Leeches have been used throughout history for a variety of different medical indications. Over exploitation of medical leech species throughout the 19th century lead to the species becoming threatened. Today medical leeches are breed in special populations.
Medicinal leech therapy is increasing in popularity to assist in wound healing where venous congestion is a problem. Leeches works to reduce the venous congestion by removing blood that can not exit the wound via the venous system. Leeches are colonised with a variety of different bacteria, including Aeromonas sp., that can cause infections in man.
Infection due to leech therapy has been identified as common complication of medicinal leech therapy . When infection occurs the rate of flap salvage decreases resulting in increased morbidity for the patient. The current evidence for leech therapy supports the use of antibiotic prophylaxis to prevent wound infections and sepsis.
The antibiotic chosen should have activity against Aeromonas sp. A number of antibiotics used as prophylaxis in leech therapy are not active against Aeromonas sp and are associated with higher rates of infection. Both sulfamethoxazole- trimethoprim and ciprofloxacin have been used successfully and have been shown to be equally effective . Australian isolates of Aeromonas sp. are generally sensitive to both agents.
Sulfamethoxazole-trimethoprim may present some advantages over ciprofloxacin, particularly in the paediatric population. Ciprofloxacin is not available as a suspension and experience with its use in children is limited. It may also be worth noting that there are a number of case reports of ciprofloxacin resistant Aeromonas infections that have resulted from leech therapy . Resistant organisms have also been isolated from leeches who have not been exposed to human blood.
Antibiotic prophylaxis is an important safety aspect of leech therapy. The antibiotic choice is not as clear, however, the current evidence would suggest both ciprofloxacin and sulfamethoxazole-trimethoprim would be appropriate. Prophylactic antibiotics should be continued throughout therapy.