RESUMO
Shiga toxin-producing Escherichia coli (STEC) are zoonotic food pathogens associated with foodborne diarrheal illness, hemorrhagic colitis, and complications such as hemolytic uremic syndrome (HUS). The ability to adhere to epithelial cells is an important virulence trait, and pathogenicity islands (PAIs) play an important role on it. Some STEC carrying a PAI named locus of enterocyte effacement (LEE-positive) have been frequently associated to HUS; however, STEC that do not carry LEE (LEE-negative) have also been associated with this outcome. The burden of disease caused by LEE-negative STEC has increased recently in several countries like Argentina, Chile, and Paraguay. A new PAI -the Locus of Adhesion and Autoagregation (LAA)-has been associated to severe disease in humans. In this study, we aimed to analyze the distribution of LAA and its possible predictor, the gene hes, in LEE-negative STEC strains isolated from Chile and Paraguay from different sources. The presence of the different LAA modules and hes were detected by PCR. LAA was found in 41.6% and 41.0% of strains isolated from Chile and Paraguay, respectively. Strains were isolated from diverse origins and belonged to several serogroups including O91, O103, and O113. The hes gene was detected in 50% of the isolates from Paraguay and Chile. Therefore, the detection of LAA and hes in STEC could complement current genetic evaluation schemes, allowing to classify LEE negative STEC strains as LAA-positive or LAA-negative STEC strains.
Assuntos
Infecções por Escherichia coli , Proteínas de Escherichia coli , Escherichia coli Shiga Toxigênica , Argentina , Chile , Proteínas de Escherichia coli/genética , Humanos , América Latina , Escherichia coli Shiga Toxigênica/genética , Fatores de Virulência/genéticaRESUMO
La litiasis renal es una patología que se caracteriza por la formación, agregación y retención de cristales en las vías urinarias. Su etiología es compleja ya que la misma puede ser el resultado de la interacción de múltiples factores tanto endógeno, metabólico como ambiental. La elevada tasa de recurrencia de la formación de cálculos puede superar el 40% en un periodo de 5 años tras el primer episodio y puede conllevar consecuencias graves para el funcionamiento renal con su consiguiente impacto en la calidad de vida del paciente(AU)
Assuntos
Humanos , Cálculos Urinários/química , Nefrolitíase/etiologia , Paraguai , SeguimentosRESUMO
Staphylococcus aureus es un patógeno capaz de causar infecciones con amplio rango de severidad y adaptarse a diferentes tejidos. Su epidemiología es compleja, por circulación de cientos de clones a nivel mundial, lo que requiere de métodos moleculares reproducibles y de alto poder discriminatorio para la identificación de los mismos. El presente estudio tuvo como objetivo principal la estandarización del análisis multi-locus de número variable de repeticiones en tándem (MLVA) para análisis de variabilidad genética de aislados de S. aureus previamente tipificados por electroforesis en gel de campo pulsado (PFGE), gold standard para tipificación de aislados. La MLVA se realizó por amplificación de 7 locus VNTR (clfA, clfB, sdrC, sdrD, sdrE, sspA y spA) por PCR. Se alcanzó un alto nivel de reproducibilidad. El empleo de cepas previamente tipificadas por análisis de secuencias multi-locus (MLST), PFGE, locus spa y cassette SCCmec, permitió validar de forma comparativa el agrupamiento generado por MLVA. Los aislados que fueron agrupados como idénticos por MLVA presentaron resultados congruentes con la totalidad de las otras técnicas moleculares y esta demostró ser más sensible que PFGE para distinguir entre aislados que presentaron patrones PFGE idénticos. La MLVA cumple todos los criterios de un método de tipificación útil.
Staphylococcus aureus is a pathogen that can produce several infections with a wide range of severity and it has the ability to adapt to different tissues. The epidemiology is complex, due to circulation of many different clones worldwide, so the analysis for its identification requires reproducible and high discriminatory power molecular methods. The aim of this study was to standardize the molecular technique multiple-locus variable number of tandem repeat analysis (MLVA) for the genetic variability analysis of S. aureus isolates, previously characterized by pulsed field gel electrophoresis (PFGE). The MLVA was made by PCR amplification of seven VNTR locus (clfA, clfB, sdrC, sdrD, sdrE, sspA y spA). A high level of reproducibility has been reached in the study. The use of isolates previously typified by multi-locus sequence typing (MLST), PFGE, locus spa and cassette SCCmec, allowed to validate the MLVA clusters comparatively. The isolates that were clustered by MLVA as the same isolate, showed the same results by other molecular techniques, and the MLVA can distinguish isolates with identical PFGE patterns. This technique meets all the criteria of a useful molecular typification technique.
