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Mobilization of blaVIM genes via the Tn6292 transposon among carbapenem-resistant Enterobacter cloacae complex isolates from colonized patients in a Spanish hospital.

UNLABELLED: The aim of this study was to perform molecular characterization of the carbapenem-resistant Enterobacter cloacae complex (ECC) isolates from colonized patients in a hospital using whole-genome sequencing (WGS) technology. As part of routine surveillance for multidrug-resistant bacterial colonization, 21 ECC isolates were recovered from patients at San Carlos Hospital in Madrid (Spain) between December 2020 and November 2024. WGS was used to determine their genetic relatedness. Furthermore, species identification, sequence type (ST), resistome, plasmid content, and flanking mobile genetic elements (MGEs) of the carbapenemase genes were derived from the WGS data. The most prevalent carbapenemase gene identified was blaVIM-1 (n = 18, 85.7%), with other notable genes including blaKPC-2 (n = 1, 4.8%), blaKPC-3 (n = 1, 4.8%), and blaOXA-48 (n = 1, 4.8%). Several blaACT and blaESBL variants were also found among the carbapenem-resistant ECC isolates. All of them carried at least one blaACT gene, with blaACT-7 (11/21) and blaTEM-type (14/21) genes being the most common AmpC and ESBL-encoding genes, respectively. Additionally, two isolates exhibited the presence of the mcr-9 gene. Overall, E. hormaechei subsp. steigerwaltii (ST93), followed by E. hormaechei subsp. hoffmanii (ST78 and ST50), were the predominant species and STs circulating among the carbapenem-resistant ECC strains. The blaVIM-1 gene was part of class 1 integrons located within a Tn3-family transposon, Tn6292. blaKPC and blaOXA-48 were linked to Tn4401 and Tn1999 transposons, respectively. In conclusion, the presence of the blaVIM within a transposon Tn6292 enhances its mobility across bacterial genomes, underscoring the value of high-throughput sequencing in monitoring the spread of carbapenem-resistant ECC isolates. IMPORTANCE: This study highlights why monitoring the spread of antibiotic-resistant bacteria in hospitals is critical. By analyzing the complete DNA of carbapenem-resistant bacteria, antibiotics were considered a last line of treatment. We found that the resistance genes are not isolated. Instead, they are embedded within mobile elements called transposons. This means that they can "jump" between different bacteria, accelerating the spread of resistance. These findings emphasize the importance of high-resolution genomic technologies to track and control the spread of these dangerous bacteria in clinical settings, helping preserve the effectiveness of life-saving treatments.

Humans↗

A De Novo 16p13.3 Triplication Underlying Early-Onset Complex Neurodegeneration.

BACKGROUND: Neurodegenerative disorders are clinically and genetically heterogeneous, characterized by progressive neuronal loss and multidomain functional decline. Despite a presumed genetic etiology, a substantial proportion of cases remain molecularly undiagnosed. OBJECTIVE: The aim was to identify the genetic cause of an early-onset neurodegenerative disorder presenting with ataxia and cognitive impairment. METHODS: Rare copy-number variants were detected via short-read whole-genome sequencing (WGS), with candidate structural models inferred using long-read WGS. We performed transcriptomic profiling of peripheral blood leukocytes by RNA sequencing, with validation using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RESULTS: We identified a de novo copy-number gain at 16p13.3. Combined copy-number profiling and long-read WGS suggested a candidate model comprising a triplicated segment in tandem with a proximal duplication, joined to a distal duplication via an inverted junction. Transcriptomic analysis demonstrated significant upregulation of ATP6V0C, AMDHD2, and PDPK1. CONCLUSIONS: These findings support a role for structural variation in early-onset neurodegeneration and highlight the value of combining short-read copy-number profiling with long-read WGS to detect and characterize complex genomic rearrangements. © 2026 International Parkinson and Movement Disorder Society.

16p13.3↗

Prevalence and chronology of colibactin-associated mutational processes and their microbiome spectra in Japanese colorectal cancer.

The incidence of colorectal cancer (CRC) has risen in recent decades, with a disproportionate increase observed among younger individuals in Japan and other countries. The etiological contribution of the gut microbiota to CRC pathogenesis is recognized, yet the mechanisms involved remain to be fully clarified. Here we integrated whole-genome sequencing (WGS) and transcriptome profiling of CRC with whole-genome metagenomic sequencing of fecal samples to interrogate host-microbiome interactions at high resolution. Application of interpretable artificial intelligence enabled the stratification of CRC into four distinct microbiome-informed subtypes. WGS analysis identified mutational signatures SBS88 and ID18, linked to colibactin exposure, as early clonal events detected in 44.8% of non-hypermutated patients. Notably, these signatures were significantly more frequent among patients born after the 1960s. Microbiome-based subclassification revealed subtype-specific clinical and molecular features. Collectively, our findings indicate that colibactin exposure constitutes a prevalent and potentially modifiable risk factor for CRC in the Japanese population.

Humans↗

A second-generation integrated map of the silkworm reveals synteny and conserved gene order between lepidopteran insects.

A second-generation linkage map was constructed for the silkworm, Bombyx mori, focusing on mapping Bombyx sequences appearing in public nucleotide databases and bacterial artificial chromosome (BAC) contigs. A total of 874 BAC contigs containing 5067 clones (22% of the library) were constructed by PCR-based screening with sequence-tagged sites (STSs) derived from whole-genome shotgun (WGS) sequences. A total of 523 BAC contigs, including 342 independent genes registered in public databases and 85 expressed sequence tags (ESTs), were placed onto the linkage map. We found significant synteny and conserved gene order between B. mori and a nymphalid butterfly, Heliconius melpomene, in four linkage groups (LGs), strongly suggesting that using B. mori as a reference for comparative genomics in Lepidotera is highly feasible.

Animals↗

Patterns of Drug Resistance, Drug Resistance Conferring Mutations and Genomic DNA Methylation Revealed in Mycobacterium tuberculosis From South Africa.

Tuberculosis remains a major public health threat globally, with drug-resistant strains undermining treatment efficacy. We analyzed 126 Mycobacterium tuberculosis (M. tuberculosis) isolates with diverse drug resistance spectra and selected 35 for whole genome sequencing (WGS) using Illumina NextSeq, SMRT PacBio Onso and SMRT PacBio Revio sequencing platforms. The study aimed to characterize drug resistance profiles, compare short- and long-read sequencing performance, identify lineages among South African isolates, detect known drug resistance mutations and their lineage-specific patterns, and utilize long-read SMRT platforms for epigenetic profiling. Multiple drug resistance mutations were identified, some lineage-specific, and notably, East-African-Indian (EAI) Lineage 1 isolates often considered less pathogenic, showed significant potential for multidrug-resistance development, including higher fluoroquinolone resistance as compared to other lineages. Three DNA motifs with methylated adenines, namely CACGCaG, CtCCaG and GaTNNNNRtAC, were detected, with methylation patterns varying by lineage and strain due to mutations in the corresponding methyltransferases (MTases). A particularly notable finding was the stable maintenance of a genetic heterogeneity in the mamB MTase, performing methylation at CACGCaG motifs. These results highlight the combined role of genetic and epigenetic variation in M. tuberculosis adaptive evolution and underscore the value of integrating long-read sequencing into TB surveillance and research.

Mycobacterium tuberculosis↗

Insights into the fate and dynamics of antibiotic resistance in multidrug-resistant Bacillus cereus during in vitro simulated gastrointestinal digestion.

Bacillus cereus, an important pathogen responsible for causing foodborne diseases worldwide, releases pore-forming enterotoxins, which target host epithelial cells, leading to osmotic lysis and ultimately manifesting as diarrheal syndrome. Moreover, some B. cereus strains carry antimicrobial resistance genes that confer multidrug resistance against a spectrum of antibiotics. Characterizing the survival traits of multidrug-resistant (MDR) B. cereus strains in the intestinal microenvironment is essential for developing targeted strategies to effectively manage diarrheal foodborne diseases caused by this pathogen. This study used whole-genome sequencing (WGS) to evaluate the pre- and post-digestion toxigenic potential, antimicrobial resistance profiles, and genetic diversity of MDR B. cereus strains isolated from food samples in Guangdong Province, China. The four B. cereus isolates investigated in this study exhibited a genetic diversity, as determined by multilocus sequence typing analysis of WGS data. All four isolates produced the diarrheal toxins Hbl, Nhe, and CytK to varying levels, indicative of their potential to cause outbreaks of foodborne diseases. Each of the four isolates exhibited resistance to more than three classes of antibiotics, fulfilling the criterion for multidrug resistance. At an initial concentration of 9 log colony-forming units (CFU)/mL, the intestinal concentration of these four isolates crossed the threshold required to induce widespread diarrhea in the general population. Under rice slurry protection, all tested isolates maintained intestinal concentration beyond the threshold when the initial concentration was increased to ≥8 log CFU/mL. Moreover, the upregulations of genes associated with acid tolerance, bile tolerance and stress response were observed in the surviving MDR B. cereus isolates. Digestion markedly altered the antibiotic resistance profiles of the MDR B. cereus isolates. In the absence of a food matrix, the MDR isolates lost their resistance to imipenem, meropenem, amoxicillin-clavulanic acid, and trimethoprim-sulfamethoxazole post-digestion and was influenced by the initial concentration of the strains. In the presence of food matrix rice slurry, the effects of digestion on the antibiotic resistance of MDR B. cereus isolates can be mitigated, enabling them to maintain their antibiotic resistance to the greatest extent. Most remarkably, after digestion, the isolates Bce055 and Bce166 exhibited newly emergent resistance to cefotetan and trimethoprim-sulfamethoxazole, respectively. Our findings clarify the fate of MDR B. cereus isolates in the gastrointestinal tract and inform the development of prevention and control strategies for foodborne diseases caused by this pathogen.

Drug Resistance, Multiple, Bacterial↗

Development and Validation of Amplicon-Based Protocol for Sequencing of Respiratory Syncytial Virus Genome.

The most prevalent cause of severe respiratory infections in children is the human respiratory syncytial virus (RSV). The advent of next-generation sequencing (NGS) has made it possible to incorporate this technology into pathogen monitoring and surveillance. Whole-genome sequencing (WGS) of RSV has now become a relatively widely used method for tracking viral evolution. Here we report an improved high-throughput RSV-WGS assay performed directly on clinical samples that is suitable for short-read sequencing platforms. A total of 100 RSV-positive samples collected between November 2022 and March 2024 fulfilled the inclusion cycle quantification criteria and were randomly included in the validation process. The WGS protocol was designed to amplify three distinct amplicons to cover the entire RSV genome. The protocol described here can be successfully replicated in several instances (approximately 95%) in samples with a relatively low viral load, typically corresponding to cycle of quantification values of 27-32. The amplicon-based protocol produced meaningful sequencing results in terms of median depth of coverage (more than 12000×) and median of mapped reads (> 1 × 106 reads). The sequences that had passed the filters showed a coverage of at least 98% across the entire genome, with cycle quantification values of 32. Based on the obtained data resulting in an easy-to-perform protocol helpful for the molecular epidemiology surveillance of RSV.

Humans↗

Genomic and phenotypic characterization of mcr-9 carrying Enterobacter oligotrophicus recovered from bovine mastitis.

Bovine mastitis (BM) is a leading cause of economic loss in the dairy industry, driven by decreased milk yields, involuntary culling, and substantial veterinary costs. A single Gram-negative isolate recovered from BM was characterized in this study. For this, antimicrobial susceptibility testing (AST) was performed using the Neg-Urine-Combo 98 panel. Whole-genome sequencing (WGS) was employed to identify antimicrobial resistance genes (ARG), virulence factors (VF) genes, plasmid replicons and prophage sequences. Comparative genomic analysis was performed through phylogenetic analysis. The BM isolate was phenotypically identified as Citrobacter rodentium, however, WGS analysis reclassified the isolate as Enterobacter oligotrophicus. Phenotypic AST revealed a resistance profile of 12%, with the isolate exhibiting resistance to β-lactams antimicrobials, specifically amoxicillin-clavulanate, ampicillin and the cephalosporin-cefoxitin. Conversely, susceptibility was demonstrated for the remaining tested antimicrobials. Genomic profiling identified 31 ARG, 10 VF genes and 6 prophage sequences within the E. oligotrophicus genome. This study provides the first evidence of E. oligotrophicus as a causative agent of BM, expanding the known spectrum of pathogens affecting the dairy industry by delivering the second complete genome of E. oligotrophicus available globally. The identification of 31 ARG, 10 VF, and 6 prophage sequences underscore the potential pathogenic risk and environmental resilience of this isolate. These findings highlight the critical role of WGS-based surveillance in identifying non-conventional mastitis pathogens and underscore the need for targeted mitigation strategies in veterinary medicine.

Animals↗

Absolute copy number aware CNV calling of sub-megabase segments in ultra-low coverage single-cell DNA sequencing data.

Recent advances in ultra-low coverage whole-genome sequencing (WGS) of single cells have enabled detailed analysis of copy number variation at a throughput approaching that of single-cell RNA sequencing. However, downstream computational methods have not seen comparable advances and are largely adaptations of deep sequencing methodology with reduced precision. Here, we present ASCENT, a computational method built to take full advantage of modern direct tagmentation-based WGS at ultra-low depth. Using joint segmentation with high-resolution bins, we accurately detect small segments, achieving accurate copy number profiles even at 100 000 reads per cell. ASCENT implements true absolute copy state inference for single cells, based on statistical modeling of coverage rather than comparison to a reference, while taking variable segment copy state into account. Further, ASCENT implements per-segment copy-neutral loss of heterozygosity (LOH) calling without the need for non-tumor or bulk WGS reference. When applied to a pediatric B-ALL sample, ASCENT finds copy-neutral LOH in a small segment and a minor subclone defined by breakpoints missed in bulk WGS. Thus, by applying appropriate computational methods, single-cell WGS provides clear advantages over bulk, even at a relatively low cell number and sequencing depth.

DNA Copy Number Variations↗

Comprehensive evaluation of new sequencer T20 and well-established T7 with 507 human samples.

The DNBSEQ-T20×2 (T20) sequencer, developed by MGI Tech, enables cost-effective human whole-genome sequencing (WGS) at 30× coverage for less than $100 per genome. Here, we evaluate the sequencing performance and data quality of the T20 platform by benchmarking it against the established DNBSEQ-T7 (T7) sequencer using 507 samples derived from blood (N = 75), stool (N = 242), and saliva (N = 190). The T20 exhibited lower sequencing quality metrics compared with the T7, with Q20 scores of 95.76%-95.83% and Q30 scores of 87.25%-87.40%, compared with 97.81%-97.93% and 93.26%-93.60%, respectively, for T7 data. Quality differences were more evident toward the end of reads, and PCR-free libraries sequenced on the T20 showed similar reductions in quality scores. The median empirical base error rate estimated from 102 ZymoBIOMICS samples was 0.33%. The T20 demonstrated comparable coverage uniformity to the T7 and showed high concordance in microbiome composition analysis, with a median Bray-Curtis dissimilarity of 0.02. Variant calling performance was highly consistent between the two platforms. Among variants with non-missing genotype calls on both platforms, 94.92% of SNPs and 87.20% of InDels showed concordant genotypes between T20 and T7. Overall, the T20 delivers reliable sequencing accuracy and reproducibility for large-scale genomic and microbiome studies, providing a cost-effective alternative for high-throughput sequencing applications.

Metagenomics↗

Fifty-four new gene-based canine microsatellite markers.

Fifty-four new markers were developed to fill in gaps in the current map of canine microsatellites and to complement existing markers that may not be sufficiently informative in highly inbred canine pedigrees. Canine genes contained on the radiation hybrid map were used to obtain the sequence of the human homolog. A BLAST search versus the canine whole genome shotgun (wgs) sequence resource was used to obtain the sequence of the canine genomic contigs containing the homolog of the corresponding human gene. Canine sequences that contained microsatellites and mapped back to the correct location in the human genome were used to design primers for amplification of the microsatellites from canine genomic DNA. Heterozygosities of the markers were tested by genotyping grandparental DNAs obtained from the Nestle Purina Reference family DNA distribution center plus DNAs from unrelated Bouviers and Irish wolfhounds. Canine map positions of markers on the July 2004 freeze of the canine genome assembly were determined by in silico PCR or BLAST.

Animals↗

In-host adaptation of Staphylococcus aureus during recurrent prosthetic joint infections: a retrospective longitudinal study.

UNLABELLED: The aim of this study was to characterize the in vivo evolution of Staphylococcus aureus strains involved in recurrent prosthetic joint infections (PJIs) both phenotypically and genomically. We conducted a monocentric retrospective study in a 1,437-bed French teaching hospital between 2013 and 2021. All patients presenting a recurrent S. aureus-related PJI-defined as at least two strains isolated from distinct clinical samples more than 90 days apart-of the knee, hip, or shoulder were included. Clinical data were reviewed, and all isolates underwent phenotypic characterization, including antimicrobial susceptibility testing, growth rate determination, biofilm production assays, metabolic profiling (API 50 CH), and virulence evaluation using the Galleria mellonella infection model. Whole-genome sequencing (WGS) was performed for all strains, followed by analyses of core-genome multilocus sequence typing (cgMLST), resistome, virulome, and mobilome composition, and single-nucleotide polymorphisms (SNPs). Thirteen patients met inclusion criteria, yielding 55 S. aureus isolates. Eight patients experienced recurrent infections caused by genetically closely related strains throughout the clinical course (median: three strains per patient; range: 2-6), whereas five patients were infected by genetically distinct strains. At baseline, isolates were genetically diverse and susceptible to methicillin and rifampicin; two showed fluoroquinolone resistance due to grlA and/or gyrA mutations. In one patient (patient C), a recurrent isolate acquired an rpoB S486L mutation, conferring rifampicin resistance after rifampicin exposure. Due to the limited sample size, it is difficult to draw definitive conclusions from the phenotypic analyses. This study highlights the adaptive evolution of S. aureus during chronic PJIs and underscores the need for further research to better understand intra-host dynamics in long-standing infections. IMPORTANCE: This study conducted in a 1,437-bed French teaching hospital analyzed the genomic and phenotypic evolution of 55 Staphylococcus aureus strains recovered in recurrent PJIs from 13 patients. The first strains showed high genotypic diversity across 12 different sequence types. Among the 13 patients, only eight experienced a true recurrence with the same strain, while five were contaminated with a different strain of S. aureus, indicating a new infection. Moreover, this study underscores the complex within-host evolution of S. aureus and highlights the phenotypical and genotypical adaptation during chronic infection.

Staphylococcus aureus↗

Whole-genome sequencing, strain composition, and predicted antimicrobial resistance of Streptococcus pneumoniae causing invasive disease in England in 2017-20: a prospective national surveillance study.

BACKGROUND: Surveillance of the invasive disease burden caused by Streptococcus pneumoniae in England is performed by the UK Health Security Agency (UKHSA). In 2017, UKHSA switched from phenotypic methods to whole-genome sequencing (WGS) approaches for pneumococcal surveillance. Here, we present the first results of national WGS surveillance, up to the start of the COVID-19 pandemic, with the aim of describing the population genomics of this important pathogen. METHODS: We examined prospective national surveillance data from England, using bacterial isolates from cases of invasive pneumococcal disease (IPD) submitted to the national reference laboratory at UKHSA. A bioinformatic pipeline was developed to quality control WGS data and routinely report species and serotype. We assembled isolate data, assigned global pneumococcal sequencing clusters (GPSCs), and predicted antimicrobial resistance (AMR) profiles for isolates that passed further quality control. We collected additional data on patient outcomes and characteristics using enhanced surveillance questionnaires completed by patients' general practitioners. We used logistic regression analysis to assess the effects of various genomic and patient characteristics on the outcomes of IPD. FINDINGS: In England, between July 1, 2017, and Feb 29, 2020, there were 15 400 cases of IPD. From these cases, 13 749 (89·3%) isolates were sequenced, passed quality control, and were included in analyses. Serotype diversity was high during the study period, with 2751 (20%) isolates serotyped as 13-valent pneumococcal conjugate vaccine (PCV13) types, whereas serotype 8 was the most prevalent serotype (n=3074 [22·4%]) overall. There were 157 GPSCs within the collection, with GSPC3 the most common, encompassing 98·7% (3033 of 3074) of serotype 8 isolates. Most isolates (n=10 198 [74·2%]) did not contain AMR-associated genes. Resistance to co-trimoxazole was the most frequently predicted resistance (n=2331 [17%]), followed by resistance to tetracycline (n=1199 [8·7%]) and β-lactams (n=1149 [8·4%]). Logistic regression analysis found the presence of AMR-associated genes significantly increased the odds of patient death (odds ratio 1·18, 95% CI 1·01-1·38). Some GPSCs were also associated with a significant increase in the odds of patient death, such as GPSC12 (1·88, 1·48-2·38). Isolates from 2018 were associated with a significant increase in the odds of patient death (1·12, 1·00-1·25), whereas younger patient age was significantly associated with a reduction in the odds of patient death compared with being aged 85 years or older. INTERPRETATION: WGS-based surveillance has allowed us to interrogate country-wide population dynamics driving changes in pneumococcal serotype frequency. Here, we observe a stable but diverse population before the COVID-19 pandemic restrictions were enforced in England, with low rates of AMR. These findings will provide the baseline for pandemic and post-pandemic data, to collectively inform implementation and development of the vaccination programme within the country. FUNDING: None.

Streptococcus pneumoniae↗

Evaluation of germline transmission of electroporation-mediated double gene-edited cattle lines.

Gene editing in livestock using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) offers a promising approach for genetic improvement in cattle. This study evaluated germline transmission and mutation stability of double-knockout cattle generated by zygote electroporation. Previously reported myostatin/beta-lactoglobulin (MSTN/BLG) and newly generated α-1,3-galactosyltransferase (GGTA1/BLG) double-knockout cattle were produced using CRISPR/Cas9-mediated genome editing. Targeted deep sequencing demonstrated extensive somatic mosaicism across multiple tissues. Computer-assisted sperm analysis (CASA) demonstrated normal sperm motility in MSTN/BLG double-knockout males. Fertilization of wild-type oocytes produced heterozygous embryos, with mutation frequencies of 37.76 ± 10.74% at the MSTN locus and 54.80 ± 7.73% at the BLG locus, as assessed by T7 endonuclease I (T7E1) assay. MSTN/BLG double-knockout sperm were subsequently used for embryo production and for artificial insemination of GGTA1/BLG double-knockout females. Healthy offspring were successfully obtained (n = 3), alongside one stillborn calf. Targeted deep sequencing of all four progenies revealed highly variable allele frequencies that deviated substantially from the approximately 50% expected for heterozygous germline transmission. In contrast, whole-genome sequencing (WGS) results were consistent with Mendelian expectations, underscoring the limitations of PCR-based targeted sequencing for assessing germline transmission in mosaic founders. These results show that CRISPR/Cas9-edited embryos generated by electroporation can develop into healthy, sexually mature cattle capable of germline transmission. While variable transmission rates were observed owing to founder mosaicism, non-mosaic F1 offspring were successfully generated. However, direct, embryo-mediated gene-editing strategies remain technically and economically challenging for large-scale commercial calf production, and reports in cattle are limited. This study provides a reference for future applications of gene-edited embryos and their germline propagation.

Animals↗

Clinical and functional characterization of a novel homozygous non-canonical splice mutation (c.1910-15_1910-11delinsTTACA) in CEP290 causing Joubert syndrome.

BACKGROUND: Joubert syndrome (JS) is a rare, predominantly autosomal recessive neurodevelopmental disorder characterized by hypotonia, motor delay, intellectual disability, oculomotor apraxia, and the hallmark "molar tooth sign" on axial view of MRI. JS is genetically heterogeneous, with pathogenic variants identified in more than 40 genes involved in primary cilia function. Among these, CEP290 is one of the most frequently mutated genes. RESULTS: In this study, we investigated two children-an 11-year-old boy (the proband) and his 5-year-old sister-both presenting with a similar phenotype consistent with JS. The parents, who self-identified as Chechen, reported distant consanguinity. The family also included a healthy 13-year-old daughter. The proband had previously been evaluated by a neurologist and underwent whole-genome sequencing (WGS); however, no causative variants were identified initially. After phenotype reassessment by a clinical geneticist, we performed a reanalysis of the raw WGS data and identified a novel homozygous intronic variant of uncertain significance (VUS), c.1910-15_1910-11delinsTTACA in CEP290 (NM_025114.4). Sanger sequencing confirmed that both the proband and his affected sister were homozygous for this variant, which they inherited from their heterozygous parents. Their healthy sister did not carry the variant. mRNA-sequencing and targeted cDNA sequencing (read depth ~ 100,000x) demonstrated that this intronic variant causes completely aberrant splicing of CEP290 pre-mRNA. Predominantly this variant causes the skipping of exon 20 in the main CEP290 transcript. Alternatively, the variant results in partial inclusion of intron 19 into the mRNA, elongation of exon 20 by 58 nucleotides, and a homozygous substitution chr12:88114573 (ACTGTGTA> TTACAGTA). No canonical mRNA isoform was detected when the variant was homozygous. Both the predicted severe truncation and the likely degradation of aberrant transcripts through nonsense-mediated decay (NMD) would correspond to complete loss of CEP290 function. Following the reclassification of this VUS to likely pathogenic, the family was able to pursue in vitro fertilization (IVF) with preimplantation genetic testing for monogenic disorders (PGT-M). CONCLUSION: Our study highlights the critical importance of proper phenotyping prior to referral for WES/WGS as well as of combining NGS with functional mRNA studies to achieve a molecular diagnosis for patients with predicted splice-site mutations in JS-associated genes. It also emphasizes the need for functional reassessment of VUS when genomic data are expected to guide reproductive decision-making within affected families.

Humans↗

Genomic characterisation of ST233 Pseudomonas aeruginosa co-producing KPC-2 and VIM-2 in Northeastern Brazil during the COVID-19 pandemic: Evidence of independent horizontal acquisition events.

BACKGROUND: Dual-carbapenemase-producing Pseudomonas aeruginosa poses a major therapeutic and epidemiological challenge worldwide, yet systematic data on KPC and VIM co-production in Brazil remain limited. The COVID-19 pandemic intensified antimicrobial use, a period temporally associated with increased carbapenemase detection globally. OBJECTIVES: To characterise the molecular epidemiology and resistance profiles of KPC and VIM co-producing P. aeruginosa isolates from Brazil (2019-2023). METHODS: Between 2019 and 2023, 1489 multidrug-resistant P. aeruginosa isolates were screened by multiplex PCR for carbapenemase-encoding genes. Co-producing isolates underwent pulsed-field gel electrophoresis (PFGE) for clonal profiling, followed by whole-genome sequencing (WGS) for high-resolution phylogenomic analysis. Antimicrobial susceptibility testing and plasmid characterisation using next-generation sequencing platforms were also performed. RESULTS: Forty-two isolates (2.8%) harboured both blaKPC-2 and blaVIM-2, with detection occurring exclusively between 2020 and 2023, temporally coinciding with the COVID-19 pandemic. PFGE identified eight distinct clonal groups, providing evidence for independent horizontal gene transfer (HGT) events, whilst WGS confirmed all isolates as the high-risk ST233 lineage. Chromosomally integrated blaVIM-2 within class 1 integrons predominated; 2 isolates carried dual chromosomal copies. Plasmid-borne blaKPC-2 was identified across heterogeneous replicons (43.3-430.1 kb), suggesting multiple independent acquisition events. All co-producing isolates displayed extensive drug resistance, retaining in vitro susceptibility only to cefiderocol and colistin. CONCLUSIONS: ST233 co-producing KPC and VIM, represents a high-risk resistance phenotype of epidemiological significance. Divergent genomic architectures suggest active horizontal dissemination across diverse genetic backgrounds rather than clonal expansion, highlighting the need for enhanced surveillance and infection control strategies.

Bacterial genomic characterisation↗

Deep-Learning Model for Tumor-Type Prediction Using Targeted Clinical Genomic Sequencing Data.

UNLABELLED: Tumor type guides clinical treatment decisions in cancer, but histology-based diagnosis remains challenging. Genomic alterations are highly diagnostic of tumor type, and tumor-type classifiers trained on genomic features have been explored, but the most accurate methods are not clinically feasible, relying on features derived from whole-genome sequencing (WGS), or predicting across limited cancer types. We use genomic features from a data set of 39,787 solid tumors sequenced using a clinically targeted cancer gene panel to develop Genome-Derived-Diagnosis Ensemble (GDD-ENS): a hyperparameter ensemble for classifying tumor type using deep neural networks. GDD-ENS achieves 93% accuracy for high-confidence predictions across 38 cancer types, rivaling the performance of WGS-based methods. GDD-ENS can also guide diagnoses of rare type and cancers of unknown primary and incorporate patient-specific clinical information for improved predictions. Overall, integrating GDD-ENS into prospective clinical sequencing workflows could provide clinically relevant tumor-type predictions to guide treatment decisions in real time. SIGNIFICANCE: We describe a highly accurate tumor-type prediction model, designed specifically for clinical implementation. Our model relies only on widely used cancer gene panel sequencing data, predicts across 38 distinct cancer types, and supports integration of patient-specific nongenomic information for enhanced decision support in challenging diagnostic situations. See related commentary by Garg, p. 906. This article is featured in Selected Articles from This Issue, p. 897.

Humans↗

Phylogenomic reconstruction of Cryptosporidium spp. captured directly from clinical samples reveals extensive genetic diversity.

Cryptosporidium is a leading cause of severe diarrhea and mortality in young children and infants in Africa and southern Asia. More than twenty Cryptosporidium species infect humans, of which C. parvum and C. hominis are the major agents causing moderate to severe diarrhea. Relatively few genetic markers are typically applied to genotype and/or diagnose Cryptosporidium. Most infections produce limited oocysts making it difficult to perform whole genome sequencing (WGS) directly from stool samples. Hence, there is an immediate need to apply WGS strategies to 1) develop high-resolution genetic markers to genotype these parasites more precisely, 2) to investigate endemic regions and detect the prevalence of different genotypes, and the role of mixed infections in generating genetic diversity, and 3) to investigate zoonotic transmission and evolution. To understand Cryptosporidium global population genetic structure, we applied Capture Enrichment Sequencing (CES-Seq) using 74,973 RNA-based 120 nucleotide baits that cover ~92% of the genome of C. parvum. CES-Seq is sensitive and successfully sequenced Cryptosporidium genomic DNA diluted up to 0.005% in human stool DNA. It also resolved mixed strain infections and captured new species of Cryptosporidium directly from clinical/field samples to promote genome-wide phylogenomic analyses and prospective GWAS studies.

Cryptosporidium↗