RESUMEN
Our understanding of the involvement of the gut microbiota (GM) in human health has expanded exponentially over the last few decades, particularly in the fields of metabolism, inflammation, and immunology. Immunosuppressive treatment (IST) prescribed to solid organ transplant (SOT) recipients produces GM changes that affect these different processes. This review aims at describing the current knowledge of how IST changes the GM. Overall, SOT followed by IST results in persistent changes in the GM, with a consistent increase in proteobacteria including opportunistic pathobionts. In mice, Tacrolimus induces dysbiosis and metabolic disorders, and alters the intestinal barrier. The transfer of the GM from Tacrolimus-treated hosts confers immunosuppressive properties, suggesting a contributory role for the GM in this drug's efficacy. Steroids induce dysbiosis and intestinal barrier alterations, and also seem to depend partly on the GM for their immunosuppressive and metabolic effects. Mycophenolate Mofetil, frequently responsible for digestive side effects such as diarrhea and colitis, is associated with pro-inflammatory dysbiosis and increased endotoxemia. Alemtuzumab, m-TOR inhibitors, and belatacept have shown more marginal impact on the GM. Most of these observations are descriptive. Future studies should explore the underlying mechanism of IST-induced dysbiosis in order to better understand their efficacy and safety characteristics.
Asunto(s)
Microbioma Gastrointestinal , Trasplante de Órganos , Animales , Disbiosis , Terapia de Inmunosupresión , Ratones , Trasplante de Órganos/efectos adversos , Tacrolimus/farmacologíaRESUMEN
The treatment of active antibody-mediated rejection (ABMR) is still a matter of debate, the place of rituximab remaining controversial. The French multicenter double-blind RITUX-ERAH study included 38 patients with ABMR in the first year of renal transplantation. All patients received plasma exchanges, intravenous immunoglobulins, and corticosteroids and were randomly assigned rituximab or placebo infusion at day 5. Additional rituximab infusions were allowed. In the intention-to-treat analysis, 12-month graft survival and renal function were not different between the rituximab and placebo groups. Long-term data are needed to conclude. Evaluation of the 7-year outcomes of the RITUX-ERAH study patients according to the rituximab or placebo treatment received. Eleven patients received placebo and 27 at least one infusion of rituximab. Seven years after ABMR, death-censored kidney allograft survival and renal function were not different between the groups. The evolution of anti-HLA sensitization was similar. There was no statistically significant difference in the incidence of infectious or neoplastic complications, but to be noted, seven cancers developed in six patients treated with rituximab (mean period of 44 months post-ABMR). In this cohort, there was no benefit 7 years after ABMR of rituximab in addition to plasma exchanges, intravenous immunoglobulins, and steroids.
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Trasplante de Riñón , Anticuerpos , Rechazo de Injerto/tratamiento farmacológico , Rechazo de Injerto/prevención & control , Supervivencia de Injerto , Humanos , Inmunosupresores , Rituximab/uso terapéuticoRESUMEN
We compared access to a kidney transplantation (KT) waiting list (WL) and to KT between people living with HIV (PLHIV) and HIV-uninfected controls. Using the REIN (the national Renal Epidemiology and Information Network registry), we included all PLHIV initiating dialysis in France throughout 2006-2010 and HIV-uninfected controls matched for age, sex, year of dialysis initiation, and the existence of a diabetic nephropathy. Patients were prospectively followed until December 2015. We used a competitive risk approach to assess the cumulative incidence of enrollment on WL and of KT, with death as a competing event (subdistribution hazard ratio adjusted on comorbidities, asdHR). There were 255 PLHIV in the REIN (median age 47 years) of whom 180 (71%) were also found in the French Hospital Database on HIV (FHDH-ANRS CO4) including 126 (70%) known to be on antiretroviral therapy with HIV viral suppression (VS). Five years after dialysis initiation, 65%, and 76%, of treated PLHIV with VS, and of HIV-uninfected controls were enrolled on a WL (asdHR 0.68; 95% CI 0.50-0.91). Access to KT was also less frequent and delayed for treated PLHIV with VS (asdHR 0.75, 95% CI, 0.52-1.10). PLHIV continue to face difficulties to access KT.
Asunto(s)
Acceso a la Información , Infecciones por VIH/complicaciones , Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Disparidades en Atención de Salud/estadística & datos numéricos , Trasplante de Riñón/estadística & datos numéricos , Diálisis Renal , Listas de Espera/mortalidad , Adulto , Estudios de Cohortes , Femenino , Estudios de Seguimiento , VIH/aislamiento & purificación , Accesibilidad a los Servicios de Salud/normas , Disparidades en Atención de Salud/normas , Humanos , Fallo Renal Crónico/cirugía , Masculino , Persona de Mediana Edad , Pronóstico , Sistema de Registros , Tasa de SupervivenciaRESUMEN
Gene expression is known to be the principle factor explaining how fast genes evolve. Highly transcribed genes evolve slowly because any negative impact caused by a particular mutation is magnified by protein abundance. However, gene expression is a phenotype that depends both on the environment and on the strains or species. We studied this phenotypic plasticity by analyzing the transcriptome profiles of four Escherichia coli strains grown in three different culture media, and explored how expression variability was linked to gene allelic diversity. Genes whose expression changed according to the media and not to the strains were less polymorphic than other genes. Genes for which transcription depended predominantly on the strain were more polymorphic than other genes and were involved in sensing and responding to environmental changes, with an overrepresentation of two-component system genes. Surprisingly, we found that the correlation between transcription and gene diversity was highly variable among growth conditions and could be used to quantify growth efficiency of a strain in a medium. Genetic variability was found to increase with gene expression in poor growth conditions. As such conditions are also characterized by down-regulation of all DNA repair systems, including transcription-coupled repair, we suggest that gene expression under stressful conditions may be mutagenic and thus leads to a variability in mutation rate among genes in the genome which contributes to the pattern of protein evolution.
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Adaptación Biológica/genética , Escherichia coli/crecimiento & desarrollo , Escherichia coli/genética , Reparación del ADN , Proteínas de Unión al ADN/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Evolución Molecular , Regulación Bacteriana de la Expresión Génica , Variación Genética , Mutagénesis , Mutación , Transcripción Genética , Activación TranscripcionalRESUMEN
BACKGROUND & AIMS: Risk for HCV/HBV infection is increased in end-stage renal disease patients. We generate updated epidemiological data. METHODS: Based on the National French registry for end-stage renal disease patients, we extracted data for patients who started dialysis or pre-emptive transplantation between January 2005 and December 2013. A positive serum HBs Ag and/or a positive HCV RNA defined HBV and HCV infections, respectively. RESULTS: In all, 72 948 patients were included among which 62.5% were men. At inclusion, 615 patients were HBV+ and 1026 HCV+. The prevalence of HBV and HCV infections were 0.84% (95% PI: 0.78-0.91) and 1.41% (95% PI: 1.32-1.49), respectively. The prevalence of HBV infection by age group increased progressively until a maximum rate at 1.80% (95% PI: 1.46-2.20) in the 4th decade, then regularly decreased. Same profile was observed for HCV prevalence, with a maximum rate at 3.14% (95% PI: 2.68-3.65) in the 4th decade. During the follow-up, we identified new HBV or HCV infections in 117 and 81 patients, respectively, with an overall incidence of 0.076% (95% PI: 0.062-0.090) and 0.053% (95%PI: 0.041-0.065) between 2005 and 2013, respectively. During the first dialysis year, HBV incidence was 0.35% (95% PI: 0.28-0.43) and that of HCV 0.21% (95% PI: 0.16-0.28). CONCLUSION: Our data highlight the need for HCV therapy for more than 1000 end-stage renal disease patients in France, sustained systematic immunization campaigns (HBV) and underlines the persistence of HBV/HCV new hand-borne nosocomial cases.
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Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis B/epidemiología , Anticuerpos contra la Hepatitis C/sangre , Hepatitis C/epidemiología , Fallo Renal Crónico/complicaciones , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Francia/epidemiología , Hepacivirus/genética , Humanos , Incidencia , Lactante , Recién Nacido , Fallo Renal Crónico/terapia , Fallo Renal Crónico/virología , Masculino , Persona de Mediana Edad , Sistema de Registros , Diálisis Renal/efectos adversos , Distribución por Sexo , Adulto JovenRESUMEN
The iron-regulatory peptide hepcidin exhibits antimicrobial activity. Having previously shown hepcidin expression in the kidney, we addressed its role in urinary tract infection (UTI), which remains largely unknown. Experimental UTI was induced in wild-type (WT) and hepcidin-knockout (Hepc-/-) mice using the uropathogenic Escherichia coli CFT073 strain. Compared with infected WT mice, infected Hepc-/- mice showed a dramatic increase in renal bacterial load. Moreover, bacterial invasion was significantly dampened by the pretreatment of WT mice with hepcidin. Infected Hepc-/- mice exhibited decreased iron accumulation in the renal medulla and significant attenuation of the renal inflammatory response. Notably, we demonstrated in vitro bacteriostatic activity of hepcidin against CFT073. Furthermore, CFT073 repressed renal hepcidin, both in vivo and in cultured renal cells, and reduced phosphorylation of SMAD kinase in vivo, suggesting a bacterial strategy to escape the antimicrobial activities of hepcidin. In conclusion, we provide new mechanisms by which hepcidin contributes to renal host defense and suggest that targeting hepcidin offers a strategy to prevent bacterial invasion.
Asunto(s)
Antiinfecciosos/farmacología , Infecciones por Escherichia coli/metabolismo , Escherichia coli/efectos de los fármacos , Hepcidinas/metabolismo , Hepcidinas/farmacología , Infecciones Urinarias/metabolismo , Animales , Antiinfecciosos/metabolismo , Carga Bacteriana/genética , Células Cultivadas , Recuento de Colonia Microbiana , Citocinas/metabolismo , Infecciones por Escherichia coli/microbiología , Femenino , Hepcidinas/genética , Hierro/metabolismo , Médula Renal/citología , Médula Renal/metabolismo , Médula Renal/microbiología , Ratones , Ratones Endogámicos CBA , Ratones Noqueados , Nefritis/metabolismo , Nefritis/microbiología , Nefritis/patología , Neutrófilos , Fosforilación , ARN Mensajero/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Proteínas Smad/metabolismo , Infecciones Urinarias/microbiologíaRESUMEN
Homologous recombination promotes genetic diversity by facilitating the integration of foreign DNA and intrachromosomal gene shuffling. It has been hypothesized that if recombination is variable among strains, selection should favor higher recombination rates among pathogens, as they face additional selection pressures from host defenses. To test this hypothesis we have developed a plasmid-based method for estimating the rate of recombination independently of other factors such as DNA transfer, selective processes, and mutational interference. Our results with 160 human commensal and extraintestinal pathogenic Escherichia coli (ExPEC) isolates show that the recombinant frequencies are extremely diverse (ranging 9 orders of magnitude) and plastic (they are profoundly affected by growth in urine, a condition commonly encountered by ExPEC). We find that the frequency of recombination is biased by strain lifestyle, as ExPEC isolates display strikingly higher recombination rates than their commensal counterparts. Furthermore, the presence of virulence factors is positively associated with higher recombination frequencies. These results suggest selection for high homologous recombination capacity, which may result in a higher evolvability for pathogens compared with commensals.
Asunto(s)
Escherichia coli/genética , Escherichia coli/patogenicidad , Recombinación Homóloga/genética , Intestinos/microbiología , Genes Bacterianos , Mutagénesis/genética , Tasa de Mutación , Virulencia/genéticaRESUMEN
BACKGROUND: Chronic kidney disease (CKD) is frequent in individuals infected with human immunodeficiency virus (HIV). Progression to end-stage renal disease can be slowed by appropriate medical management. METHODS: To assess whether active promotion of guidelines improves CKD management, we conducted a cluster randomized controlled trial within the French Hospital Database on HIV (FHDH-ANRS CO4). We randomized 46 centers participating in the FHDH to either simple information on guideline availability or active promotion with a multifaceted and repeated intervention comprising reminders and audit feedback and targeting of local opinion leaders carried out between April 2009 and April 2010. Outcome measure was CKD management adequacy assessed before and 2 years after the beginning of the intervention in HIV-infected patients with moderate to severe CKD. CKD management was considered adequate in case of referral to a nephrologist or if proteinuria, blood pressure, low-density lipoprotein cholesterol level, and glycemia had been measured during the previous year and medications had been prescribed when necessary. RESULTS: Three hundred six patients were enrolled, of whom 238 (78%) completed the 2 years of follow-up. During the study period, the percentage of patients receiving adequate CKD management improved from 64.1% to 70.4% (+6.3%) in the active arm and from 68.3% to 75.6% (+7.3%) in the control arm (adjusted mean difference, -0.7 percentage points [95% confidence interval: -9.2 to 7.9]; P = .95). The biggest impact of active promotion was on the management of proteinuria and blood pressure. CONCLUSIONS: Adequate compliance with CKD management guidelines improved slightly between 2009 and 2011, with no difference between the simple information and active promotion arms. CLINICAL TRIALS REGISTRATION: CCTIRS 10.150 and CNIL DR-2010-379.
Asunto(s)
Infecciones por VIH/complicaciones , Fallo Renal Crónico , Anciano , Femenino , Tasa de Filtración Glomerular , Infecciones por VIH/epidemiología , Humanos , Fallo Renal Crónico/complicaciones , Fallo Renal Crónico/epidemiología , Fallo Renal Crónico/terapia , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Resultado del TratamientoRESUMEN
BACKGROUND: Neoscytalidium species (formerly Scytalidium species) are black fungi that usually cause cutaneous infections mimicking dermatophytes lesions. Very few publications have reported invasive or disseminated infections. CASE PRESENTATION: In this paper, we report the clinical presentations, treatments and outcomes of five cases of invasive Neoscytalidium infections with cutaneous involvement, including two cases with disseminated infection, in five renal transplant recipients. To our knowledge, this is the first report of a series-albeit small-of renal transplant patients in whom this infection was identified. All cases occurred in a single hospital in Paris, France, between 2001 and 2011. Patients all originate from tropical area. CONCLUSION: Treatments of Neoscytalidium infection varied greatly, underlining the lack of a recommendation for a standardized treatment. All patients were cured after long-term antifungal therapy and/or surgical excision. Interestingly, one patient with disseminated infection involving the left elbow, the right leg, the lungs and the nasal septum was cured by medical therapy only without surgery. This may suggest that in contrast to others mycoses (such as mucormycosis), an adequate medical treatment could be sufficient for treating Neoscytalidium. We also point out the difficulties we had in diagnosing two patients with Kaposi's sarcoma because of the similarity of the lesions. Furthermore, our report underlines the need to check for this rare infection in immunocompromised kidney transplant recipients originating from tropical areas.
Asunto(s)
Ascomicetos , Trasplante de Riñón/efectos adversos , Feohifomicosis/etiología , Receptores de Trasplantes , Anciano , Ascomicetos/aislamiento & purificación , Ascomicetos/patogenicidad , Emigrantes e Inmigrantes , Femenino , Francia , Humanos , Huésped Inmunocomprometido , Masculino , Persona de Mediana Edad , Hongos Mitospóricos/aislamiento & purificación , Hongos Mitospóricos/patogenicidad , Feohifomicosis/tratamiento farmacológico , Feohifomicosis/patología , Sarcoma de Kaposi/diagnóstico , Clima TropicalRESUMEN
Tenofovir disoproxil fumarate (TDF), the first nucleotidic inhibitor of HIV reverse transcription, became available in 2001. It has been extensively used worldwide and is now the most prescribed antiretroviral (ARV) drug. Its high antiviral activity and favorable metabolic profile are responsible for its success. Furthermore, TDF has been associated with other ARVs to form new combined antiretroviral treatments in only one tablet once-a-day, which increases treatment adherence. Fears of potential nephrotoxicity that tenofovir would have in common with two other drugs from the same family (adefovir, used to treat hepatitis B, and cidofovir, used to treat cytomegalovirus infections) were alleviated by the early clinical trials. Yet, in 2001, the first case of TDF-induced acute nephrotoxicity was published. Numerous cases have been published since then, and it is now established that TDF presents a tubular toxicity risk. Some facilitating factors have been identified, such as co-prescription of didanosine or boosted protease inhibitor, preexisting CKD, low body weight, and associated diabetes mellitus. Conversely, whether TDF is nephrotoxic in the long term is a highly debated question. Some studies suggest a decreased GFR when TDF is prescribed for a long period, while others indicate that TDF is safe for the kidneys even after many years of use. Here we review the differences in patient characteristics, study designs, and measured outcomes that can possibly explain these conflicting findings. We conclude with rational recommendation for appropriate TDF prescription.
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Adenina/análogos & derivados , Antirreumáticos/efectos adversos , Infecciones por VIH/tratamiento farmacológico , Riñón/efectos de los fármacos , Ácidos Fosforosos/efectos adversos , Insuficiencia Renal/inducido químicamente , Adenina/efectos adversos , Ensayos Clínicos como Asunto , Humanos , Incidencia , Riñón/patología , Riñón/fisiopatología , Insuficiencia Renal/epidemiología , Insuficiencia Renal/patología , Insuficiencia Renal/fisiopatología , Factores de RiesgoRESUMEN
Urinary tract infections occur more frequently in diabetic patients than in the general population, with a relative risk ranging from 1.5 to 4, depending on the type of infection. The reasons underlying this higher susceptibility have not been established with certainty; urine glucose excression (which could facilitate bacterial urinary proliferation), immunodeficiency, a modified urothelium (resulting in a higher bacterial adhesion), and chronic neurologic bladder dysfunction have been advocated. Clinical presentation, bacterial epidemiology, and treatment of urinary tract infections in diabetic patients are similar to that of the general population. Accordingly, diabetes mellitus has recently been withdrawn from the list of criteria which define an urinary tract infection as complicated. Asymptomatic bacteriuria is particularly frequent in diabetic patients and should be checked routinely as it constitutes an important risk for subsequent symptomatic infection.
Asunto(s)
Bacteriuria/diagnóstico , Bacteriuria/etiología , Complicaciones de la Diabetes/microbiología , Pielonefritis/diagnóstico , Pielonefritis/etiología , HumanosRESUMEN
Objective: Data about efficacy and safety of the latest COVID-19 treatments as nirmatrelvir/ritonavir (n/r) or Sotrovimab is scarce in solid organ transplant recipients in the Omicron era. This study aims at describing the outcome of kidney transplant recipients (KTRs) presenting Omicron infection according to their management: n/r, sotrovimab or no specific treatment. Patients and methods: We conducted a monocentric, retrospective observational study, including KTRs diagnosed Omicron infection between January and May 1st 2022 and compared their outcome (primary outcome defined as hospital admission for COVID-19 within a month after symptoms onset) according to early COVID-19 management. Results: Forty-five patients were included: 22 treated (12 n/r, 10 sotrovimab) and 23 with no specific treatment. The groups were statistically comparable. Two patients were admitted for COVID-19: one in each group, resulting in a non-different probability of the primary outcome at on month (p=0.9). Three patients presented tacrolimus overdose including two with acute kidney injury. Conclusions: There was no difference in outcome according to early therapeutic management: n/r, sotrovimab or no specific treatment. Our study both underlines a decreased severity of Omicron COVID-19 in KTRs (probably related to vaccinal immunity and decreased virulence of Omicron) and a potential severe adverse effects with n/r.
Objectif: Les données sur l'efficacité et la sécurité des derniers traitements de la Covid-19 sont peu nombreuses à l'ère du variant Omicron. Cette étude avait pour objectif de décrire l'évolution des transplantés rénaux (TR) présentant une infection à Omicron selon le traitement précoce reçu : nirmatrelvir/ritonavir (n/r), sotrovimab, ou pas de traitement. Patients et méthodes: Il s'agissait d'une étude monocentrique rétrospective observationnelle incluant tous les TR présentant une infection confirmée à Omicron entre le 1er janvier 2022 et le 1er mai 2022 et comparant leur évolution (critère de jugement principal : admission hospitalière pour Covid-19 à un mois du début des symptômes) selon leur prise en charge. Résultats: Quarante-cinq patients ont été inclus : 22 traités (12 n/r et 10 sotrovimab) et 23 non traités. Les groupes étaient statistiquement comparables. Seulement deux patients ont présenté le critère de jugement principal : un n/r et un non traité, avec une probabilité à un mois non différente (p = 0,9). Trois patients sur 12 ont en revanche présenté des surdosages en tacrolimus dans le groupe n/r, dont deux avec une insuffisance rénale aiguë. Conclusions: Dans les limites d'un petit effectif, nous n'avons pas montré de bénéfice au traitement précoce par n/r ou sotrovimab. On peut évoquer un effet de l'immunité vaccinale et une baisse de virulence du SARS-CoV-2. En revanche, les effets secondaires du n/r ne sont pas anodins avec des surdosages sévères malgré des protocoles de service précis. La balance bénéfice-risque de ces traitements doit être rediscutée.
Asunto(s)
Lesión Renal Aguda , COVID-19 , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Trasplante de Riñón , Humanos , Hospitalización , Receptores de TrasplantesRESUMEN
OBJECTIVE: Anemia is common in critically ill patients, due to inflammation and blood loss. Anemia can be associated with iron deficiency and low serum hepcidin levels. However, iron administration in this setting remains controversial because of its potential toxicity, including oxidative stress induction and sepsis facilitation. The objective of this work was to determine the efficacy and toxicity of iron administration using a mouse model mimicking critical care anemia as well as a model of acute septicemia. DESIGN: Prospective, randomized, open label controlled animal study. SETTING: University-based research laboratory. SUBJECTS: C57BL/6 and OF1 mice. INTERVENTIONS: Intraperitoneal injection of zymosan inducing generalized inflammation in C57BL/6 mice, followed in our full model by repeated phlebotomies. A dose equivalent to 15 mg/kg of ferric carboxymaltose was injected intravenously on day 5. To assess the toxicity of iron in a septicemia model, OF1 mice were simultaneously injected with iron and different Escherichia coli strains. MEASUREMENTS AND MAIN RESULTS: To investigate the effect of iron on oxidative stress, we measured reactive oxygen species production in the blood using luminol-amplified chemiluminescence and superoxide dismutase 2 messenger RNA levels in the liver. These markers of oxidative stress were increased after iron administration in control mice but not in zymosan-treated mice. Liver catalase messenger RNA levels decreased in iron-treated control mice. Iron administration was not associated with increased mortality in the septicemia model or in the generalized inflammation model. Iron increased hemoglobin levels in mice fed with a low iron diet and subjected to phlebotomies and zymosan 2 wks after treatment administration. CONCLUSIONS: Adverse effects of intravenous iron supplementation by ferric carboxymaltose seem to be minimal in our animal models. Furthermore, iron appears to be effective in correcting anemia, despite inflammation. Studies of efficacy and safety of iron in critically ill patients are warranted.
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Anemia/tratamiento farmacológico , Compuestos Férricos/administración & dosificación , Compuestos Férricos/toxicidad , Hematínicos/administración & dosificación , Hematínicos/toxicidad , Maltosa/análogos & derivados , Animales , Péptidos Catiónicos Antimicrobianos/genética , Péptidos Catiónicos Antimicrobianos/metabolismo , Catalasa/genética , Catalasa/metabolismo , Dieta , Modelos Animales de Enfermedad , Hemoglobinas , Hepcidinas , Inflamación/inducido químicamente , Inyecciones Intravenosas , Hierro/administración & dosificación , Hierro/análisis , Hígado/química , Hígado/metabolismo , Luminiscencia , Maltosa/administración & dosificación , Maltosa/toxicidad , Ratones , Ratones Endogámicos C57BL , Flebotomía , ARN Mensajero/metabolismo , Distribución Aleatoria , Especies Reactivas de Oxígeno/sangre , Sepsis/tratamiento farmacológico , Bazo/química , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Oligoelementos/administración & dosificación , Zimosan/farmacologíaRESUMEN
The Escherichia coli species represents one of the best-studied model organisms, but also encompasses a variety of commensal and pathogenic strains that diversify by high rates of genetic change. We uniformly (re-) annotated the genomes of 20 commensal and pathogenic E. coli strains and one strain of E. fergusonii (the closest E. coli related species), including seven that we sequenced to completion. Within the approximately 18,000 families of orthologous genes, we found approximately 2,000 common to all strains. Although recombination rates are much higher than mutation rates, we show, both theoretically and using phylogenetic inference, that this does not obscure the phylogenetic signal, which places the B2 phylogenetic group and one group D strain at the basal position. Based on this phylogeny, we inferred past evolutionary events of gain and loss of genes, identifying functional classes under opposite selection pressures. We found an important adaptive role for metabolism diversification within group B2 and Shigella strains, but identified few or no extraintestinal virulence-specific genes, which could render difficult the development of a vaccine against extraintestinal infections. Genome flux in E. coli is confined to a small number of conserved positions in the chromosome, which most often are not associated with integrases or tRNA genes. Core genes flanking some of these regions show higher rates of recombination, suggesting that a gene, once acquired by a strain, spreads within the species by homologous recombination at the flanking genes. Finally, the genome's long-scale structure of recombination indicates lower recombination rates, but not higher mutation rates, at the terminus of replication. The ensuing effect of background selection and biased gene conversion may thus explain why this region is A+T-rich and shows high sequence divergence but low sequence polymorphism. Overall, despite a very high gene flow, genes co-exist in an organised genome.
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Escherichia coli/genética , Genoma Bacteriano , Elementos Transponibles de ADN , Evolución Molecular , Genética , Genoma , Genómica , Funciones de Verosimilitud , Modelos Biológicos , Modelos Genéticos , Filogenia , Polimorfismo Genético , Recombinación GenéticaRESUMEN
Introduction: SARS-CoV-2 pandemic evolved in 2 consecutive waves during 2020. Improvements in the management of COVID-19 led to a reduction in mortality rates among hospitalized patients during the second wave. Whether this progress benefited kidney transplant recipients (KTRs), a population particularly vulnerable to severe COVID-19, remained unclear. Methods: In France, 957 KTRs were hospitalized for COVID-19 in 2020 and their data were prospectively collected into the French Solid Organ Transplant (SOT) COVID registry. The presentation, management, and outcomes of the 359 KTRs diagnosed during the first wave were compared to those of the 598 of the second wave. Results: Baseline comorbidities were similar between KTRs of the 2 waves. Maintenance immunosuppression was reduced in most patients but withdrawal of antimetabolite (73.7% vs. 58.4%, P < 0.001) or calcineurin inhibitor (32.1% vs. 16.6%, P < 0.001) was less frequent during the second wave. Hydroxychloroquine and azithromycin that were commonly used during the first wave (21.7% and 30.9%, respectively) but were almost abandoned during the second wave. In contrast, the use of high dose corticosteroids doubled (19.5% vs. 41.6%, P < 0.001). Despite these changing trends in COVID-19 management, 60-day mortality was not statistically different between the 2 waves (25.3% vs. 23.9%; Log Rank, P = 0.48) and COVID-19 hospitalization period was not associated with death due to COVID-19 in multivariate analysis (Hazard ratio 0.89, 95% confidence interval 0.67-1.17, P = 0.4). Conclusion: We conclude that changing of therapeutic trends during 2020 did not reduce COVID-19 related mortality among KTRs. Our data indirectly support the importance of vaccination and neutralizing monoclonal anti-SARS-CoV-2 antibodies to protect KTRS from severe COVID-19.
RESUMEN
Finding two or more genotypes of a single species within an infected sample is a not infrequent event. In this work, three Escherichia coli strains of decreasing extra-intestinal virulence (pathogenic B2S and B1S strains, and the avirulent K-12 MG1655 strain) were tested in septicaemia and urinary tract infection (UTI) mouse models, either separately or in pairs. Survival was monitored and bacteria were counted in various organs. Serum interleukin (IL)-6, tumour necrosis factor alpha (TNFα) and IL-10 were measured. We show that a mix of high amounts of B1S or of MG1655 with low amounts of B2S killed more rapidly (B1S), or killed more mice (MG1655), than either high amounts of B1S, high amounts of MG1655 or low amounts of B2S separately in the mouse septicaemia model. This bacterial synergy persisted when high amounts of dead or abnormal-LPS K-12 cells were injected together with a low amount of B2S. In both septicaemia and UTI models, significantly more bacteria were recovered from the organs of mice injected with the MG1655/B2S mix than from those of mice injected with the inocula separately. Consistently, in the septicaemia model, more IL-6 was secreted before death by the mice that were injected with the mix of bacteria than by the mice that were injected with the inocula separately. The synergistically enhanced mortality in the case of co-infection in the septicaemia model persisted in RFcγ(-/-), Myd88(-/-) and IL-6(-/-) knockout mice. This synergistically increased virulence resulting from the interaction between an avirulent and a pathogenic strain of the same bacterial species raises questions about the role of avirulent bacteria in the development of some extra-intestinal infections.
Asunto(s)
Bacteriemia/mortalidad , Infecciones por Escherichia coli/mortalidad , Escherichia coli K12/fisiología , Escherichia coli/patogenicidad , Infecciones Urinarias/mortalidad , Animales , Bacteriemia/microbiología , Bacteriemia/patología , Modelos Animales de Enfermedad , Escherichia coli/clasificación , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/patología , Escherichia coli K12/genética , Escherichia coli K12/aislamiento & purificación , Femenino , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Especificidad de Órganos , Infecciones Urinarias/microbiología , Infecciones Urinarias/patología , VirulenciaRESUMEN
BACKGROUND: The impact of sarcopenia in patients undergoing simultaneous liver and kidney transplantation (SLKT) has not been fully delineated. The aim of this single-centre-cohort-study was to evaluate the impact of sarcopenia on the clinical outcomes. METHODS: Between 2003 and 2018, 79 patients underwent SLKT. Sarcopenia was assessed via the total psoas muscle area (TPA) at the level of the 3rd. lumbar vertebra. Sarcopenia threshold was TPAâ¯<â¯1460â¯mm2 (women) and <1560â¯mm2 (men). We identified post-operative biliary, vascular and digestive complications. Survival analysis was performed by the Kaplan Meier method (log-rank test). RESULTS: We included 43/79 SLKT recipients (56%male, median age of 58 [53-63] years). The prevalence of cirrhosis was 74% (nâ¯=â¯32) with median MELD-score of 21 (20-22) and that of polycystic-liver-disease was 26% (nâ¯=â¯11). End-stage-renal-disease of unknown origin was 36.2% (nâ¯=â¯12). Dialysis before transplantation was performed in 54,8% (nâ¯=â¯23) of patients. The median TPA was 1138 (926-1510)â¯mm2, and sarcopenia was detected in 72% of patients (nâ¯=â¯31). No difference in patient or death-censored graft-survival between sarcopenic and non-sarcopenic groups at 1 year was reported. Also, no differences at 6-months' post-transplant-complication-free and infection-free-survival rates were found. CONCLUSION: In this cohort of patients, no differences were observed in patients, grafts, complications or infection-free survival between sarcopenic or no sarcopenic SLKT patients. Future multi-centre studies are needed to validate and extend the generalisability of these findings.