Seropositivity to Shiga toxin 2 among Argentinian urban and rural residents. Association with sociodemographic and exposure factors.

BACKGROUND: Shiga toxin-producing Escherichia coli (STEC) are enteric pathogens that cause hemolytic-uremic syndrome (HUS). Ruminants, especially cattle, are their main reservoir. This study describes the seroepidemiology of STEC in rural and urban populations in Argentina, a country with a high HUS incidence. METHODS: A cross-sectional study was performed in patients without gastrointestinal symptoms. IgG antibodies against Stx2 were detected by western blotting. RESULTS: Anti-Stx2 antibodies were detected in 14.56% of serum samples, more frequently in rural (19.38%) than urban residents (12%). Seropositivity was associated with lower socioeconomic status (SES). Among the other variables considered, thawing homemade hamburgers before cooking them, and the lack of knowledge about HUS were also associated with seropositivity. A multivariate logistic regression analysis performed with the variables that were statistically significant showed that only the SES index remained significant. As SES was measured based on several variables, we further analyzed each one of them and found that the lack of a high education level was statistically associated with seropositivity. CONCLUSIONS: The present findings have implications for STEC prevention efforts, highlighting the importance of considering SES and risks factors linked to different SES levels when targeting consumer-level public health interventions.

Factors associated with sporadic verotoxigenic Escherichia coli infection in children with diarrhea from the Central Eastern Area of Argentina.

Verotoxigenic Escherichia coli (VTEC) are one of the most important emerging foodborne pathogens and the principal cause of hemolytic uremic syndrome (HUS). This entity has been recognized worldwide as a priority issue in the field of zoonoses and public health, and Argentina is the country with the highest incidence of HUS in children less than 5 years of age.The lack of specific treatment, combined with the high morbidity rate of VTEC infection, makes prevention the main tool for reducing the incidence of HUS. The current work aimed at assessing the factors associated with sporadic VTEC infection in children with acute diarrhea from the Central Eastern area of Argentina where the incidence rate of HUS in children under 5 is the highest worldwide. A univariate analysis was performed to identify potential factors associated with VTEC infection by calculating odds ratios (OR) with 95% confidence intervals (CI). Then, a multivariate logistic regression model was performed. Interaction and association between significant factors were checked. "Recent consumption of food prepared outside home" (OR: 2.4, 95% CI 1.05-5.7) and "recent vegetables consumption" (OR=0.4; 0.2-0.8) were identified as independent factors associated with VTEC infection. We believe that the data obtained from this study further the current knowledge about the epidemiology of VTEC infection in Argentina and could be considered when planning strategies for the prevention of the disease.

Anemia inflamatoria: fisiopatología, diagnóstico y tratamiento / Inflammatory anemia: phisiopathology, diagnosis and treatment / Anemia inflamatória: fisiopatologia, diagnóstico e tratamento

La anemia de la Inflamación (AI) es considerada la segunda causa más frecuente de anemia a nivel mundial después de la deficiencia de hierro. Se observa comúnmente en infecciones crónicas, tumores, traumas, y desórdenes inflamatorios. La AI es típicamente normocítica normocrómica usualmente moderada y se produce por una hipoferremia como resultado del secuestro de hierro en el sistema retículo endotelial, de la reducción de la eritropoyesis y de la inhibición de la absorción del hierro en intestino. La patogenia de la AI está mediada por citoquinas inflamatorias y hepcidina, péptido producido en el hígado, que regulan la homeostasis del hierro, actúan suprimiendo la eritropoyesis, y la vida media de los eritrocitos se encuentra ligeramente acortada. Los métodos diagnósticos de rutina que se describen en esta revisión pueden ser de utilidad, pero quedará un grupo de estados anémicos con alta sospecha de AI que no podrán ser fácilmente clasificados. Recientemente se han desarrollado inmunoensayos para determinar hepcidina y citoquinas inflamatorias que podrán colaborar, en un futuro, para un diagnóstico correcto. Existen actualmente modelos experimentales de AI en ratones, los cuales podrían ser útiles para evaluar diferentes tratamientos. En este sentido, los inhibidores de la hepcidina y diversos moduladores inflamatorios aparecen como terapias prometedoras.

Anemia da inflamação (AI) é considerada a segunda causa mais comum de anemia em todo o mundo após a deficiência de ferro. É geralmente observada em infecções crônicas, tumores, traumas e distúrbios inflamatórios. A AI é tipicamente normocítica normocrômica comumente moderada e ocorre por uma hipoferremia como resultado do sequestro de ferro no sistema retículo endotelial, da redução da eritropoiese e da inibição da absorção do ferro no intestino. A patogenia da AI é mediada por citocinas inflamatórias e hepcidina, peptídeo produzido no fígado, que regulam a homeostase do ferro, agem suprimindo a eritropoiese e a meia-vida dos eritrócitos é levemente diminuída. Os métodos de diagnóstico de rotina descritos nesta revisão podem ser úteis, mas ficará um grupo de estados anêmicos com alta suspeita de AI que não poderão ser classificados facilmente. Recentemente têm sido desenvolvidos imunoensaios para determinar hepcidina e citocinas inflamatórias, que poderão colaborar no futuro, para um diagnóstico certo. Existem atualmente modelos experimentais de AI em ratos que poderiam ser úteis para avaliar diferentes tratamentos. A este respeito, os inibidores de hepcidina e vários moduladores inflamatórios aparecem como terapias promissoras.

Role and clinical course of verotoxigenic Escherichia coli infections in childhood acute diarrhoea in Argentina.

The aim of this study was to investigate the role and clinical course of verotoxigenic Escherichia coli (VTEC) infections in children with acute diarrhoea from Argentina, the country with the highest worldwide incidence of haemolytic uraemic syndrome (HUS). To accomplish this objective, 437 samples from children up to 6 years old with acute diarrhoea were collected and processed. More than 60 % of the children studied presented watery or mucous diarrhoea without blood, and in 25.2 % of the cases the samples contained blood. In a first screening, a multiplex PCR was performed to detect the presence of the vt(1), vt(2), eae, ehxA and saa virulence genes. The strains were then isolated and analysed to characterize their serotypes, virulence genes, antibiotic susceptibility profiles and verotoxin (VT) production. Forty-four of the 437 samples (10.1 %) were positive for VTEC virulence genes. VTEC-infected patients presented different types of diarrhoea (27.3 % belonged to the non-bloody type). Several serotypes and virulence genotypes were found. Isolates belonged to the serotypes O157 : H7, O145 : H(-), O26 : H11, O121 : H19, O111 : H2 and O118 : H2. HUS developed in 16 (36.4 %) patients positive for VTEC virulence genes. All of the VTEC isolates produced a cytopathic effect on Vero cell monolayers, confirming the ability to express VT. Despite most strains being sensitive to all of the antimicrobials studied, a positive association between clinical progression to HUS and antibiotic therapy was observed for the total number of patients studied, as well as for the VTEC(+) group. In conclusion, the data obtained in this study increase our knowledge of the role and clinical course of VTEC infection in childhood acute diarrhoea beyond bloody diarrhoea, and might be considered for the prevention, diagnosis and management of this disease. It is possible that the optimal approach for VTEC diagnosis could be using multiplex PCR to search for the presence of the vt(1), vt(2), eae and ehxA genes.