Reciprocal immune benefit based on complementary production of antibiotics by the leech Hirudo verbana and its gut symbiont Aeromonas veronii

The medicinal leech has established a long-term mutualistic association with Aeromonas veronii, a versatile bacterium which can also display free-living waterborne and fish- or human-pathogenic lifestyles. Here, we investigated the role of antibiotics in the dynamics of interaction between the leech and its gut symbiont Aeromonas. By combining biochemical and molecular approaches, we isolated and identified for the first time the antimicrobial peptides (AMPs) produced by the leech digestive tract and by its symbiont Aeromonas. Immunohistochemistry data and PCR analyses evidenced that leech AMP genes are induced in the gut epithelial cells when Aeromonas load is low (starved animals), while repressed when Aeromonas abundance is the highest (post blood feeding). The asynchronous production of AMPs by both partners suggests that these antibiotic substances (i) provide them with reciprocal protection against invasive bacteria and (ii) contribute to the unusual simplicity of the gut microflora of the leech. This immune benefit substantially reinforces the evidence of an evolutionarily stable association between H. verbana and A. veronii. Altogether these data may provide insights into the processes making the association with an Aeromonas species in the digestive tract either deleterious or beneficial.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Hirudo verbana AMP genes are induced when Aeromonas load is low (starved animals) and repressed when load is high (post-blood meal). Asynchronous AMP production by both partners provides reciprocal protection against invasive bacteria.

Explore cómo esta investigación se conecta con la práctica clínica

More peer-reviewed studies in Seguridad y control de infecciones.

• Leech-Assisted Flap Salvage — Systematic Review of 277 Cases — Whitaker et al. (2012)
• Effects of hirudotherapy on liver functions, lipid profile, and insulin sensitivity in rats with metabolic syndrome — Bilden A et al. (2026)
• Efficacy and Safety of Hirudotherapy for Improving Sperm Quality Parameters in Male Infertility: A Randomized Controlled Trial — Abtahi-Forooshani M et al. (2026)
• Improvement of patient care through hirudotherapy and the management of leeches from their reception to their disposal in France — Vaesken C et al. (2023)
• Hirudotherapy in Medicine and Dentistry — Jha K et al. (2015)
• Management of Chronic Non-healing Wounds by Hirudotherapy — Iqbal A et al. (2017)
• Hirudotherapy attenuates arthritic pain in patients with various chronic pain syndromes: A retrospective analysis — Loeser J et al. (2020)
• Hirudotherapy (medicinal leeches) for treatment of upper airway obstruction in a dog — Trenholme H, Masseau I, Reinero C (2021)
• Analysis of antibiotic resistant infections associated with hirudotherapy — Brauer P et al. (2024)
• Leech Me Alone! Atraumatic Hemarthrosis after Hirudotherapy — Curcio J, Lloyd C (2020)

Browse all ASH-analysed research →