Over the past several years, countless patients have benefitted from the use of leeches in microsurgery. As you know, leeches are used to overcome the problem of venous congestion by creating prolonged localised bleeding uniquely characteristic of the leech bite. The artificial circulation gives the graft time to re-establish its own circulation, normally 3-5 days.

The practitioner should be aware, however, that if the arterial supply is insufficient, the graft is very vulnerable indeed to infection from any outside source, including the leech.

It is well known that the leech gut contains an endosymbiotic bacterium Aeromonas hydrophila. This bacterium is a true symbiont. Not only is it a normal part of the leech gut flora, it is the only micro-organism present in the leech digestive tract and is in fact essential for the leech to grow.

Aeromonas hydrophila is not at all common especially in water, and is normally not a pathogen. However, like most bacterial species Aeromonas hydrophila has been implicated as a pathogen in exceptional circumstances. Whilst it is easily knocked out with antibiotics such as Augmentin, the practitioner should use discretion, especially when dealing with tissue which is or is likely to become compromised by poor arterial supply. Like any potent drug the clinician needs to weigh up the potential benefits against possible risks. To assist clinical judgement a copy of our Data Sheet "Endosymbiosis in the leech" should be on file with your Chief Pharmacist. If you have any questions or need advice please contact us immediately.

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