MicrobiologyOpen最新文献

Pseudomonas aeruginosa is found in 48%–52% of chronic wound biofilms, where its resistance to antimicrobials and host immunity presents a major clinical challenge. Although hypochlorous acid (HOCl) is known to be an effective antimicrobial, its mechanism of action remains unclear because standard experimental conditions often produce a mixture of HOCl and hypochlorite (OCl⁻), making it difficult to isolate the effects of HOCl. Here, we use proteomic profiling to investigate the effects of a pure, stable HOCl gel on P. aeruginosa biofilms in a physiologically relevant chronic wound model. We applied HOCl gel (5.7 mM, pH 6) to mature P. aeruginosa biofilms established in a wound-mimicking flow model. Proteins were analyzed using tandem mass tag (TMT)-based quantitative proteomics, identifying 1,878 proteins. HOCl treatment significantly reduced biofilm viability and altered the abundance of 330 proteins. We observed substantial depletion of proteins involved in biosynthesis, virulence, antibiotic resistance, and biofilm formation, alongside enrichment of stress response proteins. These findings indicate a shift toward survival phenotypes and weakened pathogenicity. Our data reveal that HOCl disrupts multiple pathways essential for P. aeruginosa survival and virulence. Crucially, our experimental design eliminates confounding factors that can lead to unintentional testing of mixed HOCl and OCl⁻ species, allowing us to assess the specific effects of HOCl. These findings call for a re-evaluation of HOCl research methodologies and reiterate the importance of realistic infection models in antimicrobial testing.

Acinetobacter baumannii is a multi-drug resistant Gram-negative coccobacillus. It is responsible for high mortality among patients in the intensive care unit. Reported A. baumannii virulence factors include the thioredoxin system which plays a critical role in gene regulation and protein reduction. The Type IV pilus (T4P) is a well-known bacterial virulence factor that is associated with adhesion and molecular exchange. Previously, our laboratory revealed the role of A. baumannii thioredoxin A (TrxA) in pathogenesis by studying a trxA deletion mutant that downregulates T4P gene expression. TrxA, a potent disulfide bond reducer, might affect the assembly of pili by targeting T4P component proteins, including PilA, the major pilin protein of T4P which contains multiple cysteine residues required for disulfide bond formation. Using a transposon library derived from the AB5075 clinical isolate, we phenotypically characterized a pilA mutant strain and compared its pathogenesis to the wild type (WT) strain as well as another trxA mutant. Whole genome sequencing was conducted to confirm the disruption of trxA and pilA genes in the corresponding mutant strains of AB5075. Alteration of bacterial surface appendages in ΔtrxA and ΔpilA was visualized by Scanning electron microscopy. Like ΔtrxA, the T4P mutant ΔpilA had marked reduction of surface pili. Bacterial attachment to excised intestinal surfaces was greatly reduced for ΔtrxA and ΔpilA. Attenuation of ΔtrxA and ΔpilA in pathogenesis was further confirmed using a mouse sepsis model. Collectively, this characterized ΔpilA deficiency in A. baumannii resulted in attenuation of virulence making it a potential therapeutic target.

The evolutionary profile of hepatitis B virus (HBV) quasispecies may influence the clinical course of chronic hepatitis B (CHB), but few studies have characterized quasispecies according to hepatitis B e antigen (HBeAg) status. In this study, we analyzed 289 full-length HBV clones from 19 treatment-naïve CHB patients with long-term infection (> 10 years), comprising nine HBeAg-positive and ten HBeAg-negative, using molecular cloning and Sanger sequencing. Compared with HBeAg-positive patients, HBeAg-negative patients displayed higher quasispecies diversity (mean intrapatient sequence divergence 1.09% vs. 0.44%) and more complex phylogenetic structures. They also exhibited a greater number of positively selected sites, with 70.8% located within known T- or B-cell epitope regions, predominantly in the surface (S), polymerase (Pol), and X regions. Classical basal core promoter (BCP) and precore (PreC) mutations were detected in 52.8% of HBeAg-negative clones, often coexisting with wild-type strains. In patients lacking these classical BCP/preC mutations but showing sustained viremia, intrahost recombination was observed. Moreover, overlapping reading frames, particularly +1 frameshifts in Pol/S region, demonstrated asymmetric distribution patterns. In patients harboring deletion mutations, intact quasispecies were also maintained. Collectively, these findings reveal multiple adaptive strategies that sustain HBV replication and immune escape in HBeAg-negative patients, providing mechanistic insights for disease monitoring and therapeutic interventions.

The gut microbiome of breeder hens plays a pivotal role in reproductive efficiency, egg quality, and progeny development. Its composition is shaped by host factors such as age and genetics, as well as environmental influences, including diet and management practices. Importantly, the breeder gut microbiome is not only dynamic but also responsive to targeted interventions that can enhance intestinal health, metabolic function, and laying performance. Vertical transmission of maternal microbes through the cloaca and egg components provides offspring with a foundational microbial community, with the yolk sac serving as a critical reservoir for early colonisers that influence gut maturation, immunity, and growth. Emerging evidence further demonstrates that maternal nutritional strategies can programme the gut microbiota of progeny and intestinal development, highlighting the breeder microbiome as both a determinant and mediator of transgenerational performance. These insights underscore the potential of microbiome-focused approaches to improve reproductive success and sustainability in poultry production.

Guillain–Barré Syndrome (GBS) is a rapidly progressing immune-mediated neuropathy that remains the leading cause of acute flaccid paralysis worldwide. A substantial proportion of GBS cases are precipitated by infectious agents, most notably Campylobacter jejuni and Haemophilus influenzae, which initiate pathogenic autoimmunity via molecular mimicry. This narrative review aimed to synthesize current evidence on the microbial triggers of GBS and elucidate the immune mechanisms linking infection to neuropathic damage. We discuss the evolving landscape of GBS pathogenesis, emphasizing the roles of ganglioside-like lipooligosaccharide (LOS), host genetic predisposition, and dysregulated immune responses. The clinical heterogeneity of GBS subtypes, including axonal and demyelinating variants, was analyzed in relation to serotype-specific antibody profiles that inform the diagnosis and prognosis. Current therapeutic interventions, including intravenous immunoglobulin and plasma exchange, are critically assessed alongside experimental strategies, such as monoclonal antibody therapies, microbiome modulation, and LOS-targeted vaccines. This review highlights microbial surveillance and precision immunotherapy in the management of GBS. Collectively, this study underscores the central role of microbiological insights in redefining the prevention, diagnosis, and treatment of this complex neuroimmune disorder.

Next-generation sequencing (NGS) has emerged as a transformative tool for infectious disease diagnosis, offering broad pathogen detection, antimicrobial resistance profiling, and syndromic panel testing. However, widespread clinical adoption remains hindered by insurance reimbursement challenges, high costs, and regulatory barriers. Unlike polymerase chain reaction (PCR), which enjoys well-established Current Procedural Terminology (CPT) codes and reimbursement pathways, many NGS-based tests lack standardized billing mechanisms, discouraging laboratories from integrating NGS into routine diagnostics. This article explores the economic, clinical, and technological considerations of targeted amplicon sequencing (tNGS) versus PCR and whole-genome sequencing (WGS), demonstrating how optimized multiplexing strategies, emerging NGS platforms, and regulatory advancements can enhance feasibility. It is argued that insurance policies must evolve to recognize NGS's superior clinical utility in detecting polymicrobial infections, emerging pathogens, and antimicrobial resistance determinants, ultimately improving patient outcomes and reducing healthcare costs. Current reagent-only costs now average US $65 per microbial genome, US $600 per 30× human genome, and US $130–600 per metagenomic sample when multiplexed; these figures continue to fall with higher multiplexing. To accelerate equitable adoption, we recommend near-term payer coverage pilots for clearly defined clinical indications, dedicated CPT pathways for infectious-disease sequencing (including metagenomic assays), and pragmatic validation frameworks that acknowledge genotype–phenotype limits while leveraging multiplexing and centralized reference workflows.

Clostridium tertium is a pathogenic bacterium that directly colonizes the gastrointestinal mucosa, causing inflammation and neutropenia. The virulence factors and pathogenic mechanisms of C. tertium are not well known. In this study, C. tertium HGMC01 was isolated by enrichment culture of human feces, and its whole chromosome genome was sequenced without extra plasmids. C. tertium HGMC01 had a larger genome and a higher gene count compared with five other C. tertium strains. A pangenome analysis of six strains showed that C. tertium HGMC01 had the highest number of unique genes and the lowest number of accessory genes clustered phylogenetically with C. tertium src5, a strain of animal origin. C. tertium HGMC01 genome showed a variety of secreted glycoside hydrolases and carbohydrate-binding modules for mucin O-glycan degradation and sialic acid catabolism including sialidase and sialic acid transporter. These genes strongly suggested that the strain could interact the human gut cells through recognition or adhesion to mucin glycans. Moreover, various mobile genetic elements in its genome also indicated the genetic diversity and plasticity of the strain to gain virulence factors and antibiotic/multidrug-resistant genes potentially acquired by horizontal gene transfer for the evolution of the pathogenicity. Additionally, experiments with human embryonic kidney cells revealed that components of C. tertium HGMC01 cell wall may play roles as virulence factors by modulating cytokine signaling pathways dependent on Toll-like receptors. Overall, this comparative genomic analysis provides information about how C. tertium strains cause disease through mucin glycan degradation, colonization, multidrug resistance, and modulation of immune responses.

Antimicrobial resistance (AMR) refers to the ability of microorganisms, such as bacteria and viruses, to resist antimicrobial medications. Current strategies for addressing this escalating issue are often labor-intensive and costly. However, advancements in artificial intelligence (AI) are enabling the rapid evaluation of extensive chemical libraries and the prediction of novel antimicrobial compounds. AI holds significant promise for medical research in treating multidrug-resistant infections by enhancing the development of new medications through the analysis of antibiotic usage, disease prevalence, and resistance patterns. The use of AI has the potential to greatly benefit research by accelerating the discovery of new antibiotics that effectively combat antibiotic-resistant microbes. Predicting trends in antibiotic resistance through the examination of large data sets by AI systems may pave the way for the creation of preventative medicines. The speed and accuracy with which AI can evaluate data are revolutionizing how scientists develop new medicines, assess potential health concerns, and find ways to prevent illness. AMR is a growing concern, and AI is playing an increasingly crucial role in this battle. Medical research utilizing AI has tremendous potential in the ongoing fight against antibiotic resistance. This review examines how AI aids in AMR diagnosis, small molecule drug development, and the detection of AMR symptoms. Further research into AMR detection and the creation of novel medications are two areas that could prove valuable in treating antimicrobial resistance.

Detection of Salmonella Enteritidis (SE) and S. Typhimurium (STm) in broiler holdings is regulated by European and Swiss law to ensure public health. Persistence of Salmonella in broiler houses may jeopardize this goal. The aim of this study was to analyze whether non-SE/STm isolated from boot socks were of clonal origin. Four Salmonella serovars from 11 broiler houses from 10 Swiss farms were selected: S. Infantis, S. Livingston and S. Welikade (meat integration A) and S. enterica subsp. enterica 13,23:i:- (integration B). The genetic relationship was evaluated by whole-genome sequencing (WGS) and core genome multilocus sequence typing (cgMLST)-based tree analysis, with a cluster being defined as < 8 cg alleles differences. The isolates of S. Infantis and S. Livingston, respectively, were shown to belong to the same serovar-specific clusters (range: 1–7 cg alleles differences), suggesting that the Salmonella strains persisted in the respective broiler houses. S. Welikade, however, showed 8–11 cg alleles differences among isolates, indicating either a reintroduction of similar but not clonal strains into the houses due to insufficient biosecurity, or the evolution of a persistent strain. Remarkably, all isolates of S. 13,23:i:- from integration B from 2013 to 2024 were clonal, suggesting dispersal and persistence in the broiler integration. The clonality of analyzed strains suggests that Salmonella can persist on farms or integration level despite disinfection after each production cycle. Hence, improved farm and vehicle cleaning and disinfection practices are essential to ensure that the next flock is not exposed to non-SE/STm Salmonella serovars.