Ethnicity influences phenotype and clinical outcomes: Comparing a South American with a North American inflammatory bowel disease cohort.

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn disease (CD), has emerged as a global disease with an increasing incidence in developing and newly industrialized regions such as South America. This global rise offers the opportunity to explore the differences and similarities in disease presentation and outcomes across different genetic backgrounds and geographic locations. Our study includes 265 IBD patients. We performed an exploratory analysis of the databases of Chilean and North American IBD patients to compare the clinical phenotypes between the cohorts. We employed an unsupervised machine-learning approach using principal component analysis, uniform manifold approximation, and projection, among others, for each disease. Finally, we predicted the cohort (North American vs Chilean) using a random forest. Several unsupervised machine learning methods have separated the 2 main groups, supporting the differences between North American and Chilean patients with each disease. The variables that explained the loadings of the clinical metadata on the principal components were related to the therapies and disease extension/location at diagnosis. Our random forest models were trained for cohort classification based on clinical characteristics, obtaining high accuracy (0.86 = UC; 0.79 = CD). Similarly, variables related to therapy and disease extension/location had a high Gini index. Similarly, univariate analysis showed a later CD age at diagnosis in Chilean IBD patients (37 vs 24; P = .005). Our study suggests a clinical difference between North American and Chilean IBD patients: later CD age at diagnosis with a predominantly less aggressive phenotype (39% vs 54% B1) and more limited disease, despite fewer biological therapies being used in Chile for both diseases.

Altered Gut Microbiome Composition and Function Are Associated With Gut Barrier Dysfunction in Healthy Relatives of Patients With Crohn's Disease.

BACKGROUND & AIMS: The gut microbiome has been suggested to play a role in gut barrier hemostasis, but data are scarce and limited to animal studies. We therefore aimed to assess whether alterations in gut microbial composition and functional pathways are associated with gut barrier function in a cohort of healthy first-degree relatives of patients with Crohn's disease. METHODS: We used the Crohn's and Colitis Canada Genetic Environmental Microbial (CCC-GEM) cohort of healthy first-degree relatives of patients with Crohn's disease. Gut barrier function was assessed using the urinary fractional excretion of lactulose-to-mannitol ratio (LMR). Microbiome composition was assessed by sequencing fecal 16S ribosomal RNA. The cohort was divided into a discovery cohort (n = 2472) and a validation cohort (n = 655). A regression model was used to assess microbial associations with the LMR. A random forest classifier algorithm was performed to assess microbial community contribution to barrier function. RESULTS: Individuals with impaired barrier function (LMR >0.025) had reduced alpha-diversity (Chao1 index, P = 4.0e-4) and altered beta-diversity (Bray-Curtis dissimilarity index, R2 = 0.001, P = 1.0e-3) compared with individuals with an LMR ≤0.025. When taxa were assessed individually, we identified 8 genera and 52 microbial pathways associated with an LMR >0.025 (q < 0.05). Four genera (decreased prevalence of Adlercreutzia, Clostridia UCG 014, and Clostridium sensu stricto 1 and increased abundance of Colidextribacter) and 8 pathways (including decreased biosynthesis of glutamate, tryptophan, and threonine) were replicated in the validation cohort. The random forest approach revealed that the bacterial community is associated with gut barrier function (area under the curve, 0.63; P = 1.4e-6). CONCLUSIONS: The gut microbiome community and pathways are associated with changes in gut barrier function. These findings may identify potential microbial targets to modulate gut barrier.

Combined Histo-endoscopic Remission but not Endoscopic Healing Alone in Ulcerative Colitis is Associated with a Mucosal Transcriptional Profile Resembling Healthy Mucosa.

BACKGROUND AND AIMS: A composite endpoint of histological and endoscopic remission is proposed to be the most complete measure of mucosal healing in ulcerative colitis [UC]. We aim to establish the prognosis, and transcriptional and microbial features of histo-endoscopic remission and activity. METHODS: A cross-sectional endoscopic rectosigmoid colon sample collection from UC patients and healthy controls [HC] was performed for histopathology and host genome-wide RNA-sequencing. Histo-endoscopic remission and histo-endoscopic activity were defined as Mayo endoscopic subscore [MES] 0-1 with and without histological activity, respectively. UC relapse, defined as symptomatic and endoscopic worsening, was retrospectively recorded for survival analysis. Unsupervised and differential gene expression analyses were performed, and the interaction between transcriptomics and mucosal gut microbiota was analysed based on the 16S rRNA gene sequencing profile. RESULTS: UC patients with histo-endoscopic remission showed a significantly lower risk of relapse compared to histo-endoscopic activity. Unsupervised analysis of the transcriptomic profile showed that histo-endoscopic remission and histo-endoscopic activity samples clustered with HC and MES 2-3 samples, respectively. A total of 452 host genes enriched for humoral immune response, antimicrobial defence, chemokine and TH17 signalling pathway were upregulated in histo-endoscopic activity compared to histo-endoscopic remission. A set of host genes with antimicrobial properties showed significant associations with mucosal microbiota. CONCLUSIONS: The rectosigmoid mucosa transcriptional profile of UC patients in histo-endoscopic remission resembles that of HC mucosa and confers a lower risk of relapse. These data support that the combination of histo-endoscopic remission could be the most appropriate definition of mucosal healing in UC.

A Role for CXCR3 Ligands as Biomarkers of Post-Operative Crohn's Disease Recurrence.

BACKGROUND AND AIMS: Crohn's disease [CD] recurrence following ileocolic resection [ICR] is common. We sought to identify blood-based biomarkers associated with CD recurrence. METHODS: CD patients undergoing ICR were recruited across six centres. Serum samples were obtained at post-operative colonoscopy. A multiplex immunoassay was used to analyse 92 inflammation-related proteins [Olink Proteomics]. Bayesian analysis was used to identify proteins associated with increasing Rutgeerts score. Identified proteins were used in receiver operating characteristic [ROC] analysis to examine the ability to identify CD recurrence [Rutgeerts score ≥i2]. Existing single cell data were interrogated to further elucidate the role of the identified proteins. RESULTS: Data from 276 colonoscopies in 213 patients were available. Median time from surgery to first and second colonoscopy was 7 (interquartile range [IQR] 6-9) and 19 [IQR 16-23] months, respectively. Disease recurrence was evident at 60 [30%] first and 36 [49%] second colonoscopies. Of 14 proteins significantly associated with Rutgeerts score, the strongest signal was seen for CXCL9 and MMP1. Among patients on anti-tumour necrosis factor drugs, CXCL9 and CXCL11 were most strongly associated with Rutgeerts score. Both are CXCR3 ligands. Incorporation of identified proteins into ROC analysis improved the ability to identify disease recurrence as compared to C-reactive protein alone: area under the curve [AUC] 0.75 (95% confidence interval [CI]: 0.66-0.82] vs 0.64 [95% CI 0.56-0.72], p = 0.012. Single cell transcriptomic data provide evidence that innate immune cells are the primary source of the identified proteins. CONCLUSIONS: CXCR3 ligands are associated with CD recurrence following ICR. Incorporation of novel blood-based candidate biomarkers may aid in identification of CD recurrence.

Integrative Analysis of Colonic Biopsies from Inflammatory Bowel Disease Patients Identifies an Interaction Between Microbial Bile Acid-inducible Gene Abundance and Human Angiopoietin-like 4 Gene Expression.

BACKGROUND AND AIMS: Microbial-derived bile acids can modulate host gene expression, and their faecal abundance is decreased in active inflammatory bowel disease [IBD]. We analysed the impact of endoscopic inflammation on microbial genes involved in bile acid biotransformation, and their interaction with host transcriptome in the intestinal mucosa of IBD patients. METHODS: Endoscopic mucosal biopsies were collected from non-inflamed and inflamed terminal ileum, ascending and sigmoid colon of IBD patients. Prediction of imputed metagenome functional content from 16S rRNA profile and real-time quantitative polymerase chain reaction [qPCR] were utsed to assess microbial bile acid biotransformation gene abundance, and RNA-seq was used for host transcriptome analysis. Linear regression and partial Spearman correlation accounting for age, sex, and IBD type were used to assess the association between microbial genes, inflammation, and host transcriptomics in each biopsy location. A Bayesian network [BN] analysis was fitted to infer the direction of interactions between IBD traits and microbial and host genes. RESULTS: The inferred microbial gene pathway involved in secondary bile acid biosynthesis [ko00121 pathway] was depleted in inflamed terminal ileum of IBD patients compared with non-inflamed tissue. In non-inflamed sigmoid colon, the relative abundance of bile acid-inducible [baiCD] microbial genes was positively correlated with the host Angiopoietin-like 4 [Angptl4] gene expression. The BN analysis suggests that the microbial baiCD gene abundance could affect Angptl4 expression, and this interaction appears to be lost in the presence of inflammation. CONCLUSIONS: Endoscopic inflammation affects the abundance of crucial microbial bile acid-metabolising genes and their interaction with Angptl4 in intestinal mucosa of IBD patients.

JAK-STAT pathway targeting for the treatment of inflammatory bowel disease.

Cytokines are involved in intestinal homeostasis and pathological processes associated with inflammatory bowel disease (IBD). The biological effects of cytokines, including several involved in the pathology of Crohn's disease and ulcerative colitis, occur as a result of receptor-mediated signalling through the Janus kinase (JAK) and signal transducer and activator of transcription (STAT) DNA-binding families of proteins. Although therapies targeting cytokines have revolutionized IBD therapy, they have historically targeted individual cytokines, and an unmet medical need exists for patients who do not respond to or lose response to these treatments. Several small-molecule inhibitors of JAKs that have the potential to affect multiple pro-inflammatory cytokine-dependent pathways are in clinical development for the treatment of IBD, with one agent, tofacitinib, already approved for ulcerative colitis and several other agents with demonstrated efficacy in early phase trials. This Review describes the current understanding of JAK-STAT signalling in intestinal homeostasis and disease and the rationale for targeting this pathway as a treatment for IBD. The available evidence for the efficacy, safety and pharmacokinetics of JAK inhibitors in IBD as well as the potential approaches to optimize treatment with these agents, such as localized delivery or combination therapy, are also discussed.

Experiencia de educación continua en línea en gastroenterología para médicos no especialistas / Experience of continuing online education in gastroenterology for non specialist medical doctors

Background: Continuing education is essential for health professions and online courses can be a good way for professional development. Aim: To describe the experience with online courses for continuing education in hepatology and gastroenterology and to analyze their educational impact. Material and Methods: A three years' experience in courses on liver diseases and digestive tract is described. Their curricular design, methodology, and the educational impact was analyzed using the four levels of the Kirkpatrick's model. Results: On average, there were 321 students per course (2015-2017). 94% were Chilean and 6% from abroad (20 countries). In the educational impact analysis, in level 1 "reaction": 93% said that the course fulfilled their expectations and 92% would recommend it. In level 2 "learning": 42% approved the courses. Level 3 "behavior" was not evaluated and level 4 "organizational change" highlighted that the traditional face-to-face continuing education model of Chilean Gastroenterology Society (SChG) changed to full distance model in these three courses, with 1284 students from South America, Asia and Europe, in a 3-years-period. Additionally, these programs were included in the Medical Society of Santiago (SMS) continuing education agenda. Conclusions: The alliance between the SMS and the SChG generated on line courses that meet the educational needs of physicians and medical students, with excellent results and student perception.

[Practical clues for a fecal microbiota transplantation by colonoscopy for recurrent Clostridium difficile infection. Experience in a University center]. / Claves prácticas para un trasplante de microbiota fecal por colonoscopía en infección por Clostridium difficile recurrente. Experiencia en un centro universitario.

Fecal microbiota transplantation (FMT) is a highly effective therapy in recurrent Clostridium difficile. The best route to administrate the fecal matter has not been established yet. However, the lower gastrointestinal route by colonoscopy is effective and safe, presenting a higher acceptance by patients. In addition, this route allows an evaluation of colonic mucosa seeking for differential diagnostics. We present a case series of FMT performed in our institution by colonoscopy, highlighting outcomes and practical aspects for its implementation.

Claves prácticas para un trasplante de microbiota fecal por colonoscopía en infección por Clostridium difficile recurrente. Experiencia en un centro universitario / Practical clues for a fecal microbiota transplantation by colonoscopy for recurrent Clostridium difficile infection. Experience in a University center

Resumen El trasplante de microbiota fecal (TMF) constituye una terapia altamente eficaz en la infección por Clostridium difficile (ICD) recurrente. La mejor vía de administración del material fecal aún no ha sido establecida; sin embargo, la vía baja a través de colonoscopía resulta eficaz, segura y de mayor aceptación por los pacientes, permitiendo además el examen de la mucosa del colon en busca de diagnósticos diferenciales. Presentamos una serie de casos de TMF realizados en nuestra institución a través de colonoscopía, destacando los resultados y aspectos prácticos para su implementación.

Fecal microbiota transplantation (FMT) is a highly effective therapy in recurrent Clostridium difficile. The best route to administrate the fecal matter has not been established yet. However, the lower gastrointestinal route by colonoscopy is effective and safe, presenting a higher acceptance by patients. In addition, this route allows an evaluation of colonic mucosa seeking for differential diagnostics. We present a case series of FMT performed in our institution by colonoscopy, highlighting outcomes and practical aspects for its implementation.

Validation of the Simplified Criteria for the Diagnosis of Autoimmune Hepatitis in Chilean-Hispanic Patients.

INTRODUCTION AND AIM: In 2008 the International autoimmune hepatitis (AIH) Group proposed the simplified diagnostic criteria for this disease. The original cohort study was performed in 11 international centers, but validation studies are scarce in Latin-America. The aim of this study is validate these criteria in Hispanic patients. MATERIAL AND METHODS: A retrospective cohort of patients undergoing percutaneous liver biopsy and follow-up of at least 12 months was recruited from a Chilean University hospital. Patients with previous immunosuppressive therapy and liver transplant recipients were excluded. The diagnostic accuracy was analyzed using as gold standard the clinical course during long-term follow-up. Sensitivity, specificity, positive and negative predictive values (PPV and NPV) and area under the ROC curve (AUROC) were calculated. RESULTS: Four hundred eighty one patients were evaluated, 294 were included. 218 (74.15%) were female, mean age 48.5 (± 12.3) years, mean follow-up 34 (± 18) months. 66 patients had AIH or overlap syndrome (22.45%), 96 (32.65%) non-alcoholic steatohepatitis, 40 (13.61%) primary biliary cholangitis, 31 (10.54%) hepatitis C, 8 (2.72%) hepatitis B, 53 (18.02%) other etiologies. The AUROC for AIH simplified criteria was 0.976. Using a cutoff ≥ 6 and ≥ 7 points, the sensitivity was 86.4% and 54.6%; specificity, 98.7% and 99.6%; PPV, 95% and 97.3%; and NPV, 96.2% and 88.6%, respectively. CONCLUSION: Simplified criteria for the diagnosis of AIH have a high accuracy in our Chilean-Hispanic cohort. The female gender is strongly associated to AIH and could help in difficult cases. Further studies with a prospective design are necessary to confirm these observations.

Serum cytokeratin-18 fragment levels as noninvasive marker of nonalcoholic steatohepatitis in the chilean population. / Fragmento sérico de citoqueratina-18 como marcador no invasivo de esteatohepatitis no alcohólica en población chilena.

Nonalcoholic steatohepatitis (NASH) is the most aggressive form of nonalcoholic fatty liver disease (NAFLD) and involves the risk of progression to more advanced stages of liver disease. Non-invasive methods are needed to identify patients with NASH. OBJECTIVE: To evaluate the diagnostic performance of the determination of serum levels of cytokeratin-18 (CK-18) as a non-invasive marker of NASH in the Chilean population. METHODS: Serum CK-18 levels were determined in a group of 41 patients with biopsy-proven NAFLD. NASH diagnosis was based on Brunt's criteria (histological parameters and ballooning), and the NAFLD activity score (NAS) and the presence of fibrosis were determined. The correlation between the NAFLD activity score (NAS) and CK-18 was evaluated with Spearman's rank correlation coefficient. A ROC curve was produced to assess the diagnostic value of CK-18 for NASH. The NAFLD fibrosis score (NFS) (to predict fibrosis and NASH) was compared to CK-18 with simple linear regression. Data were expressed in median [25th-75th percentile] and evaluated with the Wilcoxon rank test. RESULTS: The mean age of the study group (23% male) was 50.4±11.1 years. 34.2% were diagnosed with NASH (NAS≥5). CK-18 levels were significantly higher in patients with NASH versus those without NASH (183.6 IU/l [97.4 to 734.4] vs. 117.2 IU/l [83.8 to 954.8], p= 0.016). CK-18 levels were a good predictor of NASH on biopsy with an area under the curve (AUC) of 0.732 (95% CI, 0.572 to 0.897). A CK-18 cut-off of 130.5 IU/l had a sensitivity of 92.9%, specificity of 63%, positive predictive value of 56.5% and negative predictive value of 94.4%, and was able to correctly classify 73.2% of patients with NASH. NFS identified advanced liver fibrosis (AUC 0.739, 95% CI, 0.56-0.91), but was of limited value to identify NASH (AUC 0.413, 95% CI, 0.21-0.61). CONCLUSION: CK-18 is a good non-invasive marker for NASH. Although NFS was found to be an accurate marker of advanced liver fibrosis, it was not of value to identify NASH. In patients with NAFLD, CK-18 and NFS could be useful in predicting NASH and liver fibrosis, respectively.

Diagnóstico y manejo de colitis ulcerosa grave: una mirada actualizada / Management of severe ulcerative colitis: an up-to-date

Ulcerative Colitis (UC) is a chronic inflammatory disease involving the colon, with alternating periods of remission and activity. Exacerbations can be severe and associated with complications and mortality. Diagnosis of severe UC is based on clinical, biochemical and endoscopic variables. Patients with severe UC must be hospitalized. First line therapy is the use of intravenous corticoids which achieve clinical remission in most patients. However, 25% of patients will be refractory to corticoids, situation that should be evaluated at the third day of therapy. In patients without response, cytomegalovirus infection must be quickly ruled out to escalate to second line therapy with biological drugs or cyclosporine. Total colectomy must not be delayed if there is no response to second line therapy, if there is a contraindication for second line therapies or there are complications such as: megacolon, perforation or massive bleeding. An active management with quick escalation on therapy allows to decrease the prolonged exposure to corticoids, reduce colectomy rates and its perioperative complications.

Consenso chileno de prevención, diagnóstico y tratamiento de la diarrea asociada a Clostridium difficile / Chilean consensus of prevention, diagnosis and treatment of Clostridium difficile-associated diarrhea

Background: Clostridium dijfficile-associated diarrhea (CDAD) has become very important due to the increase in its incidence, severity, recurrence and the associated economic burden. Having a national consensus guideline is essential to improve its management. Objective: To build a multidisciplinary and evidence-based consensus in prevention, diagnosis and treatment of CDAD. Methods: We convened a panel of experts in the field of infectious diseases, gastroenterology, evidence-based medicine and consensus methodology. The panel conducted a structured review of published literature in CDAD evaluating evidence levels and recommendation degree according to the methodology proposed by the GRADE working-group. A modified three-round Delphi technique was used to reach a consensus among the experts. Results: A group of 16 experts was established, 12 of them answered 18 clinically relevant questions. The levels of agreement achieved by the panel of 16 experts were 79% in the first round and 100% in the second and third round. The main consensus recommendations in prevention are: restricting the use of proton-pump inhibitors, primary prophylaxis with probiotics in antibiotics users, education of health personnel, isolation for patients hospitalized with CDAD, and cleaning the rooms exposed to C. difficile with products based in chlorine or hydrogen peroxide. In the diagnosis: use of biology molecular-based techniques is preferred and if not available, glutamate dehydrogenase-based algorithms may be recommended. With regard to treatment: the use of oral metronidazole in mild-moderate CDAD and oral vancomycin in severe CDAD are recommended. Treat the first recurrence with the same antibiotics according to severity. In the case of second and subsequent recurrences consider prolonged therapy with vancomycin, rifaximin or fecal microbiota transplant. Conclusion: The first Chilean consensus on prevention, diagnosis and treatment of CDAD is presented, which is a major step in improving national standards in the management of this disease.

Introducción: La diarrea asociada a Clostridium difficile (DACD) ha adquirido gran relevancia debido al aumento en su incidencia, gravedad, capacidad de recurrencia y carga económica asociada. Contar con una guía de consenso local es fundamental para mejorar su manejo. Objetivo: Elaborar un consenso multidisciplinara y basado en la evidencia en la prevención, diagnóstico y tratamiento de la DACD. Métodos: Se convocó a un panel de expertos en el área de enfermedades infecciosas, gastroenterología, medicina basada en la evidencia y metodología de consenso. El panel realizó una revisión estructurada de la literatura científica publicada en DACD evaluando el nivel de la evidencia y recomendación utilizando el sistema GRADE. Una técnica de Delfi modificada de tres rondas fue utilizada para alcanzar un consenso entre los expertos. Resultados: Se estableció un grupo de 16 expertos, 12 de ellos respondieron 18 preguntas de relevancia clínica. Los niveles de acuerdo alcanzados por el panel de 16 expertos fueron de 79% en la primera ronda y 100% en la segunda y tercera ronda. Las principales recomendaciones en prevención son: restricción del uso de inhibidores de la bomba de protones, profilaxis primaria con probióticos en usuarios de antimicrobianos de corto plazo, educación del personal de salud, aislamiento de contacto en pacientes hospitalizados con DACD y aseo de las habitaciones expuestas a C. difficile con productos en base a cloro o peróxido de hidrógeno. En el diagnóstico se recomienda: el uso de técnicas basadas en biología molecular y como alternativa algoritmos en base a glutamato deshidrogenasa. Con respecto al tratamiento, se recomienda el uso de metronidazol oral en DACD leve-moderada y vancomicina oral en DACD grave. El tratamiento de la primera recurrencia es con los mismos antimicrobianos de acuerdo a la gravedad, considerando en la segunda recurrencia y posteriores terapia prolongada con vancomicina, rifaximina o trasplante de microbiota fecal. Conclusión: Se presenta el primer consenso chileno en prevención, diagnóstico y tratamiento de DACD, paso trascendental en mejorar los estándares locales en el manejo de esta enfermedad.

Clostridium difficile: desde el metronidazol al trasplante fecal / Clostridium difficile: from metronidazole to fecal transplant

Clostridium difficile has become one of the main health care-associated infections. During the last decade increase in its incidence, recurrence, colectomy rate and mortality rate has made it necessary to establish the effectiveness of traditional therapies and has motivated the development of new therapies. New antibiotic treatments and alternative therapies have challenged management algorithms, especially in recurrent C. difficile infection. These include the fidaxomicin antibiotic which is selective against C. difficile and fecal microbiota transplantation. This review discussed therapies that are currently in use, their place in management algorithms and provides insight on developing therapies.

Clostridium difficile se ha convertido en una de las principales infecciones asociada a la atención de salud. El aumento en la última década de su incidencia, recurrencia, tasa de colectomía y mortalidad ha hecho necesario establecer la efectividad de las terapias tradicionalmente usadas y ha motivado el desarrollo de nuevas terapias. Nuevos tratamientos antibióticos, así como terapias alternativas a los antibióticos han desafiado los algoritmos de manejo, sobre todo en la infección por C. difficile recurrente. Entre éstos destacan el antibiótico fidaxomicina que es selectivo contra C. difficile y el trasplante de microbiota fecal. En esta revisión se analizan las terapias en uso actualmente, su lugar en los algoritmos de manejo y se dan luces sobre las terapias en desarrollo.

Rendimiento de índices pronósticos en infección asociada a Clostridium difficile grave: Análisis retrospectivo en un hospital universitario / Performance of prognostic index in severe Clostridium difficile-associated infection: Retrospective analysis in a university hospital

Introduction: By consensus severe, Clostridium difficile-associated infection (CDAI) is one that results in hospitalization in ICU, colectomy or death within 30 days. Multiple prognostic indices (IP) attempt to predict these adverse events. Objective: To evaluate the performance of 4 PI in predicting severe CDI. Methods: Hospitalized patients ≥ 18 years old with ICD were retrospectively evaluated. Patients with recurrent infection or hematological cancer were excluded. Four PI were evaluated: UPMC version 1, Calgary version 1, Hines VA and Calgary version 2. Results: Seven of 81 patients (8.1%) met the definition of severe CDI. Positive predicted value (PPV) and negative predicted value (NPV) of PI ranged from 20-75% and 91.3-95.7%, respectively. Only Hines VA index had a satisfactory Kappa index (0.74; 95% CI 0.41-1) with a PPV of 75% and NPV of 95,7%. However, because of the variables included, this PI could be calculated only in 32.6% of patients. Conclusion: Hines VA index has the best predicted value and agreement to rule out a severe CDI. Like others PI it has the limitation of including difficult variables to assess in all patients and tends to overestimate an unfavorable course.

Introducción: Por consenso, la infección asociada a Clostridium difficile (IACD) grave es aquella que resulta en hospitalización en unidad de cuidados intensivos, colectomía o muerte dentro de 30 días. Múltiples índices pronósticos (IP) intentan predecir estos eventos adversos. Objetivo: evaluar el rendimiento de cuatro IP en la predicción de IACD grave. Metodología: pacientes hospitalizados ≥ 18 años con IACD fueron evaluados retrospectivamente. Se excluyeron pacientes con infección recurrente o cáncer hematológico. Se evaluaron cuatro IP: UPMC versión 1, Calgary versión 1, Hines VA y Calgary versión 2. Resultados: Siete de 81 pacientes (8,1%) presentaron una IACD grave. El valor predictor positivo (VPP) y valor predictor negativo (VPN) de los IP varió entre 20-75% y 91,3-95,7%, respectivamente. Sólo el índice de Hines VA tuvo un índice Kappa satisfactorio (0,74;IC 95% 0,46-1) con un VPP de 75% y un VPN de 95,7%. Sin embargo, por las variables incluidas en este IP, sólo pudo ser calculado en 32,6% de los pacientes. Conclusión: El índice de Hines VA presenta el mejor valor predictor y concordancia para descartar una IACD grave. Como otros IP, tiene la limitación de incluir variables difícilmente evaluables en todos los pacientes y tiende a sobreestimar un curso desfavorable.

Esporas de Clostridium difficile y su relevancia en la persistencia y transmisión de la infección / Clostridium difficile spores and its relevance in the persistence and transmission of the infection

C. difficile is an anaerobic spore former pathogen and the most important etiologic agent of nosocomial and community acquired antibiotics associated diarrheas. C. difficile infections (CDI) are responsible for an elevated rate of morbidity in developed and developing countries. Although the major virulence factors responsible for clinical symptoms of CDI are the two toxins TcdA and TcdB, C. difficile spores are the main vehicle of infection, persistence and transmission of CDI. Recent work has unrevealed unique properties of C. difficile spores that make them remarkable morphotypes of persistence and transmission in the host, including their resistance to antibiotics, the host immune response and disinfectants. The present review summarizes relevant aspects of C. difficile spore biology that have major implications from a clinical and medical perspective.

Clostridium difficile es un patógeno anaerobio, formador de esporas y el agente etiológico más importante de las diarreas asociadas a antimicrobianos, tanto nosocomiales como adquiridas en la comunidad. Las infecciones asociadas a C. difficile poseen una elevada tasa de morbilidad en países desarrollados y en vías de desarrollo. Los dos factores de virulencia principales son TcdA y TcdB, toxinas que causan la remodelación del citoesqueleto lo cual desencadena los síntomas clínicos asociados a esta enfermedad infecciosa. A pesar que las esporas de C. difficile son el principal vehículo de infección, persistencia en el hospedero y de transmisión, pocos estudios se han enfocado sobre este clave aspecto. Es altamente probable que la espora juegue roles esenciales en los episodios de recurrencia y de transmisión horizontal de la infección por este microorganismo. Estudios recientes han revelado características únicas de las esporas de C. difficile que las hacen capaces de ser altamente transmisibles y persistir dentro del hospedero. Más aún, algunas de estas propiedades están relacionadas con la resistencia de sus esporas a los desinfectantes más comúnmente usados en los recintos hospitalarios. La presente revisión resume los conocimientos más relevantes en la biología de las esporas de C. difficile, con un énfasis en aquellos aspectos con implicancias clínicas, incluido el control de infecciones en el ambiente hospitalario.

[Performance of prognostic index in severe Clostridium difficile-associated infection: retrospective analysis in a university hospital]. / Rendimiento de índices pronósticos en infección asociada a Clostridium difficile grave: Análisis retrospectivo en un hospital universitario.

INTRODUCTION: By consensus severe, Clostridium difficile-associated infection (CDAI) is one that results in hospitalization in ICU, colectomy or death within 30 days. Multiple prognostic indices (IP) attempt to predict these adverse events. OBJECTIVE: To evaluate the performance of 4 PI in predicting severe CDI. METHODS: Hospitalized patients ≥ 18 years old with ICD were retrospectively evaluated. Patients with recurrent infection or hematological cancer were excluded. Four PI were evaluated: UPMC version 1, Calgary version 1, Hines VA and Calgary version 2. RESULTS: Seven of 81 patients (8.1%) met the definition of severe CDI. Positive predicted value (PPV) and negative predicted value (NPV) of PI ranged from 20-75% and 91.3-95.7%, respectively. Only Hines VA index had a satisfactory Kappa index (0.74; 95% CI 0.41-1) with a PPV of 75% and NPV of 95,7%. However, because of the variables included, this PI could be calculated only in 32.6% of patients. CONCLUSION: Hines VA index has the best predicted value and agreement to rule out a severe CDI. Like others PI it has the limitation of including difficult variables to assess in all patients and tends to overestimate an unfavorable course.

Validation study of systems for noninvasive diagnosis of fibrosis in nonalcoholic fatty liver disease in Latin population.

Background. The incidence of liver cirrhosis is significantly high in Latin population. The high prevalence of nonalcoholic fatty liver disease NAFLD is likely partially responsible for these figures. Liver biopsy is not a practical diagnostic option in this scenario. The validation of noninvasive markers of fibrosis is important in populations with a high prevalence of NAFLD. Aim. To compare the diagnostic value of noninvasive assessment systems to detect fibrosis in a cohort of Latin patients with biopsy-proven NAFLD. Material and methods. Patients with biopsy-proven NAFLD were included. Noninvasive evaluations included calculations of NAFLD fibrosis, FIB-4, BARD scores, APRI, and AST/ALT ratio. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver-operating characteristic curve (AUROC) were calculated. Results. A total of 228 patients (mean age, 48.6 ± 12.7 years) were included. Fifty-one percent were women; 48% were overweight and 23% were obese. The severity of fibrosis was classified as G0, 56.6%; G1, 25%; G2, 6.6%; G3, 7%; and G4, 4.8%. The AUROC values for advanced fibrosis were 0.72 for the NAFLD fibrosis score, 0.74 for FIB-4 score, 0.67 for AST/ALT ratio, 0.66 for APRI score, and 0.65 for BARD score. In 54% of patients with undetermined FIB-4 score and in 60% of patients with undetermined NAFLD fibrosis score, fibrosis was observed in the liver biopsy. Conclusions. The NAFLD fibrosis, FIB-4, and APRI scores can be used for the noninvasive diagnosis of fibrosis. However, 25% of patients evaluated by these methods have an indeterminate degree of fibrosis.

Prospective comparison of a commercial multiplex real-time polymerase chain reaction and an enzyme immunoassay with toxigenic culture in the diagnosis of Clostridium difficile-associated infections.

Clostridium difficile infections (CDI) is a leading cause of nosocomial infections worldwide. The changes in the epidemiology of CDI during the past years, including the appearance of new epidemic strains of C. difficile that cause CDI episodes with increased severity, have led to the development of molecular methods with improved sensitivity and specificity. This study was designed to compare the performances of one antigen assay (Vidas, bioMérieux) and one molecular assay (GeneXpert, Cepheid). Fecal specimens from hospitalized patients (n = 230) suspected of having CDI were tested by both assays. Eleven specimens were positive and 202 were negative for both methods. After discrepant analysis by C. difficile toxigenic culture with broth enrichment and neutralization assay, the total numbers of stool specimens classified as positive and negative for toxigenic C. difficile were 23 (10%) and 206 (89.6%), respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value for GeneXpert were 91.7%, 99%, 91.7%, and 99%, and for Vidas were 48%, 99%, 84.6%, and 94.5%, respectively. The sensitivity and PPV of polymerase chain reactoin GeneXpert assay far exceeded those of the EIA Vidas assay. The clinical characteristics of concordant and discrepant study patients were similar with the exception of the number of previous CDI episodes, which were higher in the concordant study patients; the clinical characteristics of both groups were similar. In conclusion, due to the appearance of more virulent strains of C. difficile during the last years that have produced dramatic changes in the epidemiology of C. difficile, we recommend that toxin enzyme immunoassays be replaced with rapid molecular-based tests for toxigenic C. difficile.