Knockdown of tgfb1a partially improves ALS phenotype in a transient zebrafish model.

Amyotrophic lateral sclerosis (ALS) corresponds to a neurodegenerative disorder marked by the progressive degeneration of both upper and lower motor neurons located in the brain, brainstem, and spinal cord. ALS can be broadly categorized into two main types: sporadic ALS (sALS), which constitutes approximately 90% of all cases, and familial ALS (fALS), which represents the remaining 10% of cases. Transforming growth factor type-ß (TGF-ß) is a cytokine involved in various cellular processes and pathological contexts, including inflammation and fibrosis. Elevated levels of TGF-ß have been observed in the plasma and cerebrospinal fluid (CSF) of both ALS patients and mouse models. In this perspective, we explore the impact of the TGF-ß signaling pathway using a transient zebrafish model for ALS. Our findings reveal that the knockdown of tgfb1a lead to a partial prevention of motor axon abnormalities and locomotor deficits in a transient ALS zebrafish model at 48 h post-fertilization (hpf). In this context, we delve into the proposed distinct roles of TGF-ß in the progression of ALS. Indeed, some evidence suggests a dual role for TGF-ß in ALS progression. Initially, it seems to exert a neuroprotective effect in the early stages, but paradoxically, it may contribute to disease progression in later stages. Consequently, we suggest that the TGF-ß signaling pathway emerges as an attractive therapeutic target for treating ALS. Nevertheless, further research is crucial to comprehensively understand the nuanced role of TGF-ß in the pathological context.

Neurological Spectrum of Epstein-Barr Virus Infection: A Rare Clinical Case.

The Epstein-Barr virus (EBV) is a DNA virus that has been infecting humans since ancient times, capable of causing a wide range of pathologies and affecting approximately 90% of the population. A 61-year-old male with no significant medical history presented with a 5-day history of imbalance and difficulty walking. Neurological examination revealed specific findings, including absent reflexes, bilateral asynergy, and gait abnormalities. Contrasting with Guillain-Barré Syndrome, lumbar puncture suggested a central nervous system infection. Serological testing confirmed Epstein-Barr virus (EBV) positivity, and intravenous immunoglobulin led to significant improvement. Electromyogram results suggested inflammatory/ipnfectious polyradiculopathy. Repeat EBV serology, showing strongly positive IgG and negative IgM, confirmed the diagnosis of Polyradiculoneuropathy secondary to EBV. This case underscores the rare neurological complications of EBV and the importance of considering viral infections in such presentations.

Clinical and genetic contributions to medical comorbidity in bipolar disorder: a study using electronic health records-linked biobank data.

Bipolar disorder is a chronic and complex polygenic disease with high rates of comorbidity. However, the independent contribution of either diagnosis or genetic risk of bipolar disorder to the medical comorbidity profile of individuals with the disease remains unresolved. Here, we conducted a multi-step phenome-wide association study (PheWAS) of bipolar disorder using phenomes derived from the electronic health records of participants enrolled in the Mayo Clinic Biobank and the Mayo Clinic Bipolar Disorder Biobank. First, we explored the conditions associated with a diagnosis of bipolar disorder by conducting a phenotype-based PheWAS followed by LASSO-penalized regression to account for correlations within the phenome. Then, we explored the conditions associated with bipolar disorder polygenic risk score (BD-PRS) using a PRS-based PheWAS with a sequential exclusion approach to account for the possibility that diagnosis, instead of genetic risk, may drive such associations. 53,386 participants (58.7% women) with a mean age at analysis of 67.8 years (SD = 15.6) were included. A bipolar disorder diagnosis (n = 1479) was associated with higher rates of psychiatric conditions, injuries and poisonings, endocrine/metabolic and neurological conditions, viral hepatitis C, and asthma. BD-PRS was associated with psychiatric comorbidities but, in contrast, had no positive associations with general medical conditions. While our findings warrant confirmation with longitudinal-prospective studies, the limited associations between bipolar disorder genetics and medical conditions suggest that shared environmental effects or environmental consequences of diagnosis may have a greater impact on the general medical comorbidity profile of individuals with bipolar disorder than its genetic risk.

Randomized comparison of oblique and perpendicular stabilizers for minimally invasive repair of pectus excavatum.

OBJECTIVES: Bar dislocation is one of the most feared complications of the minimally invasive repair of pectus excavatum. METHODS: Prospective randomized parallel-group clinical trial intending to assess whether oblique stabilizers can reduce bar displacement in comparison with regular stabilizers used in minimally invasive repair of pectus excavatum. Additionally, we evaluated pain, quality of life and other postoperative complications. Participants were randomly assigned to surgery with perpendicular (n = 16) or oblique stabilizers (n = 14) between October 2017 and September 2018 and followed for 3 years. Bar displacements were evaluated with the bar displacement index. Pain scores were evaluated through visual analogue scale and quality of life through the Pectus Excavatum Evaluation Questionnaire. RESULTS: Control group average displacement index was 17.7 (±26.7) and intervention group average displacement index was 8.2 (±10.9). There was 1 reoperation in each group that required correction with 2 bars. Bar displacement was similar among groups (P = 0.12). No other complications were recorded. There was no statistically significant difference on pain score. There was a significant difference between pre- and postoperative composite scores of the participants' body image domain and psycho-social aspects in both groups. The difference between the pre- and postoperative participants' perception of physical difficulties was greater and statistically significant in the intervention group. CONCLUSIONS: There was no statistical difference in the use of perpendicular or oblique stabilizers, but the availability of different models of stabilizers during the study suggested that this can be advantageous. The trial is registered at ClinicalTrials.gov, number NCT03087734.

Pharmacogenomic overlap between antidepressant treatment response in major depression & antidepressant associated treatment emergent mania in bipolar disorder.

There is increasing interest in individualizing treatment selection for more than 25 regulatory approved treatments for major depressive disorder (MDD). Despite an inconclusive efficacy evidence base, antidepressants (ADs) are prescribed for the depressive phase of bipolar disorder (BD) with oftentimes, an inadequate treatment response and or clinical concern for mood destabilization. This study explored the relationship between antidepressant response in MDD and antidepressant-associated treatment emergent mania (TEM) in BD. We conducted a genome-wide association study (GWAS) and polygenic score analysis of TEM and tested its association in a subset of BD-type I patients treated with SSRIs or SNRIs. Our results did not identify any genome-wide significant variants although, we found that a higher polygenic score (PGS) for antidepressant response in MDD was associated with higher odds of TEM in BD. Future studies with larger transdiagnostic depressed cohorts treated with antidepressants are encouraged to identify a neurobiological mechanism associated with a spectrum of depression improvement from response to emergent mania.

Modeling Spinal Muscular Atrophy in Zebrafish: Current Advances and Future Perspectives.

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by degeneration of lower motor neurons (LMNs), causing muscle weakness, atrophy, and paralysis. SMA is caused by mutations in the Survival Motor Neuron 1 (SMN1) gene and can be classified into four subgroups, depending on its severity. Even though the genetic component of SMA is well known, the precise mechanisms underlying its pathophysiology remain elusive. Thus far, there are three FDA-approved drugs for treating SMA. While these treatments have shown promising results, their costs are extremely high and unaffordable for most patients. Thus, more efforts are needed in order to identify novel therapeutic targets. In this context, zebrafish (Danio rerio) stands out as an ideal animal model for investigating neurodegenerative diseases like SMA. Its well-defined motor neuron circuits and straightforward neuromuscular structure offer distinct advantages. The zebrafish's suitability arises from its low-cost genetic manipulation and optical transparency exhibited during larval stages, which facilitates in vivo microscopy. This review explores advancements in SMA research over the past two decades, beginning with the creation of the first zebrafish model. Our review focuses on the findings using different SMA zebrafish models generated to date, including potential therapeutic targets such as U snRNPs, Etv5b, PLS3, CORO1C, Pgrn, Cpg15, Uba1, Necdin, and Pgk1, among others. Lastly, we conclude our review by emphasizing the future perspectives in the field, namely exploiting zebrafish capacity for high-throughput screening. Zebrafish, with its unique attributes, proves to be an ideal model for studying motor neuron diseases and unraveling the complexity of neuromuscular defects.

High Concentrations of Cannabidiol Induce Neurotoxicity in Neurosphere Culture System.

Recent studies have demonstrated that cannabinoids are potentially effective in the treatment of various neurological conditions, and cannabidiol (CBD), one of the most studied compounds, has been proposed as a non-toxic option. However, the adverse effects of CBD on neurodevelopmental processes have rarely been studied in cell culture systems. To better understand CBD's influence on neurodevelopment, we exposed neural progenitor cells (NPCs) to different concentrations of CBD (1 µM, 5 µM, and 10 µM). We assessed the morphology, migration, differentiation, cell death, and gene expression in 2D and 3D bioprinted models to stimulate physiological conditions more effectively. Our results showed that CBD was more toxic at higher concentrations (5 µM and 10 µM) and affected the viability of NPCs than at lower concentrations (1 µM), in both 2D and 3D models. Moreover, our study revealed that higher concentrations of CBD drastically reduced the size of neurospheres and the number of NPCs within neurospheres, impaired the morphology and mobility of neurons and astrocytes after differentiation, and reduced neurite sprouting. Interestingly, we also found that CBD alters cellular metabolism by influencing the expression of glycolytic and ß-oxidative enzymes in the early and late stages of metabolic pathways. Therefore, our study demonstrated that higher concentrations of CBD promote important changes in cellular functions that are crucial during CNS development.

Learning From a National Quality Improvement Collaborative for Brief Resolved Unexplained Events.

OBJECTIVE: In 2016, the American Academy of Pediatrics published the Brief Resolved Unexplained Event (BRUE) Clinical Practice Guideline (CPG). A multicenter quality improvement (QI) collaborative aimed to improve CPG adherence. METHODS: A QI collaborative of 15 hospitals aimed to improve testing adherence, the hospitalization of lower-risk infants, the correct use of diagnostic criteria, and risk classification. Interventions included CPG education, documentation practices, clinical pathways, and electronic medical record integration. By using medical record review, care of emergency department (ED) and inpatient patients meeting BRUE criteria was displayed via control or run charts for 3 time periods: pre-CPG publication (October 2015 to June 2016), post-CPG publication (July 2016 to September 2018), and collaborative (April 2019 to June 2020). Collaborative learning was used to identify and mitigate barriers to iterative improvement. RESULTS: A total of 1756 infants met BRUE criteria. After CPG publication, testing adherence improved from 56% to 64% and hospitalization decreased from 49% to 27% for lower-risk infants, but additional improvements were not demonstrated during the collaborative period. During the collaborative period, correct risk classification for hospitalized infants improved from 26% to 49% (ED) and 15% to 33% (inpatient) and the documentation of BRUE risk factors for hospitalized infants improved from 84% to 91% (ED). CONCLUSIONS: A national BRUE QI collaborative enhanced BRUE-related hospital outcomes and processes. Sites did not improve testing and hospitalization beyond the gains made after CPG publication, but they did shift the BRUE definition and risk classification. The incorporation of caregiver perspectives and the use of shared decision-making tools may further improve care.

Hox genes control homocercal caudal fin development and evolution.

Ancient bony fishes had heterocercal tails, like modern sharks and sturgeons, with asymmetric caudal fins and a vertebral column extending into an elongated upper lobe. Teleost fishes, in contrast, developed a homocercal tail characterized by two separate equal-sized fin lobes and the body axis not extending into the caudal fin. A similar heterocercal-to-homocercal transition occurs during teleost ontogeny, although the underlying genetic and developmental mechanisms for either transition remain unresolved. Here, we investigated the role of hox13 genes in caudal fin formation as these genes control posterior identity in animals. Analysis of expression profiles of zebrafish hox13 paralogs and phenotypes of CRISPR/Cas9-induced mutants showed that double hoxb13a and hoxc13a mutants fail to form a caudal fin. Furthermore, single mutants display heterocercal-like morphologies not seen since Mesozoic fossil teleosteomorphs. Relaxation of functional constraints after the teleost genome duplication may have allowed hox13 duplicates to neo- or subfunctionalize, ultimately contributing to the evolution of a homocercal tail in teleost fishes.

Immunohistochemical characterisation of the adult Nothobranchius furzeri intestine.

Nothobranchius furzeri is emerging as an exciting vertebrate organism in the field of biomedicine, developmental biology and ecotoxicology research. Its short generation time, compressed lifespan and accelerated ageing make it a versatile model for longitudinal studies with high traceability. Although in recent years the use of this model has increased enormously, there is still little information on the anatomy, morphology and histology of its main organs. In this paper, we present a description of the digestive system of N. furzeri, with emphasis on the intestine. We note that the general architecture of the intestinal tissue is shared with other vertebrates, and includes a folding mucosa, an outer muscle layer and a myenteric plexus. By immunohistochemical analysis, we reveal that the mucosa harbours the same type of epithelial cells observed in mammals, including enterocytes, goblet cells and enteroendocrine cells, and that the myenteric neurons express neurotransmitters common to other species, such as serotonin, substance P and tyrosine hydroxylase. In addition, we detect the presence of a proliferative compartment at the base of the intestinal folds. The description of the normal intestinal morphology provided here constitutes a baseline information to contrast with tissue alterations in future lines of research assessing pathologies, ageing-related diseases or damage caused by toxic agents.

The cost of primary care: An experience analysis in an urban setting

Objectives@#PhilHealth’s present health benefit scheme is largely centered on in-patient services. This inadvertently incentivizes hospital admissions for increased access to benefit coverage. To address this problem, this study proposes a costing method to comprehensively finance outpatient care. The objective of this paper is to estimate an annual primary care benefit package (PCBP) cost based on experience analysis (actual benefit usage) on the first year of implementation at an urban pilot site. @*Methods@#A cost analysis was conducted to assess a disease-agnostic primary care benefit package for an urban outpatient government facility over the first year of implementation. Costing information was gathered through staff interviews, accounting documents, and usage data from the electronic health records system available on-site. @*Results@#The annual primary care cost was defined as the estimated financial coverage for eligible employees and their eligible dependents (n=15,051). The annual utilization rate for consultations was reported at 51%. Of patients who consulted, approximately 38% accessed free available diagnostic procedures and 48% availed of free available medicines. Based on these usage rates, the annual primary care cost for the first year was computed at PhP 403.22 per capita. @*Conclusion@#Our study shows that on the first year of coverage in a government run urban outpatient facility, an allocation of PhP 403.22 per capita can allow coverage for a disease-agnostic package (comprehensive); this amount excludes out-of-pocket expenses incurred by the target population of this study. This amount is feasible only when coopted with opportunistic registration, reduction of untargeted check-ups, prior contextual community engagement, and streamlining of patient-transactions through an electronic health record (EHR).

Health benefit utilization and out-of-pocket expenses in outpatient care and hospitalizations: Baseline surveys of three primary care sites in the Philippines

Background@#The Philippine Primary Care Studies (PPCS) is a network of pilot studies that developed, implemented, and tested strategies to strengthen primary care in the country. These pilot studies were implemented in an urban, rural, and remote setting. The aim is to use the findings to guide the policies of the national health insurance program (PhilHealth), the main payor for individualized healthcare services in the country.@*Objective@#The objective of this report is to compare baseline outpatient benefit utilization, hospitalization, and health spending, including out-of-pocket (OOP) expenses, in three health settings (urban, rural, and remote). These findings were used to contextualize strategies to strengthen primary care in these three settings.@*Methods@#Cross-sectional surveys were carried out using an interviewer-assisted questionnaire on a random sample of families in the urban site, and a stratified random sample of households in the rural and remote sites. The questionnaire asked for out-patient and hospitalization utilization and spending, including the OOP expenses. @*Results@#A total of 787 families/households were sampled across the three sites. For outpatient benefits, utilization was low in all sites. The remote site had the lowest utilization at only 15%. Unexpectedly, the average annual OOP expenses for outpatient consults in the remote site was PhP 571.92/per capita. This is 40% higher than expenses shouldered by families in the rural area, but similar with the urban site. For hospital benefits, utilization was lowest in the remote site (55.7%) compared to 75.0% and 78.1% for the urban and rural sites, respectively. OOP expenses per year were highest in the remote site at PhP 2204.44 per capita, probably because of delay in access to healthcare and consequently more severe conditions. Surprisingly, annual expenses per year for families in the rural sites (PhP 672.03 per capita) were less than half of what families in the urban sites spent (PhP 1783.38 per capita). @*Conclusions@#Compared to families in the urban site and households in the rural sites, households in remote areas have higher disease rates and consequently, increased need for outpatient and inpatient health services. When they do get sick, access to care is more difficult. This leads to lower rates of benefit utilization and higher out-of-pocket expenses. Thus, provision of “equal” benefits can inadvertently lead to “inequitable” healthcare, pushing disadvantaged populations into a greater disadvantage. These results imply that health benefits need to be allocated according to need. Families in poorer and more remote areas may require greater subsidies.

Diagnostic Performance of Deep Learning Models for Gastric Intestinal Metaplasia Detection in Narrow-band Images.

Gastric Intestinal Metaplasia (GIM) is one of the precancerous conditions in the gastric carcinogenesis cascade and its optical diagnosis during endoscopic screening is challenging even for seasoned endoscopists. Several solutions leveraging pre-trained deep neural networks (DNNs) have been recently proposed in order to assist human diagnosis. In this paper, we present a comparative study of these architectures in a new dataset containing GIM and non-GIM Narrow-band imaging still frames. We find that the surveyed DNNs perform remarkably well on average, but still measure sizeable inter-fold variability during cross-validation. An additional ad-hoc analysis suggests that these baseline architectures may not perform equally well at all scales when diagnosing GIM.Clinical relevance- Enhanching a clinician's ability to detect and localize intestinal metaplasia can be a crucial tool for gastric cancer management policies.

Diversity, Taxonomic Novelty, and Encoded Functions of Salar de Ascotán Microbiota, as Revealed by Metagenome-Assembled Genomes.

Salar de Ascotán is a high-altitude arsenic-rich salt flat exposed to high ultraviolet radiation in the Atacama Desert, Chile. It hosts unique endemic flora and fauna and is an essential habitat for migratory birds, making it an important site for conservation and protection. However, there is limited information on the resident microbiota's diversity, genomic features, metabolic potential, and molecular mechanisms that enable it to thrive in this extreme environment. We used long- and short-read metagenomics to investigate the microbial communities in Ascotán's water, sediment, and soil. Bacteria predominated, mainly Pseudomonadota, Acidobacteriota, and Bacteroidota, with a remarkable diversity of archaea in the soil. Following hybrid assembly, we recovered high-quality bacterial (101) and archaeal (6) metagenome-assembled genomes (MAGs), including representatives of two putative novel families of Patescibacteria and Pseudomonadota and two novel orders from the archaeal classes Halobacteriota and Thermoplasmata. We found different metabolic capabilities across distinct lineages and a widespread presence of genes related to stress response, DNA repair, and resistance to arsenic and other metals. These results highlight the remarkable diversity and taxonomic novelty of the Salar de Ascotán microbiota and its rich functional repertoire, making it able to resist different harsh conditions. The highly complete MAGs described here could serve future studies and bioprospection efforts focused on salt flat extremophiles, and contribute to enriching databases with microbial genome data from underrepresented regions of our planet.

Protective effect of nitroglycerin ointment and dimethyl sulfoxide on necrosis of skin flaps in rats.

OBJECTIVE: To compare the protective effect of nitroglycerin ointment 2% and Dimethylsulfoxide (DMSO) in dorsal flaps of the rat. METHODS: A blind, experimental study was conducted in 24 male Wistar rats, with a mean weight of 320 (286-376) grams. Group 1: Control. Petrolatum jelly (Vaseline), n = 8, Group 2: Nitroglycerin (NTG) ointment 2% (Nitro-Bid, Altana Co.) n = 8, and Group 3: DMSO gel 90% (Neogen corp. Lexington KY, 40611), n = 8. RESULTS: A total of 24 rats were operated on in the 6-month period of this study. Using a non-parametric Mann-Whitney U-test analysis, a statistically significant p was obtained between the control group and 2% NTG ointment, both in the area of necrosis and in the healthy area (p = 0.026). In contrast, the comparison between DMSO [CH3) 2SO] and the control group (p = 0.180) and between both study groups, with a p = 0.18, was not significant. CONCLUSIONS: Our study concluded that there is a protective effect of 2% NTG ointment for flap survival in relation to the control group (petrolatum). DMSO administered topically did not show a protective effect, compared to the control group.

OBJETIVO: Comparar el efecto protector del ungüento de nitroglicerina 2% y el dimetilsulfoxido 90% en colgajos dorsales en ratas. MÉTODOS: Se realizó un estudio experimental ciego en 24 ratas Wistar macho, con un peso medio de 320 gramos. Grupo 1: Control. Petrolato n = 8, Grupo 2: Nitroglicerina unguento al 2 % (Nitro-Bid, Altana Co.), n = 8, Grupo 3. Dimetilsulfóxido al 90% (Neogen corp. Lexington KY.), n = 8. RESULTADOS: Un total de 24 ratas fueron operadas en el período de 6 meses de este estudio. Mediante un análisis no paramétrico de la prueba U de Mann Whitney, se obtuvo una p estadísticamente significativa entre el grupo control y la pomada de nitroglicerina al 2%, tanto en el área de necrosis como en el área sana (p = 0.026). Por el contrario, la comparación entre DMSO y el grupo control (p = 0.180) y entre ambos grupos de estudio, con una p = 0.18, no fue significativa. CONCLUSIONES: Nuestro estudio concluyó que existe un efecto protector de la pomada de nitroglicerina al 2% para la supervivencia del colgajo en relación al grupo control (vaselina). El DMSO administrado por vía tópica no mostró un efecto protector, en comparación con el grupo de control.

Pathological beige remodeling induced by cancer cachexia depends on the disease severity and involves mainly the trans-differentiation of mature white adipocytes.

In cancer associated cachexia (CAC), white adipose tissue undergoes morphofunctional and inflammatory changes that lead to tissue dysfunction and remodeling. In addition to metabolic changes in white adipose tissues (WAT), adipose tissue atrophy has been implicated in several clinical complications and poor prognoses associated with cachexia. Adipocyte atrophy may be associated with increased beige remodeling in human CAC as evidenced by the "beige remodeling" observed in preclinical models of CAC. Even though beige remodeling is associated with CAC-induced WAT dysfunction, there are still some open questions regarding their cellular origins. In this study, we investigated the development of beige remodeling in CAC from a broader perspective. In addition, we used a grading system to identify the scAT as being affected by mice weight loss early and intensely. Using different in vitro and ex-vivo techniques, we demonstrated that Lewis LLC1 cells can induce a switch from white to beige adipocytes, which is specific to this type of tumor cell. During the more advanced stages of CAC, beige adipocytes are mainly formed from the transdifferentiation of cells. According to our results, humanizing the CAC classification system is an efficient approach to defining the onset of the syndrome in a more homogeneous manner. Pathological beige remodeling occurred early in the disease course and exhibited phenotypic characteristics specific to LLC cells' secretomes. Developing therapeutic strategies that recruit beige adipocytes in vivo may be better guided by an understanding of the cellular origins of beige adipocytes emitted by CAC.

Antidepressant-Associated Treatment Emergent Mania: A Meta-Analysis to Guide Risk Modeling Pharmacogenomic Targets of Potential Clinical Value.

BACKGROUND: The purpose of this study was to review the association between the SLC6A4 5-HTTLPR polymorphism and antidepressant (AD)-associated treatment emergent mania (TEM) in bipolar disorder alongside starting a discussion on the merits of developing risk stratification models to guide when not to provide AD treatment for bipolar depression. METHODS: Studies that examined the association between clinical and genetic risk factors, specifically monoaminergic transporter genetic variation, and TEM were identified. A meta-analysis was performed using the odds ratio to estimate the effect size under the Der-Simonian and Laird model. RESULTS: Seven studies, referencing the SLC6A4 5-HTTLPR polymorphism and TEM (total N = 1578; TEM+ =594, TEM- = 984), of 142 identified articles were included. The time duration between the start of the AD to emergence of TEM ranged from 4 to 12 weeks. There was a nominally significant association between the s allele of the 5-HTTLPR polymorphism and TEM (odds ratio, 1.434; 95% confidence interval, 1.001-2.055; P = 0.0493; I2 = 52%). No studies have investigated norepinephrine or dopamine transporters. CONCLUSION: Although the serotonin transporter genetic variation is commercially available in pharmacogenomic decision support tools, greater efforts, more broadly, should focus on complete genome-wide approaches to determine genetic variants that may contribute to TEM. Moreover, these data are exemplary to the merits of developing risk stratification models, which include both clinical and biological risk factors, to guide when not to use ADs in bipolar disorder. Future studies will need to validate new risk models that best inform the development of personalized medicine best practices treating bipolar depression.

Antimicrobial resistance, pathogenic potential, and genomic features of carbapenem-resistant Klebsiella pneumoniae isolated in Chile: high-risk ST25 clones and novel mobile elements.

Multidrug- and carbapenem-resistant Klebsiella pneumoniae (CR-Kp) are critical threats to global health and key traffickers of resistance genes to other pathogens. Despite the sustained increase in CR-Kp infections in Chile, few strains have been described at the genomic level, lacking details of their resistance and virulence determinants and the mobile elements mediating their dissemination. In this work, we studied the antimicrobial susceptibility and performed a comparative genomic analysis of 10 CR-Kp isolates from the Chilean surveillance of carbapenem-resistant Enterobacteriaceae. High resistance was observed among the isolates (five ST25, three ST11, one ST45, and one ST505), which harbored 44 plasmids, most carrying genes for conjugation and resistance to several antibiotics and biocides. Ten plasmids encoding carbapenemases were characterized, including novel plasmids or variants with additional resistance genes, a novel genetic environment for blaKPC-2, and plasmids widely disseminated in South America. ST25 K2 isolates belonging to CG10224, a clone traced back to 2012 in Chile, which recently acquired blaNDM-1, blaNDM-7, or blaKPC-2 plasmids stood out as high-risk clones. Moreover, this corresponds to the first report of ST25 and ST45 Kp producing NDM-7 in South America and ST505 CR-Kp producing both NDM-7 and KPC-2 worldwide. Also, we characterized a variety of genomic islands carrying virulence and fitness factors. These results provide baseline knowledge for a detailed understanding of molecular and genetic determinants behind antibiotic resistance and virulence of CR-Kp in Chile and South America. IMPORTANCE In the ongoing antimicrobial resistance crisis, carbapenem-resistant strains of Klebsiella pneumoniae are critical threats to public health. Besides globally disseminated clones, the burden of local problem clones remains substantial. Although genomic analysis is a powerful tool for improving pathogen and antimicrobial resistance surveillance, it is still restricted in low- to middle-income countries, including Chile, causing them to be underrepresented in genomic databases and epidemiology surveys. This study provided the first 10 complete genomes of the Chilean surveillance for carbapenem-resistant K. pneumoniae in healthcare settings, unveiling their resistance and virulence determinants and the mobile genetic elements mediating their dissemination, placed in the South American and global K. pneumoniae epidemiological context. We found ST25 with K2 capsule as an emerging high-risk clone, along with other lineages producing two carbapenemases and several other resistance and virulence genes encoded in novel plasmids and genomic islands.

Markov-Based Neural Networks for Heart Sound Segmentation: Using Domain Knowledge in a Principled Way.

This work considers the problem of segmenting heart sounds into their fundamental components. We unify statistical and data-driven solutions by introducing Markov-based Neural Networks (MNNs), a hybrid end-to-end framework that exploits Markov models as statistical inductive biases for an Artificial Neural Network (ANN) discriminator. We show that an MNN leveraging a simple one-dimensional Convolutional ANN significantly outperforms two recent purely data-driven solutions for this task in two publicly available datasets: PhysioNet 2016 (Sensitivity: 0.947 ±0.02; Positive Predictive Value : 0.937 ±0.025) and the CirCor DigiScope 2022 (Sensitivity: 0.950 ±0.008; Positive Predictive Value: 0.943 ±0.012). We also propose a novel gradient-based unsupervised learning algorithm that effectively makes the MNN adaptive to unseen datum sampled from unknown distributions. We perform a cross dataset analysis and show that an MNN pre-trained in the CirCor DigiScope 2022 can benefit from an average improvement of 3.90% Positive Predictive Value on unseen observations from the PhysioNet 2016 dataset using this method.