Identification and analysis of seven effector protein families with different adaptive and evolutionary histories in plant-associated members of the Xanthomonadaceae.

The Xanthomonadaceae family consists of species of non-pathogenic and pathogenic γ-proteobacteria that infect different hosts, including humans and plants. In this study, we performed a comparative analysis using 69 fully sequenced genomes belonging to this family, with a focus on identifying proteins enriched in phytopathogens that could explain the lifestyle and the ability to infect plants. Using a computational approach, we identified seven phytopathogen-enriched protein families putatively secreted by type II secretory system: PheA (CM-sec), LipA/LesA, VirK, and four families involved in N-glycan degradation, NixE, NixF, NixL, and FucA1. In silico and phylogenetic analyses of these protein families revealed they all have orthologs in other phytopathogenic or symbiotic bacteria, and are involved in the modulation and evasion of the immune system. As a proof of concept, we performed a biochemical characterization of LipA from Xac306 and verified that the mutant strain lost most of its lipase and esterase activities and displayed reduced virulence in citrus. Since this study includes closely related organisms with distinct lifestyles and highlights proteins directly related to adaptation inside plant tissues, novel approaches might use these proteins as biotechnological targets for disease control, and contribute to our understanding of the coevolution of plant-associated bacteria

Mixed strain pathogen populations accelerate the evolution of antibiotic resistance in patients

Antibiotic resistance poses a global health threat, but the within-host drivers of resistance remain poorly understood. Pathogen populations are often assumed to be clonal within hosts, and resistance is thought to emerge due to selection for de novo variants. Here we show that mixed strain populations are common in the opportunistic pathogen P. aeruginosa. Crucially, resistance evolves rapidly in patients colonized by multiple strains through selection for pre-existing resistant strains. In contrast, resistance evolves sporadically in patients colonized by single strains due to selection for novel resistance mutations. However, strong trade-offs between resistance and growth rate occur in mixed strain populations, suggesting that within-host diversity can also drive the loss of resistance in the absence of antibiotic treatment. In summary, we show that the within-host diversity of pathogen populations plays a key role in shaping the emergence of resistance in response to treatment

Functional cooperativity between the trigger factor chaperone and the ClpXP proteolytic complex

A functional association is uncovered between the ribosome-associated trigger factor (TF) chaperone and the ClpXP degradation complex. Bioinformatic analyses demonstrate conservation of the close proximity of tig, the gene coding for TF, and genes coding for ClpXP, suggesting a functional interaction. The effect of TF on ClpXP-dependent degradation varies based on the nature of substrate. While degradation of some substrates are slowed down or are unaffected by TF, surprisingly, TF increases the degradation rate of a third class of substrates. These include λ phage replication protein λO, master regulator of stationary phase RpoS, and SsrA-tagged proteins. Globally, TF acts to enhance the degradation of about 2% of newly synthesized proteins. TF is found to interact through multiple sites with ClpX in a highly dynamic fashion to promote protein degradation. This chaperone–protease cooperation constitutes a unique and likely ancestral aspect of cellular protein homeostasis in which TF acts as an adaptor for ClpXP

Mixed strain pathogen populations accelerate the evolution of antibiotic resistance in patients

Antibiotic resistance poses a global health threat, but the within-host drivers of resistance remain poorly understood. Pathogen populations are often assumed to be clonal within hosts, and resistance is thought to emerge due to selection for de novo variants. Here we show that mixed strain populations are common in the opportunistic pathogen P. aeruginosa. Crucially, resistance evolves rapidly in patients colonized by multiple strains through selection for pre-existing resistant strains. In contrast, resistance evolves sporadically in patients colonized by single strains due to selection for novel resistance mutations. However, strong trade-offs between resistance and growth rate occur in mixed strain populations, suggesting that within-host diversity can also drive the loss of resistance in the absence of antibiotic treatment. In summary, we show that the within-host diversity of pathogen populations plays a key role in shaping the emergence of resistance in response to treatment

Guía de práctica clínica para el diagnóstico y tratamiento de la distrofia muscular de Duchenne. Sociedad Peruana de Neurología. Versión Corta

Objetivo: Elaborar una guía de práctica clínica peruana para el diagnóstico y tratamiento de la Distrofia Muscular de Duchenne y Becker (DMD). Materiales y métodos: Se conformó un grupo elaborador de la guía (GEG) que incluyó médicos especialistas en neurología, neuropediatría, genética y metodología. El GEG formuló ocho preguntas para desarrollar las recomendaciones de la Guía de Práctica Clínica (GPC). Se realizó una búsqueda sistemática en Medline, Scopus y CCRT durante el periodo enero-abril 2021 para responder a las preguntas PICO. La certeza de la evidencia fue evaluada usando la metodología Grading of Recommendations Assessment, Development, and Evaluation (GRADE).  Resultados: Las preguntas PICO, se orientaron para explorar el tamizaje, diagnóstico y tratamiento de la DMD. Se formularon 15 recomendaciones (10 fuertes, 5 condicionales) y 11 puntos de buena práctica clínica Conclusión: Se presenta la guía para el diagnóstico y tratamiento de la DMD, elaborada bajo una metodología basada en las evidencias actuales.

Clinical and Laboratory Features in Anti-NF155 Autoimmune Nodopathy

BACKGROUND AND OBJECTIVES: To study the clinical and laboratory features of antineurofascin-155 (NF155)-positive autoimmune nodopathy (AN). METHODS: Patients with anti-NF155 antibodies detected on routine immunologic testing were included. Clinical characteristics, treatment response, and functional scales (modified Rankin Scale [mRS] and Inflammatory Rasch-built Overall Disability Scale [I-RODS]) were retrospectively collected at baseline and at the follow-up. Autoantibody and neurofilament light (NfL) chain levels were analyzed at baseline and at the follow-up. RESULTS: Forty NF155+ patients with AN were included. Mean age at onset was 42.4 years. Patients presented with a progressive (75%), sensory motor (87.5%), and symmetric distal-predominant weakness in upper (97.2%) and lower extremities (94.5%), with tremor and ataxia (75%). Patients received a median of 3 (2-4) different treatments in 46 months of median follow-up. Response to IV immunoglobulin (86.8%) or steroids (72.2%) was poor in most patients, whereas 77.3% responded to rituximab. HLA-DRB1*15 was detected in 91.3% of patients. IgG4 anti-NF155 antibodies were predominant in all patients; anti-NF155 titers correlated with mRS within the same patient (r = 0.41, p = 0.004). Serum NfL (sNfL) levels were higher in anti-NF155+ AN than in healthy controls (36.47 vs 7.56 pg/mL, p < 0.001) and correlated with anti-NF155 titers (r = 0.43, p = 0.001), with I-RODS at baseline (r = -0.88, p < 0.001) and with maximum I-RODS achieved (r = -0.58, p = 0.01). Anti-NF155 titers and sNfL levels decreased in all rituximab-treated patients. DISCUSSION: Anti-NF155 AN presents a distinct clinical profile and good response to rituximab. Autoantibody titers and sNfL are useful to monitor disease status in these patients. The use of untagged-NF155 plasmids minimizes the detection of false anti-NF155+ cases. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that anti-NF155 antibodies associate with a specific phenotype and response to rituximab

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Within-Host Fine-Scale Evolutionary Dynamics of Infectious Bacterial Populations

Bacteria have a remarkable ability to adapt to numerous challenges in their environment and this evolutionary potential of bacterial pathogens has dire negative impact on human health. Understanding the fine-scale evolutionary dynamics of bacterial populations over the course of infections will help improve therapeutic strategies. In cystic fibrosis (CF) patients, lung infections caused by opportunistic pathogens such as Pseudomonas aeruginosa, Burkholderia multivorans, and Burkholderia dolosa are associated with high rates of mortality. In this thesis, I present a high-resolution view of the evolutionary dynamics of these three individual bacterial populations longitudinally sampled from CF patients. First, I analyzed the genomes of 233 P. aeruginosa isolates collected over the course of one year. This work revealed the expansion of two sub-lineages. I identified various mutations in these sub-lineages occurring in loci previously known to be associated with virulence and antibiotic resistance. Next, I investigated 111 B. multivorans isolates collected from a CF patient over the course of an early incident, chronic infection spanning one year, and after lung-transplantation. I employed a genome wide association study approach to find genetic variants associated with resistance to three antibiotic families. I observed that variants associated with resistance to β-lactam antibiotics were overrepresented in recombinogenic regions. Lastly, I examined whether the fine-scale evolutionary dynamics of B. dolosa, the most abundant bacteria in the lungs of the studied patient, was associated with shifts in the host’s clinical status from clinical stability to pulmonary exacerbation. Preliminary results do not suggest a correlation between the evolution of B. dolosa with the onset of a pulmonary exacerbation. Throughout these studies, I found unprecedented depth of genotypic diversity as these CF pathogens evolve in short time scales and strong signals of parallel evolution. Overall, this thesis reveals the power of deep, longitudinal sampling and the importance of using high-resolution approaches to study within-host evolution of bacterial pathogens as they undergo rapid, extensive changes that lower-resolution studies would not capture. This work provides an in-depth view of patient specific bacterial population dynamics, which is a step towards developing therapeutic strategies in which treatment may be tailored specifically to each CF patient.Ph.D

Assemblies for 'Mixed strain pathogen populations accelerate the evolution of antibiotic resistance in patients'

&lt;p&gt;Antibiotic resistance poses a global health threat, but the within-host drivers of resistance remain poorly understood. Pathogen populations are often assumed to be clonal within hosts, and resistance is thought to emerge due to selection for de novo variants. Here we show that mixed strain populations are common in the opportunistic pathogen &lt;i&gt;P. aeruginosa&lt;/i&gt;. Crucially, resistance evolves rapidly in patients colonized by multiple strains through selection for pre-existing resistant strains. In contrast, resistance evolves sporadically in patients colonized by single strains due to selection for novel resistance mutations. However, strong trade-offs between resistance and growth rate occur in mixed strain populations, suggesting that within-host diversity can also drive the loss of resistance in the absence of antibiotic treatment. In summary, we show that the within-host diversity of pathogen populations plays a key role in shaping the emergence of resistance in response to treatment.&lt;/p&gt

Primer acercamiento hacia la resolución de conflicto en la escuela, segundo ciclo de educación general básica

Tesis (Psicopedagogía)El problema de la violencia escolar, que se da dentro de la educación chilena, trasciende fronteras y tiempos, existe hace muchas décadas y se presenta en todos los países del mundo. La violencia dentro de las salas de clases produce efectos devastadores en el ambiente escolar especialmente en los miembros de aquella comunidad. Investigaciones propuestas por el (Programa Interdisciplinario de Investigaciones en Educación), PIIE (Mejoramiento de la Calidad de la Educación en Enseñanza Media) MECE media, (Instituto Nacional de la Juventud) INJUD, demuestran p eocupación por el caso, realizando estudios en el período que abarca la enseñanza media. Sin embargo, no se abarca aún el periodo escolar del segundo ciclo de Educación General Básica ( de quinto a octavo)