Abstract
Background:
Infections with Aeromonas spp. are a recognized complication of leech therapy for circulatory complications in replanted digits. Ciprofloxacin is commonly used empirically for Aeromonas coverage in such cases. Evolving resistance patterns of Aeromonas should be considered in designing an antibiotic strategy.
Methods:
Three consecutive patients with complicated replantations had site cultures yielding Aeromonas isolates resistant to ciprofloxacin. These cultures were analyzed to identify effective antibiotic agents.
Results:
Each Aeromonas isolate, and each additional site organism, was sensitive to cefepime.
Conclusion:
Our routine antibiotic coverage for leech application has been changed to cefepime. Aeromonas sensitivities and resistances should be monitored to adapt to future changes in appropriate antibiotics.
Medicinal leeches are a recognized strategy for the treatment of insufficient or absent venous circulation in replanted digits. Leech applications that provide temporary venous circulation can increase the survival of replanted digits having only patent arterial circulation from 20% in digits treated only with anticoagulation to 60%–80% with leech treatment [1–3]. Sufficient venous capillary return can occur across the site of replantation to allow discontinuation of leeches in four to six days [4,5].
Leech therapy can be complicated by infection with Aeromonas hydrophila and related species, which are enteric organisms of the leech. Such infections most commonly occur with leech applications to ischemic or necrotic tissues, and failing and failed replanted fingers provide such environments. The infections can range from low-grade, localized cellulitis to invasive soft-tissue destruction and sepsis [6,7].
Avoidance of Aeromonas infection complicating leech therapy begins with not placing leeches on tissues without arterial inflow or on tissues with devitalized margins or evolving wounds [6]. Antibiotics can play a role in preventing Aeromonas infections associated with leech therapy. This role is based on the observation that leeches ingest antibiotics with their blood meals. Therefore, if a patient is receiving antibiotics at the same time as leech therapy, Aeromonas populations can be suppressed in the leech, so the chance of infection is minimized [8].
Empiric antibiotic therapy presumed to be effective against Aeromonas species is a common adjunct to leech therapy, but the efficacy of antibiotics is related to the susceptibilities of the organism [9]. Ciprofloxacin is commonly used, but increasing Aeromonas resistance patterns are being reported, casting doubt on the reliability of this antibiotic in replanted digits treated with leeches [10].
We recently encountered three cases of ciprofloxacin-resistant Aeromonas contaminating failed finger replants. These cases led us to reconsider our routine antibiotic adjuncts to leech therapy.
Materials and Methods
Three consecutive patients with failed finger replants were identified as having ciprofloxacin-resistant Aeromonas isolates. These patients were analyzed for wound sites, Aeromonas culture sensitivities, and additional bacteria identified in culture.
Results
The three patients underwent finger replantation with vascular complications, leech applications, and eventual failure (Table 1). All three patients had wound cultures positive for Aeromonas, two with A. hydrophila and one with A. veronii. Two of these patients had additional organisms in their site cultures (Table 2).
Profile of Injuries
Pathogens Isolated
The sensitivities of the pathogens are summarized in Table 3. All of the Aeromonas cultured, as well as the other organisms, were resistant to ciprofloxacin. All of the Aeromonas were sensitive to cefepime, as were the other cultured pathogens.
Antibiotic Sensitivities of Organisms Isolated
Intermediate sensitivity.
Discussion
Consistent with frequently reported practice, we routinely administered ciprofloxacin as an adjunct to leech therapy [11]. For decades, however, A. hydrophila and related species identified in leech-related wound cultures have demonstrated evolving patterns of antibiotic resistance. For adjunctive antibiotic administration to be effective, these patterns must be anticipated and defined [12–14]. In addition, multiple organisms should be considered in managing hand injuries. Whereas the Aeromonas flora are derived from leeches, the other organisms reflect the environment of the injuries.
In our three patients, cefepime was effective against the Aeromonas isolates as well as the additional organisms detected in these wounds. We have changed our antibiotic choice related to leech use from ciprofloxacin to cefepime on the basis of the analysis of these cases. These data support the use of carbapenems and aminoglycosides as back-up options in cases of cephalosporin allergy.
Conclusion
Antibiotic administration remains a recognized component of leech therapy, but practices utilizing leeches should monitor the sensitivities of the associated Aeromonas isolates to establish effective antibiotic choices in the eventuality of Aeromonas resistance.
Footnotes
Author Disclosure Statement
The authors have nothing to disclose.