Symbiosis of Aeromonas veronii biovar sobria and Hirudo medicinalis, the medicinal leech: a novel model for digestive tract associations
Microbiology published in Infect Immun (1999)
Abstract
Hirudo medicinalis, the medicinal leech, is applied postoperatively in modern medicine. Infections by Aeromonas occur in up to 20% of patients unless a preemptive antibiotic treatment is administered. The associated infections demonstrate the need for a better understanding of the digestive tract flora of H. medicinalis. Early studies reported the presence of a single bacterial species in the digestive tract and suggested that these bacteria were endosymbionts contributing to the digestion of blood. In this study, we cultivated bacteria from the digestive tract and characterized them biochemically. The biochemical test results identified the isolates as Aeromonas veronii biovar sobria. This species identification was supported by sequence comparison of a variable region of the genes coding for 16S rRNA. In a colonization assay, a rifampin-resistant derivative of a symbiotic isolate was fed in a blood meal to H. medicinalis. The strain colonized the digestive tract rapidly and reached a concentration similar to that of the native bacterial flora. For the first 12 h, the in vivo doubling time was 1.2 h at 23 degreesC. After 12 h, at a density of 5 x 10(7) CFU/ml, the increase in viable counts ceased, suggesting a dramatic reduction in the bacterial growth rate. Two human fecal isolates, identified as Aeromonas hydrophila and A. veronii biovar sobria, were also able to colonize the digestive tract. These data demonstrate that the main culturable bacterium in the crop of H. medicinalis is A. veronii biovar sobria and that the medicinal leech can be used as a model for digestive tract association of Aeromonas species.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
First definitive identification of Aeromonas veronii biovar sobria as the dominant culturable bacterium in the Hirudo medicinalis crop, with up to 20% rate of post-procedure infections absent prophylaxis.
Por qué esto importa para la hirudoterapia
Este estudio cultivó y caracterizó bacterias del tubo digestivo de Hirudo medicinalis, identificando la principal bacteria cultivable como Aeromonas veronii biovar sobria mediante pruebas bioquímicas y comparación de la secuencia del gen 16S rRNA. El resumen informa de que un derivado rifampicin-resistente de un aislado simbiótico colonizó rápidamente el buche de la sanguijuela (tiempo de duplicación in vivo de 1,2 h a 23 °C), alcanzando las densidades de la flora nativa, y de que aislados fecales humanos de A. hydrophila y A. veronii biovar sobria también pudieron colonizar. Esto es directamente relevante para el ámbito de ASH, ya que la infección por Aeromonas se presenta en hasta un 20 % de los pacientes sometidos a terapia con sanguijuelas, y la caracterización de la flora simbiótica resulta esencial para comprender y manejar esta complicación clínicamente significativa. El estudio aporta datos microbiológicos fundacionales más que desenlaces clínicos de hirudoterapia.
Citación
Symbiosis of Aeromonas veronii biovar sobria and Hirudo medicinalis, the medicinal leech: a novel model for digestive tract associations.
Graf J · Infection and immunity, 1999
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Añadido a la biblioteca ASH: May 26, 2026 · Última actualización del sitio: 18 de junio de 2026