Frontiers in Microbiology最新文献

Sulfate-reducing microorganisms (SRM) can contribute to souring and to the corrosion of infrastructure built to support many industrial operations, including in aquatic environments. While chemicals such as biocides can effectively treat planktonic cells, less is known about biocide efficacy for treating established biofilms potentially plaguing infrastructure. We used a biofilm flow cell system to examine the efficacy of sodium nitroprusside (SNP, a nitrosating compound proposed as a "green" biocide) and alkyl dimethyl benzyl ammonium chloride (ADBAC), a membrane-disrupting biocide used across many sectors, to mitigate existing SRM biofilms. Biofilms were treated with various amounts of SNP (15-750 ppm) or ADBAC (25-500 ppm) for 10-14 h. Biofilm responses were tracked by measuring sulfide concentrations and were also analyzed for microbial community composition and by microscopy. Planktonic SRM cultures were inhibited by 15 ppm SNP, while biofilms were only transiently inhibited by 15-750 ppm SNP. Planktonic cultures were inhibited by 10 ppm ADBAC, but 50 ppm ADBAC did not suppress sulfide production in existing biofilms. ADBAC added at 100 ppm to the biofilms showed transient inhibition while the 250 and 500 ppm treatments completely inhibited sulfidogenesis. Two-photon microscopy showed primarily viable cells following the 50 ppm ADBAC treatments, a mix of viable and non-viable cells following the 100 ppm ADBAC treatment, and non-viable cells following the 250 and 500 ppm ADBAC treatments, confirmed by quantitative analysis of the images. 16S rRNA gene sequencing showed the prevalence of Desulfobulbus and either Desulfomicrobium or Pseudomonas in active biofilms, with these taxa differentially persisting after many of the biocide treatments. The results revealed that higher doses of biocides are needed to effectively treat existing SRM biofilms compared to planktonic cells, and that biocide dosing may only be transiently effective. Studying the effects of chemical treatments on sessile rather than planktonic communities in aquatic environments may lead to more effective treatment strategies to mitigate problematic biofilms plaguing infrastructure degradation across many industries.

Post-transcriptional regulation is the predominant mode of gene expression control in Trypanosoma brucei, yet the underlying regulatory elements and proteins remain poorly defined. AU- and GU-rich elements (AREs and GREs) are common post-transcriptional regulatory motifs. To investigate their roles in T. brucei, we analyzed transcriptomic datasets and extracted 5,840 genes with defined 5' and 3' untranslated regions (UTRs), including 327 that are developmentally regulated between the parasite's two life stages. Computational analysis revealed that AU- and GU-rich elements are widespread and enriched in the 3'UTRs of developmentally regulated mRNAs as well as in transcripts with long half-lives. Functional assays demonstrated regulatory activity of AREs and GREs within the 3'UTRs of five representative genes (ICP, TOP2, MCC-β, PK, and KREPB6), with differential effects on reporter expression. Notably, the GREs in the ICP and TOP2 3'UTRs destabilized reporter transcripts in procyclic-form trypanosomes but enhanced expression in bloodstream forms. RNA pulldown assays further identified DRBD2 as a potential GRE-binding protein, and DRBD2 knockdown reduced ICP mRNA abundance in procyclic trypanosomes. Collectively, these findings demonstrate that AREs and GREs are critical regulatory elements in T. brucei, exhibiting gene-specific and context-dependent functions. Elucidating their regulatory roles and identifying additional binding proteins will provide new insights into the mechanisms of post-transcriptional control in this parasite.

Environmental pollution has emerged as a pervasive global health threat, yet its effects extend far beyond direct organ toxicity. Increasing evidence reveals that the gut microbiota serves as a central mediator of pollutant-induced physiological dysfunctions. This review integrates recent advances on how air pollutants, heavy metals, persistent organic pollutants, and emerging contaminants perturb microbial composition, metabolic activity, and host-microbe signaling. Pollutant exposure alters microbial-derived metabolites such as short-chain fatty acids, bile acids, and tryptophan derivatives, thereby impairing intestinal barrier integrity and immune homeostasis. These microbiota-driven disturbances trigger oxidative stress, chronic inflammation, and neuroendocrine dysregulation, contributing to metabolic disorders, immune imbalance, neurotoxicity, and carcinogenesis. Mechanistically, redox imbalance, activation of TLR4/NF-κB and NLRP3 pathways, and dysregulation of AhR signaling represent critical intersections linking environmental exposure to disease. By elucidating these molecular and ecological connections, this review underscores the gut microbiotaas a key target and therapeutic entry point for mitigating the health impacts of environmental pollution and guiding microbiota-based interventions for disease prevention.

Respiratory tract infections (RTIs) are among the most prevalent diseases in human society and pose a major global health threat, affecting millions annually. A wide range of pathogens, primarily viruses and bacteria, cause RTIs. These infections often present with similar symptoms, which limits effective clinical treatment. Extensive research has addressed RTIs, with ongoing discussion regarding their current status and advancements in detection technologies. Novel laboratory methods that offer rapid, sensitive, and specific results now supplement traditional diagnostic approaches. In this review, we summarize the infection characteristics and detection methods of common respiratory pathogens, evaluate the effectiveness and limitations of current detection methods, and aim to promote advancements in laboratory diagnosis and explore the potential of emerging technologies in this field.

Microplastic pollution fosters the development of distinct microbial biofilm communities, termed the plastisphere, that vary across environmental contexts. Here, we used 16S rRNA gene sequencing combined with machine learning (ML) approaches to explore plastisphere microbial diversity and the interactions between potential plastic-degrading bacteria (PDBs) and non-plastic-degrading bacteria (NDBs) across ocean, surface water, and wastewater habitats. Our findings reveal that wastewater plastispheres harbor the most diverse and compositionally even microbial communities, likely driven by complex nutrient loads, pollutant inputs, and high microbial seeding potential. Genus-level analysis of potential PDBs indicated habitat-specific taxa, including Pseudomonas, Acinetobacter, and Aquabacterium in wastewater, Flavobacterium and Alteromonas in ocean, and Psychrobacter and Novosphingobium in surface waters. Network analyses using Pearson's correlation and Random Forest modeling uncovered consistent co-occurrence patterns between potential PDBs and diverse NDB taxa such as Clostridium_sensu_stricto_5, Lachnospiraceae_UCG-001, and Cloacibacterium, suggesting potential facilitative interactions, including redox modulation, nutrient exchange, and biofilm support. ML tools proved effective in identifying key taxa and potential ecological interactions, but their application remains limited by taxonomic resolution, lack of functional validation, and insufficient integration of environmental metadata. These findings underscore the ecological complexity of plastisphere communities and the need for community-level approaches in plastic biodegradation research.

Spring viremia of carp (SVC), caused by spring viremia of carp virus (SVCV), is a highly contagious disease that poses a serious threat to cyprinid aquaculture and international trade, and it is listed as a notifiable disease by the World Organization for Animal Health (WOAH). Effective surveillance and control of SVCV rely on accurate and highly sensitive molecular diagnostic methods. However, several previously published RT-qPCR assays contain mismatches between primer/probe sequences and viral genomes, which may lead to false-negative results and reduced diagnostic reliability. In this study, a whole-genome comparison of 24 representative SVCV strains covering all four genotypes (SVCVa-d) was conducted, and a new primer-probe set (Cefas AR) targeting a highly conserved region of the L gene was designed. Reaction conditions were optimized, and the assay was rigorously validated in accordance with the WOAH Manual of Diagnostic Tests for Aquatic Animals. The developed RT-qPCR assay exhibited excellent analytical performance, with a limit of detection of 1.28 copies/μL, diagnostic sensitivities of 100% for cell-culture isolates and 96.6% for tissue samples, and a diagnostic specificity of 100%. In addition, the assay demonstrated strong reproducibility and consistency across nine independent laboratories. In conclusion, the WOAH-validated RT-qPCR assay developed in this study provides a highly sensitive, specific, and reliable tool for rapid screening, routine surveillance, and confirmatory diagnosis of SVCV, supporting sustainable aquaculture development and international aquatic animal health management.

Background: The normal intestinal microbiota undergoes rapid and notable changes in patients in the intensive care unit (ICU) because of factors such as host physiological stress, changes in gastrointestinal function, and antibiotic exposure. Different specimen types are used for intestinal microbial analysis because of sampling difficulties. Therefore, this study conducted a meta-analysis to investigate changes in the intestinal microbiota of patients admitted to the ICU and whether using different specimen types affects microbiota analysis.

Methods: A systematic review was conducted encompassing studies published in electronic databases up to May 1, 2024. We included 11 studies that compared the abundance and diversity of the gut microbiota between ICU patients and healthy cohorts (HC). A standardized mean difference (SMD) meta-analysis using random effects models was performed to quantify microbial differences, including an assessment of various sampling methods.

Results: After ICU admission, the intestinal microbiota of patients differed significantly from that of the normal population, showing lower diversity and richness. A significant difference in beta diversity was also observed. Specifically, the relative abundances of Proteobacteria and Fusobacteria were elevated in ICU patients, while Firmicutes abundance was diminished. Crucially, the comparison of stool versus rectal swab specimens demonstrated no significant difference in the measured alpha diversity of the gut microbiota.

Conclusion: The early intestinal microbiota of patients in the ICU differed from that of healthy individuals. A comprehensive understanding of the early changes in the intestinal microbiota of patients in the ICU can help formulate prevention and treatment strategies. Furthermore, using feces and swab samples for analysis did not significantly affect the diversity of the intestinal microecology. Therefore, rectal swabs may be an attractive method for sampling the gut microbiota and metabolome.

Systematic review registration: PROSPERO Registration number is CRD42022385146 (Available from: https://www.crd.york.ac.uk/PROSPERO/view/CRD42022385146).

Introduction: This study clarifies the taxonomic identity of Bacillus paralicheniformis MHN12 and maps the genetic foundations of its beneficial traits. It also provides functional insights into the salinity-stress response and paves the way for the development of MHN12 as a potential bioinoculant to enhance crop stress resilience and productivity.

Methods: The endophytic strain MHN12, isolated from Vigna radiata, was initially identified as Bacillus licheniformis based on its 16S rRNA sequence. To ascertain its identity and ensure accurate taxonomic classification, a comparative genomic analysis based on genome relatedness indexes and secondary metabolite biosynthetic gene clusters was conducted, involving MHN12 and 22 other B. paralicheniformis strains.

Results and discussion: There were high similarities among the strains and antiSMASH revealed the presence of biosynthetic gene clusters specifically fengycin and bacitracin in MHN12 encoded by the genomes of B. paralicheniformis but absent in B. licheniformis. The whole genome analysis of B. paralicheniformis MHN12, focusing on identifying genes contributing to its potential to promote plant growth and abiotic stress tolerance was also performed. Genes linked to chemotaxis, motility, polysaccharide synthesis, plant growth promoting traits, antimicrobial and stress mitigation compounds were annotated. This highlights MHN12's potential to efficiently colonize plants, stimulate their growth, and protect them from environmental stresses and pathogens. In vitro assays also supported the genomic data, demonstrating MHN12's ability to synthesize enzymatic antioxidants and exopolysaccharides (EPS) while retaining plant growth promoting traits under salinity stress. Gas chromatography (GC)-based analysis revealed modulation of plasma membrane lipids aiding MHN12 to combat salt stress.

Staphylococcus aureus is a leading cause of skin and wound infections worldwide, with methicillin-resistant strains (MRSA) posing a persistent clinical challenge due to antibiotic tolerance and biofilm formation. Lactoferrin, an iron-binding glycoprotein abundant in mammals' secretions and neutrophil granules, has emerged as a promising multifunctional agent that could help manage staphylococcal skin and wound infections, as it combines direct antimicrobial activity with immunomodulatory and tissue-repair effects. This mini-review aims to synthesize current evidence on the role of lactoferrin in the prevention and treatment of staphylococcal skin and wound infections, focusing on its antimicrobial mechanisms, modulation of host responses, and therapeutic applications. In vitro studies demonstrate that lactoferrin inhibits S. aureus growth through iron sequestration and membrane disruption, and it can also disrupt biofilm formation and persistence. Additionally, experiments showed that lactoferrin modulates inflammation, reduces oxidative stress, and promotes fibroblast migration and collagen deposition, facilitating wound closure. Lactoferrin incorporated into hydrogels, films, or nanocarriers enhanced antibacterial activity and synergized with antibiotics or bacteriophages in preclinical models. Nonetheless, variability in dosing, formulation, and study design limits cross-study comparisons, and potential bacterial resistance mechanisms remain underexplored. Therefore, further controlled and standardized studies are needed in order to optimize clinical translation and integration into modern wound care.

Hospital wastewater (HWW) is a complex matrix of pharmaceutical residues, antibiotic resistance genes (ARGs), pathogens, and emerging contaminants that threaten public health and ecosystems. Conventional wastewater treatment plants (WWTPs) often fail to eliminate persistent compounds like carbamazepine and sulfamethoxazole, contributing to antimicrobial resistance and environmental toxicity. This review explores advanced treatment strategies with a focus on bioremediation and phytoremediation. Microbial approaches using bacteria, fungi, algae such as Labrys portucalensis, Trametes versicolor, and Chlorella vulgaris demonstrate degradation of pharmaceuticals and ARGs. Similarly, phytoremediation with species like Typha angustifolia and Vetiveria zizanioides supports on-site through rhizospheric uptake. Integrated systems combining membrane bioreactors (MBRs), advanced oxidation processes (AOPs), constructed wetlands (CWs), and microbial consortia offer enhanced removal efficiency and ARG reduction. While hybrid systems show strong potential, they face challenges such as high costs, difficulties in large-scale application, and limited regulation. Overall, this review highlights how integrating biological and technological methods provides a practical and sustainable path forward for treating hospital wastewater (HWW) and reducing its environmental and health impacts. A multidisciplinary, globally coordinated approach is essential for sustainable HWW management.