Intestinal flora of the medicinal leech Hirudinaria manillensis
Research article published in Journal of reconstructive microsurgery (1994)
Abstract
Medicinal leeches are widely used to treat venous congestion in microvascular surgery. Aeromonas hydrophila infection, following application of the leech species Hirudo medicinalis, is a recognized complication. Administration of antibiotics directed at Aeromonas has been successful in minimizing complications of infection from this organism. A different leech species, Hirudinaria manillensis, has recently been introduced for microsurgical use. A study of the enteric content of 30 of these leeches showed that Aeromonas hydrophila was isolated in only 20 percent of animals, while the majority of remaining positive cultures were single and mixed gram-negative rods. All organisms isolated were sensitive to current recommended coverage for Aeromonas hydrophila. This study suggests that the enteric flora of different leech species may be variable and should be carefully characterized, to direct appropriate prophylactic therapy prior to release of new species for clinical use.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Medicinal leeches are widely used to treat venous congestion in microvascular surgery. Aeromonas hydrophila infection, following application of the leech species Hirudo medicinalis, is a recognized complication.
Why This Matters for Hirudotherapy
This study examined the enteric bacterial flora of Hirudinaria manillensis, a leech species recently introduced for microsurgical applications, by culturing intestinal contents from 30 specimens. Aeromonas hydrophila was isolated in only 20% of leeches, with other gram-negative rods predominant among remaining positive cultures; all organisms were sensitive to antibiotics currently recommended for Aeromonas coverage. This work is directly relevant to hirudotherapy because leech-associated infection is a recognized clinical complication, and characterizing the gut microbiota of alternative therapeutic species informs prophylactic antibiotic strategies and patient safety. The findings underscore that enteric flora can vary across leech species, challenging extrapolations drawn from the better-studied Hirudo medicinalis. However, the study provides microbiological culture data from 30 leeches with no associated clinical infection rates or patient outcome data, so its direct bearing on actual infection risk or prophylactic efficacy in clinical hirudotherapy remains limited.
Citation
Intestinal flora of the medicinal leech Hirudinaria manillensis.
Bickel K et al. · Journal of reconstructive microsurgery, 1994
Added to ASH library: March 18, 2026 · Site last updated: June 18, 2026