Genotypic Characterization of Non-O157 Shiga Toxin–Producing Escherichia coli in Beef Abattoirs of Argentina

The non-O157 Shiga toxin-producing Escherichia coli (STEC) contamination in carcasses and feces of 811 bovines in nine beef abattoirs from Argentina was analyzed during a period of 17 months. The feces of 181 (22.3%) bovines were positive for non-O157 STEC, while 73 (9.0%) of the carcasses showed non-O157 STEC contamination. Non-O157 STEC strains isolated from feces (227) and carcasses (80) were characterized. The main serotypes identified were O178:H19, O8:H19, O130:H11, and O113:H21, all of which have produced sporadic cases of hemolytic-uremic syndrome in Argentina and worldwide. Twenty-two (7.2%) strains carried a fully virulent stx/eae/ehxA genotype. Among them, strains of serotypes O103:[H2], O145:NM, and O111:NM represented 4.8% of the isolates. XbaI pulsed-field gel electrophoresis pattern analysis showed 234 different patterns, with 76 strains grouped in 30 clusters. Nine of the clusters grouped strains isolated from feces and from carcasses of the same or different bovines in a lot, while three clusters were comprised of strains distributed in more than one abattoir. Patterns AREXSX01.0157, AREXBX01.0015, and AREXPX01.0013 were identified as 100% compatible with the patterns of one strain isolated from a hemolytic-uremic syndrome case and two strains previously isolated from beef medallions, included in the Argentine PulseNet Database. In this survey, 4.8% (39 of 811) of the bovine carcasses appeared to be contaminated with non- O157 STEC strains potentially capable of producing sporadic human disease, and a lower proportion (0.25%) with strains able to produce outbreaks of severe disease.Fil: Masana, Marcelo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: D´Astek, B. A.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Palladino, Pablo Martín. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Galli, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: del Castillo, Lourdes Leonor. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; ArgentinaFil: Carbonari, Claudia Carolina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Leotta, Gerardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Vilacoba, Elisabet. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Irino, K.. Instituto Adolfo Lutz. Seção de Bacteriologia; BrasilFil: Rivas, M.. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; Argentin

Whole-Genome Sequencing Applied to the Molecular Epidemiology of Shiga Toxin-Producing Escherichia coli O157:H7 in Argentina

Shiga toxin-producing Escherichia coli strains are worldwide associated with sporadic human infections and outbreaks. In this work, we report the availability of high-quality draft whole-genome sequences for 19 O157:H7 strains isolated in Argentina.Fil: Masana, Marcelo Oscar. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; Argentina.Fil: Carbonari, Claudia Carolina. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Fittipaldi, Nahuel. Public Health Ontario. Toronto Laboratories; Canada. University of Toronto. Department of Laboratory Medicine and Pathobiology; Canada.Fil: Teatero, Sarah. Public Health Ontario. Toronto Laboratories; Canada.Fil: Athey, Taryn B. T. Public Health Ontario. Toronto Laboratories; Canada.Fil: Pianciola, Luis. Subsecretaría de Salud de Neuquén. Laboratorio Central; Argentina.Fil: Melano, Roberto G. Public Health Ontario. Toronto Laboratories; Canada. University of Toronto. Department of Laboratory Medicine and Pathobiology; Canada.Fil: Rivas, Marta. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Chinen, Isabel. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina

Whole genome sequencing identifies independent outbreaks of Shigellosis in 2010 and 2011 in La Pampa Province, Argentina

AbstractShigella sonnei is an emergent cause of diarrheal disease in middle-income countries. The organism causes endemic disease and is also associated with sporadic outbreaks in susceptible populations. In 2010 and 2011 there were two suspected outbreaks of diarrheal disease caused by S. sonnei in La Pampa province in central Argentina. Aiming to confirm these as outbreaks and provide insight into the relationship of the strains causing these infections we combined antimicrobial susceptibility testing and pulsed field gel electrophoresis (PFGE) with whole genome sequencing (WGS). Antimicrobial susceptibility testing suggested the two events were unrelated; organisms isolated in 2010 exhibited resistance to trimethoprim sulphate whereas the 2011 S. sonnei were non-susceptible against ampicillin, trimethoprim sulphate and cefpodoxime. PFGE profiling confirmed the likelihood of two independent outbreaks, separating the isolates into two main XbaI restriction profiles. We additionally performed WGS on 17 isolates associated with these outbreaks. The resulting phylogeny confirmed the PFGE structure and separated the organisms into two comparatively distantly related clones. Antimicrobial resistant genes were common, and the presence of an OXA-1 was likely associated with resistance to cefpodoxime in the second outbreak. We additionally identified novel horizontally transferred genetic material that may impinge on the pathogenic phenotype of the infecting strains. Our study shows that even with a lack of supporting routine data WGS is an indispensible method for the tracking and surveillance of bacterial pathogens during outbreaks and is becoming a vital tool for the monitoring of antimicrobial resistant strains of S. sonnei.</jats:p

VIII Encuentro de Docentes e Investigadores en Historia del Diseño, la Arquitectura y la Ciudad

Acta de congresoLa conmemoración de los cien años de la Reforma Universitaria de 1918 se presentó como una ocasión propicia para debatir el rol de la historia, la teoría y la crítica en la formación y en la práctica profesional de diseñadores, arquitectos y urbanistas. En ese marco el VIII Encuentro de Docentes e Investigadores en Historia del Diseño, la Arquitectura y la Ciudad constituyó un espacio de intercambio y reflexión cuya realización ha sido posible gracias a la colaboración entre Facultades de Arquitectura, Urbanismo y Diseño de la Universidad Nacional y la Facultad de Arquitectura de la Universidad Católica de Córdoba, contando además con la activa participación de mayoría de las Facultades, Centros e Institutos de Historia de la Arquitectura del país y la región. Orientado en su convocatoria tanto a docentes como a estudiantes de Arquitectura y Diseño Industrial de todos los niveles de la FAUD-UNC promovió el debate de ideas a partir de experiencias concretas en instancias tales como mesas temáticas de carácter interdisciplinario, que adoptaron la modalidad de presentación de ponencias, entre otras actividades. En el ámbito de VIII Encuentro, desarrollado en la sede Ciudad Universitaria de Córdoba, se desplegaron numerosas posiciones sobre la enseñanza, la investigación y la formación en historia, teoría y crítica del diseño, la arquitectura y la ciudad; sumándose el aporte realizado a través de sus respectivas conferencias de Ana Clarisa Agüero, Bibiana Cicutti, Fernando Aliata y Alberto Petrina. El conjunto de ponencias que se publican en este Repositorio de la UNC son el resultado de dos intensas jornadas de exposiciones, cuyos contenidos han posibilitado actualizar viejos dilemas y promover nuevos debates. El evento recibió el apoyo de las autoridades de la FAUD-UNC, en especial de la Secretaría de Investigación y de la Biblioteca de nuestra casa, como así también de la Facultad de Arquitectura de la UCC; va para todos ellos un especial agradecimiento

The Importance of Shiga Toxin-Producing Escherichia coli O145:NM[H28]/H28 Infections in Argentina, 1998&ndash;2020

Shiga toxin-producing Escherichia coli (STEC) is known as a pathogen associated with food-borne diseases. The STEC O145 serogroup has been related with acute watery diarrhea, bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Argentina has the highest rate of HUS worldwide with 70% of the cases associated with STEC infections. We aimed to describe the epidemiology and genetic diversity of STEC O145 strains isolated across Argentina between 1998&ndash;2020. The strains isolated from 543 cases of human disease and four cattle, were pheno-genotipically characterized. Sequencing of five strains was performed. The strains were serotyped as O145:NM[H28]/H28, O145:H25, and O145:HNT, and mainly characterized as O145:NM[H28]/stx2a/eae/ehxA (98.1%). The results obtained by sequencing were consistent with those obtained by traditional methods and additional genes involved in different mechanisms of the pathogen were observed. In this study, we confirmed that STEC O145 strains are the second serogroup after O157 and represent 20.3% of HUS cases in Argentina. The frequency of STEC O145 and other significant serogroups is of utmost importance for public health in the country. This study encourages the improvement of the surveillance system to prevent severe cases of human disease

Non-O157:H7 Shiga Toxin Producing Escherichia coli in Bovine Rectums and Surface Water Streams on a Beef Cattle Farm in Argentina

The purposes of this study were to detect non-O157 Shiga toxin-producing Escherichia coli (STEC) in bovine rectums and water in a beef cattle farm in Argentina, and to determine the pathogenic potential of the circulating strains. During the study, 292 rectal swabs from healthy animals and 79 environmental water samples were collected. The rectal swabs and one loop of the Moore swabs, enriched in Escherichia coli broth for 24 h at 37°C, were streaked on MacConkey agar plates and incubated overnight at 37°C. The isolates were characterized by biochemical tests and serotyped. Nonmotile STEC strains were typed for their H-specific (fliC) antigens by polymerase chain reaction (PCR). Isolates were characterized by detection of stx1, stx2, and their variants, eae, ehxA, and saa genes. Macrorestriction fragment analysis by pulsed-field gel electrophoresis (PFGE) was performed using the PulseNet standardized protocol. From 371 samples analyzed, 36.6% of rectal swabs and 34.2% of water samples were non-O157 STEC-positive by PCR, and 110 strains from rectal swabs, but only three from water, were isolated. The strains were grouped into 24 different serotypes, from which, O103:[H2] (n = 12), O136:H12 (n = 8), O178:H19 (n = 8), and O103:NM (n = 5) were most prevalent, representing 29.2% of the isolates. Predominant genotypes were stx1/eae/ehxA (16.8%) and stx2/saa/ehxA (15.9%). PFGE analysis revealed 56 different patterns, with 65 strains grouped in 19 clusters of 100% similarity. Two STEC O124:H19 strains isolated from rectal swabs and water with a 5-month interval harbored the stx1/stx2/saa/ehxA genotype, and showed an indistinguishable PFGE profile. By comparison, some XbaI-PFGE patterns identified in the present study were identical to the profiles of strains isolated from human, food, and animal sources included in the Argentine PulseNet database. By PCR, similar non-O157 detection rates were found in rectal swabs and water. However, the methodology for water samples needs to be improved, since only three strains from the total number of positive samples were recovered.Fil: Tanaro, José Daniel. Universidad Nacional de Entre Ríos. Facultad de Bromatología; ArgentinaFil: Galli, Lucía. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Lound, Liliana Haydee. Universidad Nacional de Entre Ríos. Facultad de Bromatología; ArgentinaFil: Leotta, Gerardo Anibal. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Piaggio, Mercedes Carolina. Universidad Nacional de Entre Ríos. Facultad de Bromatología; ArgentinaFil: Carbonari, Claudia Carolina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; ArgentinaFil: Kinue, Irino. Escola Nacional de Saude Publica Sergio Arouca; BrasilFil: Rivas, Marta. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; Argentin

Whole-Genome Sequencing Applied to the Molecular Epidemiology of Shiga Toxin-Producing Escherichia coli

Shiga toxin-producing Escherichia coli strains are worldwide associated with sporadic human infections and outbreaks. In this work, we report the availability of high-quality draft whole-genome sequences for 19 O157:H7 strains isolated in Argentina

Frequency, characterization and genotypic analysis of Shiga toxin-producing Escherichia coli in beef slaughterhouses of Argentina = Frecuencia, caracterización y análisis genotípico de Escherichia coli productor de toxina Shiga en frigoríficos de carne bovina de Argentina

The objectives of this study were: (1) to estimate STEC frequency in hide and carcass samples taken from beef slaughterhouses supplying the domestic market in Argentina, (2) to establish the pheno-genotypic characteristics of STEC and non-toxigenic Escherichia coli of serogroups O26, O45, O103, O121, O111, O145 or O157 isolated from the analyzed samples and, (3) to study their clonal relatedness. Sixty hides and 60 carcasses were analyzed. At the screening step, 48% of hide and 80% of carcass samples tested positive for the stx gene by endpoint PCR. The STEC isolation rate was 5% for hides and 8% for carcasses. The isolation rate of STEC-positive for O26, O45, O103, O111, O145 or O157 serogroups was 0% for hides and 2% for carcasses. With the purpose of studying the clonal relatedness of isolates, macrorestriction fragment analysis by pulsed-field gel electrophoresis was performed. The results indicated cross-contamination between hides and between carcasses of animals in the same lot and, that the origin of carcass contamination was their own hide, or the hides of other animals in the same lot. The high detection rate at the screening step, especially in carcasses, and the evidence of cross-contamination show the need to apply additional in-plant intervention strategies aimed at preventing carcass contamination.Los objetivos del presente estudio fueron tres: 1) estimar la frecuencia de Escherichia coli productor de toxina Shiga (STEC) en muestras de cuero y carcasa de bovinos en frigoríficos de consumo interno de Argentina; 2) realizar la caracterización feno-genotípica de las cepas STEC y de Escherichia coli no toxigénicas pertenecientes a los serogrupos O26, O45, O103, O121, O145 u O157 aisladas a partir de las muestras analizadas; 3) establecer la relación clonal de ese conjunto de cepas. Se analizaron 60 cueros y 60 carcasas. En la etapa de tamizaje, el gen stx se detectó en el 48% de las muestras de cuero y en el 80% de las muestras de carcasa por una PCR de punto final. La frecuencia de recuperación de cepas STEC fue del 5% en cueros y del 8% en carcasas, y la de cepas STEC positivas para los serogrupos O26, O45, O103, O121, O111, O145 u O157 fue del 0% en los cueros y del 2% en las carcasas. La relación clonal de las cepas aisladas se investigó a través de electroforesis de campo pulsado y análisis de los patrones de macrorrestricción generados. Los resultados demostraron la existencia de contaminación cruzada entre cueros y carcasas de animales pertenecientes a un mismo lote, y también que el origen de la contaminación fue el propio cuero del animal o el cuero de otros animales pertenecientes al mismo lote. Los altos porcentajes de detección en la etapa de tamizaje, especialmente en carcasas, y la evidencia de contaminación cruzada ponen de manifiesto la necesidad de evaluar la implementación de estrategias de intervención tendientes a evitar la contaminación de carcasas.Instituto de Tecnología de AlimentosFil: Cap, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnologia de Alimentos; Argentina.Fil: Carbonari, Claudia C. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos Malbrán”. Instituto Nacional de Enfermedades Infecciosas. Servicio Fisiopatogenia; Argentina.Fil: D’Astek, Beatriz A. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos Malbrán”. Instituto Nacional de Enfermedades Infecciosas. Servicio Fisiopatogenia; Argentina.Fil: Zolezzi, Gisela. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos Malbrán”. Instituto Nacional de Enfermedades Infecciosas. Servicio Fisiopatogenia; Argentina.Fil: Deza, Natalia. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos Malbrán”. Instituto Nacional de Enfermedades Infecciosas. Servicio Fisiopatogenia; Argentina.Fil: Palladino, Pablo Martín. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; Argentina.Fil: Masana, Marcelo Oscar. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; Argentina.Fil: Chinen, Isabel. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos Malbrán”. Instituto Nacional de Enfermedades Infecciosas. Servicio Fisiopatogenia; Argentina.Fil: Rivas, Marta. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos Malbrán”. Instituto Nacional de Enfermedades Infecciosas. Servicio Fisiopatogenia; Argentina

Subtyping of Escherichia coli O157:H7 Strains Isolated from Human Infections and Healthy Cattle in Argentina

Shiga toxin–producing Escherichia coli (STEC) cause nonbloody (NBD) and bloody diarrhea (BD), and hemolytic uremic syndrome (HUS). Cattle have been described as their main reservoir. STEC O157:H7 is recognized as the predominant serotype in clinical infections, but much less is known about the dominant subtypes in humans and animals or their genetic relatedness. The aims of this study were to compare the STEC O157 subtypes found in sporadic human infections with those in the bovine reservoir using stx-genotyping, phage typing, and XbaI– pulsed-field gel electrophoresis (PFGE), and correlate the subtypes with the severity of clinical manifestations. The 280 STEC O157:H7 strains collected included in this study were isolated from HUS (n = 122), BD (n = 69), and NBD (n = 30) cases, and healthy carriers (n = 5), and from bovines (n = 54) in the abattoirs. The stx-genotyping showed that stx2/stx2c(vh-a) was predominant in human (76.1%) and in bovine strains (55.5%), whereas the second more important genotype was stx2 (20.8%) in human and stx2c(vh-a) (16.7%) in cattle strains. In human strains, PT4 (37.6%), PT49 (24.3%), and PT2 (18.6%) were the most frequent PTs (80.5%). In bovine isolates, PT2 (26%), PT39 (16.7%), and PT4 and PT49 (11.1% each) were predominant. By XbaI-PFGE, all 280 strains yielded 148 patterns with 75% similarity, and 169 strains were grouped in 37 clusters. Identical PT-PFGE-stx profile combinations were detected in strains of both origins: PT4-AREXH01.0011-stx2/stx2c(vh-a) (12 humans and one bovine), PT4-AREXH01.0543-stx2/stx2c(vh-a) (one human and four bovines), PT2-AREXH01.0076-stx2/stx2c(vh-a) (one human and four bovines), PT49-AREXH01.0175-stx2/stx2c(vh-a) (seven humans and one bovine), and PT49- AREXH01.0022-stx2/stx2c(vh-a) (seven humans and one bovine). No correlation was found among the stx-genotypes, the phage type, and the clinical symptoms.Fil: Del Castillo, Lourdes L. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; Argentina.Fil: D’Astek, Beatriz A. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Miliwebsky, Elizabeth. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Carbonari, Claudia Carolina. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Palladino, Pablo Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; Argentina.Fil: Deza, Natalia. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Chinen, Isabel. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Manfredi, Eduardo. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina.Fil: Leotta, Gerardo A. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Masana, Marcelo Oscar. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; Argentina.Fil: Rivas, Marta. Instituto Nacional de Enfermedades Infecciosas-ANLIS ‘‘Dr. Carlos G. Malbrán’’. Servicio Fisiopatogenia; Argentina

The Importance of Shiga Toxin-Producing <i>Escherichia coli</i> O145:NM[H28]/H28 Infections in Argentina, 1998–2020

Shiga toxin-producing Escherichia coli (STEC) is known as a pathogen associated with food-borne diseases. The STEC O145 serogroup has been related with acute watery diarrhea, bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Argentina has the highest rate of HUS worldwide with 70% of the cases associated with STEC infections. We aimed to describe the epidemiology and genetic diversity of STEC O145 strains isolated across Argentina between 1998–2020. The strains isolated from 543 cases of human disease and four cattle, were pheno-genotipically characterized. Sequencing of five strains was performed. The strains were serotyped as O145:NM[H28]/H28, O145:H25, and O145:HNT, and mainly characterized as O145:NM[H28]/stx2a/eae/ehxA (98.1%). The results obtained by sequencing were consistent with those obtained by traditional methods and additional genes involved in different mechanisms of the pathogen were observed. In this study, we confirmed that STEC O145 strains are the second serogroup after O157 and represent 20.3% of HUS cases in Argentina. The frequency of STEC O145 and other significant serogroups is of utmost importance for public health in the country. This study encourages the improvement of the surveillance system to prevent severe cases of human disease