Prevalence of genes encoding the type three secretion system and the effectors AexT and AexU in the Aeromonas veronii group
Basic science published in DNA Cell Biol (2009)
Abstract
The prevalence of important virulence factors, the type III secretion system (T3SS) and two T3SS-dependent toxins, AexT and AexU, was evaluated in the Aeromonas veronii group (AVG). Members of the AVG have a broad host range, including vertebrates and invertebrates, and form a variety of associations, spanning from pathogenic to mutualistic. Our AVG strain collection consists of human, duck, eel, and leech isolates. These isolates were examined for the presence of the T3SS, AexT, and AexU through PCR analysis. Two loci of the T3SS, ascV and ascF-ascG, and aexT and aexU were PCR amplified and sequenced from these isolates. All 20 environmental and clinical isolates possessed the T3SS and both effectors, which indicates a much greater prevalence than reported by previous studies. Sequence analysis of the C-terminal domains of aexT and aexU revealed a much higher nucleotide substitution rate for aexU (19.7%) when compared to aexT (4%). The lack of sequence variability among aexT homologs suggests that it has a conserved function among the AVG. The increased variation of the aexU sequence suggests the presence of different alleles, which indicates that it may serve different functions.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
All 20 Aeromonas veronii human, duck, eel, and leech isolates carry T3SS and effectors AexT and AexU.
Por qué esto importa para la hirudoterapia
Este estudio evaluó la prevalencia del sistema de secreción tipo III (T3SS) y dos toxinas dependientes del T3SS (AexT y AexU) en 20 aislamientos del grupo Aeromonas veronii procedentes de fuentes humanas, de pato, de anguila y de sanguijuela. Todos los aislamientos poseían el T3SS y ambos efectores, lo que indica una prevalencia mucho mayor que la reportada previamente; AexT mostró secuencias conservadas, mientras que AexU exhibió mayor variabilidad, lo que sugiere diferentes roles funcionales. Esto es indirectamente relevante para el dominio de ASH al caracterizar los factores de virulencia en simbiontes bacterianos que incluyen aislamientos de sanguijuela, contribuyendo a la comprensión de la microbiología de Aeromonas asociada a sanguijuelas. Sin embargo, el estudio no aborda la hirudoterapia, los componentes salivales de la sanguijuela ni las aplicaciones clínicas; los aislamientos de sanguijuela representan solo una de las varias fuentes examinadas.
Citación
Prevalence of genes encoding the type three secretion system and the effectors AexT and AexU in the Aeromonas veronii group.
Silver AC, Graf J · DNA and cell biology, 2009
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: 18 de junio de 2026