First Record of Larval Secretions of Cochliomyia macellaria (Fabricius, 1775) (Diptera: Calliphoridae) Inhibiting the Growth of Staphylococcus aureus and Pseudomonas aeruginosa

First description of immature stages and notes on the biology of the blow fly, Calliphora lopesi Mello, 1962

Several species of the worldwide distributed genus Calliphora Robineau-Desvoidy (Insecta, Diptera, Calliphoridae) are medically important vectors and agents of myiasis. Furthermore, these flies are relevant in forensics because they are found in corpses. Information regarding the taxonomy, bionomics and distribution of Calliphora species endemic to South America, including Calliphora lopesi Mello, is scarce. To expand knowledge on C. lopesi, this study presents descriptions of eggs, larvae, puparia and developmental data at 14, 17, 20, 23 and 26 ± 1°C for the first time. Adult flies were collected from the field and kept in the laboratory to obtain samples for morphological and biological studies. Immatures were examined using light and scanning electron microscopy. To assess the growth rate, 10 specimens from each temperature group were randomly removed from the diet and weighed every 24 h from larval hatching until pupation. The minimum developmental threshold, thermal constant and linear development-rate equations were calculated for each stage. Considering weight gain records and survival rates, the optimum temperature for the development of C. lopesi ranges from 23 to 26°C. A key to third-instar larvae of known Neotropical species of Calliphora was also provided to assist in identification. The information provided in this study should be useful in expanding knowledge about Neotropical Calliphoridae species of forensic importance.

In vitro antibacterial activity and synergetic effect of crude extract of the Wohlfahrtia nuba (Diptera: Sarcophagidae) flesh fly larvae

Multidrug-resistant pathogens have become ubiquitous, and effective treatment alternatives are urgently required. Maggot therapy is a promising agent that is being studied to overcome antibiotic-resistant pathogens. This study evaluated the antibacterial activity of the larvae extract of the Wohlfahrtia nuba (wiedmann) (Diptera: Sarcophagidae) flesh fly on the growth of five pathogenic bacterial species (methicillin-sensitive Staphylococcus aureus [ATCC 29213], methicillin-resistant Staphylococcus aureus [ATCC BAA-1680], Pseudomonas aeruginosa [ATCC 27853], Escherichia coli [ATCC 25922], and Salmonella typhi [ATCC 19430]) in vitro by using different techniques. Resazurin-based turbidimetric assay demonstrated that the W. nuba maggot exosecretion (ES) was potent against all the bacterial species tested, and according to the determined minimum inhibitory concentration (MIC) for each bacterium, gram-negative bacteria were more sensitive than gram-positive bacteria. Additionally, colony-forming unit assay showed that maggot ES was able to inhibit bacterial growth rate for all bacterial species tested, where the highest bacterial reduction was observed with methicillin-sensitive S. aureus (MSSA) followed by S. typhi. Moreover, maggot ES was shown to be concentration-dependent, where 100 μL of ES at 200 mg/mL was bactericidal towards methicillin-resistant S. aureus (MRSA) and P. aeruginosa compared with 100 μL at the MIC of the ES. Moreover, based on the result of agar disc diffusion assay, maggot extract was more efficient against P. aeruginosa and E. coli than the remaining reference strains tested. Furthermore, the combination between regular antibiotics with maggot ES at different concentrations indicated that ES acts synergistically with the tested antibiotics against the five bacterial models.

How Rearing Systems for Various Species of Flies Benefit Humanity

Flies (Diptera) have played a prominent role in human history, and several fly species are reared at different scales and for different beneficial purposes worldwide. Here, we review the historical importance of fly rearing as a foundation for insect rearing science and technology and synthesize information on the uses and rearing diets of more than 50 fly species in the families Asilidae, Calliphoridae, Coelopidae, Drosophilidae, Ephydridae, Muscidae, Sarcophagidae, Stratiomyidae, Syrphidae, Tachinidae, Tephritidae, and Tipulidae. We report more than 10 uses and applications of reared flies to the well-being and progress of humanity. We focus on the fields of animal feed and human food products, pest control and pollination services, medical wound therapy treatments, criminal investigations, and on the development of several branches of biology using flies as model organisms. We highlight the relevance of laboratory-reared Drosophila melanogaster Meigen as a vehicle of great scientific discoveries that have shaped our understanding of many biological systems, including the genetic basis of heredity and of terrible diseases such as cancer. We point out key areas of fly-rearing research such as nutrition, physiology, anatomy/morphology, genetics, genetic pest management, cryopreservation, and ecology. We conclude that fly rearing is an activity with great benefits for human well-being and should be promoted for future advancement in diverse and innovative methods of improving existing and emerging problems to humanity.

Unravelling the potential of insects for medicinal purposes - A comprehensive review

Entomotherapy, the use of insects for medicinal purposes, has been practised for centuries in many countries around the world. More than 2100 edible insect species are eaten by humans, but little is known about the possibility of using these insects as a promising alternative to traditional pharmaceuticals for treating diseases. This review offers a fundamental understanding of the therapeutic applications of insects and how they might be used in medicine. In this review, 235 insect species from 15 orders are reported to be used as medicine. Hymenoptera contains the largest medicinal insect species, followed by Coleoptera, Orthoptera, Lepidoptera, and Blattodea. Scientists have examined and validated the potential uses of insects along with their products and by-products in treating various diseases, and records show that they are primarily used to treat digestive and skin disorders. Insects are known to be rich sources of bioactive compounds, explaining their therapeutic features such as anti-inflammatory, antimicrobial, antiviral, and so on. Challenges associated with the consumption of insects (entomophagy) and their therapeutic uses include regulation barriers and consumer acceptance. Moreover, the overexploitation of medicinal insects in their natural habitat has led to a population crisis, thus necessitating the investigation and development of their mass-rearing procedure. Lastly, this review suggests potential directions for developing insects used in medicine and offers advice for scientists interested in entomotherapy. In future, entomotherapy may become a sustainable and cost-effective solution for treating various ailments and has the potential to revolutionize modern medicine.

Antibacterial and antifungal activity of excretions and secretions of Calliphora vicina

Antibiotic-resistant bacteria pose a major threat to global health in the 21st century, requiring a quick, cheap and effective response from public health officials. This study evaluated the antimicrobial activity of native excretions/secretions (NES) produced by third instar (3 days old) larvae of Calliphora vicina using a protocol adapted from the Institute of Clinical and Laboratory Standards (CLSI). The microorganisms tested were: Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and the fungus Candida albicans. After the incubation period, the suspensions were diluted and spread on nutrient agar plates to count the colony-forming units. A turbidimetric test also was carried out to test the action of the NES of C. vicina against S. aureus, a very common bacterial species, with an enormous capacity for adaption and resistance, being one of the bacteria of medical importance that causes the most hospital and community infections in the world. According to our results, the NES of C. vicina exhibits antimicrobial activity at different dilutions, being most effective against the gram-negative bacteria E. coli and K. pneumoniae.

Larval therapy from the patient’s perspective

Objective: to describe the perception of the patient undergoing larval therapy. Method: qualitative, exploratory-descriptive study, using oral history as a data collection technique and methodological framework, in the form of oral life history. Six patients with difficult-to-heal wounds participated in the study, followed by the dressing committee of a teaching hospital in Natal, Rio Grande do Norte, undergoing larval therapy. Results: the testimonies of the patients/collaborators point to various values, such as belief, fear, acceptance, improvement of the wound and pain. They revealed that there is no major objection and that clarification regarding the treatment instituted proved to be important in the acceptance decision. Conclusion: the feelings expressed by the patients, such as improvement of the wound, reduction of pain and odor, optimization of the healing process, emergence of sparks of hope regarding the return to their life, among others, translate the benefits of Larval Therapy (LT). Despite the seizure caused by the animal’s movement over the affected area and the disgust it causes to some professionals and people, LT was considered wonderful, especially for its effectiveness in cleaning the wound without the need for new invasive procedures such as cutting and surgical debridement.

Terapia larval sob a ótica do paciente

Objetivo: descrever a percepção do paciente submetido à terapia larval. Método: estudo qualitativo, exploratório-descritivo, tendo como técnica de coleta de dados e referencial metodológico a historia oral, na modalidade da história oral de vida. Participaram do estudo seis pacientes com feridas de difícil cicatrização, acompanhados pela comissão de curativos de um hospital escola em Natal, Rio Grande do Norte, submetidos à terapia larval. Resultados: os depoimentos dos pacientes/colaboradores apontam diversos valores, como crença, medo, aceitação, melhora da ferida e da dor. Revelaram que não há grande objeção e que o esclarecimento em relação ao tratamento instituído mostrou-se importante na decisão de aceitação. Conclusão: os sentimentos expressos pelos pacientes, como melhora da ferida, diminuição da dor e odor, otimização do processo de cicatrização, surgimento de centelhas de esperança quanto ao retorno à sua vida, dentre outros traduzem os benefícios da Terapia Larval (TL). Apesar do fervilhamento provocado pelo movimento do animal sobre a área acometida e da repulsa que causa a alguns profissionais e pessoas, a TL foi considerada maravilhosa, especialmente por sua eficácia na limpeza da ferida sem a necessidade de novos procedimentos invasivos como desbridamento cortante e cirúrgico.

First Report on the Use of Larvae of Cochliomyia macellaria (Diptera: Calliphoridae) for Wound Treatment in Veterinary Practice

Factors contributing to the delay or prevention of the natural wound healing process include infection and ineffective conventional treatment. Alternative therapies, such as the maggot debridement therapy (MDT), may be helpful for successful treatment in these cases. Aiming to disseminate information about the possibility of using other species of flies for wound treatment, besides the best known Lucilia sericata Meigen, 1826 (Diptera, Calliphoridae), we report here a successful MDT case with the application of Cochliomyia macellaria (Fabricius, 1775) larvae to treat an infected wound with extensive area of necrotic tissue in a dog. Five sterile larvae were applied to each square-cm of lesion and kept on the animal for only 48 h. The healing was successful, from both qualitative and quantitative points of view. The ratio of wound healing (RWH) reached almost 50% on the 5th day and 100% on the 14th day after MDT. Although the overall animal prognosis had been unfavorable, mainly due to the sepsis, the patient began to recover and had improved clinical condition from the fifth day after MDT. This study shows the importance and effectiveness of MDT in promoting faster and more complete healing of a complex wound.

Bactericidal Activity of Chrysomya rufifacies and Cochliomyia macellaria (Diptera: Calliphoridae) Larval Excretions-Secretions Against Staphylococcus aureus (Bacillales: Staphylococcaceae)

The inhibitory effect of Chrysomya rufifacies (Macquart) and Cochliomyia macellaria (Fabricius) larval excretions-secretions (ES) on Staphylococcus aureus was determined using a portable colorimetric method without the need for any dedicated spectral instrument. Polystyrene 96 well microplates were used and 100 μl of the bacterial inoculum (5 × 105 CFU/ml) plus 100 μl of the dipteran exosecretions at different concentrations were added to each well. Subsequently, 50 μl of a 1% solution of the triphenyl tetrazolium chloride stain was added to each well to determine the bacterial viability. The color development in each well was measured with the ImageJ software S. aureus was exposed to different concentrations of the ES of both species individually. At a concentration of 800 ppm ES of C. rufifacies or Co. macellaria, bacterial growth was inhibited 97.45 ± 1.70% and 82.21 ± 1.88%, respectively. As expected, exposure to a lower concentration (i.e., 50 ppm) was less inhibitory (C. rufifacies ES, 77.65 ± 4.25% and Co. macellaria ES, 43.54 ± 4.63%). This study demonstrates for the first time the bactericidal activity of C. rufifacies and Co. macellaria ES against S. aureus. This finding is promising as it could result in the identification and synthesis of proteins capable of suppressing pathogen development in wounds. Additionally, the proposed method can simplify the use of expensive laboratory instruments for antimicrobial activity determination.

Spatial and Temporal Variation of the Blowflies Community (Diptera: Calliphoridae) From an Urban Area in Northern South America

Blowflies (Diptera: Calliphoridae) are necrophagous flies with ecological, medical, veterinary, and forensic importance. These flies carry pathogens that they spread to animals and humans, and produce myiasis. Furthermore, they are useful tools in forensic science as indicators of postmortem intervals, and in biomedicine they are successfully used in larval therapy. This study aimed to assess the spatiotemporal variation of the blowflies community from the urban area of Sincelejo City, located in the Colombian Caribbean region. Samplings were conducted from May 2012 to April 2013, using Van Someren Rydon-traps baited with bovine meat, fish, and chicken that decomposed for 48 h. Six species were registered, Cochliomyia macellaria (Fabricius, 1775) was the most abundant, followed by Lucilia eximia (Wiedemann, 1819) and Chrysomya albiceps (Wiedemann, 1819), while Chloroprocta idioidea (Robineau-Desvoidy, 1830), Chrysomya megacephala (Fabricius, 1794), and Lucilia cuprina (Wiedemann, 1830) presented the least individuals. The blowflies community did not change significantly throughout the sampling months or between the periods of low or high rainfall, nor was it influenced by weather variables. Although the species composition was the same in all sampled localities, species abundances presented significant differences. The possible causes of this pattern are discussed herein. Sex ratios were female biased for all the recorded species, except C. idioidea. Our findings provide the first assessment of the blowflies community from the urban area of Sincelejo City.

In vitro evaluation of the association of medicinal larvae (Insecta, Diptera, Calliphoridae) and topical agents conventionally used for the treatment of wounds

Wound healing is a complex process involving multiple biochemical and cellular events and represents a neglected public health issue. As a consequence, millions of people worldwide suffer from chronic wounds. The search for new treatment alternatives is therefore an important issue. In the context of wound healing, Maggot Debridement Therapy (MDT) is an inexpensive treatment with few contraindications and very promising results. This study aimed to evaluate the in vitro feasibility and implications of larvae (= MDT) use when combined with topical agents as a strategy to identify additive or synergistic combinations. The weight and survival rate of Cochliomyia macellaria (Fabricius) (Insecta, Diptera, Calliphoridae) larvae reared in an in vitro wound with either honey, hydrogel, 10% papain gel, essential fatty acids (EFA), collagenase, or silver sulfadiazine were evaluated after 24, 48 and 72 h. Hydrogel (for weight: 24 and 72 h; for survival: 24 h) and 10% papain gel (for weight: 48 h; for survival: 48 and 72 h) demonstrated the least interference in larval weight gain and survival rate, when compared to the control group. The results obtained in this study showed that the combined use of larvae and hydrogel or 10% papain gel may be promising to maximize the tissue repair. Honey, EFA and collagenase could be used to prepare the bed of the dry wounds to receive the MDT.

Bioprospection of immature salivary glands of Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae)

Larval therapy (LT) comprises the application of sterile Calliphoridae larvae for wound debridement, disinfection, and healing in humans and animals. Larval digestion plays a key role in LT, where the salivary glands and gut produce and secrete proteolytic and antimicrobial substances. The objective of this work was to bioprospect the salivary glands of Chrysomya megacephala (Fabricius, 1794) larvae, using ultrastructural, morphological, and histological observations, and the total protein electrophoretic profile. The salivary glands present a deferent duct, originating from the buccal cavity, which bifurcates into efferent ducts that insert through a slight dilatation to a pair of tubular-shaped tissues, united in the region of fat cells. Histologically, the secretion had protein characteristics. Cell cytoplasm presented numerous free ribosomes, autophagic vacuoles, spherical and elongated mitochondria, atypical Golgi complexes, and dilated rough endoplasmic reticulum. In the apical cytoplasm, secretory granules and microvilli secretions demonstrated intense protein synthesis, basal cytoplasm with trachea insertions, and numerous mitochondria. The present work described the ultrastructure and morphology of C. megacephala third instar salivary glands, confirming intense protein synthesis and the molecular weight of soluble proteins.