Old World Leech Gut Microbial Community Structure Conserved in a New World Leech
Basic science / microbiology published in Appl Environ Microbiol (2021)
Abstract
Leeches are found in terrestrial, aquatic, and marine habitats on all continents. Sanguivorous leeches have been used in medicine for millennia. Modern scientific uses include studies of neurons, anticoagulants, and gut microbial symbioses. Hirudo verbana, the European medicinal leech, maintains a gut community dominated by two bacterial symbionts, Aeromonas veronii and Mucinivorans hirudinis, which sometimes account for as much as 97% of the total crop microbiota. The highly simplified gut anatomy and microbiome of H. verbana make it an excellent model organism for studying gut microbial dynamics. The North American medicinal leech, Macrobdella decora, is a hirudinid leech native to Canada and the northern United States. In this study, we show that M. decora symbiont communities are very similar to those in H. verbana. We performed an extensive study using field-caught M. decora and purchased H. verbana from two suppliers. Deep sequencing of the V4 region of the 16S rRNA gene allowed us to determine that the core microbiome of M. decora consists of Bacteroides, Aeromonas, Proteocatella, and Butyricicoccus. The analysis revealed that the compositions of the gut microbiomes of the two leech species were significantly different at all taxonomic levels. The R2 value was highest at the genus and amplicon sequence variant (ASV) levels and much lower at the phylum, class, and order levels. The gut and bladder microbial communities were distinct. We propose that M. decora is an alternative to H. verbana for studies of wild-caught animals and provide evidence for the conservation of digestive-tract and bladder symbionts in annelid models.IMPORTANCE Building evidence implicates the gut microbiome in critical animal functions such as regulating digestion, nutrition, immune regulation, and development. Simplified, phylogenetically diverse models for hypothesis testing are necessary because of the difficulty of assigning causative relationships in complex gut microbiomes. Previous research used Hirudo verbana as a tractable animal model of digestive-tract symbioses. Our data show that Macrobdella decora may work just as well without the drawback of being an endangered organism and with the added advantage of easy access to field-caught specimens. The similarity of the microbial community structures of species from two different continents reveals the highly conserved nature of the microbial symbionts in sanguivorous leeches.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Comparative 16S rRNA gene microbiome analysis demonstrating conservation of Aeromonas + Mucinivorans + Bacteroides core microbiome between Old World Hirudo verbana and New World Macrobdella decora medicinal leeches. Distinct gut vs bladder communities established.
Por qué esto importa para la hirudoterapia
Este estudio de secuenciación del gen 16S ARNr (región V4) caracterizó los microbiomas intestinal y vesical de Macrobdella decora norteamericanas capturadas en el campo y los comparó con los de Hirudo verbana adquiridas comercialmente, identificando un microbioma central de M. decora compuesto por Bacteroides, Aeromonas, Proteocatella y Butyricicoccus. Para la hirudoterapia y la ASH, este trabajo es relevante porque los simbiontes intestinales de las sanguijuelas medicinales pueden influir en la salud de la sanguijuela, la digestión de la sangre ingerida y potencialmente en la estabilidad de los componentes bioactivos del secretoma utilizados clínicamente; los autores proponen a M. decora como un modelo comparativo no amenazado y accesible en el campo para la investigación de esta simbiosis. Según el resumen, las composiciones del microbioma intestinal de las dos especies fueron significativamente diferentes en todos los niveles taxonómicos (con tamaños del efecto menores en los rangos más amplios), al mismo tiempo que se mantuvo la conservación de los tipos de simbiontes entre continentes. Advertencia honesta: se trata de un estudio descriptivo de la estructura de la comunidad, y no constituye evidencia de que estas diferencias del microbioma afecten la eficacia terapéutica, el rendimiento de anticoagulantes ni los desenlaces clínicos.
Citación
Old World Leech Gut Microbial Community Structure Conserved in a New World Leech.
McClure EA et al. · Applied and environmental microbiology, 2021
Contexto clínico relacionado
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: 18 de junio de 2026