Microbiota Dynamics: A Key Factor in Hirudotherapy-Related Infections?

Microbiome study published in Microorganisms (2025)

Zuletzt aktualisiert: 18. Juni 2026Geprüft von: ASH Editorial Board

Forschungsartikel – EvidenzreviewArtikelreferenz

Evidence: Research reportSicherheit & InfektionskontrolleGenomik & ProteomikKarasartova D et al. · Microorganisms, 2025

Abstract

The gastrointestinal microbiota of medicinal leeches is particularly interesting due to their blood-feeding habits, increasing medical use, and risk of pathogen transmission. Three groups of Hirudo verbana were used to study the leech microbiota: farmed leeches fasting for a long time, farmed leeches recently fed with bovine blood, and wild specimens fed with amphibian blood. The microbiota of the leeches' mouth, pharynx, crop, and intestine was analyzed. Metasequencing analyses were performed using amplification of the 16S rRNA V3-V4 region on a NovaSeq Illumina platform. The relative abundance of bacterial microbiota included environmental bacteria from the families Rhizobiaceae, Comamonadaceae, Sphingobacteriaceae, Phreatobacteraceae, Myxococcaceae, Chitinophagaceae, Rhodospirillaceae, and Bdellovibrionaceae, as well as symbiotic/probiotic bacteria such as Mucinivorans, Aeromonas, Vagococcus, Lactobacillales, and Morganella. Significant differences were found in the different regions of the digestive system among the three groups of leeches, and environmental bacteria were present in all groups to varying degrees. A negative correlation was found between the dominant environmental and the symbiotic/probiotic bacteria. In contrast, a positive correlation was found between environmental and symbiotic/probiotic bacteria, indicating their association with host factors. Microbiota diversity, abundance, and bacterial correlations may be influenced by factors such as the leech's fasting state, blood meal source, and environmental conditions. The identified opportunistic pathogens, such as Rickettsia, Anaplasma, and Treponema, identified for the first time in H. verbana, should be taken into consideration when using this leech in hirudotherapy. Our results show that extensive screening for opportunistic and pathogenic agents should be performed on leeches intended for medical use. Long-fasting leeches and leeches cultured in specialized farms are recommended for hirudotherapy.

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

Publication typeJournal Article

Zusammenfassung

16S rRNA metagenomic study of leech gastrointestinal microbiota across mouth, pharynx, crop and intestine in farmed (fed/fasting) versus wild leeches. Identifies opportunistic pathogens and recommends long-fasting farm-raised leeches for hirudotherapy.

Warum dies für die Hirudotherapie relevant ist

Diese 16S-rRNA(V3–V4)-Metasequenzierungsstudie charakterisierte die Mikrobiota des Verdauungstrakts von Hirudo verbana in drei Gruppen: gezüchtete, lang fasten gehaltene Blutegel; gezüchtete, kürzlich mit Rinderblut gefütterte Blutegel; sowie wildlebende, mit Amphibienblut gefütterte Exemplare. Es wurden taxonspezifische Unterschiede zwischen Mund/Pharynx, Kropf und Darm festgestellt, wobei umweltassoziierte sowie symbiotische/probiotische Bakterien je nach Fastenzustand, Blutmahlzeit-Quelle und Umweltbedingungen variierten; erstmals wurden Rickettsia, Anaplasma und Treponema bei H. verbana identifiziert. Für die ASH und die Hirudotherapie ist dies unmittelbar relevant, da blutegelassoziierte opportunistische Pathogene die Patientensicherheit beeinträchtigen können und mikrobiologisches Screening sowie Beschaffungspraktiken informieren können. Eine ehrliche Einschränkung besteht darin, dass die Studie mikrobielle Gemeinschaften und Korrelationen charakterisiert; sie zeigt weder klinische Infektionsraten, beweist nicht, dass die nachgewiesenen Taxa Infektionen verursachen, noch belegt sie, dass irgendein bestimmtes Screening- oder Fastenprotokoll das Risiko eliminiert.