteritidis and Infantis, with a high proportion of multidrug-resistant isolates. Potentially transferable plasmids carrying ARGs, such as bla_CTX-M, qnrS1, sul2, and mcr-1.1, were frequently detected, indicating a risk of horizontal transfer during transmission. Genomic epidemiological investigation of our sequenced strains and their associated cgMLST HierCC clusters revealed both persistent Salmonella lineages, such as Enteritidis HC50-87 and Agona HC20-419, and emerging China-specific lineages, including Enteritidis HC20-10145 and Typhimurium HC50-2304. The estimated divergence times of these lineages mostly dated to the late mid-20th century, coinciding with the intensification of poultry farming in China. These findings highlight the power of genomic epidemiology in uncovering antimicrobial resistance patterns and transmission dynamics, underscoring the need for strengthened Salmonella surveillance.

Vaccination remains a cornerstone of infection prevention in adult solid organ transplant (SOT) recipients, a population at heightened risk for vaccine-preventable diseases due to chronic immunosuppression and comorbidities. Updated guidelines from the American Society of Transplantation Infectious Diseases Community of Practice (AST IDCOP) and other international bodies emphasize the need for timely and comprehensive vaccination strategies before and after transplantation. This review synthesizes current literature and practice guidelines on vaccination in adult solid organ transplant (SOT) candidates and recipients. Published peer-reviewed studies, clinical trials, and consensus guidelines were evaluated, with emphasis on vaccination timing, safety, immunogenicity, dosing strategies, and serologic response monitoring in the SOT population. Comprehensive vaccination planning before transplantation, combined with appropriate post-transplant booster strategies, remains vital to improving long-term outcomes in SOT recipients. This review provides clinicians with an updated, evidence-based framework for integrating evolving vaccination guidelines into the care of adult transplant patients.

Mesozooplankton play a pivotal role in marine pelagic food webs, mediating energy and matter transfer between primary producers and higher trophic levels. Daya Bay, a semi-enclosed bay located in the northern South China Sea, has undergone significant environmental changes due to anthropogenic activities, such as thermal discharge from nuclear power plants and eutrophication. This study examined the mesozooplankton community structure, feeding preferences, and food web organization through four seasonal cruises (May 2022, February 2023, August 2023, and November 2023), employing stable isotope analysis and a Bayesian Isotopic Mixing Model. Results indicate that mesozooplankton abundance and diversity were lower in regions affected by thermal discharge, suggesting a suppressive effect of elevated temperatures. Seasonal shifts in dominant species were observed: Penilia avirostris and Dolioletta gegenbauri dominated the community in spring, while Noctiluca scintillans blooms occurred in summer and winter. Isotopic analysis revealed distinct trophic strategies: copepods exhibited omnivorous habits, whereas cladocerans and tunicates showed stronger herbivorous tendencies. N. scintillans functioned as a high-trophic omnivore, preying on copepod larvae and competing for food resources. Overall, the mesozooplankton community was characterized by an omnivory-dominated trophic network, which enhanced resilience yet remains sensitive to anthropogenic disturbances. This study clarifies how human-induced environmental changes reshape trophic pathways in subtropical coastal waters, providing a valuable reference for long-term monitoring and ecosystem management in Daya Bay.

Heavy metal pollution poses a serious threat to soil ecosystems worldwide, as long-term exposure can alter microbial community functioning and reduce overall ecosystem resilience. This study investigated the impact of heavy metal contamination in technogenic industrial areas of the East Kazakhstan Region on soil microbial communities. Soil samples were collected for chemical and metagenomic analyses. Concentrations of Zn, Pb, Cu, and Cd were quantified by flame atomic absorption spectrometry (FAAS). Using long-read whole-metagenome nanopore sequencing, we conducted strain-level profiling of soils with different levels of metal contamination. This approach provided high-resolution taxonomic data, enabling detailed characterization of microbial community structure. Heavy metal exposure did not significantly reduce microbial diversity or richness but influences the quality of community composition. Metal-resistant taxa dominated contaminated soils. Overall, the results highlight the value of long-read sequencing for resolving strain-level responses to environmental contamination.

This research utilized the CRISPR/Cas9 editing method to generate six mutant strains of Escherichia coli (E. coli) DH5α targeting specific genes. The functional characterization and phenotypic analysis confirmed the regulatory roles of these genes in modifying membrane permeability. The variations in membrane permeability among the mutant strains were assessed by measuring electrical conductivity, ortho-nitrophenyl-β-D-galactopyranoside (ONPG) hydrolysis, and propidium iodide (PI) fluorescence, with E. coli DH5α:ompA' exhibiting the most pronounced increase in membrane permeability. The function of these genes in transformation was analyzed from physicochemical and microscopic perspectives. Assays of plasmid transformation efficiency revealed a significant enhancement in the E. coli DH5α:ompA' mutant strain, underscoring the critical function of outer membrane proteins in DNA acquisition. Permeability simulations were performed utilizing the E. coli DH5α:ompA' mutant strain, grounded in a previously established model. The quantitative correlation between transformation efficiency and membrane permeability in this mutant conformed to the equation T = aP + c.

Raw meat-based diets (RMBDs) have become increasingly popular among pet owners, despite well-documented risks of contamination with pathogenic bacteria capable of causing severe illness in companion animals. This report describes a fatal case of botulism in a 3-year-old female Labrador Retriever weighing 37 kg that was fed exclusively RMBD. The dog presented with acute-onset flaccid paralysis of the limbs approximately 48 h after possible ingestion of decomposing raw meat discarded in household waste. Supportive therapy, including fluid administration, nutritional support and eventual mechanical ventilation was provided. However, the patient developed progressive respiratory failure and died. The presence of Clostridium botulinum type C neurotoxin was confirmed in the dog serum by neutralization test in mice. The case suggests RMBD as a potential source of botulism toxins, particularly when derived from improperly stored meat products. The findings underscore the importance of detailed dietary history in dogs presenting with acute flaccid paralysis and reinforce the need for heightened awareness regarding the microbiological risks associated with raw feeding practices.

A rapid decline of coral reefs is taking place around the world, with climate warming being the biggest driver behind this deterioration. Efforts to increase coral climate resilience via bioengineering methods have thus become urgent, and there is hope that such interventions can help corals and coral reefs survive until a time when no further climate warming occurs and perhaps a future of climate cooling is imaginable. The manipulation of coral-associated bacterial communities is among the less advanced interventions currently being explored. Nevertheless, early findings provide confidence that some level of thermal enhancement can be achieved via the inoculation of corals with beneficial bacteria. The small number of studies available, however, is limited in terms of the traits used to select candidate bacteria and their ability to ascribe host enhancement to specific bacterial taxa and functions. Further, findings to date are unable to decipher whether candidate bacteria integrate stably within the coral microbiome. These shortcomings prevent assessment of the efficacy of bacterial manipulation to enhance the long-term thermal resilience of corals on the reef. Here we summarise the state-of-play of the field and provide recommendations to fast-track this approach via fine-tuning experimental designs and methods.

Antibiotic resistance is arguably one of the greatest threats to global health today. The worldwide emergence of multidrug-resistant and hypervirulent Klebsiella pneumoniae underscores the urgent need for alternative treatments. Bacteriophages (phages) are considered one of the most promising alternatives to address this crisis. In this review, we summarize current knowledge of phage-host interactions and highlight recent advances in phage therapy against K. pneumoniae, including phage cocktails, antibiotic combination therapy, and treatments based on phage-derived proteins. Despite their tremendous therapeutic potential, significant challenges remain. We therefore also discuss strategies to optimize phage research and recent innovations in the field.