Characterisation of Shiga toxin-producing Escherichia coli O157 strains isolated from humans in Argentina, Australia and New Zealand

Background: Shiga toxin-producing Escherichia coli (STEC) is an important cause of bloody diarrhoea (BD), non-bloody diarrhoea (NBD) and the haemolytic uraemic syndrome (HUS). In Argentina and New Zealand, the most prevalent STEC serotype is O157:H7, which is responsible for the majority of HUS cases. In Australia, on the other hand, STEC O157:H7 is associated with a minority of HUS cases. The main aims of this study were to compare the phenotypic and genotypic characteristics of STEC O157 strains isolated between 1993 and 1996 from humans in Argentina, Australia and New Zealand, and to establish their clonal relatedness. Results: Seventy-three O157 STEC strains, isolated from HUS (n = 36), BD (n = 20), NBD (n = 10), or unspecified conditions (n = 7) in Argentina, Australia and New Zealand, were analysed. The strains were confirmed to be E. coli O157 by biochemical tests and serotyping. A multiplex polymerase chain reaction (PCR) was used to amplify the stx1, stx2 and rfbO157 genes and a genotyping method based on PCR-RFLP was used to determine stx1 and stx2 variants. This analysis revealed that the most frequent stx genotypes were stx2/stx 2c (vh-a) (91%) in Argentina, stx2 (89%) in New Zealand, and stx1/stx2 (30%) in Australia. No stx 1-postive strains were identified in Argentina or New Zealand. All strains harboured the eae gene and 72 strains produced enterohaemolysin (EHEC-Hly). The clonal relatedness of strains was investigated by phage typing and pulsed-field gel electrophoresis (PFGE). The most frequent phage types (PT) identified in Argentinian, Australian, and New Zealand strains were PT49 (n = 12), PT14 (n = 9), and PT2 (n = 15), respectively. Forty-six different patterns were obtained by XbaI-PFGE; 37 strains were grouped in 10 clusters and 36 strains showed unique patterns. Most clusters could be further subdivided by BlnI-PFGE. Conclusion: STEC O157 strains isolated in Argentina, Australia, and New Zealand differed from each other in terms of stx-genotype and phage type. Additionally, no common PFGE patterns were found in strains isolated in the three countries. International collaborative studies of the type reported here are needed to detect and monitor potentially hypervirulent STEC clones.Fil: Leotta, Gerardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Miliwebsky, Elizabeth S.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Chinen, Isabel. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Espinosa, Estela M.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Azzopardi, Kristy. University of Melbourne; AustraliaFil: Tennant, Sharon M.. University of Melbourne; AustraliaFil: Robins Browne, Roy M.. University of Melbourne; AustraliaFil: Rivas, Marta. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentin

Characterisation of Shiga toxin-producing <it>Escherichia coli </it>O157 strains isolated from humans in Argentina, Australia and New Zealand

Abstract Background Shiga toxin-producing Escherichia coli (STEC) is an important cause of bloody diarrhoea (BD), non-bloody diarrhoea (NBD) and the haemolytic uraemic syndrome (HUS). In Argentina and New Zealand, the most prevalent STEC serotype is O157:H7, which is responsible for the majority of HUS cases. In Australia, on the other hand, STEC O157:H7 is associated with a minority of HUS cases. The main aims of this study were to compare the phenotypic and genotypic characteristics of STEC O157 strains isolated between 1993 and 1996 from humans in Argentina, Australia and New Zealand, and to establish their clonal relatedness. Results Seventy-three O157 STEC strains, isolated from HUS (n = 36), BD (n = 20), NBD (n = 10), or unspecified conditions (n = 7) in Argentina, Australia and New Zealand, were analysed. The strains were confirmed to be E. coli O157 by biochemical tests and serotyping. A multiplex polymerase chain reaction (PCR) was used to amplify the stx1, stx2 and rfbO157 genes and a genotyping method based on PCR-RFLP was used to determine stx1 and stx2 variants. This analysis revealed that the most frequent stx genotypes were stx2/stx2c (vh-a) (91%) in Argentina, stx2 (89%) in New Zealand, and stx1/stx2 (30%) in Australia. No stx1-postive strains were identified in Argentina or New Zealand. All strains harboured the eae gene and 72 strains produced enterohaemolysin (EHEC-Hly). The clonal relatedness of strains was investigated by phage typing and pulsed-field gel electrophoresis (PFGE). The most frequent phage types (PT) identified in Argentinian, Australian, and New Zealand strains were PT49 (n = 12), PT14 (n = 9), and PT2 (n = 15), respectively. Forty-six different patterns were obtained by XbaI-PFGE; 37 strains were grouped in 10 clusters and 36 strains showed unique patterns. Most clusters could be further subdivided by BlnI-PFGE. Conclusion STEC O157 strains isolated in Argentina, Australia, and New Zealand differed from each other in terms of stx-genotype and phage type. Additionally, no common PFGE patterns were found in strains isolated in the three countries. International collaborative studies of the type reported here are needed to detect and monitor potentially hypervirulent STEC clones.</p

Characterisation of Shiga toxin-producing Escherichia coli O157 strains isolated from humans in Argentina, Australia and New Zealand

Background: Shiga toxin-producing Escherichia coli (STEC) is an important cause of bloody diarrhoea (BD), non-bloody diarrhoea (NBD) and the haemolytic uraemic syndrome (HUS). In Argentina and New Zealand, the most prevalent STEC serotype is O157:H7, which is responsible for the majority of HUS cases. In Australia, on the other hand, STEC O157:H7 is associated with a minority of HUS cases. The main aims of this study were to compare the phenotypic and genotypic characteristics of STEC O157 strains isolated between 1993 and 1996 from humans in Argentina, Australia and New Zealand, and to establish their clonal relatedness. Results: Seventy-three O157 STEC strains, isolated from HUS (n = 36), BD (n = 20), NBD (n = 10), or unspecified conditions (n = 7) in Argentina, Australia and New Zealand, were analysed. The strains were confirmed to be E. coli O157 by biochemical tests and serotyping. A multiplex polymerase chain reaction (PCR) was used to amplify the stx1, stx2 and rfbO157 genes and a genotyping method based on PCR-RFLP was used to determine stx1 and stx2 variants. This analysis revealed that the most frequent stx genotypes were stx2/stx 2c (vh-a) (91%) in Argentina, stx2 (89%) in New Zealand, and stx1/stx2 (30%) in Australia. No stx 1-postive strains were identified in Argentina or New Zealand. All strains harboured the eae gene and 72 strains produced enterohaemolysin (EHEC-Hly). The clonal relatedness of strains was investigated by phage typing and pulsed-field gel electrophoresis (PFGE). The most frequent phage types (PT) identified in Argentinian, Australian, and New Zealand strains were PT49 (n = 12), PT14 (n = 9), and PT2 (n = 15), respectively. Forty-six different patterns were obtained by XbaI-PFGE; 37 strains were grouped in 10 clusters and 36 strains showed unique patterns. Most clusters could be further subdivided by BlnI-PFGE. Conclusion: STEC O157 strains isolated in Argentina, Australia, and New Zealand differed from each other in terms of stx-genotype and phage type. Additionally, no common PFGE patterns were found in strains isolated in the three countries. International collaborative studies of the type reported here are needed to detect and monitor potentially hypervirulent STEC clones.Instituto de Genética Veterinari

Vigilancia de diarrea sanguinolenta asociada a Escherichia coli productor de toxina Shiga en Argentina

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.En Argentina, el síndrome urémico hemolítico asociado a Escherichia coli productor de toxina Shiga (STEC-SUH) es endémico y, desde 2000, de notificación obligatoria. Sin embargo, la información sobre diarrea sanguinolenta (DS) asociada a STEC (DS-STEC) es limitada. Se realizó un estudio prospectivo desde octubre de 2018 hasta junio de 2019 en siete hospitales de tercer nivel y 18 unidades de referencia de diferentes provincias argentinas, con el objetivo de determinar la frecuencia de casos de DS-STEC en 714 niños de 1 a 9 años que tuvieron DS (I) y la tasa de progresión de DS a SUH en dicha cohorte (II). También se evaluó el número y distribución regional de casos de STEC-SUH en los mismos hospitales en dicho período. Veintinueve casos de DS (4,1%) fueron STEC-positivos, determinados por Shiga Toxin Quik Chek (STQC) o PCR múltiple (mPCR). Las frecuencias más altas se encontraron en el sur del área relevada (Neuquén, 8,7%; Bahía Blanca, 7,9%), en niños de 12 a 23 meses (8,8%), en verano. Cuatro casos de DS-STEC (13,8%) progresaron a SUH, de tres a nueve días después del inicio de la diarrea. Se registraron 27 niños con STEC-SUH, estos fueron mayoritariamente <5 años (77,8%) del sexo femenino (51,9%). El 44% de estos casos fueron Stx-positivos por STQC y todos por mPCR. Los serotipos más comunes fueron O157:H7 y O145:H28, y el genotipo predominante fue stx2a, solo o asociado, en DS y SUH. Considerando el comportamiento endémico del SUH y su alta incidencia, estos datos muestran que la tasa de casos de DS-STEC es baja. Sin embargo, su reconocimiento temprano es importante para el seguimiento e inicio del tratamiento de sostén.Fil: Rivas, Marta. Inmunova S.A.; ArgentinaFil: Pichel, Mariana. Inmunova S.A.; ArgentinaFil: Colonna, Mariana. Inmunova S.A.; ArgentinaFil: Casanello, Adrián López. No especifíca;Fil: Alconcher, Laura F.. Hospital Municipal General de Agudos Doctor José Penna; ArgentinaFil: Galavotti, Jimena. Hospital Municipal General de Agudos Doctor José Penna; ArgentinaFil: Principi, Iliana. Gobierno de la Provincia de Mendoza. Hospital Pediátrico Humberto Notti; ArgentinaFil: Araujo, Sofía Pérez. Gobierno de la Provincia de Mendoza. Hospital Pediátrico Humberto Notti; ArgentinaFil: Ramírez, Flavia B.. Provincia del Neuquén. Hospital Provincial Neuquén "Dr. E. Castro Rendón"; ArgentinaFil: González, Gladys. Provincia del Neuquén. Hospital Provincial Neuquén "Dr. E. Castro Rendón"; ArgentinaFil: Pianciola, Luis. Laboratorio Central; ArgentinaFil: Mazzeo, Melina. Laboratorio Central; ArgentinaFil: Suarez, Ángela. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Oderiz, Sebastián. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; ArgentinaFil: Ghezzi, Lidia F.R.. Hospital Italiano; ArgentinaFil: Arrigo, Diego J.. Hospital Italiano; ArgentinaFil: Paladini, José H.. Gobierno de la Provincia de Santa Fe. Hospital de Niños Doctor Orlando Alassia.; ArgentinaFil: Baroni, María R.. Gobierno de la Provincia de Santa Fe. Hospital de Niños Doctor Orlando Alassia.; ArgentinaFil: Pérez, Susana. Hospital Doctor Lucio Molas ; Gobierno de la Provincia de la Pampa;Fil: Tamborini, Ana. Hospital Doctor Lucio Molas ; Gobierno de la Provincia de la Pampa;Fil: Chinen, Isabel. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Miliwebsky, Elizabeth S.. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Goldbaum, Fernando Alberto. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; Argentina. Inmunova S.A.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Muñoz, Luciana. Inmunova S.A.; ArgentinaFil: Spatz, Linus. Inmunova S.A.; ArgentinaFil: Sanguineti, Santiago. Inmunova S.A.; ArgentinaFil: Lucarelli, Lucas Iván. Inmunova S.A.; ArgentinaFil: Fennen, Lara Parada. Inmunova S.A.; ArgentinaFil: Valles, Patricia. Inmunova S.A.; ArgentinaFil: Poidomani, Ana María. Inmunova S.A.; ArgentinaFil: Huerga, María. Inmunova S.A.; ArgentinaFil: Fioravanti, Leonardo. Inmunova S.A.; ArgentinaFil: De Rose, Emanuel. Inmunova S.A.; ArgentinaFil: Crivaro, Eugenia. Inmunova S.A.; ArgentinaFil: Pallaoro, Nerina. Inmunova S.A.; ArgentinaFil: Prado, Analia. Inmunova S.A.; ArgentinaFil: Coccia, Paula Alejandra. Inmunova S.A.; ArgentinaFil: Ferraris, Verónica. Inmunova S.A.; ArgentinaFil: Aro, Carolina. Inmunova S.A.; ArgentinaFil: Castañeira, Mariana. Inmunova S.A.; ArgentinaFil: Rodríguez Llach, Andrea. Inmunova S.A.; ArgentinaFil: Casabona, Luis Marcelo. Inmunova S.A.; Argentin