Search Results (111)

Microbial remediation serves as a cost-effective and eco-friendly tactic for petroleum-contaminated sites. In real-world practices, petroleum-degrading microbial consortia display prominent superiority over single strains. To tap into their intrinsic synergistic degradation capacity, it is essential to dissect microbial commonalities, individual traits and functional complementarity for complicated bioremediation scenarios. This study applied bibliometric approaches to collect 15 well-documented representative petroleum-hydrocarbon-degrading strains, and summarized research progress via comparative genomic analysis. Pseudomonas aeruginosa, Bacillus subtilis and Rhodococcus erythropolis are the most frequently reported degraders with remarkable petroleum removal performance. Moreover, co-occurrence network analysis identifies Pseudomonas, Bacillus, Acinetobacter and Rhodococcus as core co-existing genera sustaining natural pollutant-degrading communities. Genomic evidence indicates these strains harbour abundant functional elements encoding diverse oxygenases, alcohol dehydrogenases, cytochrome P450 monooxygenases and key LuxR-, AraC- and GntR-family regulatory factors. P. aeruginosa has the highest copy numbers of catabolic enzyme genes, consistent with its outstanding degradation phenotype. Degraders from different genera exhibit high genetic heterogeneity, with accessory gene clusters significantly enriched in hydrocarbon degradation pathways. Six strains including P. aeruginosa and R. erythropolis assemble a complete gene cascade targeting recalcitrant polycyclic aromatic hydrocarbons. This work provides reliable genomic support for rational strain screening and synthetic-consortium optimization, facilitating knowledge-driven strategies for efficient petroleum bioremediation. Full article

Cronobacter sakazakii is a rare, life-threatening neonatal pathogen. In this study, we profiled antimicrobial resistance genes (ARGs), plasmid replicons, virulence genes, sequence types (STs), and core-genome phylogeny across all publicly available clinical C. sakazakii genomes from the United States (n = 116). All isolates harbored exclusively chromosomally encoded bla_CSA variants. IncFIB and rep cluster 574 co-occurred in 93.1% of isolates as a conserved backbone among 17 replicon types. Among 49 virulence genes, 13 formed a universal core (flagellar motility and type VI secretion); accessory genes such as the yersiniabactin cluster were sporadic. ARG, plasmid replicon, and virulence gene contents were strongly structured by ST, dominated by ST4, ST1, ST8, and ST13. Stratified testing shows most pairwise associations were confounded by clonal lineage, except the IncFIB-rep cluster 574 co-carriage and an IncFII-hcp/tssD association, significant after ST stratification but not multiple testing correction. Core-genome phylogenetics identified 16 clusters, from a large ST4-dominated group to nine singletons, corroborated by ST monophyly; a genomically identical ST1 pair, nine years apart, indicated long-term clonal persistence. Ancestral state reconstruction distinguished stable single acquisitions from features with repeated turnover. Core-genome and gene-content phylogenies demonstrated substantial discordance despite significant overall correlation. These findings provide a genomic framework for clinical C. sakazakii population structure in the United States. Full article

Yersinia enterocolitica is a psychrotrophic foodborne bacterium that can proliferate at refrigeration temperatures and is frequently associated with animal-source foods, raising concerns about food safety and public health. However, genomic data on Y. enterocolitica isolates from South Korea are limited, despite the increasing use of whole-genome sequencing (WGS) in bacterial surveillance. Herein, 91 Y. enterocolitica isolates recovered from chicken, pork, beef, and duck samples collected nationwide in 2024 were analyzed using WGS to elucidate their genomic diversity and genomic features. Phylogenomic analysis predicted all isolates as biotype 1A (sub-biotype 1Aa) and revealed substantial genetic diversity, comprising 27 sequence types and 43 core-genome types. Pan-genome analysis identified 11,230 gene clusters, revealing an open pan-genome in which accessory and unique gene clusters were assigned to predicted functional categories associated with metabolism, defense mechanisms, and stress responses. Although the canonical virulence plasmid pYV was absent, conserved chromosomal virulence-associated genes involved in adhesion (yapE), invasion (inv), secretion, and enterotoxicity (ystB) were detected. Antimicrobial resistance genes were predominantly intrinsic, particularly blaA and vat(F), whereas acquired resistance genes were identified sporadically. These findings provide a genomic baseline for biotype 1A Y. enterocolitica isolates recovered from animal-source foods in South Korea. The functional and public health significance of the detected virulence-associated loci requires further phenotypic investigation. Full article

Clostridium perfringens type A causes neonatal clostridial enteritis, hemorrhagic enteritis, and sudden death syndrome in cattle. This study examined a fatal outbreak at a fattening farm housing 58 adult yaks in Southwest China, with an incidence of 22.41% (13/58) and a 100% case fatality rate. Histopathology of deceased yaks showed widespread multi-organ hemorrhage and severe hemorrhagic enteritis. A specific PCR assay amplified the alpha-toxin gene of Clostridium perfringens, while no other pathogens were detected. Clostridium perfringens was isolated from small intestinal contents using TSC agar, designated strain CQ1, and identified as type A through toxinotyping. Whole-genome sequencing revealed that strain CQ1 carries the core alpha-toxin gene along with key accessory virulence determinants (pfoA, colA, and cloSI). Phylogenomic analysis based on core single-nucleotide polymorphisms revealed that strain CQ1 is clustered into a distinct, independent evolutionary lineage with an existing historical yak isolate and a canine-origin isolate. Intraperitoneal challenge in mice confirmed its extreme lethality, causing 100% mortality within 36 h with severe intestinal necrosis. These findings provide fundamental genetic resources for understanding the virulence mechanisms and genetic background of this pathogen and offer critical insights for preventing and controlling clostridial diseases in high-altitude yak farming. Full article

Background/Objectives: Tubulins (Tub) are central components of microtubules, but intraspecific variation and developmental expression of the Tub family in Gossypium barbadense remain poorly characterized. This study aimed to characterize the GbTub family using a pan-genome framework and identify candidates associated with fiber development and strength. Methods: A total of 50 GbTub genes were identified in the G. barbadense 3-79 reference genome, and their orthologous presence–absence patterns were subsequently assessed across 12 additional G. barbadense accessions. Phylogenetic, presence–absence variation (PAV), Ka/Ks, structural variation (SV), RNA-seq, RT-qPCR, co-expression, and GO enrichment analyses were integrated. Results: Among the 50 reference-defined GbTub genes, 43 were classified as core genes, 6 as near-core genes, and 1 as an accessory gene, and the encoded proteins were classified into α-, β-, and γ-tubulin clades. All genes showed Ka/Ks < 1. Twenty-three GbTub genes differed between the fiber-strength-contrasting accessions 5917 and PimaS-7, and representative expression trends were supported by RT-qPCR. Network analysis prioritized 10 GbTub candidates based on degree centrality. GbTub21 was the sole SV-associated GbTub gene displaying significant differential expression between accessions harboring versus lacking the corresponding SV. Non-Tub neighbors of the candidate hub genes were enriched for cytoskeletal, intracellular-transport, and plasma-membrane functions. Conclusions: The pan-genome analysis reveals strong conservation with limited intraspecific variation in the GbTub family. Co-expression profiles nominate candidates associated with fiber secondary-wall development, and their causal contribution to fiber strength awaits functional dissection. Full article

Bovine-associated Klebsiella pneumoniae is an important bacterial species linking animal health, microbial ecology, and One Health-oriented antimicrobial resistance research. In this study, we performed a global genomic analysis of 1291 publicly available bovine-associated K. pneumoniae genomes collected from 18 countries between 2005 and 2024 using data retrieved from NCBI. MLST, core-genome phylogenetic analysis, pangenome analysis, CARD, VFDB, and PlasmidFinder were used to characterize sequence types, genomic diversity, antimicrobial resistance-associated genes, virulence-associated genes, and plasmid replicons. A total of 256 sequence types were identified, among which ST107 was the most common. Core-genome phylogenetic analysis revealed multiple genomic lineages, while pangenome analysis identified 46,325 gene clusters, including 1967 core genes and 40,595 cloud genes, indicating an open pangenome structure and substantial accessory gene diversity. Virulence-associated genes were unevenly distributed, with yagZ/ecpA being the most frequently detected determinant. In total, 138 antimicrobial resistance-associated genes or potential resistance determinants were detected across 16 antimicrobial categories, including clinically important β-lactamase- and carbapenemase-associated genes. IncF-family plasmid replicons, particularly IncFIB(K)_1_Kpn3, were frequently detected, suggesting widespread plasmid replicon-associated genomic backgrounds; however, physical co-localization between resistance genes and specific plasmid backbones could not be confirmed. Overall, this study reveals the genetic diversity, resistance-associated gene reservoir potential, heterogeneity of virulence-associated genes, and plasmid replicon backgrounds of bovine-associated K. pneumoniae. Importantly, the genome-predicted AMR potential identified in this study should not be interpreted as confirmed phenotypic resistance without further experimental validation. These findings provide genomic insights for risk surveillance, candidate control-target screening, and microbiota-oriented intervention research. Full article

Fusarium oxysporum f. sp. radicis-cucumerinum (Forc) V03-2g and Fusarium oxysporum f. sp. radicis-lycopersici (Forl) ZUM2407 both cause foot and root rot in cucumber, but differ in host range. Forc V03-2g possesses Secreted in Xylem (SIX) effector genes, whereas Forl ZUM2407 does not, raising questions about their distinct infection strategies on this host. Using comparative transcriptomic analysis (in cucumber at 7 and 14 days post-inoculation (dpi) and in tomato at 2 dpi) we show that Forl ZUM2407 induces a delayed defense response in cucumber compared to Forc V03-2g. In turn, Forc V03-2g rapidly activates accessory chromosome effectors on cucumber, while Forl ZUM2407 initially deploys core chromosome genes, activating distinct from Forc V03-2g accessory genes only by 14 dpi. Thereby, Forc V03-2g and Forl ZUM2407 use distinct accessory gene repertoires (unique to each strain) and distinct core gene transcription strategies to infect the same host. Full article

Background/Objectives: Streptococcus agalactiae is one of the most significant pathogens causing infections in humans and mastitis in dairy cattle. This work focused on a comprehensive comparative pan-genomic analysis of bovine and human Group B Streptococcus to elucidate the genetic mechanisms underlying host adaptation and dissemination. Methods: Isolates of S. agalactiae from quarter milk samples from dairy herds in Lombardy (Italy), along with human strains, were considered. Whole genome sequencing was used to compare core and accessory genomes, assign sequence types, and find virulence and resistance factors. Results: 30 sequence types were detected, of which two (ST12 and ST23) in common between bovine and human. The allele frequencies for resistance determinants revealed elevated rates for tetM (59.8% overall, 66.5% in human clinical isolates), ermB (17.3% overall, 20.4% in human clinical isolates), and ant(6)la (8.9% overall, 12.8% in human clinical isolates). Bovine strains had accessory gene clusters linked to lactose metabolism and immunological evasion, whereas human isolates were concentrated in regions related to adhesion and antibiotic resistance. Conclusions: Comparative pan-genomics show that there is a small genetic overlap between bovine and human Group B Streptococcus populations. Full article

Listeria monocytogenes is a ubiquitous Gram-positive bacterium responsible for listeriosis, a foodborne zoonotic disease affecting humans and animals. Although infection in immunocompetent individuals is often asymptomatic or limited to mild self-limiting gastroenteritis, Listeria monocytogenes may cause severe invasive disease in vulnerable groups, including pregnant women, neonates, elderly individuals, and immunocompromised patients. Although the incidence of listeriosis is relatively low compared with many other foodborne pathogens, the high hospitalization and mortality rates associated with clinical cases make this bacterium a major concern for food safety and public health. The evolutionary success of L. monocytogenes reflects the interaction between a conserved core genome and a dynamic accessory genome shaped by horizontal gene transfer (HGT), ecological selection, and expansion of specific clones. Transient intestinal carriage in humans and animals, potentially influenced by gut microbiome composition, creates ecological interfaces where plasmids, transposons, prophages, and integrative conjugative elements contribute to the exchange of antimicrobial resistance determinants, virulence factors, and stress tolerance systems. Virulence diversification is further influenced by the differential distribution of pathogenicity islands such as LIPI-1, LIPI-3, and LIPI-4 across specific clonal lineages. These evolutionary processes occur across interconnected farm, food-production, environmental, and clinical ecosystems consistent with the One Health framework. Advances in whole-genome sequencing have clarified lineage-specific gene flow, expansion of specific clones, and the dynamics of the resistome and mobilome in L. monocytogenes populations. This narrative review aims to synthesize current knowledge on the mobile genetic elements and ecological interfaces that shape horizontal gene transfer in L. monocytogenes. Its novelty lies in integrating antimicrobial resistance, virulence-associated genomic islands, stress adaptation, and gut microbiome-mediated selection within a One Health and metapopulation framework. The main message of this review is that HGT should be interpreted as a context-dependent contributor to L. monocytogenes adaptation, acting together with clonal background, ecological selection, and mobile genetic elements. Full article

Common bean (Phaseolus vulgaris L.) is a strategic crop whose sustainable production depends on symbiosis with nitrogen-fixing bacteria. However, the composition and functional potential of the nodule microbiome in varieties adapted to semi-arid regions, such as northern Mexico, remain poorly documented. Therefore, this study evaluated the influence of host genotype on nodule-associated bacterial communities in three improved varieties (Pinto Bravo, NOD1, and Jamapa) under conventional management, using high-throughput sequencing of the V3–V4 regions of the 16S rRNA gene. Alpha and beta diversity analyses showed no significant differences among varieties, indicating a similar nodular microbiome regardless of genotype. At the phylum level, Proteobacteria and Bacteroidota predominated, suggesting a conserved microbial core. At the genus level, Rhizobium was the most abundant taxon, while non-rhizobial genera such as Acinetobacter and the JC017 lineage were also detected. Functional prediction using PICRUSt2 revealed conserved metabolic profiles, with dominant pathways associated with amino acid biosynthesis, carbon metabolism, aerobic respiration, and fatty acid biosynthesis, indicating metabolic redundancy linked to tolerance to osmotic, thermal, and oxidative stress. The results suggest that under semi-arid conditions, the symbiotic interaction is governed by mechanisms at the host species level (P. vulgaris), which ensure the recruitment of a functional core microbiome, whereas intraspecific variation among improved varieties may influence the recruitment of specific accessory taxa. Full article

Staphylococcus aureus is a globally distributed bacterium that spans interconnected human, animal, and environmental niches and is a major driver of antimicrobial resistance. Environmental and wildlife-associated isolates from hospital-surrounding settings remain underrepresented in comparative genomic studies. To address this gap, we integrated a newly sequenced environmental isolate recovered from pigeon fecal samples collected around a hospital into a standardized pangenome framework composed of 99 reproducibly selected RefSeq genomes plus the environmental isolate S_S3. Using uniform genome annotation and orthologous gene family clustering, we identified an open pangenome of 8366 gene families (Heaps’ law γ = 0.275), consistent with the high genomic plasticity previously reported for S. aureus. The core genome stabilized at approximately 1757 genes, including 1651 genes conserved across all genomes. Gene frequency spectra showed a dominant cloud genome and a structured shell fraction contributing to interstrain differentiation. Jaccard-based gene content similarity resolved clusters shaped mainly by accessory gene composition. The environmental isolate retained the complete core genome, carried only 15 isolate-specific gene families (0.18% of the pangenome), and clustered within an established lineage. Its unique content included a lincosamide resistance-associated locus and efeB, a gene potentially related to heme or iron metabolism and oxidative stress response. These findings highlight a conserved genomic backbone over a dynamic accessory reservoir and support One Health genomic surveillance that includes wildlife-associated niches, while indicating that the environmental isolate fits within the broader gene content diversity observed in the analyzed dataset. Full article

Monascus sp. NP1 is a significant filamentous fungus with valuable properties for food industries. Initially isolated from the fermented rice product ang-kak, this strain is known for its ability to produce natural pigments. In this study, we therefore sequenced its genome together with the 26S rRNA D1/D2 domain and ITS fragment for identifying species of Monascus sp. NP1, and further conducted functional annotations of its overall genes related to metabolic capability and growth adaptation using comparative genomics. As a result, promisingly, the NP1 strain was identified as Monascus purpureus with the genome sequences, which was shown to be 23.54 Mb with a GC content of 49.01%. Genome annotation predicted 8031 protein-encoding genes. Comparative genomics between NP1 and 11 other related strains revealed 6024 core groups, 2204 accessory groups, and 5 strain-specific groups. Metabolic pathway analysis promisingly showed carbohydrate metabolism as the most enriched category, particularly central carbon metabolism involving key precursors, e.g., acetyl-CoA and pyruvate that support energy generation and the biosynthesis of pigments, fatty acids, and lipids. These findings highlighted the metabolic versatility and adaptive growth potential of M. purpureus NP1. This study provides key genetic insights into the cellular functions of M. purpureus NP1, laying the groundwork for exploring metabolic properties. It offers a comprehensive understanding for developing targeted applications of M. purpureus NP1 as an alternative fungal cell factory in food and nutrition. Full article

Campylobacter jejuni is a major zoonotic pathogen that circulates among birds, livestock, humans, and environmental reservoirs, yet the genomic mechanisms that enable persistence and transmission across divergent hosts remain incompletely understood. Here, we sequenced 61 C. jejuni isolates recovered from multiple host-associated sources in Shenzhen, China, from 2016 to 2023, and analyzed them together with 312 dereplicated publicly available high-quality reference genomes. Phylogenomic analyses resolved three major clades, including one avian-restricted clade and two clades showing frequent cross-host occurrence. Human-associated isolates displayed lower coding density than mammal-associated isolates and significantly higher proteome-level carbon and nitrogen demands than avian-associated isolates. Comparative genomic analyses further revealed strong host-associated divergence in chromosome-encoded, plasmid-encoded, and horizontally acquired gene repertoires. In human-derived isolates, 11 dataset-specific human-unique KEGG genes and 48 human-unique virulence-associated genes were identified, and human-associated strains showed the strongest multidrug-resistance signal across both chromosome-encoded and mobile-gene compartments. Resistance-associated functions enriched in human-associated genomes included antibiotic inactivation, efflux-mediated resistance, target protection/replacement/alteration, reduced permeability, and nutrient-acquisition-associated resistance. By contrast, core host-interaction loci remained under strong purifying selection, indicating that major human-associated traits were linked more closely to mobile gene acquisition than to extensive mutation-driven diversification. Together, these findings support a proposed genome-partition framework of host adaptation in C. jejuni, in which relatively stable chromosomal backgrounds are complemented by rapid plasmid- and horizontal-transfer-mediated acquisition of high-impact accessory genes. Full article

The genus Listeria comprises diverse bacteria with significant public health relevance, particularly Listeria monocytogenes. A comparative genomic analysis of ten representative Listeria species was conducted using 33 high-quality genome assemblies to investigate core and accessory genome dynamics and identify candidate diagnostic loci. Pangenome reconstruction was performed using the Roary Integer Linear Programming Bacterial Annotation Pipeline (RIBAP) to classify core, soft-core, and accessory genes, while average nucleotide identity (ANI) analysis assessed genomic relatedness across thresholds of 60–95%. Functional annotation of core and species-specific genes was conducted using Genome Annotation and Information Analysis (GAIA). Core genes were highly conserved and associated with essential cellular functions, whereas the accessory genome contributed to species-level diversification and ecological adaptation. Candidate molecular markers were derived from accessory genes and evaluated based on presence/absence across genomes, retaining loci present in ≥80% of target strains and absent in non-target strains. Experimental validation of selected primers was performed using two L. monocytogenes reference strains (ATCC 19117 and ATCC BAA-679) with conventional PCR and gel electrophoresis to confirm expected amplicon sizes and specificity. These findings establish a genome-informed, specificity-driven framework for marker development and highlight the accessory genome as a valuable source of diagnostic loci, supporting accurate detection, epidemiological surveillance, and food safety monitoring. Full article

Non-O1/non-O139 Vibrio cholerae strains are widely distributed in aquatic environments worldwide and are increasingly recognized as potential reservoirs of antimicrobial resistance and virulence-associated determinants. In this study, we performed an integrated phenotypic and genomic analysis of 116 V. cholerae isolates collected in 2024 from environmental and clinical sources in Jiaxing, China, including 106 non-O1/non-O139 isolates, 9 O1 isolates, and 1 O139 isolate. Antimicrobial susceptibility testing showed that most isolates remained susceptible to β-lactam/β-lactamase inhibitor combinations, third-generation cephalosporins, carbapenems, and tigecycline, whereas resistance was more frequently observed for ampicillin, streptomycin, nalidixic acid, and ciprofloxacin. Based on the non-susceptibility criteria of Maitrakas et al., 19 of 116 isolates (16.4%) were classified as multidrug-resistant, whereas none met the definition of extensively drug-resistant. Genomic analysis identified diverse resistance determinants, including plasmid-mediated quinolone resistance genes (qnrVC variants) and quinolone resistance-determining region mutations in gyrA and parC. Virulence-associated genes showed heterogeneous distributions: core regulatory and hemolysis-related genes were highly prevalent, whereas classical cholera toxin genes were largely absent. Several accessory virulence factors, including the RTX toxin operon, chxA, ninth, and makA, were detected in subsets of isolates. Core genome multilocus sequence typing revealed substantial genetic diversity, with environmental and clinical isolates distributed across multiple lineages and showing no clear clustering by isolation source. Overall, these data demonstrate the diverse antimicrobial resistance, virulence-associated gene repertoires, and population structure of the Jiaxing V. cholerae collection, with particular relevance to the predominant non-O1/non-O139 population. Full article