The role of leech water sampling in choice of prophylactic antibiotics in medical leech therapy
Wilmer A, Slater K, Yip J, Carr N, Grant J (2013) · Microsurgery · n=14
Study Profile
- Design
- prospective microbiological surveillance evaluation study of bacterial isolates and antibiotic susceptibilities in leech tank water sampled twice weekly for 2.5 months (Pathology & Laboratory Medicine, University of British Columbia, Vancouver, Canada)
- Sample size (n)
- 14
- Intervention
- 14 surveillance cultures yielding 21 Aeromonas isolates with antibiotic susceptibility testing; conducted following a clinical incident in which ciprofloxacin-resistant Aeromonas hydrophila was cultured from a failed three-digit replantation after medical leech therapy
- Comparator
- Not applicable — surveillance study with environmental versus clinical isolate cross-comparison
- Primary endpoint
- Proportion of Aeromonas species isolates susceptible to ciprofloxacin versus sulfamethoxazole-trimethoprim (SXT); changes in institutional prophylactic antibiotic policy
- Primary result
- Across 14 surveillance cultures, 21 Aeromonas isolates were recovered; 71.4% were susceptible to ciprofloxacin while 100% were susceptible to sulfamethoxazole-trimethoprim (SXT); institutional policy was changed to SXT as prophylactic antibiotic of choice with periodic culture-based refinement
- Follow-up duration
- 2.5 months of twice-weekly surveillance cultures
- PMID
- 23417901
Key Findings
- Direct link between leech tank water Aeromonas and post-MLT patient infection demonstrated in a Canadian academic center
- 28.6% of environmental Aeromonas isolates were ciprofloxacin-resistant — a clinically significant resistance signal
- 100% of isolates remained susceptible to sulfamethoxazole-trimethoprim (SXT) at this institution
- Demonstrates the value of routine environmental surveillance cultures to refine antibiotic prophylaxis policy
- Adds to the body of evidence that the standard ciprofloxacin prophylaxis is not universally adequate
Limitations
- Single-center Canadian experience — resistance patterns vary geographically and over time
- Case-triggered surveillance design rather than systematic baseline characterization
- Short 2.5-month surveillance period
- Mechanism of resistance acquisition not investigated in this study
- No randomized comparison of antibiotic regimens with patient-level infection outcomes
Clinical Implications
Wilmer 2013 is a foundational safety-surveillance study that should be cited whenever local leech-therapy protocols are designed. The data motivate routine environmental microbiology, demonstrate that ciprofloxacin resistance is real in leech tank water, and support SXT (or culture-tailored alternatives) as a second-line or first-line prophylactic option depending on local Aeromonas susceptibility patterns. For US clinicians, this trial complements Beka 2018 and Reese 2015 in framing the antibiotic-stewardship dimension of leech therapy, particularly under K040187 microsurgical-flap indications where infection signals can compromise tissue salvage.
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