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Generado por el Ministerio de Salud de la Nación Dirección Nacional de Epidemiología este boletín contiene información de actualización de encefalitis equina, dengue y arbovirus, enfermedades respiratorias agudas. Informe especial de síndrome urémico hemolítico. Alerta epidemiológicas internaciones y destacados de boletines jurisdiccionales.

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Shiga-toxin-producing Escherichia coli (STEC) is associated with diarrhea and hemolytic uremic syndrome (HUS). STEC infections in Costa Rica are rarely reported in children. We gathered all the records of STEC infections in children documented at the National Children's Hospital, a tertiary referral hospital, from 2015 to 2020. Clinical, microbiological, and genomic information were analyzed and summarized. A total of 3,768 diarrheal episodes were reviewed. Among them, 31 STEC were characterized (29 fecal, 1 urine, and 1 bloodstream infection). The prevalence of diarrheal disease due to STEC was estimated at 0.8% (n = 29/3,768), and HUS development was 6.4% (n = 2/31). The stx1 gene was found in 77% (n = 24/31) of STEC strains. In silico genomic predictions revealed a predominant prevalence of serotype O118/O152:H2, accompanied by a cluster exhibiting allele differences ranging from 33 to 8, using a core-genome multilocus sequence typing (cgMLST) approach. This is the first study using a genomic approach for STEC infections in Costa Rica.IMPORTANCEThis study provides a comprehensive description of clinical, microbiological, genomic, and demographic data from patients who attended the only pediatric hospital in Costa Rica with Shiga-toxin-producing Escherichia coli (STEC) infections. Despite the low prevalence of STEC infections, we found a predominant serotype O118/O152:H2, highlighting the pivotal role of genomics in understanding the epidemiology of public health threats such as STEC. Employing a genomic approach for this pathogen for the first time in Costa Rica, we identified a higher prevalence of STEC in children under 2 years old, especially those with gastrointestinal comorbidities, residing in densely populated regions. Limitations such as potential geographic bias and lack of strains due to direct molecular diagnostics are acknowledged, emphasizing the need for continued surveillance to uncover the true extent of circulating serotypes and potential outbreaks in Costa Rica.

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AIMS: Shiga toxin-producing Escherichia coli-haemolytic uraemic syndrome (STEC-HUS) is considered a toxaemic disorder in which early intervention with neutralizing antibodies may have therapeutic benefits. INM004, composed of F (ab')2 fragments from equine immunoglobulins, neutralizes Stx1/Stx2, potentially preventing the onset of HUS. METHODS: A single-centre, randomized, phase 1, single-blind, placebo-controlled clinical trial to evaluate INM004 safety, tolerance and pharmacokinetics (PK) in healthy adult volunteers, was conducted; in stage I, eight subjects were divided in two cohorts (n = 4) to receive a single INM004 dose of 2 or 4 mg kg-1, or placebo (INM004:placebo ratio of 3:1). In stage II, six subjects received three INM004 doses of 4 mg kg-1 repeated every 24 h, or placebo (INM004:placebo ratio of 5:1). RESULTS: Eight subjects (57.1%) experienced mild treatment-emergent adverse events (TEAEs); most frequent were rhinitis, headache and flushing, resolved within 24 h without changes in treatment or additional intervention. No serious AEs were reported. Peak concentrations of INM004 occurred within 2 h after infusion, with median Cmax values of 45.1 and 77.7 µg mL-1 for 2 and 4 mg kg-1, respectively. The serum concentration of INM004 declined in a biphasic manner (t1/2 range 30.7-52.9 h). Systemic exposures increased with each subsequent dose in a dose-proportional manner, exhibiting accumulation. Geometric median Cmax and AUC values were 149 and 10 300 µg h mL-1, respectively, in the repeated dose regimen. Additionally, samples from subjects that received INM004 at 2 mg kg-1 showed neutralizing capacity against Stx1 and Stx2 in in vitro assays. CONCLUSIONS: The results obtained in this first-in-human study support progression into the phase 2 trial in children with HUS.

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BACKGROUND: A substantial proportion of patients with Escherichia coli-hemolytic uremic syndrome (STEC-HUS) evolve to chronic kidney disease (CKD). The objectives of this study were to evaluate long-term kidney outcomes and to identify CKD predictors. METHODS: In this single-center retrospective study, long-term outcomes of patients were analyzed according to the presence of complete recovery (CR) or CKD at last visit. Then, they were grouped into favorable (CR + CKD1) or poor (CKD2-5) outcome to compare predictors at diagnosis (sex, age, leukocytes, creatinine, hemoglobin, HUS severity score), dialysis duration, and follow-up time between them. RESULTS: Of 281 patients followed up for a median of 12 years, 139 (49%) had CR, 104 (37%) CKD1, 27 (10%) CKD2-4, and 11 (4%) CKD5. Thirty-eight patients progressed to CKD2-5 after a median of 4.8 years, 7% in the first 5 years, increasing to 8%, 10%, and 14% after 5-10 years, 10-15 years, and > 15 years, respectively. They were younger, had higher baseline hemoglobin and leukocytes, and required longer dialysis and follow-up than those with favorable outcome. By multivariate analysis, days of dialysis and follow-up time remained as independent predictors of poor outcome. The best cutoff for days of dialysis was 10 days. After 5 years, 20% of those dialyzed ≥ 10 days evolved to CKD2-5 versus 1% of those non-dialyzed or dialyzed < 10 days. CONCLUSIONS: Fifty-one percent of patients evolved to CKD after 12 years of follow-up and 14% to CKD2-5. Ten days of dialysis was the best cutoff to recognize outcomes. In some cases, kidney damage was evident after 15 years of surveillance, highlighting the need for follow-up until adulthood in all STEC-HUS patients.

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In Argentina, hemolytic uremic syndrome (HUS) caused by EHEC has the highest incidence in the world. EHEC infection has an endemo-epidemic behavior, causing 20-30% of acute bloody diarrhea syndrome in children under 5 years old. In the period 2016-2020, 272 new cases per year were notified to the National Health Surveillance System. Multiple factors are responsible for HUS incidence in Argentina including person-to-person transmission. In order to detect possible EHEC carriers, we carried out a preliminary study of the frequency of kindergarten teachers with anti-LPS antibodies against the most prevalent EHEC serotypes in Argentina. We analyzed 61 kindergarten teachers from 26 institutions from José C. Paz district, located in the suburban area of Buenos Aires province, Argentina. Fifty-one percent of the plasma samples had antibodies against O157, O145, O121 and O103 LPS: 6.4% of the positive samples had IgM isotype (n=2), 61.3% IgG isotype (n=19) and 32.3% IgM and IgG (n=10). Given that antibodies against LPS antigens are usually short-lived specific IgM detection may indicate a recent infection. In addition, the high percentage of positive samples may indicate a frequent exposure to EHEC strains in the cohort studied, as well as the existence of a large non-symptomatic population of adults carrying pathogenic strains that could contribute to the endemic behavior through person-to-person transmission. The improvement of continuous educational programs in kindergarten institutions could be a mandatory measure to reduce HUS cases not only in Argentina but also globally.

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[RESUMEN]. El síndrome urémico hemolítico (SUH) es una entidad endémica en nuestro país y constituye la primera causa de insuficiencia renal aguda en la edad pediátrica y la segunda de insuficiencia renal crónica. Se define por la aparición simultánea de anemia hemolítica microangiopática, trombocitopenia y daño parenquimatoso renal. Las manifestaciones iniciales incluyen insuficiencia renal aguda, hipertensión arterial y sintomatología neurológica hasta en un 30% de los casos aproximadamente. Dentro de las manifestaciones del sistema nervioso central se encuentran las convulsiones, irritabilidad, letargo, encefalopatía y coma. (1,2) Realizamos un estudio descriptivo, retrospectivo a partir de la revisión de historias clínicas de 53 pacientes menores de 16 años de edad, con diagnóstico de SUH derivados al servicio de pediatría, tanto cuidados intermedios como UTIP del Hospital El Cruce en el periodo de tiempo de enero del 2010 hasta septiembre del 2023 con el objetivo de describir la tasa de afectación neurológica y evaluar secuelas a largo plazo. Conclusiones: De los 53 niños con diagnóstico de SUH, 14 presentaron manifestaciones a nivel del SNC, es decir un 26% del total. Las manifestaciones que prevalecieron fueron las convulsiones y el estatus convulsivo. 3 de 14 pacientes permanecieron con secuelas neurológicas, los 11 restantes presentaron recuperación completa (89%). Si bien la afectación neurológica es menos común que la afectación renal, sigue siendo una causa de mortalidad aguda y discapacidad a largo plazo entre los pacientes con SUH.

[ABSTRACT]. Hemolytic uremic syndrome is an endemic entity in our country which establishes the main cause of acute kidney failure in children. It also represents the second cause of chronic kidney failure. Its main clinical manifestations are microangiopathic hemolytic anemia, thrombocytopenia and kidney injury. Early clinical manifestations are characterized by hypertension, acute kidney failure and neurological involvement in up to 30% of children with HUS. Seizures, irritability, lethargy, encephalopathy, and coma are the most common central nervous system manifestations. (1,2) We identified 53 children under the age of 16, between January 2010 and September 2023 with a confirmed diagnosis of SUH at El Cruce hospital . Patients came from intermediate care or had PICU admission. Our objective was to describe the neurological involvement rate in HUS and long term sequels. Of the 53 patients with HUS, 14 had central nervous system manifestations, which represents 26% of children with the diagnosis. Most frequent manifestations included seizures and convulsive status. 3 of 14 patients remained with neurological sequels, the last 11 showed total recovery. Even though Neurological involvement is less common than renal injury, it still represents one of the causes of acute mortality and long term disability in patients with HUS.

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El síndrome hemolítico urémico secundario a Streptococcus pneumoniae (SHU-Sp) es una complicación poco frecuente de las enfermedades invasoras por S. pneumoniae. Presenta una alta morbimortalidad, con requerimiento de transfusiones de glóbulos rojos y plaquetas, terapia de sustitución de la función renal de inicio precoz y más prolongada, así como mayores complicaciones a largo plazo, comparado con las formas secundarias a infección entérica por Escherichia coli productora de toxina Shiga. Presentamos el caso clínico de una preescolar de dos años, previamente sana, vacunada con tres dosis de PCV13, que desarrolló una insuficiencia renal aguda, anemia hemolítica y plaquetopenia, en el contexto de una neumonía con empiema y bacteriemia por S. pneumoniae.

Streptococcus pneumoniae associated hemolytic uremic syndrome (Sp-HUS) is an uncommon complication of invasive pneumococcal infections. Patients with Sp-HUS have a higher mortality and long term morbidity than those due to HUS from Shiga toxin-producing Escherichia coli infections (STEC-HUS). They often require more red blood cells and platelet transfusions, and early initiation of renal substitution therapy, presenting a higher rate of arterial hypertension and chronic renal disease in the long term, compared to STEC-HUS. We report a healthy 2 year-old infant, vaccinated with three doses PCV13, that developed acute renal failure, hemolytic anemia and thrombocytopenia in the course of a complicated pneumococcal pneumonia with empyema and bacteremia.

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Shiga-toxin producing Escherichia coli (STEC) infections can cause from bloody diarrhea to Hemolytic Uremic Syndrome. The STEC intestinal infection triggers an inflammatory response that can facilitate the development of a systemic disease. We report here that neutrophils might contribute to this inflammatory response by secreting Interleukin 1 beta (IL-1ß). STEC stimulated neutrophils to release elevated levels of IL-1ß through a mechanism that involved the activation of caspase-1 driven by the NLRP3-inflammasome and neutrophil serine proteases (NSPs). Noteworthy, IL-1ß secretion was higher at lower multiplicities of infection. This secretory profile modulated by the bacteria:neutrophil ratio, was the consequence of a regulatory mechanism that reduced IL-1ß secretion the higher were the levels of activation of both caspase-1 and NSPs, and the production of NADPH oxidase-dependent reactive oxygen species. Finally, we also found that inhibition of NSPs significantly reduced STEC-triggered IL-1ß secretion without modulating the ability of neutrophils to kill the bacteria, suggesting NSPs might represent pharmacological targets to be evaluated to limit the STEC-induced intestinal inflammation.

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The aim of this study was to perform a quantitative microbial risk assessment (QMRA) of Shiga toxin-producing Escherichia coli hemolytic uremic syndrome (STEC-HUS) linked to the consumption of Kosher beef produced in Argentina and consumed in Israel in children under 14 years. A probabilistic risk assessment model was developed to characterize STEC prevalence and contamination levels in the beef supply chain (cattle primary production, cattle transport, processing and storage in the abattoir, for export and at retail, and home preparation and consumption). The model was implemented in Microsoft Excel 2016 with the @Risk add-on package. Results of 302 surveys with data collected in Israel were as follows: 92.3% of people consumed beef, mostly at home, and 98.2% preferred levels of cooking that ensured STEC removal from the surface of beef cuts. The preferred degree of ground beef doneness was "well-done" (48.2%). Cooking preference ranged from red to "medium-well done" (51.8%). Median HUS probability from Argentinean beef cut and ground beef consumption in children under 14 years old was <10-15 and 8.57x10-10, respectively. The expected average annual number of HUS cases and deaths due to beef cut and ground beef consumption was zero. Risk of infection and HUS probability correlated with salting effect on E. coli count, processing raw beef before vegetables, ways of storage and refrigeration temperature at home, joint consumption of salad and beef cuts, degree of beef doneness and cutting board washing with detergent after each use with beef and vegetables. The STEC-HUS risk in Israel from consumption of bovine beef produced in Argentina was negligible. The current QMRA results were similar to those of previous beef cut consumption QMRA in Argentina and lower than any of the QMRA performed worldwide in other STEC-HUS linked to ground beef consumption. This study confirms the importance of QMRA to estimate and manage the risk of STEC-HUS from beef consumption. The impact variables identified in the sensitivity analysis allowed us to optimize resources and time management, to focus on accurate actions and to avoid taking measures that would not have an impact on the risk of STEC-HUS.

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Introduction: Shiga-toxin (Stx) producing Escherichia coli (STEC) O157:H7 is the most frequent serotype associated with hemolytic uremic syndrome (HUS) after gastrointestinal infections. Protection against HUS secondary to STEC infections has been experimentally assayed through the generation of different vaccine formulations. With focus on patients, the strategies have been mainly oriented to inhibit production of Stx or its neutralization. However, few approaches have been intended to block gastrointestinal phase of this disease, which is considered the first step in the pathogenic cascade of HUS. The aim of this work was to assay H7 flagellin as a mucosal vaccine candidate to prevent the systemic complications secondary to E. coli O157:H7 infections. Materials and methods: The cellular and humoral immune response after H7 nasal immunization in mice were studied by the analysis of systemic and intestinal specific antibody production, as well as cytokine production and lymphocyte proliferation against H7 flagellin ex vivo. Results: Immunized mice developed a strong and specific anti-H7 IgG and IgA response, at systemic and mucosal level, as well as a cellular Th1/Th2/Th17 response. H7 induced activation of bone marrow derived dendritic cells in vitro and a significant delayed-type hypersensitivity (DTH) response in immunized mice. Most relevant, immunized mice were completely protected against the challenge with an E. coli O157:H7 virulent strain in vivo, and surviving mice presented high titres of anti-H7 and Stx antibodies. Discussion: These results suggest that immunization avoids HUS outcome and allows to elicit a specific immune response against other virulence factors.

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In Argentina, hemolytic uremic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli (STEC-HUS) infection is endemic, and reliable data about prevalence and risk factors have been available since 2000. However, information about STEC-associated bloody diarrhea (BD) is limited. A prospective study was performed during the period October 2018-June 2019 in seven tertiary-hospitals and 18 referral units from different regions, aiming to determine (i) the frequency of STEC-positive BD cases in 714 children aged 1-9 years of age and (ii) the rate of progression of bloody diarrhea to HUS. The number and regional distribution of STEC-HUS cases in the same hospitals and during the same period were also assessed. Twenty-nine (4.1%) of the BD patients were STEC-positive, as determined by the Shiga Toxin Quik Chek (STQC) test and/or the multiplex polymerase chain reaction (mPCR) assay. The highest frequencies were found in the Southern region (Neuquén, 8.7%; Bahía Blanca, 7.9%), in children between 12 and 23 month of age (8.8%), during summertime. Four (13.8%) cases progressed to HUS, three to nine days after diarrhea onset. Twenty-seven STEC-HUS in children under 5 years of age (77.8%) were enrolled, 51.9% were female; 44% were Stx-positive by STQC and all by mPCR. The most common serotypes were O157:H7 and O145:H28 and the prevalent genotypes, both among BD and HUS cases, were stx2a-only or -associated. Considering the endemic behavior of HUS and its high incidence, these data show that the rate of STEC-positive cases is low among BD patients. However, the early recognition of STEC-positive cases is important for patient monitoring and initiation of supportive treatment.

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ABSTRACT: Background : Mesenchymal stem cells (MSCs) can be activated by different bacterial toxins. Lipopolysaccharides and Shiga Toxin (Stx) are the main toxins necessary for hemolytic uremic syndrome development. The main etiological event in this disease is endothelial damage that causes glomerular destruction. Considering the repairing properties of MSC, we aimed to study the response of MSC derived from induced pluripotent stem cells (iPSC-MSC) to LPS and/or Stx and its effect on the restoration of injured endothelial cells. Methods : iPSC-MSC were treated with LPS and or/Stx for 24 h and secretion of cytokines, adhesion, and migration were measured in response to these toxins. In addition, conditioned media from treated iPSC-MSC were collected and used for proteomics analysis and evaluation of endothelial cell healing and tubulogenesis using human microvascular endothelial cells 1 as a source of endothelial cells. Results : The results obtained showed that LPS induced a proinflammatory profile on iPSC-MSC, whereas Stx effects were less evident, even though cells expressed the Gb 3 receptor. Moreover, LPS induced on iPSC-MSC an increment in migration and adhesion to a gelatin substrate. Addition of conditioned media of iPSC-MSC treated with LPS + Stx, decreased the capacity of human microvascular endothelial cells 1 to close a wound, and did not favor tubulogenesis. Proteomic analysis of iPSC-MSC treated with LPS and/or Stx revealed specific protein secretion patterns that support the functional results described. Conclusions : iPSC-MSC activated by LPS acquired a proinflammatory profile that induces migration and adhesion to extracellular matrix proteins but the addition of Stx did not activate any repair program to ameliorate endothelial damage, indicating that the use of iPSC-MSC to regenerate endothelial injury caused by LPS and/or Stx in hemolytic uremic syndrome could not be the best option to consider to regenerate a tissue injury.

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BACKGROUND: In Argentina, Hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli (STEC HUS), is the main cause of acute kidney injury and the second cause of end-stage renal disease (ESRD) in children. In recent decades, strategies have been implemented to reduce progression to ESRD, but it is not known whether the cumulative incidence of HUS requiring kidney transplantation (KTx) has decreased. We aimed to determine whether the cumulative incidence of STEC HUS in children undergoing KTx decreased and compared outcomes of HUS-related KTx vs. those related to other etiologies. METHODS: All patients who underwent KTx at our institution were evaluated. The cohort was divided into quintiles (Q), and we compared the cumulative incidence of HUS-related KTx vs KTx due to other etiologies. RESULTS: A total of 1000 consecutive KTx were included. The cumulative incidence of HUS-related KTx was 11%. HUS was the second cause of KTx in Q1: 17% (1988-1995); Q2: 13.5% (1996-2003); Q3: 11.5% (2004-2009) and third cause in Q4: 10% (2010-2015) and Q5: 3% (2016-2021). The cumulative incidence of HUS-related KTx decreased in Q4 and Q5 compared to Q1, Q2, and Q3 and the decline was even steeper when comparing Q4 to Q5 (p:0.019). There was no difference in graft survival in patients with HUS vs. congenital anomalies of kidney and urinary tract (CAKUT) but better than in those with focal segmental glomerulosclerosis (FSGS). CONCLUSIONS: In this cohort, the cumulative incidence of HUS-related KTx decreased, which may have been due to the implementation of nephroprotective strategies.

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El síndrome urémico hemolítico (SUH), descripto en 1955, se caracteriza por la tríada de anemia hemolítica no inmunomediada, trombocitopenia y lesión renal aguda. En su patogenia interviene la toxina Shiga, producida con mayor frecuencia por E. coli O157:H. Puede manifestarse a cualquier edad, aunque es infrecuente en adultos, y se desarrolla en forma esporádica o en brote. Se presenta con un cuadro de dolor abdominal, diarrea, fiebre y vómitos. Puede afectar el sistema nervioso central, pulmones, páncreas y corazón. En adultos, el síndrome evoluciona tras un período de incubación de 1 semana posterior a la diarrea y tiene alta morbimortalidad, a diferencia de los casos pediátricos. Presentamos el caso de una paciente adulta, que cursó internación por síndrome urémico hemolítico. (AU)

Hemolytic uremic syndrome (HUS), described in 1955, is characterized by the triad of non-immune mediated hemolytic anemia, thrombocytopenia, and acute kidney injury. Shiga toxin, produced most frequently by E coli O157:H, is involved in its pathogenesis. Hus can manifest at any age, although it is rare in adults and develops sporadically or in outbreaks. HUS presents with a picture of abdominal pain, diarrhea, fever and vomiting. It can affect the central nervous system, lungs, pancreas, and heart.In adults, the syndrome evolves after an incubation period of 1 week after diarrhea, with high morbidity and mortality, unlike pediatric cases.We present the case of an adult patient who was hospitalized for hemolytic uremic syndrome. (AU)

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Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen that causes gastroenteritis and Hemolytic Uremic Syndrome. Cattle are the main animal reservoir, excreting the bacteria in their feces and contaminating the environment. In addition, meat can be contaminated by releasing the intestinal content during slaughtering. Here, we evaluated the safety and immunogenicity of a vaccine candidate against STEC that was formulated with two chimeric proteins (Chi1 and Chi2), which contain epitopes of the OmpT, Cah and Hes proteins. Thirty pregnant cows in their third trimester of gestation were included and distributed into six groups (n = 5 per group): four groups were administered intramuscularly with three doses of the formulation containing 40 µg or 100 µg of each protein plus the Quil-A or Montanide™ Gel adjuvants, while two control groups were administered with placebos. No local or systemic adverse effects were observed during the study, and hematological parameters and values of blood biochemical indicators were similar among all groups. Furthermore, all vaccine formulations triggered systemic anti-Chi1/Chi2 IgG antibody levels that were significantly higher than the control groups. However, specific IgA levels were generally low and without significant differences among groups. Notably, anti-Chi1/Chi2 IgG antibody levels in the serum of newborn calves fed with colostrum from their immunized dams were significantly higher compared to newborn calves fed with colostrum from control cows, suggesting a passive immunization through colostrum. These results demonstrate that this vaccine is safe and immunogenic when applied to pregnant cows during the third trimester of gestation.

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BACKGROUND: Long-term kidney outcomes of non-dialyzed children with Shiga-toxin Escherichia Coli hemolytic uremic syndrome (STEC-HUS) have been scantily studied. Therefore, we aimed to evaluate kidney outcomes and prognostic markers in these patients. METHODS: Non-dialyzed STEC-HUS patients followed for at least 5 years were included. They were grouped and compared according to kidney status at last visit: complete recovery (CR) or chronic kidney disease (CKD). Predictors of CKD evaluated at diagnosis were sex, age, leukocytes, hematocrit, hemoglobin (Hb), and serum creatinine (sCr). Peak sCr and time of follow-up were also analyzed. RESULTS: A total of 122 patients (62 female, median age at diagnosis 1.6 years) with a median follow-up of 11.3 years were included. At last visit, 82 (67%) had CR, 36 (30%) had CKD stage 1, and 4 (3%) had stage 2. No patient developed CKD stage 3-5. Median time to CKD was 5 years (IQR 3.1-8.76 years). Of the 122 patients, 18% evolved to CKD in the first 5 years, increasing to 28% at 10 and 33% at 20 years of follow-up. Serum Cr at diagnosis and peak sCr were significantly higher in patients with CKD than in those with CR. CONCLUSIONS: One third of non-dialyzed STEC-HUS patients evolved to CKD after a median time of 5 years. However, CKD may appear even after 15 years of CR. Serum Cr was significantly higher among patients who evolved to CKD. These data reinforce that all non-dialyzed patients should be followed until adulthood. A higher resolution version of the Graphical abstract is available as Supplementary information.

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INTRODUCTION: A better understanding of hemolytic-uremic syndrome (HUS) pathophysiology significantly changed its treatment and prognosis. The aim of this study is to characterize the clinical features, severity, management, and outcomes of HUS patients. MATERIALS AND METHODS: Retrospective study of HUS patients admitted to a Pediatric Nephrology Unit between 1996 and 2020. Demographic and clinical data regarding etiology, severity, treatment strategies, and patient outcome were collected. RESULTS: Twenty-nine patients with HUS were admitted to our unit, but four were excluded. Median age at diagnosis was two years (2 months - 17 years). Clinical manifestations included diarrhea, vomiting, oliguria, hypertension, and fever. During the acute phase, 14 patients (56%) required renal replacement therapy. Infectious etiology was identified in seven patients (five Escherichia coli and two Streptococcus pneumoniae). Since 2015, 2/7 patients were diagnosed with complement pathway dysregulation HUS and there were no cases of infectious etiology detected. Six of these patients received eculizumab. The global median follow-up was 6.5 years [3 months-19.8 years]. One patient died, seven had chronic kidney disease, four of whom underwent kidney transplantation, one relapsed, and seven had no sequelae. CONCLUSION: These results reflect the lack of infectious outbreaks in Portugal and the improvement on etiological identification since genetic testing was introduced. The majority of patients developed sequels and mortality was similar to that of other countries. HUS patients should be managed in centers with intensive care and pediatric nephrology with capacity for diagnosis, etiological investigation, and adequate treatment. Long-term follow-up is essential.

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Shiga toxin 2 (Stx2) from enterohemorrhagic Escherichia coli (EHEC) produces hemorrhagic colitis, hemolytic uremic syndrome (HUS), and acute encephalopathy. The mortality rate in HUS increases significantly when the central nervous system (CNS) is involved. Besides, EHEC also releases lipopolysaccharide (LPS). Many reports have described cognitive dysfunctions in HUS patients, the hippocampus being one of the brain areas targeted by EHEC infection. In this context, a translational murine model of encephalopathy was employed to establish the deleterious effects of Stx2 and the contribution of LPS in the hippocampus. The purpose of this work is to elucidate the signaling pathways that may activate the inflammatory processes triggered by Stx2, which produces cognitive alterations at the level of the hippocampus. Results demonstrate that Stx2 produced depression-like behavior, pro-inflammatory cytokine release, and NF-kB activation independent of the ERK1/2 signaling pathway, while co-administration of Stx2 and LPS reduced memory index. On the other hand, LPS activated NF-kB dependent on ERK1/2 signaling pathway. Cotreatment of Stx2 with LPS aggravated the pathologic state, while dexamethasone treatment succeeded in preventing behavioral alterations. Our present work suggests that the use of drugs such as corticosteroids or NF-kB signaling inhibitors may serve as neuroprotectors from EHEC infection.

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BACKGROUND: Chronic kidney-related sequelae after STEC-HUS occur in 20-40% of patients. Hyperuricemia (HU) may cause acute and chronic toxicity involving the kidneys. We retrospectively assessed if there was an association between the presence of HU during the acute illness and that of kidney-related sequelae in children with STEC-HUS. METHODS: Children with STEC-HUS who had clinical and laboratory data at 2 years of follow-up were included in this case-control study. Univariate and multivariate analyses were performed between patients with (cases) or without (controls) kidney-related sequelae to identify factors associated with outcomes, including different measures of serum uric acid (sUA) (baseline level, peak, and duration of HU). HU was defined as sUA > 8 mg/dL. RESULTS: Of 86 patients included, 77.9% had HU. Patients with sequelae (n = 41) had a higher prevalence of HU (41/41 vs. 26/45, p < 0.01), higher baseline leukocyte count, serum creatinine (sCr), and sUA levels as well as lower sodium than controls. During hospitalization, cases also had higher sCr peak, sUA peak and duration of HU, requirement and duration of dialysis, extrarenal complications, and hypertension. By multivariate analysis, after adjusting for length of dialysis, only duration of HU (p = 0.0005; OR 1.7, 95% CI 1.27-2.36) remained as an independent predictor of sequelae, with a best cutoff of 5.5 days (AUC 0.95, specificity 80%, sensitivity 100%). CONCLUSIONS: The presence of HU is a common finding in children with STEC-HUS and its duration during the acute stage was associated with kidney-related sequelae, regardless of the duration of dialysis. A higher resolution version of the Graphical abstract is available as Supplementary Information.

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