Maggot therapy for the treatment of intractable wounds

Animal healer for refractory diseases: Myth or reality?

A vast amount of knowledge has been acquired through human activities such as farming, hunting, and fishing. Throughout history, humans have utilized living creatures for disease treatment, relying on the natural world's healing powers. The special "healers" may be able to treat patients via the power of nature. However, there was no systematic introduction or summary of these treatments. Therefore, we conducted a literature review based on PubMed, Google Scholar, Web of Science, Scopus, CNKI and WanFang DATA. Here, we defined this unique method as "animal healer" and six common kinds of animal healers were reviewed. These are fish therapy, pet therapy, worm therapy, leech therapy, maggot therapy, and bee therapy. According to the different characteristics of healers, treatment methods mainly included bite, parasitism, contact and communication. With the advantages of green and effectiveness, animal healers have great therapy potential against a variety of refractory diseases. The main purpose of this review is to draw people's attention to animal healer, promote it to become a possible clinical treatment strategy, and make further exploration in species cultivation, mechanism research, animal welfare, standard setting, safety evaluation and other aspects. In the future, animal healers will play an increasingly important role in medicine and hopefully solve more medical problems and dilemmas.

Larval Therapy and Larval Excretions/Secretions: A Potential Treatment for Biofilm in Chronic Wounds? A Systematic Review

Chronic wounds present a global healthcare challenge and are increasing in prevalence, with bacterial biofilms being the primary roadblock to healing in most cases. A systematic review of the to-date knowledge on larval therapy's interaction with chronic-wound biofilm is presented here. The findings detail how larval therapy-the controlled application of necrophagous blowfly larvae-acts on biofilms produced by chronic-wound-relevant bacteria through their principle pharmacological mode of action: the secretion and excretion of biologically active substances into the wound bed. A total of 12 inclusion-criteria-meeting publications were identified following the application of a PRISMA-guided methodology for a systematic review. The findings of these publications were qualitatively analyzed to provide a summary of the prevailing understanding of larval therapy's effects on bacterial biofilm. A further review assessed the quality of the existing evidence to identify knowledge gaps and suggest ways these may be bridged. In summary, larval therapy has a seemingly unarguable ability to inhibit and degrade bacterial biofilms associated with impaired wound healing. However, further research is needed to clarify and standardize the methodological approach in this area of investigation. Such research may lead to the clinical application of larval therapy or derivative treatments for the management of chronic-wound biofilms and improve patient healing outcomes at a time when alternative therapies are desperately needed.

Acknowledging extraordinary women in the history of medical entomology

Throughout history, women have been actively involved in the advancement of science, while struggling to overcome challenges to participate and a lack of recognition. Prior to 1950, most women were not included in the lists of "classical" descriptions of the iconic scientific figures nor included in the most relevant historical accounts. Since the second half of the twentieth century, great efforts have been made to recognize the contributions of women to the advancement of science, especially since formal scientific careers have been dominated by men, with limited (or no) access to women. Despite these challenging social, political and cultural contexts, many women have succeeded in making significant advancements, and their contributions are now being acknowledged. Such efforts have led to the publication of recent reviews and compilations on outstanding women in biological sciences. The field of medical entomology is inherently interdisciplinary, focusing on insects and other arthropods that affect human health, with input primarily from the biological and medical sciences and a strong public health perspective. Several reviews and book chapters describing the history of medical entomology have been published over the decades, but few women are mentioned in these publications, even though many women have contributed to this field. Much of the information on these women is currently scattered throughout the published literature and historical records on a wide range of topics, including activism, virology, vector control and even acarology. Considering that there is no single available compilation of women contributors in the history of medical entomology, this review aims to provide a list of 22 women and their contributions to this field. The list includes women from diverse backgrounds, born in the late 1800s and before 1950, who directly impacted medical entomology in various ways and in different regions of the world. This compilation is far from exhaustive, but it aims to identify role models and examples of extraordinary women to motivate the evolving future of this field.

Clinical outcome of Maggot Debridement Therapy followed by Negative Pressure Wound Therapy for chronic hand wound with Multi-Drug Resistant Organism infection: Two cases and review of the literature

The advancement in science and research has led to development of medical maggots which feed exclusively on dead tissue. Medical maggots have three important functions namely debridement, disinfection, and stimulation of wound healing. The modern use of medical maggots now goes by the term "Maggot Debridement Therapy" (MDT) for use in wound management. MDT is still used infrequently due to the effectiveness of surgical debridement and antibiotics for treatment of wound infection. Lately, there was emergence of Multi-Drug Resistant Organism (MDRO) likely due to inappropriate antibiotics usage. Maggot secretions have been shown to be effective in inhibiting some MDRO, for example, Methicillin-resistant Staphylococcus aureus, thus making MDT an attractive option for wounds with MDRO. We report two patients with multiple medical comorbidities, diagnosed with serious MDRO Diabetic Hand Infections treated with three cycles of MDT followed by Negative Pressure Wound Therapy.

A molecular approach to maggot debridement therapy with Lucilia sericata and its excretions/secretions in wound healing

Chronic wounds caused by underlying physiological causes such as diabetic wounds, pressure ulcers, venous leg ulcers and infected wounds affect a significant portion of the population. In order to treat chronic wounds, a strong debridement, removal of necrotic tissue, elimination of infection and stimulation of granulation tissue are required. Maggot debridement therapy (MDT), which is an alternative treatment method based on history, has been used quite widely. MDT is an efficient, simple, cost-effective and reliable biosurgery method using mostly larvae of Lucilia sericata fly species. Larvae can both physically remove necrotic tissue from the wound site and stimulate wound healing by activating molecular processes in the wound area through the enzymes they secrete. The larvae can stimulate wound healing by activating molecular processes in the wound area through enzymes in their excretions/secretions (ES). Studies have shown that ES has antibacterial, antifungal, anti-inflammatory, angiogenic, proliferative, hemostatic and tissue-regenerating effects both in vivo and in vitro. It is suggested that these effects stimulate wound healing and accelerate wound healing by initiating a direct signal cascade with cells in the wound area. However, the enzymes and peptides in ES are mostly still undefined. Examining the molecular content of ES and the biological effects of these ingredients is quite important to illuminate the molecular mechanism underlying MDT. More importantly, ES has the potential to have positive effects on wound healing and to be used more as a therapeutic agent in the future, so it can be applied as an alternative to MDT in wound healing.

Efficacy of maggot debridement therapy on refractory leg ulcers of Behçet disease: an open-label study

BACKGROUND

Cutaneous ulcers of Behçet disease (BD) are rare but have high morbidity and resistance to conventional therapies. An important and essential aspect of ulcer management is debridement. Regarding maggot therapy (MT), excretions of the green bottle fly, Lucilia sericata, have been shown to have the ability to remove necrotic debris and promote healing.

AIM

To evaluate the efficacy of MT for cutaneous ulcers of BD.

METHODS

In this open-label trial, patients with BD with refractory leg ulcers suitable for MT were enrolled. Maggot application was performed until complete debridement was achieved, and all patients were followed up for 12 months afterwards to assess the total healing of ulcers.

RESULTS

In total, 24 patients with 32 ulcers were enrolled. Using MT, 91.6% of all ulcers were completely debrided. Mean time to debridement was 14.9 days and mean number of cycles required was 5.3. Mean ulcer size was decreased by 23% with treatment. Time to debridement was positively correlated with pretreatment ulcer size and ulcer duration (P = 0.01 and P < 0.01) but not with ulcer depth, comorbidities, smoking, age or sex (P > 0.05 for all). During follow-up, 79.1% of all ulcers healed completely. Mean time required for total healing was positively correlated with ulcer duration, pretreatment and post-treatment ulcer area, ulcer depth and mean time to total debridement (P < 0.03, P = 0.00, P = 0.04 and P < 0.01, respectively).

CONCLUSIONS

To our knowledge, the findings presented in this first and unique study may provide key answers about factors affecting success rate of MT in BD cutaneous ulcers.

Aural Myiasis: A Case Report and Literature Review

Myiasis is a type of parasitosis caused by the larvae of diptera. It commonly occurs in tropical and subtropical zones. The infestation of nose and ears can be extremely dangerous if the larvae destroy the bone and penetrate into the brain, in which case the fatality rate is reported to be as high as 8%. Here, we report a case of aural myiasis in a patient with congenital mental retardation. Twelve maggots were removed mechanically, and the patient was treated with appropriate antibiotics.

Maggot Debridement Therapy in Malaysia

Maggot therapy, also known as maggot debridement therapy, larval therapy, biodebridement, or biosurgery, is a type of biotherapy involving the intentional application of live, disinfected fly larvae or maggots into the nonhealing wound of a human or animal to debride the necrotic wound, reduce bacterial contamination of the wound as well as enhance the formation of healthy granulation tissue and stimulate healing in nonhealing wounds. In addition, van der Plas et al reported that the use of the medicinal larvae as natural remover of necrotic and infected tissue had prevented amputation in 11 selected patients. In Malaysia, Aaron et al had demonstrated prevention of amputation in 25 patients.

Efficacy of UV-C Ray Sterilization of Calliphora vicina (Diptera: Calliphoridae) Eggs for Use in Maggot Debridement Therapy

Maggot debridement therapy (MDT) is a simple wound debridement technique. It is a natural treatment licensed by the Food and Drug Administration (FDA) and is increasingly used in the United States and in Europe. This treatment is safe when the larvae originate from laboratory stocks of eggs that have been sterilized. In this study, a simple, inexpensive microbe decontamination technique is described. It yields eggs that are free of chemical residues and are easy to handle, meeting the growing demand for medicinal larvae in hospitals or medical centers. Three treatments (T1, T2, T3) involving 3, 6, and 12 min of exposure to ultraviolet (UV-C) rays, respectively, were compared. Egg sterility was evaluated by culture in thioglycollate broth, incubated at 32°C ± 2.5°C under aerobic conditions for up to 14 d. The UV-C radiation sterilization process obtained satisfactory results after 12 min exposure (treatment 3). Larval viability was 57%, pupal viability was 54%, and 54% of the adults emerged. The sex ratio was 50%, within the expected values. There were no morphological abnormalities associated to the UV-C treatment in the flies. In conclusion sterilization by UV-C rays is indicated to obtain sterile larvae destined for MDT.

Beneficial effects of extracts from Lucilia sericata maggots on burn wounds in rats

Lucilia sericata maggots have beneficial properties; however, their protective effects on burn wounds have yet to be fully elucidated. In the present study, a deep second‑degree burn rat model was used to investigate the burn wound healing properties of aqueous extract of maggots (MAE). The anti‑inflammatory, antioxidative and antibacterial activities were examined. In addition, the protein expression levels of Akt, vascular endothelial growth factor A (VEGFA) and nuclear factor‑κB (NF‑κB) were detected by western blotting. The findings of the present study revealed that MAE treatment increased burn wound healing and hydroxyproline content in the burn‑treated rats. A total of seven compounds (MAE‑P1‑P7) were separated from MAE and a comparative study was performed to identify the major active component. The results demonstrated that MAE‑P6 exerted greater antibacterial activity compared with the other compounds. MAE‑P6 treatment reduced tissue levels of malondialdehyde, tumor necrosis factor‑α and interleukin‑6, and increased superoxide dismutase activity. Furthermore, MAE‑P6 increased the expression levels of VEGFA and reduced NF‑κB expression through Akt, which was verified by treatment with the Akt‑specific inhibitor, LY294002. In conclusion, the present study demonstrated that the beneficial effects of MAE on burn wound healing were due to its antibacterial, antioxidative and anti‑inflammatory activities. MAE‑P6 reduced the release of inflammatory cytokines via the Akt/NF‑κB signaling pathway, and regulated angiogenesis and vasopermeability via the Akt/VEGFA pathway.

Evaluation of Sterilized Artificial Diets for Mass Rearing the Lucilia sericata (Diptera: Calliphoridae)

The impact of six sterilized diets (blood-yeast agar diet, decomposed beef liver diet, powdered beef liver diet, powdered fish diet, milk-based diet, and a chemically defined diet) on Lucilia sericata (Meigen) larvae reared at three densities (10 larvae, 20 larvae, and 40 larvae on 20 g diet) was determined in comparison to fresh beef liver as a control. Specifically, the effects of these diets on the following traits of L. sericata were measured: 1) pupal weight, 2) pupation percentage, 3) eclosion percentage, as well as 4) adult longevity. The experiment included two trials with five technical replicates in each. Lucilia sericata did not successfully develop on the powdered fish, milk-based, or chemically defined diets. Overall, the liver-based diets (decomposed and powdered) resulted in the most similar fly development to the fresh beef liver. Larvae reared on blood-yeast agar diet resulted in a significantly (increased 20.56% ± 8.09%) greater pupation rate than those reared on the decomposed and powdered beef liver diets. Pupae from larvae fed the fresh beef liver were significantly larger (6.27 ± 1.01 mg, 4.05 ± 0.94 mg larger, respectively) than those reared on the blood-yeast agar diet, decomposed beef liver, and powdered beef liver diets. Overall, results revealed larvae reared on sterilized liver-based diets resulted in traits similar to those raised on fresh beef liver. Owing to low costs the sterile liver-based diets could be produced and used with limited infrastructure and economic incomes.

Maggot Debridement Therapy in the Palliative Setting

Success rates of Maggot Debridement Therapy (MDT) differ, but range from 70% to 80%. In this article it is argued that wound closure is not always feasible and is not always the aim of the treatment. A patient is described in whom the intent of MDT was not wound closure, but infection removal, reduction of odor, and eventually prevention of a below knee amputation. This succeeded: the pain was diminished, the odor reduced, and the wound showed signs of healing. Still the patient died. In maggot literature, as with other wound treatments, outcome is recorded as closed or as failed. In our opinion, MDT has other indications besides wound closure.

Viability of Lucilia sericata maggots after exposure to wound antiseptics

After debridement and before dressing a wound with maggots of calliphorid flies, one frequently performed step is the application of antiseptics to the prepared wound bed. However, the concomitant application of antiseptic agents during maggot therapy is regarded controversial as antiseptics may interfere with maggots' viability. In this experimental in vitro study, the viability of fly maggots was investigated after exposure to various antiseptics frequently used in wound care. Here, we show that Lucilia sericata fly maggots can survive up to an hour's exposure to wound antiseptics such as octenidine, povidone-iodine or polihexanide. Concomitant short-term application of wound antiseptics together with maggots on wound beds is tolerated by larvae and does not impair their viability.

Developmental Variation of Indian Thermophilic Variety of Scuttle Fly Megaselia (Megaselia) scalaris (Loew, 1866) (Diptera: Phoridae) on Different Substrates

The scuttle flies (Diptera: Phoridae) are important in forensic dipterology, because of their necrophagous habit. They are amongst the first wave of insects visiting human corpses in mechanically barricaded environments; hence their immature stages are generally used for estimation of PMI. The effect of different substrates commonly used for developmental studies was studied to analyze the variation of growth of the thermophilic variety of Megaselia (M.) scalaris prevalent in India on GDM, EDM, and SMS (n = 3). One approach of PMI estimation depends on larvae collected from the crime scene and comparing them with reference data derived from larval rearing to establish PMI. Results showed that there was a significant variation in avg. length (F(2,111) = 15.79873, p = 0.000000917), width (F(2,111) = 14.60528, p = 0.00000234), and biomass (F(2,111) = 37.01727, p = 0.000000000000482) of the immature stages in the three media and the larvae grow maximally in the SMS medium. The results of the present study thus provide baseline data on the growth and developmental pattern of the Megaselia (M.) scalaris, which can be utilized in conjunction with specific geoclimatic reference data, for forensic entomological studies and also for using the phorid as a biocontrol agent of pestiferous insects.

Maggot Debridement Therapy for Chronic Wounds

This article presents a general overview of maggot debridement therapy, as used in the management of chronic infected wounds. Much has been written about this treatment method, both historically and in the past decade. Current clinical practice is discussed and clinical and laboratory research are reviewed, with attention to the inherent challenges of such research. The nature of microbial and fungal bio-film formation in chronic wounds is considered, although little is yet known of the extent and characterization of this phenomenon. The prospects for the future are addressed. These include the need for globally acceptable criteria for clinical outcomes and guidelines for “best practice,” together with the pressing need for appropriately structured randomized controlled studies.

Diabetic foot disease: From the evaluation of the “foot at risk” to the novel diabetic ulcer treatment modalities

The burden of diabetic foot disease (DFD) is expected to increase in the future. The incidence of DFD is still rising due to the high prevalence of DFD predisposing factors. DFD is multifactorial in nature; however most of the diabetic foot amputations are preceded by foot ulceration. Diabetic peripheral neuropathy (DPN) is a major risk factor for foot ulceration. DPN leads to loss of protective sensation resulting in continuous unconscious traumas. Patient education and detection of high risk foot are essential for the prevention of foot ulceration and amputation. Proper assessment of the diabetic foot ulceration and appropriate management ensure better prognosis. Management is based on revascularization procedures, wound debridement, treatment of infection and ulcer offloading. Management and type of dressing applied are tailored according to the type of wound and the foot condition. The scope of this review paper is to describe the diabetic foot syndrome starting from the evaluation of the foot at risk for ulceration, up to the new treatment modalities.

Next Generation Sequencing Identifies Five Major Classes of Potentially Therapeutic Enzymes Secreted by Lucilia sericata Medical Maggots

Lucilia sericata larvae are used as an alternative treatment for recalcitrant and chronic wounds. Their excretions/secretions contain molecules that facilitate tissue debridement, disinfect, or accelerate wound healing and have therefore been recognized as a potential source of novel therapeutic compounds. Among the substances present in excretions/secretions various peptidase activities promoting the wound healing processes have been detected but the peptidases responsible for these activities remain mostly unidentified. To explore these enzymes we applied next generation sequencing to analyze the transcriptomes of different maggot tissues (salivary glands, gut, and crop) associated with the production of excretions/secretions and/or with digestion as well as the rest of the larval body. As a result we obtained more than 123.8 million paired-end reads, which were assembled de novo using Trinity and Oases assemblers, yielding 41,421 contigs with an N50 contig length of 2.22 kb and a total length of 67.79 Mb. BLASTp analysis against the MEROPS database identified 1729 contigs in 577 clusters encoding five peptidase classes (serine, cysteine, aspartic, threonine, and metallopeptidases), which were assigned to 26 clans, 48 families, and 185 peptidase species. The individual enzymes were differentially expressed among maggot tissues and included peptidase activities related to the therapeutic effects of maggot excretions/secretions.

Towards next generation maggot debridement therapy: transgenic Lucilia sericata larvae that produce and secrete a human growth factor

BACKGROUND

Diabetes and its concurrent complications impact a significant proportion of the population of the US and create a large financial burden on the American health care system. FDA-approved maggot debridement therapy (MDT), the application of sterile laboratory-reared Lucilia sericata (green bottle fly) larvae to wounds, is a cost-effective and successful treatment for diabetic foot ulcers and other medical conditions. Human platelet derived growth factor-BB (PDGF-BB) is a secreted dimeric peptide growth factor that binds the PDGF receptor. PDGF-BB stimulates cell proliferation and survival, promotes wound healing, and has been investigated as a possible topical treatment for non-healing wounds. Genetic engineering has allowed for expression and secretion of human growth factors and other proteins in transgenic insects. Here, we present a novel concept in MDT technology that combines the established benefits of MDT with the power of genetic engineering to promote healing. The focus of this study is to create and characterize strains of transgenic L. sericata that express and secrete PDGF-BB at detectable levels in adult hemolymph, whole larval lysate, and maggot excretions/ secretions (ES), with potential for clinical utility in wound healing.

RESULTS

We have engineered and confirmed transgene insertion in several strains of L. sericata that express human PDGF-BB. Using a heat-inducible promoter to control the pdgf-b gene, pdgf-b mRNA was detected via semi-quantitative PCR upon heat shock. PDGF-BB protein was also detectable in larval lysates and adult hemolymph but not larval ES. An alternative, tetracycline-repressible pdgf-b system mediated expression of pdgf-b mRNA when maggots were raised on diet that lacked tetracycline. Further, PDGF-BB protein was readily detected in whole larval lysate as well as larval ES.

CONCLUSIONS

Here we show robust, inducible expression and production of human PDGF-BB protein from two conditional expression systems in transgenic L. sericata larvae. The tetracycline-repressible system appears to be the most promising as PDGF-BB protein was detectable in larval ES following induction. Our system could potentially be used to deliver a variety of growth factors and anti-microbial peptides to the wound environment with the aim of enhancing wound healing, thereby improving patient outcome in a cost-effective manner.

Maggot Debridement Therapy in Disaster Medicine

BACKGROUND

When disaster strikes, the number of patients requiring treatment can be overwhelming. In low-income countries, resources to assist the injured in a timely fashion may be limited. As a consequence, necrosis and wound infection in disaster patients is common and frequently leads to adverse health outcomes such as amputations, chronic wounds, and loss of life. In such compromised health care environments, low-tech and cheap wound care options are required that are in ready supply, easy to use, and have multiple therapeutic benefits. Maggot debridement therapy (MDT) is one such wound care option and may prove to be an invaluable tool in the treatment of wounds post-disaster.

DISCUSSION

This report provides an overview of the wound burden experienced in various types of disaster, followed by a discussion of current treatment approaches, and the role MDT may play in the treatment of complex wounds in challenging health care conditions. Maggot debridement therapy removes necrotic and devitalized tissue, controls wound infection, and stimulates wound healing. These properties suggest that medicinal maggots could assist health care professionals in the debridement of disaster wounds, to control or prevent infection, and to prepare the wound bed for reconstructive surgery. Maggot debridement therapy-assisted wound care would be led by health care workers rather than physicians, which would allow the latter to focus on reconstructive and other surgical interventions. Moreover, MDT could provide a larger window for time-critical interventions, such as fasciotomies to treat compartment syndrome and amputations in case of life-threatening wound infection.

RECOMMENDATIONS

There are social, medical, and logistic hurdles to overcome before MDT can become widely available in disaster medical aid. Thus, research is needed to further demonstrate the utility of MDT in Disaster Medicine. There is also a need for reliable MDT logistics and supply chain networks. Integration with other disaster management activities will also be essential.

CONCLUSIONS

In the aftermath of disasters, MDT could play an important role facilitating timely and efficient medical treatment and improving patient outcomes. Existing social, medical, and logistic barriers will need to be overcome for MDT to be mainstreamed in Disaster Medicine.

Growth and survival of blowfly Lucilia sericata larvae under simulated wound conditions: implications for maggot debridement therapy

Maggot debridement therapy has become a well-established method of wound debridement. Despite its success, little information is available about the optimum duration of the treatment cycle and larval growth in wounds. This study examines the development of Lucilia sericata (Diptera: Calliphoridae) larvae under two containment conditions (bagged and free range) under simulated wound conditions and assesses the impact of transport and further storage of larvae on their survival and growth. There was no significant difference in size between bagged and free-range larvae over the 72-h experimental period. Larvae grew fastest 8-24 h after inoculation and completed their growth at 40-48 h. Mortality rates were similar (0.12-0.23% per hour) in both containment conditions and did not differ significantly (P = 0.3212). Survival of free-range larvae was on average 16% lower than survival of bagged larvae. Refrigeration of larvae upon simulated delivery for > 1 day reduced their survival to < 50% and caused a reduction in growth of up to 30% at 12 h, but not at 48 h, of incubation. Therefore, it is recommended that free-range larvae are left in the wound for a maximum of 40-48 h, and bagged larvae for 48-72 h. Larvae should be used within 24 h of delivery to avoid high mortality caused by prolonged refrigeration.

Maggots as potential vector for pathogen transmission and consequences for infection control in waste management

BACKGROUND AND AIMS

Debridement therapy with sterile bred larvae in non-healing wounds is a widely accepted safe and efficient treatment modality. However, during application in the contaminated wound bed microbial contamination with potential microbial pathogen spread after escape from the wound or after unreliable disposal procedure may happen, particularly in the case of not using bio-bags. The aims of this work were first to investigate the release of ingested bacteria into the environment by maggots and second to examine the common practice of freezing the maggots after use and/or disposal in trash-bags. Potential methods for hygienic safe disposal of used maggots should be deduced.

METHODS

First, Maggots were contaminated with S. aureus by allowing them to crawl over an agar surface completely covered with bacterial growth over 24 h at 37°C. After external disinfection maggots were transferred onto sterile Columbia agar plates and shedding of S. aureus was visualized. Second, maggots were frozen at -20°C for 1, 2, 5, 10, 30, and 60 min. After exposure, the larvae were transferred onto Columbia blood agar with consecutive incubation at 37°C over 48 h. The larvae were analyzed visually for mobility and eating activities. The frozen bodies of dead larvae were examined for viable bacteria.

RESULTS

We could demonstrate that maggots release formerly ingested pathogens (S. aureus). Freezing at -20°C for at least 60 min was able to kill all maggots, however the contaminant bacteria inside could survive.

CONCLUSION

Since freezing is apparently able to kill maggots but not to reliabely inactivate the ingested bacterial pathogens, we recommend the disposal of free-range larvae in screw cap vials after use to achieve full hygienic control.

Lucimycin, an antifungal peptide from the therapeutic maggot of the common green bottle fly Lucilia sericata

We report the identification, cloning, heterologous expression and functional characterization of a novel antifungal peptide named lucimycin from the common green bottle fly Lucilia sericata. The lucimycin cDNA was isolated from a library of genes induced during the innate immune response in L. sericata larvae, which are used as therapeutic maggots. The peptide comprises 77 amino acid residues with a molecular mass of 8.2 kDa and a pI of 6.6. It is predicted to contain a zinc-binding motif and to form a random coil, lacking β-sheets or other secondary structures. Lucimycin was active against fungi from the phyla Ascomycota, Basidiomycota and Zygomycota, in addition to the oomycete Phytophtora parasitica, but it was inactive against bacteria. A mutant version of lucimycin, lacking the four C-terminal amino acid residues, displayed 40-fold lower activity. The activity of lucimycin against a number of highly-destructive plant pathogens could be exploited to produce transgenic crops that are resistant against fungal diseases.

Sarconesiopsis magellanica (Diptera: Calliphoridae) excretions and secretions have potent antibacterial activity

The most important mechanism for combating infection using larval therapy depends on larval excretions and secretions (ES). The present work was aimed at evaluating Sarconesiopsis magellanica (Diptera: Calliphoridae) ES antibacterial activity in six bacterial strains (three Gram-positive and three Gram-negative) and comparing this to the effect of Lucilia sericata-derived ES. Antibacterial activity at 50μg/mL minimum inhibitory concentration (MIC) was observed for Staphylococcus epidermidis ATCC-12228 and Staphylococcus aureus ATCC-29213 strains, when the turbidimetry test involving S. magellanica ES was used; the rest of the bacterial strains (Staphylococcus aureus ATCC-6538, Pseudomonas aeruginosa ATCC-10145, Pseudomonas aeruginosa ATCC-9027 and Pseudomonas aeruginosa ATCC-27853) were inhibited at a 100μg/mL MIC. Twice the amount was required to inhibit the aforementioned bacteria with L. sericata-derived ES using this same technique; a similar trend was observed when the agar diffusion method was used instead. Furthermore, when the previously established MIC for each bacterial strain was used, their colonies became reduced following 1-6h incubation with S. magellanica derived ES, whilst the reduction occurred from 2 to 6hours with those from L. sericata. Although the MIC for each strain obtained with ciprofloxacin was lower than those established when using either blowfly derived-ES, the gradual reduction of the colonies occurred at a longer incubation time (6h or more). The results showed that S. magellanica ES antibacterial activity was more potent and effective, compared to that of L. sericata-derived ES.

[Microbial stress of skin and wounds in clinical aspects and practice. Between search and destroy and monitor and relax]

The antibiotic treatment of microbial pathogens of the skin and wounds could so far not fulfil the expectations of an effective and permanent elimination of pathogens so that local treatment with antiseptic agents as a flanking measure to wound cleansing and debridement has become increasingly more established. Because an antiseptic treatment does not actually represent a treatment of infections, the current antimicrobial treatment strategy for infections in skin and wound areas consists of combined antibiotic and flanking antiseptic administration following debridement. However, the combined therapy is not always successful. There is an urgent need for new forms of therapy particularly to combat multiresistant pathogens in biofilms in infections of chronic and other complicated wounds.

Sterilization of Chrysomya putoria (Insecta: Diptera: Calliphoridae) eggs for use in biotherapy

Large-scale, quality-controlled laboratory production of fly larvae is needed for biotherapy. The objective of this study was to assess the action of glutaraldehyde on the sterilization of Chrysomya putoria eggs by applying pharmaceutical sterility tests. Egg masses with 0.600 g were divided into three parts of 0.200 g, the eggs were separated using sterile distilled water, and the suspensions obtained were mixed with activated 2% glutaraldehyde solution. After 15-min contact, the suspensions were filtered through Whatman filter paper, and the glutaraldehyde residue obtained in the filtrate was neutralized by rinsing with Tryptone Soy Broth. The treated eggs were placed aseptically on Petri dishes containing gauze moistened with sterile saline solution. About 10% of the sterilized mass was transferred to test tubes containing Tryptone Soy Broth and Fluid Thioglycollate Broth. The tubes were incubated, respectively, at 22.5 and 35.0°C for 14 d to verify egg mass sterility. The plates containing the rest of the eggs (90%) were sealed with plastic film and kept in a climatized chamber at 30°C/d, 28°C per night, 60 ± 10% relative humidity, and under a 12-h light period to assess insect viability and survival. Each experiment was carried out in triplicate using a biological class II safety cabinet. No change in color or turgidity was observed with the agent tested, proving the sterility of the product and that there was no trace of contamination. Forty larvae (in three replications) in the periods of 12, 24, and 48 h after sterilization, when transferred to diet, produced larvae, pupae, and total viability similar to the control (larvae without sterilization). However, for the 72-h treatment, larvae and total viability were significantly lower than for the other treatments. There was no significant difference for the pupal stage. The product tested was shown to be efficacious for use as a sterilizer of C. putoria eggs for all the parameters assessed.

Growth and Survival of Bagged Lucilia sericata Maggots in Wounds of Patients Undergoing Maggot Debridement Therapy

Maggot debridement therapy (MDT) is an established method of debridement of nonhealing wounds. Despite intense clinical research about its efficacy and effects of substances produced by the larvae, growth and development of maggots in the wounds remain largely unexplored. In the present study, the bags with larvae (n = 52), which had been used to debride traumatic, ischemic, diabetic and venous ulcers, were collected and examined. Survival, length, width and larval instar of the maggots within each bag were recorded and analyzed with respect to the wound type and duration of the treatment. Survival of maggots after a 48-h cycle of MDT ranged between 63.6 and 82.7%. Maggots in venous ulcers had on average 9–19% higher mortality than maggots within traumatic, ischemic, and diabetic ulcers. Length of larvae after 48 h cycle of MDT reached on average 7.09–9.68 mm, and average width varied between 1.77 and 2.26 mm. Larvae in venous ulcers were significantly smaller after 48 h, but not after 72 h treatment compared to the other wound types. Further studies should be aimed to identify other patient-associated factors which might influence growth and survival of the larvae during maggot debridement therapy.

Maggot debridement therapy for peripheral arterial disease

INTRODUCTION

Maggots are potent debriding agents capable of removing necrotic tissue and slough; however, it is still unclear which wounds are most likely to benefit from maggot debridement therapy (MDT). Thus, we performed this retrospective review to gain insight into the patient and therapy characteristics influencing outcome.

PATIENTS AND METHODS

We reviewed patients with foot ulcers caused by critical limb ischemia, encountered during the period between June 2005 and May 2010. The treatment outcomes were defined as effective or ineffective.

RESULTS

There were 16 patients with 16 leg ulcers. The patients were 13 men and 3 women, with an average age of 67.2 years (range, 47-85 years). Ten (63%) of the 16 ulcers were treated effectively. According to univariate analyses, an ankle brachial pressure index (ABI) lower than 0.6 (p = 0.03) had a negative impact on the outcome of MDT; however, outcome was not influenced by gender, obesity, ischemic heart disease, diabetes mellitus, hemodialysis, smoking, or laboratory findings.

CONCLUSIONS

Some patient characteristics, such as gender, obesity, ischemic heart disease, diabetes mellitus, hemodialysis, and smoking, do not seem to contraindicate eligibility for MDT. However, a limb with an ABI lower than 0.6 is less likely to benefit. (English Translation of J Jpn Coll Angiol 2011; 51: 209-213.).

The use of split-thickness skin grafts on diabetic foot ulcerations: a literature review

Diabetic foot ulcerations are historically difficult to treat despite advanced therapeutic modalities. There are numerous modalities described in the literature ranging from noninvasive topical wound care to more invasive surgical procedures such as primary closure, skin flaps, and skin grafting. While skin grafting provides faster time to closure with a single treatment compared to traditional topical wound treatments, the potential risks of donor site morbidity and poor wound healing unique to the diabetic state have been cited as a contraindication to its widespread use. In order to garner clarity on this issue, a literature review was undertaken on the use of split-thickness skin grafts on diabetic foot ulcers. Search of electronic databases yielded four studies that reported split-thickness skin grafts as definitive means of closure. In addition, several other studies employed split-thickness skin grafts as an adjunct to a treatment that was only partially successful or used to fill in the donor site of another plastic surgery technique. When used as the primary closure on optimized diabetic foot ulcerations, split-thickness skin grafts are 78% successful at closing 90% of the wound by eight weeks.

A de novo transcriptome assembly of Lucilia sericata (Diptera: Calliphoridae) with predicted alternative splices, single nucleotide polymorphisms and transcript expression estimates

The blow fly Lucilia sericata (Diptera: Calliphoridae) (Meigen) is a nonmodel organism with no reference genome that is associated with numerous areas of research spanning the ecological, evolutionary, medical, veterinary and forensic sciences. To facilitate scientific discovery in this species, the transcriptome was assembled from more than six billion bases of Illumina and twenty-one million bases of 454 sequence derived from embryonic, larval, pupal, adult and larval salivary gland libraries. The assembly was carried out in a manner that enabled identification of putative single nucleotide polymorphisms (SNPs) and alternative splices, and that provided expression estimates for various life history stages and for salivary tissue. The assembled transcriptome was also used to identify transcribed transposable elements in L. sericata. The results of this study will enable blow fly biologists, dipterists and comparative genomicists to more rapidly develop and test molecular and genetic hypotheses, especially those regarding blow fly development and salivary gland biology.

Polymicrobial interactions: impact on pathogenesis and human disease

Microorganisms coexist in a complex milieu of bacteria, fungi, archaea, and viruses on or within the human body, often as multifaceted polymicrobial biofilm communities at mucosal sites and on abiotic surfaces. Only recently have we begun to appreciate the complicated biofilm phenotype during infection; moreover, even less is known about the interactions that occur between microorganisms during polymicrobial growth and their implications in human disease. Therefore, this review focuses on polymicrobial biofilm-mediated infections and examines the contribution of bacterial-bacterial, bacterial-fungal, and bacterial-viral interactions during human infection and potential strategies for protection against such diseases.

Insect natural products and processes: new treatments for human disease

In this overview, some of the more significant recent developments in bioengineering natural products from insects with use or potential use in modern medicine are described, as well as in utilisation of insects as models for studying essential mammalian processes such as immune responses to pathogens. To date, insects have been relatively neglected as sources of modern drugs although they have provided valuable natural products, including honey and silk, for at least 4-7000 years, and have featured in folklore medicine for thousands of years. Particular examples of Insect Folk Medicines will briefly be described which have subsequently led through the application of molecular and bioengineering techniques to the development of bioactive compounds with great potential as pharmaceuticals in modern medicine. Insect products reviewed have been derived from honey, venom, silk, cantharidin, whole insect extracts, maggots, and blood-sucking arthropods. Drug activities detected include powerful antimicrobials against antibiotic-resistant bacteria and HIV, as well as anti-cancer, anti-angiogenesis and anti-coagulant factors and wound healing agents. Finally, the many problems in developing these insect products as human therapeutic drugs are considered and the possible solutions emerging to these problems are described.

Maggot debridement therapy for postsurgical wound infection in scoliosis: a case series in five patients

STUDY DESIGN

Case series of 5 patients who developed resistant wound infection after scoliosis surgery.

OBJECTIVE

To present maggot debridement therapy (MDT) as an effective alternative to the conventional treatment in postsurgical infection in scoliosis.

SUMMARY OF BACKGROUND DATA

Numerous clinical reports have been published that describe outstanding effects of MDT, most notable on debridement, cleansing, disinfection, and healing of indolent wounds, many of which have previously failed to respond to conventional treatment. However, till date no reports have been found in the literature describing its use for the treatment of wound infection after scoliosis surgery, which has relatively longer and deeper wound.

METHODS

A total of 5 patients (2 females and 3 males) who developed wound infection after scoliosis correction surgery were included in this study. All were operated for neuromuscular scoliosis using posterior approach with pedicle screw fixation. All developed deep wound infection within 2 to 6 weeks of surgery, which was resistant to all kinds of conventional therapy. MDT applied in all using prepared commercially available maggot bags, and dressing was changed twice a week till wound shows signs of healing. After confirming negative culture, MDT was stopped and routine dressings or secondary closure was done. During the treatment, wound appearance, size, and development of healing were observed.

RESULTS

There were 1 patient with paralytic scoliosis and 4 with cerebral palsy. All wound healed completely within 5.2 ± 1.8 weeks of MDT or 8.8 ± 3.8 cycles of MDT. There was no recurrence on final follow-up of 21.6 ± 5.9 months. Wound size was also decreased from 24.2 ± 3.3 cm of pre-MDT to 11.8 ± 4.5 cm post-MDT showing 51.2% reduction in wound size. There was partial implant removal in 2 cases before MDT; however, no further implant extraction was needed in any case after MDT. Treatment was tolerated well by all patients without any obvious complications due to MDT.

CONCLUSION

We would propose to use MDT for the treatment of wound infection after scoliosis surgery as an effective alternative to conventional treatment. In this way, implant extraction could be avoided without losing any correction.

Clinical research on the bio-debridement effect of maggot therapy for treatment of chronically infected lesions

OBJECTIVE

To evaluate the bio-debridement effect of maggot therapy for treating chronically infected lesions.

METHODS

A retrospective study was conducted of 25 patients with diabetic foot ulcers and 18 patients with pressure ulcers after spinal cord injury treated by maggot therapy or traditional dressing. Changes in the lesions were observed and bacterial cultures tested.

RESULTS

All ulcers healed completely. The times taken to achieve bacterial negativity, granulation and healing of lesions were all significantly shorter in the maggot therapy group than in the control group, both for diabetic foot ulcers (P < 0.05) and pressure ulcers (P < 0.05).

CONCLUSION

Maggot therapy is a safe and effective method for treating chronically infected lesions.

Fatty acid extracts from Lucilia sericata larvae promote murine cutaneous wound healing by angiogenic activity

BACKGROUND

fatty acids are considered to be effective components to promote wound healing and Lucilia sericata larvae are applied clinically to treat intractable wounds. We aimed to investigate the effect of fatty acid extracts from dried Lucilia sericata larvae on murine cutaneous wound healing as well as angiogenesis.

RESULTS

On day 7 and 10 after murine acute excision wounds creation, the percent wound contraction of fatty acid extracts group was higher than that of vaseline group. On day 3, 7 and 10 after wounds creation, the wound healing quality of fatty acid extracts group was better than that of vaseline group on terms of granulation formation and collagen organization. On day 3 after wounds creation, the micro vessel density and vascular endothelial growth factor expression of fatty acid extracts group were higher than that of vaseline group. Component analysis of the fatty acid extracts by gas chromatography-mass spectrometry showed there were 10 kinds of fatty acids in total and the ratio of saturated fatty acid, monounsaturated fatty acid and polyunsaturated fatty acid (PUFA) was: 20.57%:60.32%:19.11%.

CONCLUSIONS

Fatty acid extracts from dried Lucilia sericata larvae, four fifths of which are unsaturated fatty acids, can promote murine cutaneous wound healing probably resulting from the powerful angiogenic activity of the extracts.

[Wounds with different aetiology treated using larval debridement therapy: presentation of two cases]

This paper describes two cases of wounds with different aetiology and dissimilar size which were treated with Larval Debridement Therapy. Two different techniques of Larval Debridement were used for each case: Free Range and BioFoam larvae. Observations and treatment were carried out in a Primary Health Centre in Barcelona, Spain. The application and observations were performed by two nurses with the collaboration of two family physicians. The Larval Therapy efficacy outcome was checked with an Ulcer Reverse Stage Scale (PUSH v2), by taking photographs and a Visual Analogue Pain Scale (VAPS) was completed by both subjects before and after the treatment. It was observed in both cases that the larval therapy caused debridement of all fibrin and collagen tissue, and the slough dropped to a normal level. As a consequence of this change the PUSH scale punctuations were improved. On the negative side, the therapy was associated with an increase in pain. The beneficial effect of applying Larval Therapy enables following a basic wound healing care plan. The larval debridement therapy did not pose any threat for the patients; they could go about their Activities of the Daily Life (ADL) without any change. These wound cases treated with larval debridement therapy are the first ones reported in the Primary Health Care field in Spain.

Flies in the ointment: a morphological and molecular comparison of Lucilia cuprina and Lucilia sericata (Diptera: Calliphoridae) in South Africa

Complementary nuclear (28S rRNA) and mitochondrial (COI) genes were sequenced from blowflies that phenotypically resembled Lucilia cuprina (W.), Lucilia sericata (Meigen) or exhibited characters of both species. The aim was to test a long-held hypothesis that these species hybridize under natural conditions in South Africa (Ullyett, 1945). Blowflies were obtained predominantly from the Cape Town metropolitan area, but reference samples were acquired for L. sericata from Pretoria. Several L. cuprina-like flies were shown to possess a conflicting combination of nuclear and mitochondrial genes that has also been seen in Hawaiian specimens. Homoplasy, sampling of pseudogenes, hybridization and incomplete lineage sorting are discussed as possible hypotheses for the pattern and the latter is concluded to represent the most likely explanation.

Maggot debridement therapy: a case study

A 59-year-old woman arrived at Vancouver General Hospital after a motor vehicle accident in which she sustained massive degloving injuries to both lower extremities. Due to her faith (she is a Jehovah's Witness), traditional interventions such as surgical debridement and revision were not possible and consent to receive blood products was not provided. WOC nursing was consulted at the request of the family to utilize maggot debridement therapy (MDT) to treat her necrotic lower extremities. Initially, the use of the Lucilia sericata larvae (maggots) was viewed as a last effort to save the patient from septicemia while awaiting surgery. However, after MDT was applied once a week for a period of 6 weeks, both legs were rendered free of necrotic tissue. The patient is now free of infection and awaiting surgery for placement of skin grafts over healthy granulation tissue achieved after MDT.

Antioxidant activities of protein-enriched fraction from the larvae of housefly, Musca domestica

The protein-enriched fraction (PEF) was isolated and purified from the larvae of housefly, Musca domestica. This study was designed to investigate amino acid compositions, antioxidative effects and protective effects of PEF on red blood cell (RBC) hemolysis, lipid peroxidation. The effects of PEF treatment were studied on aged mice liver lipid peroxidation and antioxidant enzyme activities, which included superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px).

RESULTS

PEF not only inhibited H(2)O(2) stimulated oxidative hemolysis of erythrocytes of mice, but also depressed malondialdehyde (MDA) production in mice liver homogenate by auto-oxidation and hepatic mitochondria expanded induced by Fe(2+)-ascorbic acid system. Compared to control group, treatments of PEF significantly increases SOD and GSH-Px activity of serum and liver homogenate in aged mice. MDA level of serum and liver homogenate decreased significantly in aged mice. In conclusion, this study demonstrates that PEF possesses antioxidative activity and might be a valuable source of natural antioxidative agents.

Biologia da mosca Phaenicia sericata em diferentes substratos

Dípteros da espécie Phaenicia sericata foram capturadas e mantidas em gaiolas teladas para avaliação de seu ciclo biológico e definição do melhor substrato para postura e desenvolvimento larval em temperatura e umidade constante (27°C e 80% UR). Foram utilizados quatro substratos em decomposição; carne bovina, de frango e de peixe bem como fígado bovino. Os três primeiros substratos não diferiram estatisticamente entre si quanto à preferência das moscas e no fígado não houve postura. Os mesmos substratos foram utilizados para alimentação das larvas, sendo observado não haver interferência no período larval. Observou-se também que a cópula ocorreu cinco dias após a pupação e a postura seis dias após a cópula. A longevidade das moscas adultas foi em média de 37 dias quando alimentadas com mel e água. Com base nesses resultados observou-se que o ciclo biológico da P. sericata foi em média de 51 dias em laboratório.

Maggot debridement therapy of infected ulcers: patient and wound factors influencing outcome - a study on 101 patients with 117 wounds

INTRODUCTION

It has been known for centuries that maggots are potent debriding agents capable of removing necrotic tissue and slough. In January 2004, the US Food and Drug Administration decided to regulate maggot debridement therapy (MDT). As it is still not clear which wounds are likely or unlikely to benefit from MDT, we performed a prospective study to gain more insight in patient and wound characteristics influencing outcome.

PATIENTS AND METHODS

In the period between August 2002 and December 2005, patients with infected wounds with signs of gangrenous or necrotic tissue who seemed suited for MDT were enrolled in the present study. In total, 101 patients with 117 ulcers were treated. Most wounds were worst-case scenarios, in which maggot therapy was a treatment of last resort.

RESULTS

In total, 72 patients (71%) were classified as ASA III or IV. In total, 78 of 116 wounds (67%) had a successful outcome. These wounds healed completely (n = 60), healed almost completely (n = 12) or were clean at least (n = 6) at last follow-up. These results seem to be in line with those in the literature. All wounds with a traumatic origin (n = 24) healed completely. All wounds with septic arthritis (n = 13), however, failed to heal and led in half of these cases to a major amputation. According to a multivariate analysis, chronic limb ischaemia (odds ratio [OR], 7.5), the depth of the wound (OR, 14.0), and older age (>or= 60 years; OR, 7.3) negatively influenced outcome. Outcome was not influenced by gender, obesity, diabetes mellitus, smoking, ASA-classification, location of the wound, wound size or wound duration.

CONCLUSIONS

Some patient characteristics (i. e. gender, obesity, smoking behaviour, presence of diabetes mellitus and ASA-classification at presentation) and some wound characteristics (i. e. location of the wound, wound duration and size) do not seem to contra-indicate eligibility for MDT. However, older patients and patients with chronic limb ischaemia or deep wounds are less likely to benefit from MDT. Septic arthritis does not seem to be a good indication for MDT.