Search Results (242)

Acute leukemias are highly aggressive hematologic malignancies that demand intensive chemotherapy regimens. However, drug toxicity remains a major barrier to treatment success and patient survival. In this context, pharmacogenomics offers a promising strategy by identifying single-nucleotide variants (SNVs) that influence drug metabolism, efficacy, and toxicity, ultimately impacting treatment outcomes. This study analyzed data from the ClinPGx/PharmGKB database to identify clinically annotated variants related to chemotherapy response in Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL). A total of 24 variants were curated for AML and 57 for ALL. Among these, nonsynonymous variants were most frequent in ALL (31.6%), while synonymous variants predominated in AML (33.3%). Although traditionally considered neutral, synonymous and intronic variants may influence gene expression through regulatory or splicing mechanisms. The analysis revealed clinically significant variants associated with chemotherapy response, particularly in the ABCB1 gene, observed in 12.5% of AML and 10.5% of ALL cases. Several variants, particularly TPMT, NUDT15, ABCC1, SLC28A3, and RARG, were associated with severe adverse effects such as myelotoxicity, mucositis, cardiotoxicity, and hepatotoxicity. This study reinforces the importance of genetic variants in modulating the therapeutic response and toxicity to chemotherapy drugs in acute leukemias. Analysis of ClinPGx/PharmGKB data emphasizes ABCB1 as a potential resistance marker and supports pre-treatment genotyping of genes like TPMT and NUDT15 to prevent severe toxicities. Future advances should include the expansion of pharmacogenetic studies in underrepresented populations and the clinical validation of new markers in prospective trials, aiming to consolidate precision medicine as a routine part of the therapeutic management of acute leukemias. Full article

Background: Functional single ventricle (FSV) comprises a heterogeneous group of congenital heart diseases (CHDs) with severe and complex abnormalities. The multifactorial etiology of the disease poses challenges in identifying specific pathogenic factors and planning effective interventions and preventive treatments for patients. Methods: Whole-exome sequencing (WES) was performed to identify variants in relevant genes in 29 FSV patients from different families. Results: In total, 95 heterozygous variants across 48 CHD-associated genes were identified, including 85 missense, four small indel, one splicing, one stop gain, and four synonymous variants. Among them, 22 were novels, 11 conflicting, and four pathogenic variants. Each patient carried from two to six variants in different genes, including at least one variant in genes associated with serious heart defects such as AXIN1, BMP2, COL6A2, GATA4, GATA5, GDF1, MESP1, MYH6, NFATC1, NKX2-6, NOTCH1, PCSK9, TBX1, TBX18, and TBX20. In addition, the variants in the COL6A1, CREBBP, DOCK6, EOGT, EP300, LRP2, MYBPC3, MYH7, SEMA3C, and ZFPM2 genes are associated with characteristic phenotypes of FSV, such as atrial septal defect, ventricular septal defect, small left heart syndrome, transposition of the great arteries, and double outlet right ventricle occurring at high frequency in patients. The prediction results suggest that these are potentially pathogenic variants in patients and may explain the phenotype in patients. Conclusions: This is the first study to identify variants associated with functional single ventricle, a complex form of congenital heart disease. Our results contribute to a general understanding of the causes of the disease, thereby guiding treatment and prevention approaches for patients. Full article

Background: Autism spectrum disorder (ASD) is a common condition with substantial personal and financial burdens of lifelong implication. Multiple twin studies have confirmed a genetic or inherited component at ~80%, higher than any other common condition. However, ASD’s rapidly accelerating prevalence, now at 1 in 31 in the USA, appears to defy a predominantly genetic basis and implicate our rapidly changing environment. A potential explanation for this paradox is a recent increase in de novo variants (DNVs), which are “new” mutations present in the patient yet absent in both parents. The present authors recently reported using trio whole-genome sequencing (trio-WGS) that DNVs highly likely to be highly disease-associated (“Principal Diagnostic Variants”, PDVs), mostly missense variants, were present in (25/50) 50% of the ASD patients clinically evaluated by our team. Methods: The current study was designed to support this observation with trio-WGS in 100 additional unrelated ASD patients. Results: De novo PDVs were identified in 47/100 (47%) of cases, in close approximation to our previous work. Using non-transcribed (up and downstream) variants for all genes as a control group, these DNV-PDVs were far more likely (p < 0.0001, OR 5.8, 95% C.I. 2.9–11) to be in SFARI-listed genes associated with ASD. Consistent with the emerging polygenic model, using the same analyses, inherited missense variants were also associated with ASD (p < 0.0001). Highly unexpectedly, silent variants, both inherited (p < 0.0001) and de novo (p < 0.007), were also statistically associated with ASD, and, among inherited variants, silent variants were more associated with ASD than were missense variants (p < 0.0001). Adding silent DNVs as PDVs increases the proportion of our subjects with at least one DNV-PDV to 55% of the subjects. Conclusions: Our proposed model for ASD, with prominent DNVs in most that are genetic yet not inherited, predicts the known predominant genetic pathogenesis and the accelerating prevalence of ASD, possibly from environmental factors, including insufficient nutrients and toxicant exposures, and/or the disrupted folate metabolism known to be associated with ASD. Limitations to this study include predominant inclusion of severely affected individuals and the lack of an unaffected control group and functional validation of variant pathogenicity. Full article

Fat volume and obesity-related genes (e.g., the FTO gene) are important candidate genes affecting energy metabolism. Single nucleotide polymorphisms (SNPs) in the FTO gene are associated with carcass, growth and meat quality traits of pigs, cattle, sheep, rabbits and ducks. The purpose of this study was to detect the single nucleotide polymorphisms in the chicken FTO gene coding region by DNA sequencing and analyze its association with the carcass and growth traits of Heying black chickens. We detected polymorphisms in exons 5, 7, 8 and 9, respectively, g.57337C>A, g.64757T>G, g.97213G>A and g.220985G>A, which are synonymous mutations. g.57337C>A mutation site CA and AA genotype individuals were significantly higher than CC genotype individuals in live weights, head weights, breast muscle weights and leg muscle weights (p < 0.05), AA genotype individuals were significantly higher than CC genotype individuals in slaughter live weights and liver weights (p < 0.05) and CA and AA genotype individuals were significantly higher than CC genotype individuals in heart weights (p < 0.01). In terms of growth traits, the weights of individuals with genotype CA at 8 weeks were significantly higher than that of individuals with genotype CC (p < 0.05), and the weights of individuals with genotype AA and CA at 10 weeks and 16 weeks were significantly higher than that of individuals with genotype CC (p < 0.05). For the g.64757T > G mutation, individuals with the TT genotype exhibited significantly higher values (p < 0.05) than those with the TG genotype across multiple traits, including slaughter weight, live weight, eviscerated weight and semi-eviscerated weight. Individuals with GG genotypes were significantly higher than individuals with TG genotypes (p < 0.05) in slaughter weights and wing weights. In terms of growth traits, the 16-week-old body weight of individuals with TT genotype was significantly higher than that of individuals with TG genotype (p < 0.01). The GA genotype exhibited significantly higher slaughter weights in the g.97213G>A variant compared to the GG genotype (p < 0.01), and in live weights, eviscerated weights, semi-eviscerated weights, leg muscle weights and wing weights, GA genotype was significantly higher than in GG genotype (p < 0.05). In terms of growth traits, GA genotype was significantly higher in individuals 8 weeks old, 10 weeks old and 16 weeks old than GG genotype (p < 0.05). g.220985G>A was significantly higher in individuals with GG genotype than GA genotype (p < 0.05). In terms of growth traits, the weight of GG genotype was significantly higher than that of GA genotype (p < 0.05). The results showed that the FTO gene may be a candidate gene related to chicken growth and slaughter traits and lays a foundation for Heying black chicken assisted breeding. Full article

Human noroviruses (HuNoVs) stand as the primary cause of acute viral gastroenteritis outbreaks worldwide, particularly impacting children under the age of five. In Russia, reports of norovirus gastroenteritis have surged, especially in the post-COVID-19 era starting in 2022, with elevated infection rates reported into 2024. These viruses exhibit significant mutational variability, leading to the emergence of recombinant strains that can evade immune responses. A comprehensive examination of the complete genome is crucial for understanding the evolution of norovirus genes and for predicting potential outbreaks. This research focuses on analyzing the genotypic composition of HuNoVs circulating in the Sverdlovsk region during 2024, using Sanger sequencing and next-generation sequencing (NGS). Biological samples were collected (n = 384) from patients diagnosed with norovirus infection within the region. Bioinformatics analysis targeted the nucleotide sequences of the ORF1/ORF2 fragment and the assembly of complete genomes for the GII.4 and GII.7 genotypes. In total, 220 HuNoVs were characterized, representing 57.3% of the collected samples. The main capsid variants forming the predominant genotypic profile included GII.4 (n = 88, 40%), GII.7 (n = 86, 39%), and GII.17 (n = 14, 6%). Using NGS, we successfully assembled 8 out of 10 complete genomes for noroviruses GII.4[P16] and GII.7[P7]. Non-synonymous substitutions appeared at amino acid sites corresponding to the subdomains of VP1 in these strains. This molecular–genetic analysis provides contemporary insights into the genotypic composition, circulation patterns, and evolutionary dynamics associated with the dominant genovariants GII.4[P16] and GII.7[P7]. Full article

Background/Objectives: Tumor mutational burden (TMB) has emerged as a potential biomarker of response to immunotherapy across multiple solid tumors. However, its role in cervical cancer remains insufficiently defined. This study aimed to evaluate the genomic landscape and TMB profile in a cohort of patients with cervical cancer treated at a tertiary gynecologic oncology center, with a focus on TMB’s associations with clinical features, HPV infection, and treatment modalities. Methods: A total of 61 patients diagnosed with cervical cancer (82.0% ca. planoepitheliale, 18.0% adenocarcinoma) were retrospectively analyzed. Tumor samples were collected during primary surgery, biopsy, or conization and subjected to targeted next-generation sequencing using the ONCOaccuPanel™ and BRCAaccuTest PLUS™ (NGeneBio). TMB was calculated as non-synonymous mutations per megabase and analyzed using NGeneAnalySys^® software. Variant classification followed ACMG guidelines. Comparative analyses were conducted between TMB-high (≥10 mut/Mb) and TMB-low subgroups, and correlations with clinical and molecular variables were assessed using univariable statistics. Results: High TMB was identified in 36 patients (59.0%), while microsatellite instability was found in only 2 cases (3.3%). No significant associations were observed between TMB status and FIGO stage, histologic subtype, or HPV 16/18 infection. However, higher TMB values were observed in patients with nodal involvement, diabetes, and HPV52 infection. A diverse spectrum of mutations was detected, with PIK3CA and ARID1A being most frequently altered. Several variants of uncertain significance were identified in genes not classically associated with cervical cancer. Conclusions: TMB-high status is relatively frequent in cervical cancer and appears to be independent of FIGO stage or histological subtype. While not predictive of clinical stage, TMB correlates with specific molecular and comorbidity profiles, suggesting its potential relevance for future patient stratification in immunotherapy trials. Full article

Sheep pox, caused by sheep pox virus (SPV), is a transboundary disease that threatens sheep production and trade. This study aimed to identify genetic, immunological, and biochemical markers associated with susceptibility to SPV in Barki ewes. A total of 100 adult ewes were examined, including 50 clinically healthy and 50 naturally infected animals. PCR detected SPV DNA in 60% of suspected scab samples, highlighting diagnostic challenges in field investigations. Blood samples were analyzed for hematological indices, cytokine profiles, acute phase proteins, oxidative stress biomarkers, iron metabolism, and hormonal parameters. Expression profiles and single-nucleotide polymorphisms (SNPs) in 15 immune and antioxidant genes were characterized from cDNA-derived sequences. Infected animals exhibited microcytic hypochromic anemia, leukocytosis, elevated proinflammatory cytokines, and reduced IL-10. Acute phase proteins, oxidative stress markers, and cortisol were increased, whereas antioxidant capacity and transferrin were reduced. Twenty-three SNPs were identified, including non-synonymous variants, which showed promising but unvalidated associations with disease status. These findings highlight immune, oxidative, and genetic alterations in SPV-infected sheep, but further longitudinal and cross-validated studies are needed to establish their diagnostic or breeding utility. Full article

As an indigenous goat breed unique to southern China, Leizhou Black Goats (LZBGs) are highly valued for their rapid growth, high reproductive performance, and superior meat quality. However, their offspring frequently exhibit symptoms of muscle atrophy and malnutrition, suggesting potential genetic defects underlying these adverse phenotypes. As a unique extracellular matrix component, collagen Q (COLQ) is specifically enriched within the synaptic basal lamina at vertebrate neuromuscular junctions (NMJs), where it anchors acetylcholinesterase (AChE) to facilitate efficient acetylcholine hydrolysis, ensuring precise neuromuscular signaling. The current investigation sought to characterize the spectrum of genetic polymorphisms within the COLQ gene and assess their correlation with key production traits, including growth performance and meat quality parameters, in the LZBG population. Previously, through whole-genome sequencing and transcriptome sequencing analyses of an LZBG population, we identified four SNPs in the COLQ gene, namely, two missense mutations (SNP1: p.238A/S and SNP3: p.47G/S), one intronic variant (SNP2), and one synonymous mutation (SNP4: p.101P/P). Population genetic analysis revealed strong linkage disequilibrium between SNP1 and SNP2. Computational modeling of protein structures predicted that the identified missense mutations may lead to alterations in protein conformation. Association analyses demonstrated significant correlations of SNP1 and SNP3 with growth and meat quality traits (p < 0.05), where SNP3 reduced COLQ expression by 0.64-fold in homozygotes. Association analysis revealed that both SNP1 and SNP3 showed significant correlations with growth and meat quality traits in LZBGs (p < 0.05). Notably, SNP3 (p.47G/S) was found to regulate COLQ gene expression, reducing its levels by 0.64-fold in homozygous individuals, suggesting its potential as a genetic marker for selecting goats with superior growth performance and muscular development characteristics. The identified genetic variants establish a foundation for marker-assisted selection in LZBG breeding programs with particular relevance to growth performance enhancement, while also advancing the understanding of COLQ’s functional mechanisms in muscle development. Full article

Staphylococcus aureus is a leading cause of skin and soft tissue infections (SSTIs), yet the bacterial genomic adaptations underlying the transition from nasal colonization to invasive infection remain incompletely defined. We sequenced and analyzed 157 S. aureus isolates (126 from SSTIs and 31 from asymptomatic nasal colonization) from a primary care network in South Texas. Using genome-wide association studies, non-synonymous single-nucleotide variant (NSNV) profiling, and machine learning, we identified strain-specific adaptations in metabolic and regulatory pathways. SSTI isolates exhibited significant enrichment of nitrogen assimilation, purine biosynthesis, menaquinone production, and anaerobic respiration genes. Elevated copy number and colocalization of phage-linked metabolic genes—including nirB, narH, and nifR3—suggest a pathoadaptive genomic island supporting infection-specific energy generation. The enrichment of α/β-hydrolase domain-encoding genes was associated with clinical severity. To quantify severity, we developed the Purulent Ulcer Skin (PUS) score, which integrates wound size, drainage, and erythema. The α/β-hydrolase and lipoprotein genes were significantly associated with higher PUS scores (higher SSTI severity) and phage-encoded virulence gene products were linked to larger wound size. Machine learning prioritized purL and other metabolic loci as key infection classifiers. NSNVs and unitig-level changes co-localized within nutrient transport, stress resistance, and cytolytic genes, supporting a model of multi-layered genomic selection. Metagenomic assemblies of nasal microbiota were enriched for Staphylococcus, Enterococcus, and Micrococcus species, core metabolic pathways, and taxon-specific virulence determinants. This underscores the roles of metabolic and virulent co-networks within nasal commensals and their adaptive capacity for pathogenic transition. These findings provide a potential genomic blueprint of S. aureus pathoadaptation during SSTI and are a step towards the development of novel therapeutic targets. Full article

The study examined the association between body composition and beverage consumption and the risk of asthma and chronic obstructive pulmonary disease (COPD) and explored the single nucleotide polymorphisms (SNPs) involved in these associations by leveraging summary statistics from genome-wide association studies (GWAS) in nonoverlapping populations. The IEU OpenGWAS project was sourced for exposure datasets: body mass index, body fat percentage, fat-free mass, total body water mass, alcohol intake frequency, and coffee intake, and selected health outcome datasets: asthma and chronic obstructive pulmonary disease. Datasets were assessed and filtered using R, followed by a two-sample Mendelian randomization analysis. The MR Egger, weighted median, inverse variance weighted, simple mode, and weighted mode methods were used to examine the association between exposures and outcomes. Heterogeneity and pleiotropy analyses were used to evaluate the reliability of results. Additionally, SNPnexus was used to ascertain SNPs linked to established phenotypes, while SNP annotation was obtained from the Ensembl BioMart database via the biomaRt package. Genes belonging to overlapping groups were visualized using ComplexHeatmap. Higher body fat percentage (OR = 1.72, 95% CI: 1.23–2.41, p = 0.002), increased BMI (OR = 1.56, CI: 1.23–1.20, p = 2.53 × 10⁻⁴), and more frequent alcohol intake (OR = 1.34, CI: 1.08–1.68, p = 0.009) were associated with elevated COPD risk. Asthma risk was similarly increased with higher body fat percentage (OR = 1.60, CI: 1.23–2.21, p = 0.001), BMI (OR = 1.54, CI: 1.29–1.84, p = 2.23 × 10⁻⁶), fat-free mass (OR = 1.21, CI: 1.02–1.44, p = 0.032), and alcohol intake frequency (OR = 1.19, CI: 1.01–1.40, p = 0.039). Total body water mass and coffee intake were not associated with asthma and COPD. SNP annotation revealed that some genetic variants that influenced the association of the exposure variables with asthma and COPD were missense variants in several genes, including the evolutionarily highly conserved gene, SLC39A8 (rs13107325; C/A/T allele), and POC5 (rs2307111; T/A/C allele), as well as intronic variants in FTO (rs56094641; A/G/T allele) and NRXN3 (rs10146997; A/G allele). The discovery of the missense variants rs13107325 and rs2307111 in SLC39A8 and POC5, respectively, in addition to other intronic and synonymous SNPs suggests that these SNPs may have some roles in the development or progression of asthma and COPD. This may contribute to the identification of molecular signatures or biomarkers that forecast the risk, development, or therapeutic response of chronic lung diseases in persons with metabolic dysregulation, including obesity. Full article

Human mitochondrial DNA (mtDNA) is a relevant marker in evolutionary and population genetics, including ancient DNA (aDNA) research, due to inherent characteristics. However, aDNA is prone to damage and sequencing artefacts, potentially confounding evolutionary interpretations. To assess evolutionary patterns in ancient and modern mtDNA, we built a phylogeny comprising 63,965 modern and 3757 ancient public mitogenomes, classified mutations by genomic region and functional effect, and analysed distribution, frequency, and predicted pathogenicity of private and pre-terminal mutations, investigating purifying selection. We compared mutation class ratios (non-synonymous, rRNA, tRNA, nonsense vs. synonymous) across ancient and modern terminal branches and pre-terminal nodes. The predicted pathogenicity of non-synonymous mutations was evaluated across major European haplogroups using three tools. Ancient variants exhibited higher ratios of potentially deleterious mutations and significantly elevated pathogenicity scores compared to modern and pre-terminal branches, highlighting a mutation load likely inflated by damage-related artefacts. Remarkably, nonsense mutations—largely incompatible with life—were over 70 times more frequent in aDNA. The correlation between mutation ratios and predicted deleteriousness across haplogroups suggests a pattern incompatible with biological persistence or relaxed selection alone. These findings highlight the importance of rigorous quality control for ancient data in evolutionary inference, molecular clock calibration, and pathogenic variant identification. Full article

Adversarial attacks in Natural Language Processing (NLP) present a critical challenge, particularly in sentiment analysis, where subtle input modifications can significantly alter model predictions. In search of more robust defenses against adversarial attacks on sentimental analysis, this research work introduces two novel defense mechanisms: the Lexicon-Based Random Substitute Model (LRSM) and the Word-Variant Voting Model (WVVM). LRSM employs randomized substitutions from a dataset-specific lexicon to generate diverse input variations, disrupting adversarial strategies by introducing unpredictability. Unlike traditional defenses requiring synonym dictionaries or precomputed semantic relationships, LRSM directly substitutes words with random lexicon alternatives, reducing overhead while maintaining robustness. Notably, LRSM not only neutralizes adversarial perturbations but occasionally surpasses the original accuracy by correcting inherent model misclassifications. Building on LRSM, WVVM integrates LRSM, Frequency-Guided Word Substitution (FGWS), and Synonym Random Substitution and Voting (RS&V) in an ensemble framework that adaptively combines their outputs. Logistic Regression (LR) emerged as the optimal ensemble configuration, leveraging its regularization parameters to balance the contributions of individual defenses. WVVM consistently outperformed standalone defenses, demonstrating superior restored accuracy and F1 scores across adversarial scenarios. The proposed defenses were evaluated on two well-known sentiment analysis benchmarks: the IMDB Sentiment Dataset and the Yelp Polarity Dataset. The IMDB dataset, comprising 50,000 labeled movie reviews, and the Yelp Polarity dataset, containing labeled business reviews, provided diverse linguistic challenges for assessing adversarial robustness. Both datasets were tested using 4000 adversarial examples generated by established attacks, including Probability Weighted Word Saliency, TextFooler, and BERT-based Adversarial Examples. WVVM and LRSM demonstrated superior performance in restoring accuracy and F1 scores across both datasets, with WVVM excelling through its ensemble learning framework. LRSM improved restored accuracy from 75.66% to 83.7% when compared to the second-best individual model, RS&V, while the Support Vector Classifier WVVM variation further improved restored accuracy to 93.17%. Logistic Regression WVVM achieved an F1 score of 86.26% compared to 76.80% for RS&V. These findings establish LRSM and WVVM as robust frameworks for defending against adversarial text attacks in sentiment analysis. Full article

This study identified four new keratin-associated protein genes (KRTAP19-n) in sheep: sKRTAP19-1, sKRTAP19-2, sKRTAP19-4, and sKRTAP19-6. These genes are closely related to the previously identified sheep genes KRTAP19-3 and KRTAP19-5, as well as to human KRTAP19-n genes. However, no clear orthologous relationships were found, suggesting complex evolutionary dynamics for this gene family. Extensive nucleotide sequence variation was observed across the four genes. sKRTAP19-1 had four variants, defined by four synonymous single-nucleotide polymorphisms (SNPs) and a variable number of “GGCTAC” hexanucleotide repeats. sKRTAP19-2 had five variants involving seven SNPs, three of which were non-synonymous. sKRTAP19-4 had five variants with nine SNPs (three being non-synonymous) and a three-nucleotide deletion. sKRTAP19-6 had eight variants, defined by 13 SNPs and a two-nucleotide consecutive substitution, with four of the SNPs being non-synonymous. One distinct variant each of sKRTAP19-4 and sKRTAP19-6 was found exclusively in Yanchi Tan sheep, with seven unique nucleotide differences compared to other variants. These unique variants were identical to the Romanov sheep genome in the region amplified (excluding the primer binding regions), suggesting a shared ancestral origin. The findings highlight considerable genetic diversity in ovine KRTAP19-n and lay a foundation for future research into their role in regulating wool fibre characteristics. Full article

Background/Objectives: Cefiderocol is a novel siderophore cephalosporin with potent in vitro activity against a broad spectrum of Gram-negative bacteria, including carbapenemase-producing Enterobacterales (CPE). However, the recent emergence of resistance in clinical settings raises important concerns regarding its long-term effectiveness. This study aims to investigate the genomic determinants associated with cefiderocol resistance in CPE isolates of human origin. Methods: Comparative genomic analyses were conducted between cefiderocol-susceptible and -resistant CPE isolates recovered from human clinical and epidemiological samples at a tertiary care hospital. Whole-genome sequencing, variant annotation, structural modelling, and pangenome analysis were performed to characterize resistance mechanisms. Results: A total of 59 isolates (29 resistant and 30 susceptible) were analyzed, predominantly comprising Klebsiella pneumoniae, Escherichia coli, and Enterobacter cloacae. The most frequent carbapenemase gene among the resistant isolates was bla_NDM, which was also present in a subset of susceptible strains. The resistant isolates exhibited a significantly higher burden of non-synonymous mutations in their siderophore receptor genes, notably within fecR, fecA, fiu, and cirA. Structural modelling predicted deleterious effects for mutations such as fecR:G104S and fecA:A190T. Additionally, porin loss and loop 3 insertions (e.g., GD/TD) in OmpK36, as well as OmpK35 truncations, were more frequent in the resistant isolates, particularly in high-risk clones such as ST395 and ST512. Genes associated with toxin–antitoxin systems (chpB2, pemI) and a hypothetical metalloprotease (group_2577) were uniquely found in the resistant group. Conclusions: Cefiderocol resistance in CPE appears to be multifactorial. NDM-type metallo-β-lactamases and missense mutations in siderophore uptake systems—especially in those encoded by fec, fhu, and cir operons—play a central role. These may be further potentiated by alterations in membrane permeability, such as porin disruption and efflux deregulation. The integration of genomic and structural approaches provides valuable insights into emerging resistance mechanisms and may support the development of diagnostic tools and therapeutic strategies. Full article

This study elucidates potential genetic determinants and mechanisms involved in the synergistic effects of daptomycin (DAP) + fosfomycin (FOF) combination therapy. Among 33 clinically derived DAP-susceptible (S)/DAP-resistant (R) isogenic strain pairs, mutations in the mprF gene occurred in 30/33 DAP-R strains, including polymorphisms of L826F (33%) or T345A/L/I (15%). Strain variants of DAP-S CB1483 serially passaged in vitro for 10 days in DAP +/− FOF identified a key non-synonymous mutation in mprF (L826F) only in the DAP monotherapy arm. Interestingly, passage in FOF alone or DAP + FOF prevented the emergence of this mprF mutation following 10-day passage. This L826F mprF polymorphism, associated with a “gain-in-function” phenotype, exhibited increased amounts of lysyl-phosphatidylglycerol (L-PG) in the cell membrane (CM). Transcriptomics revealed a relatively modest number (~10) of distinct genes that were significantly up- or downregulated (≥2 log fold) in both the DAP-S and DAP-R strain pairs upon DAP + FOF exposures (vs. DAP or FOF alone). Of note, DAP + FOF decreased expression of lrgAB and sdrE and increased the expression level of fosB. In a rabbit infective endocarditis (IE) model, the DAP-R CB185 strain treated with DAP +/− FOF showed significantly reduced lrgB expression in vegetations compared with DAP treatment alone. Overall, these findings indicate that DAP + FOF therapy impacts MRSA through multiple specific mechanisms, enhancing bacterial clearance. Full article