Aeromonas, acclimation, and penicillin as complications when leeches are applied to skin flaps in rabbits

Abstract

The medicinal leech, Hirudo medicinalis, has been recognized by plastic surgeons for its ability to reduce congestion and improve blood flow in grafted skin flaps by withdrawing excess blood. The leech's ability to digest blood is due to the presence of Aeromonas hydrophila in the gut of the leech. In this report we describe the occurrence of Aeromonas hydrophila septicaemia in rabbits used in a study to evaluate the efficacy of the medicinal leech on abdominal skin flap survival. In New Zealand White rabbits, twin 5 × 10 cm abdominal skin flaps were prepared and the epigastric vein was ligated to produce a model of venous congested skin. After 12 hours, a leech was applied to one of the congested abdominal flaps and skin survivability was assessed and compared with the unleeched flap. Five rabbits died acutely approximately 24 hours post-operatively. Gross necropsy, bacteriology and histopathology findings indicated that A. hydrophila was the causative agent of the septicaemia-toxaemia syndrome with an associated pneumonia and typhlitis. Review of the management and the experimental surgery protocol suggested that the two major disposing factors of Aeromonas septicaemia in these rabbits were stress and excessive prophylactic administration of penicillin.

Recent advances in the study of the taxonomy, pathogenicity, and infectious syndromes associated with the genus Aeromonas

“…Responses in mice were strain dependent and were characterized by epidermal sloughing, alopecia, and/or abscess formation; three avirulent strains produced no observable effect. A potential model for studying Aeromonas wound infections induced by medicinal leech therapy has also been reported (110). This model involves the creation of two abdominal flaps in rabbits by aseptic techniques prior to the application of leeches.…”

Salvage of Venous Congestion Using Medicinal Leeches for Traumatic Nasal Flap

“…Aeromonas hydrophilius found in the gut of the leech aid digestion of the ingested blood and denature ingested haemoglobin. Leeches use the globin and the bacteria use the haem [8,9]. In situ, leeches tend not to move until they have finished feeding, after which they promptly fall off.…”

External decontamination of wild leeches with hypochloric acid

“…Hemoglobin that is sucked by the leech is denaturated by aeromonas . One of the products, heme, is used by aeromonas and the other, globulin, is used by the leech[10]. This shows the endosymbiotic relationship of leeches and aeromonas.…”

“…These are usually susceptible to third generation cephalosporins, aminoglycosides, tetracyclines and quinolones. Lineaweaver et al recommended third generation cephalosporins for the prophylaxis of surgical procedures after which leeches were utilised [10,12]. …”