Postprandial Aeromonas hydrophila cultures and antibiotic levels of enteric aspirates from medicinal leeches applied to patients receiving antibiotics.

Increasing use of medicinal leeches has been accompanied by increasing numbers of reports of Aeromonas hydrophila infections after leech application on or near damaged tissue. We examined the enteric contents of postprandial leeches after their application to patients receiving antibiotics. We found measurable levels of antibiotic in the leech enteric contents, and in leeches applied to patients receiving an antibiotic effective against Aeromonas hydrophila, there was a significant decrease in positive Aeromonas enteric cultures. Suppression of leech enteric bacteria by antibiotic administration to the patient may be an effective strategy to prevent invasive infection by Aeromonas hydrophila as well as bacterial colonization of devitalized tissue that could be the source of late infection. Clinical studies will be required to clarify whether suppression of leech enteric flora results in a decrease in infections associated with leech use.     

Antibiotic sensitivities of Aeromonas hydrophila cultured from medicinal leeches

Increased use of medicinal leeches (Hirudo medicinalis) for the treatment of venous congestion in flaps and replanted parts has coincided with reports of soft tissue infections following leech application. We cultured the gullets of 20 medicinal leeches to re-examine the antibiotic sensitivities of Aeromonas hydrophila, the leech enteric organism associated with reported infections. These isolates reflected reported resistance to penicillin and first generation cephalosporins as well as sensitivity to gentamicin, tetracycline and chloramphenicol. Additionally, the cultures were sensitive to cefamandol, cefoxitin and two third generation cephalosporins (cefoperazone and cefotaxime). These findings suggest that cefamandol, cefoxitin and some third generation cephalosporins may have a role as perioperative antibiotics in replantation and flap surgery. These antibiotics might provide prophylaxis against Aeromonas hydrophila infection when leech use is required.     

Aeromonas species isolated from medicinal leeches

Aeromonas hydrophila infections are a recognized complication of the use of medicinal leeches. The authors performed an experiment designed to find a safe and practical way to sterilize the leech gut of pathogenic organisms. Leeches were incubated for a 12-hour period in solutions of antibiotic effective against A. hydrophila. The incubations in the antibiotic solutions failed to eradicate pathogenic bacteria from the gut of the leeches. The authors examined cultures of bacteria isolated from the guts of the commonly used Hirudo medicinalis (European leech) and found a wide variety of pathogenic organisms. A. hydrophila is widely believed to be the most common enteric pathogen, but the authors found A. sobria more frequently in their experiment. They also cultured the guts of the leech H. michaelseni recently used clinically in South Africa. A. caviae was the most common pathogen encountered in these leeches. A. caviae and A. sobria cause a spectra of disease similar to A. hydrophila. The authors endorse the current recommendation that all patients who have leech therapy for congested flaps or replants receive broad-spectrum prophylactic antibiotics. This appears to be the safest and simplest way to prevent leech-related infections.     

Sensitivities of Aeromonas hydrophila cultured from medicinal leeches to oral antibiotics

Infections associated with medicinal leech application are caused by Aeromonas hydrophila, an organism that resides in the leech gut. We cultured the intestinal tracts of 25 leeches and evaluated the efficacy of oral antibiotics against Aeromonas hydrophila. Cultures of this organism showed no sensitivity to ampicillin and inconsistent sensitivity to cephalothin (equivalent to cephalexin). The Aeromonas hydrophila cultures did show consistent sensitivity to ciprofloxacin, tetracycline, and trimethoprim-sulfamethoxasole. These three antibiotics should be considered if oral antibiotic coverage is used in association with leech application.     

Acute postoperative infection with Aeromonas hydrophila after using medical leeches for treatment of venous congestion

Introduction

Venous convulsion after reconstructive microsurgery procedures is one major complication a surgeon has to deal with. Today, especially in the field of reconstructive microsurgery, medicinal leech therapy enjoys a renaissance. The potential risks such as infections associated with leech therapy are generally underestimated and not sufficiently discussed in literature.

Method/patients

We present five male patients with an average age of 47 years. All patients suffered from a trauma incident, which had to be treated as an emergency. Three patients showed, postoperatively, a venous congestion after the reconstructive procedures. Another two patients with flap reconstruction and flap training developed venous problems after 12 and 14 days. In all five cases, the indication was given to use medical leeches (Hirudo medicinalis). In all the patients, a local infection of the injured extremity could be regarded after beginning with the leech treatment. The treatment duration with medical leeches for postoperative venous congestion was an average of 6 days.

Results

The reconstructive procedures in all five cases were unfortunately unsuccessful as major local infections were observed. Microbiological analyses showed, in all cases, an infection with Aeromonas hydrophila.

Conclusion

We recommend making a considered indication for leech therapy, to diagnose wound infections early and to think about prophylactic antibiotics in patients with leech application.     

Leech therapy and bleeding wound techniques to relieve venous congestion

Temporary restoration of capillary skin blood flow can be established by using leeches or by the creation of a dermal wound and the promotion of continued bleeding from the wound site in a flap with venous occlusion. An increasing restoration of capillary flow occurred with initial application of the leech and tended to exceed other techniques of restoring flow. However, all techniques of exsanguination, including leech therapy, restored very low perfusion over a two-hour course of therapy for a volume of tissue simulating a distal finger replant. The temporary increase in flap perfusion with a single leech application was greatest during the feeding activity of the leech and tapered off after the leech was satiated, to approximate flows achieved with local heparin injection and a punch wound.     

Aeromonas hydrophila infection complicating digital replantation and revascularization

Two cases of thumb replantation and one of finger revascularization complicated by Aeromonas hydrophila infection are reported. Two digits were lost because of infection in soft tissue and osteomyelitis. One thumb had extensive necrosis. In all cases the infection was difficult to eradicate, probably because of ischemia. All three patients sustained their injuries while cutting meat or fish. These infection sources have not been previously reported. Note is made of Aeromonas hydrophila in medicinal leeches that are used in microvascular surgery and the potential for iatrogenic infection.     

Determining the appropriate number and duration of leech therapy in congested tissues using tissue spectrophotometry and laser Doppler flowmetry

A universal protocol determining the number of leeches and their application time does not exist. The aim of this study, therefore, is to quantify perfusion dynamics in venous congested tissues after leech application to get more detailed information about changes due to leech‐induced skin microcirculation and to evaluate the usability of the Oxygen to See (O2C) device in terms of determining the appropriate number of leeches and the duration of therapy. Twelve patients with the need for leech therapy participated in the study. Perfusion dynamics of the congested tissue was assessed using the O2C device, which determines blood flow (BF), the relative amount of hemoglobin (rHB), and the oxygen saturation (SO2). Measurements were carried out before leech application and on various intervals like 10 minutes, one hour, and three hours after leech application. The leech application effectuated after 10 minutes a nonsignificant perfusion improvement, which further increased after one hour with a significant reduction of the relative amount of hemoglobin and a significant increase of blood flow and oxygen saturation (BF= +56.7%; rHB= ?25.5%; SO2= +53.7%). After three hours, the values returned to the levels before leech administration. In two cases, in which further administration of leeches within the measurement period was necessary, no substantial perfusion changes were obtained. The results of this study forms a more precise pattern of microcirculatory changes of leech therapy in congested tissues. According to our measurements a venous drainage improvement can be expected in congested tissue one hour after leech administration. The O2C seems to be a useful method to determine the appropriate number and duration of leech therapy.     

Aeromonas hydrophila water-associated traumatic wound infections: a review

The bacterium Aeromonas hydrophila is commonly found in natural bodies of water, and is a potential invasive pathogen for those who suffer trauma while submerged in water. Five patients treated by the authors and 18 previously reported patients were reviewed to further define the characteristics of A. hydrophila wound infections. Although Aeromonas has been isolated from salt and brackish water, all 23 cases occurred following contact with fresh water. Signs of infection usually appeared 8-48 hours following puncture or laceration injury. The foot or leg were most commonly involved. Infection was frequently rapidly progressive; fascia, tendon, muscle, bone, or joint involvement occurred in 39% of cases. In addition to A. hydrophila, other aerobic and anaerobic bacteria were found in 48% of cases. Aeromonas infection should be suspected in cases of early and rapidly progressive wound infection following trauma in fresh water. Broad-spectrum antimicrobial therapy and appropriate surgical care should be promptly instituted.     

A case of septicaemia due to Aeromonas hydrophila

A case of Aeromonas hydrophila septicaemia is reported, arising from the use of leeches in an attempt to salvage a replanted arm. It is believed that this is the first report of this complication.     

Clinical and scientific considerations in leech therapy for the management of acute venous congestion: an updated review

Any surgical intervention that involves the manipulation of veins, large or small, carries the risk of acute venous congestion. Venous congestion is the product of an imbalance between arterial inflow and venous outflow, and results in the stasis of blood in the tissues that are normally drained by the affected veins. The resultant lack of tissue perfusion causes hypoxia, acidosis, and arterial thrombi formation, which can potentially progress to tissue necrosis and wet gangrene. In the past several decades, the use of leeches (Hirudo medicinalis) has been rediscovered as an effective method of relieving acute venous congestion. This updated review of leech therapy focuses on the use of medicinal leeches in a variety of clinical conditions characterized by acute venous congestion, and points out the experimental use of leeches in other pathological entities. A discussion of the recent scientific findings that explain the possible mechanisms of action of leech therapy is also provided.     

Medicinal leeches and the microsurgeon: a four-year study, clinical series and risk benefit review

Background: There are case reports and small series in the literature relating to the use of medicinal leeches by plastic surgeons; however, larger series from individual units are rare. The aim of this article is to present a comprehensive 4‐year case series of the use of medicinal leeches, discuss the current evidence regarding indications, risks, and benefits and highlight the recent updates regarding leech speciation. Methods: Patients prescribed leeches in a 4‐year period (July 2004–2008) were collated from hospital pharmacy records (N = 35). The number of leeches used, demographic, clinical, and microbiological details were retrospectively analyzed. Results: Thirty‐five patients were treated with leeches. The age range was 2 to 98 years (mean = 49.3). Leeches were most commonly used for venous congestion in pedicled flaps and replantations. Blood transfusions were necessary in 12 cases (34%) [mean = 2.8 units, range 2–5 units]. Our infection rate was 20% (7/35) including five infections with Aeromonas spp. (14.2%). The proportion of patients becoming infected after leech therapy was significantly greater in the group of patients that did not receive prophylactic antibiotic treatment (Fisher's Exact test P = 0.0005). In total, 14 cases (40%) were salvaged in entirety, in 7 cases 80% or more, in 2 cases 50 to 79%, and in 1 case less than 50% of the tissues were salvaged. In 11 cases (31%), the tissues were totally lost. Conclusion: Our study highlights both the benefits and the risks to patients in selected clinical situations and also the potential risks. The routine use of antibiotic prophylaxis is supported. In view of the emerging evidence that Hirudo verbana are now used as standard leech therapy, and the primary pathogen is Aeromonas veronii, until a large prospective multicenter study is published, large series of patients treated with leeches should be reported. © 2011 Wiley‐Liss, Inc. Microsurgery, 2011.     

Aeromonas hydrophila wound infection of the hand initially presenting as clostridial myonecrosis

A traumatic hand laceration in a previously health 17-year-old boy resulted in a rapidly progressive palmar space infection, with gas formation, in the soft tissues caused by Aeromonas hydrophila. Typically associated with aquatic injuries, A. hydrophila was not initially suspected since the injury did not occur near water. Physicians treated trauma-related soft tissue infections, particularly when the initial Gram stain shows many polymorphonuclear leukocytes and gram-negative bacilli, must consider the possibility of an Aeromonas infection even if the injury occurred in a nonaquatic environment. Appropriate therapy, including vigorous wound debridement and an aminoglycoside antibiotic, will be curative in an immunologically normal host.     

Digit replantation applying the leech Hirudo medicinalis

Digits that were formerly assessed as nonreplantable may now be replanted with the help of the leech Hirudo medicinalis. The early experience with a series of patients who had relative contraindications for replantation is reported. In each case, venous repair was either marginal or technically impossible. Postoperative venous congestion developed following replantation and was treated with the application of medicinal leeches. Patient acceptance was high, and no infections developed. No patient required transfusion. The authors conclude that the use of medicinal leeches shows promise as a safe and effective method of providing temporary venous drainage in replanted digits.     

Comparing a mechanical device with medicinal leeches for treating venous congestion.

OBJECTIVE: To compare mechanical device therapy to medicinal leech therapy for treating venous congestion. STUDY DESIGN: Fasciocutaneous flaps of 9 x 7-cm (porcine model, n = 11) were elevated and the associated veins clamped for 15 hours. Device-treated flaps (n = 6) were treated with up to 3 devices/flap. Leech-treated flaps (n = 5) were treated with 75 leeches/flap (5 leeches/hour). Treatment evaluation parameters included: blood volume removed, skin color, surface perfusion, tissue oxygen tension, and endpoint histology. RESULTS: No significant differences were seen in blood volume removed, surface perfusion, and oxygen tension. However, significant differences were seen in skin color change over time. Histological assessment showed mild congestion in 5/5 leech-treated flaps and 2/6 device-treated flaps. CONCLUSION: Device therapy was comparable to leech therapy for decongesting a 9 x 7-cm flap over a 15-hour period. However, digital images and significant differences in skin color change over time demonstrate that device therapy promotes more global decongestion versus leech therapy.     

Enterobacter asburiae and Aeromonas hydrophila: soft tissue infection requiring debridement

Enterobacter asburiae and Aeromonas hydrophila are gram-negative bacilli that have been isolated in soil and water. Enterobacter asburiae can cause an array of diseases, and exposure to A hydrophila can cause soft tissue infections, including necrotizing faciitis.A healthy-appearing 22-year-old man presented with an innocuous soft tissue injury to his leg due to an all-terrain vehicle crash. He received intravenous antibiotics and was discharged with prophylactic oral antibiotics. After the rapid onset of high fevers (102°F-103°F) <24 hours postinjury, he returned to the emergency department. Emergent surgical debridement was performed, and broad-spectrum intravenous antibiotics were started. Fevers persisted, and the patient underwent repeat extensive surgical debridement and antibiotic bead placement <30 hours after the initial surgical debridement and broad-spectrum antibiotics. Intraoperative cultures found E asburiae and A hydrophila in the wound. Following a long course of antibiotics and a skin graft, he fully recovered and had no functional deficits 1 year postoperatively.Extensive research revealed that these organisms are rare in soft tissue infections. E asburiae is opportunistic but has not been reported as a primary wound organism, and A hydrophila infections have been reported following motor vehicle crashes involving wound contamination. At presentation, it is challenging to determine rare organisms in a timely fashion; however, emergent extensive surgical intervention of an accelerated aberrant disease process should be considered to avoid catastrophic outcomes.     

Bacterial flora of Hirudo medicinalis and their antibiotic sensitivities in the Middle Black Sea Region, Turkey.

The rate of infectious complications of leech therapy is almost 20% because Hirudo medicinalis has endosymbiotic bacteria. The aim of this study was to determine the bacterial flora of H. medicinalis and their antibiotic sensitivities in a region in Turkey. Sixteen adult leeches were collected in Middle Black Sea region, Turkey. They were rubbed onto blood agar plates directly under ether anesthesia to obtain surface cultures. They were then killed to obtain mouth and gut cultures. Culture swabs were applied to blood agar, eosin methylene blue agar, and ampicillin blood agar plates. Gut contents were applied to blood culture medium as well. Bacteria were isolated in 15 of 16 leech surfaces, in 7 of 16 mouths, and in 15 of 16 guts. Isolated bacteria were identified with Analytical Profile Index 32 E and Analytical Profile Index 20 NE (fermentative and nonfermentative respectively). Most common types of cultured bacteria were Aeromonas hydrophila (N = 25), Ochrobacter anthropi (N = 23), nonfermenting Gram-negative rods (N = 12), Acinetobacter lwoffi (N = 3), and A. sobria (N = 2) in 73 isolates. A standard disk diffusion test was performed on isolated bacteria. All isolates were 100% susceptible to ciprofloxacin, cefotaxime, ceftazidime, gentamicin, and trimethoprim/sulfamethoxazole. Because leeches are carriers of Aeromonas and other bacteria, appropriate antibiotic prophylaxis should be administrated to the patient who needs leech therapy. Antibacterial agents can be determined by the resistance pattern of the bacterial flora of regional H. medicinalis.     

Use of leeches in plastic and reconstructive surgery: a review

Leeches possess properties that make them uniquely able to assist with venous compromised tissue. Their saliva contains an anticoagulant and a histamine-like vasodilator that promote local bleeding, a local anesthetic, and hyaluronidase that promotes the local spread of the other leech salivary secretions into the wound/bite. In addition, active pharyngeal peristalsis further promotes the egress of venous blood. Resurgence in the use of leeches has been stimulated by Upton in the United States and Mahaffey in Europe. Currently, leeches are used at many microsurgical centers to provide critical venous outflow for compromised tissue replantations and transfers that might otherwise be unsalvageable. As the use of leeches becomes more widespread, knowledge of leech biology and physiology is important. This review reports on Hirudo medicinalis, the species used most often medically in Europe and the United States.     

Salvage of partial facial soft tissue avulsions with medicinal leeches

BACKGROUND: Medicinal leeches have been demonstrated to be extremely useful and safe in the salvage of venous outflow compromised tissue, particularly in digit replants and various forms of flaps. OBJECTIVE: To demonstrate the utility of medicinal leeches in the salvage of venous outflow-compromised traumatic soft tissue avulsions in key facial structures. METHODS: A retrospective review of 4 cases involving the external ear, nose, lip, and scalp in which apparent venous outflow compromise was present. Medicinal leeches were applied acutely in each of these 4 cases, salvaging each of the partially avulsed soft tissue segments. RESULTS: Complete or near complete salvage of each soft tissue segment after using medicinal leeches. CONCLUSIONS: Although it is unusual for a partial soft tissue avulsion of the face to require medicinal leech therapy, situations may occur in which there is adequate arterial inflow but inadequate venous outflow. In such cases, medicinal leeches may play a very important role in salvaging the soft tissue segment. This is particularly important in vital structures such as the ear, nose, lip, and eyelid in which acute or secondary reconstruction is complex. EBM RATING: C.     

The role of leech water sampling in choice of prophylactic antibiotics in medical leech therapy

Medical leech therapy (MLT) with Hirudo medicinalis is well established as a treatment for venous congestion of tissue flaps, grafts, and replants. Unfortunately, this treatment is associated with surgical site infections with bacterial species, most commonly Aeromonas hydrophila, which is an obligate symbiot of H. medicinalis. For this reason, prophylactic antibiotics are recommended in the setting of MLT. After culturing Aeromonashydrophila resistant to ciprofloxacin from a tissue specimen from a patient with a failed replant of three digits post‐MLT, we performed environmental surveillance cultures and antibiotic susceptibility testing on water collected from leech tanks. This surveillance was performed twice weekly for 2.5 months. Fourteen surveillance cultures demonstrated 21 isolates of Aeromonas species, 71.4% of which were ciprofloxacin susceptible. All isolates were sulfamethoxazole‐trimethoprim (SXT) susceptible. The prophylactic antibiotic regimen of choice for leech therapy at our institution is SXT, with culture of tank water to refine antimicrobial choice if necessary. This study demonstrates the importance of regular surveillance to detect resistant Aeromonas species in medical leeches; however optimal practice has not been established. © 2013 Wiley Periodicals, Inc. Microsurgery, 2013.