American Society of Hirudotherapy

Indigenous bacterial flora of medicinal leeches and their susceptibilities to 15 antimicrobial agents

Microbiology article published in Journal of Medical Microbiology (1996)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Safety & Infection ControlNonomura H, Kato N, Ohno Y, Itokazu M, Matsunaga T, Watanabe K · Journal of medical microbiology, 1996

Abstract

Surface bacterial flora, as well as homogenates, of medical leeches, Hirudo medicinalis and Hirudinaria manillensis, were surveyed and the susceptibility of these isolates to 15 antimicrobial agents was examined. Aeromonas spp. were isolated from all leeches, and Pseudomonas fluorescens and other glucose-non-fermenting gram-negative rods (NF-GNR) were frequent isolates. Isolates were highly resistant to cephalosporins but susceptible to carbapenems, aminoglycosides and ofloxacin. The results indicate that prophylaxis with antimicrobial agents active against Aeromonas spp. and NF-GNR is necessary to avoid opportunist infections caused by indigenous leech flora during medical leech therapy on immunocompromised patients.

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

Publication typeJournal Article
Indexed MeSH termsAeromonasAnimalsAnti-Bacterial AgentsEnterobacteriaceaeGram-Negative BacteriaLeechesPseudomonasStaphylococcusYersinia

Summary

Survey of surface and homogenate bacterial flora of Hirudo medicinalis and Hirudinaria manillensis with susceptibility testing against 15 antimicrobial agents; Aeromonas spp. and Pseudomonas fluorescens isolated, with high resistance to cephalosporins.

Why This Matters for Hirudotherapy

This study surveyed surface and homogenate bacterial flora of Hirudo medicinalis and Hirudinaria manillensis and tested isolate susceptibilities to 15 antimicrobial agents. Aeromonas spp. were recovered from all leeches, with Pseudomonas fluorescens and other non-fermenting gram-negative rods frequent; isolates were highly cephalosporin-resistant but susceptible to carbapenems, aminoglycosides, and ofloxacin. For hirudotherapy, this is directly relevant because it informs antibiotic prophylaxis aimed at preventing opportunistic infections from indigenous leech flora, particularly in immunocompromised patients. The abstract does not state the study design or sample size, so scope cannot be characterized further, and the findings are in-vitro susceptibility data rather than clinical outcomes.

Citation

Indigenous bacterial flora of medicinal leeches and their susceptibilities to 15 antimicrobial agents.

Nonomura H, Kato N, Ohno Y, Itokazu M, Matsunaga T, Watanabe K · Journal of medical microbiology, 1996

DOI

Added to ASH library: May 26, 2026 · Site last updated: June 18, 2026

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.