A new method for the production of sterile colonies of Lucilia sericata

In vitro multitarget activity of sulfadiazine substituted triazenes as antimicrobial, cytotoxic, and larvicidal agents

Multidrug resistance (MDR) causes difficulties in the treatment of infections and cancer. Research and development studies have become increasingly important for the strategy of preventing MDR. There is a need for new multitarget drug research and advancement to reduce the development of drug resistance in drug-drug interactions and reduce cost and toxic effects. This study aimed to determine the effects of multi-target triazene compounds on antibacterial, antifungal, antiviral, cytotoxic, and larvicidal activities were investigated in vitro. A series of 12 novel of 1,3-diaryltriazene-substituted sulfadiazine (SDZ) derivatives were synthesized, and the obtained pure products characterized in detail by spectroscopic and analytic methods (FT-IR, 1 H-NMR, 13 C-NMR, and melting points). The antibacterial and antifungal activities of these derivatives (AH1-12) were determined by broth microdilution method. All derivatives have been evaluated in cell-based assays for cytotoxic and antiviral activities against Modified Vaccinia Virus Ankara. The larvicidal efficacy of these chemical compounds was also investigated by using Lucilia sericata (L. sericata) larvae. Twelve 1,3-diaryltriazene-substituted SDZ derivatives (AH1-12) were designed and developed as potent multitargeted compounds. Among them, the AH1 derivative showed the most antibacterial and antifungal activity. Besides, synthesized derivatives AH2, AH3, AH5, and AH7 showed higher antiviral activity than SDZ. All synthesized derivatives showed higher cytotoxic activity than SDZ. Also, they showed larvicidal activity at 72 h of the experiment. As a result, these compounds might be great leads for the development of next-generation multitargeted agents.

Therapeutic effects of Lucilia sericata larval excretion/secretion products on Leishmania major under in vitro and in vivo conditions

Background

Leishmaniasis is a neglected infectious disease caused by protozoa of the genus Leishmania. The disease generally manifests as characteristic skin lesions which require lengthy treatment with antimonial drugs that are often associated with adverse side effects. Therefore, a number of studies have focused on natural compounds as promising drugs for its treatment. This study aimed to evaluate the effects of larval excretion/secretion products (ES) of Lucilia sericata in crude and fractionated forms on Leishmania major, by using in vitro and in vivo models.

Methods

The in vitro experiments involved evaluation of ES on both promastigotes and macrophage-engulfed amastigotes, whereas the in vivo experiments included comparative treatments of skin lesions in L. major-infected mice with Eucerin-formulated ES and Glucantime.

Results

The half maximal inhibitory concentrations of the crude ES, > 10-kDa ES fraction, < 10-kDa ES fraction, and Glucantime were 38.7 μg/ml, 47.6 μg/ml, 63.3 μg/ml, and 29.1 μg/ml, respectively. Significant differences were observed between percentage viabilities of promastigotes treated with the crude ES and its fractions compared with the negative control (P < 0.0001). The crude ES was more effective on amastigotes than the two ES fractions at 300 μg/ml. The macroscopic measurements revealed that the reduction of lesion size in mice treated with the crude ES followed quicker cascades of healing than that of mice treated with Glucantime and the ES fractions.

Conclusions

The present study showed that the larval ES of L. sericata in both crude and fractionated forms are effective for both intracellular and extracellular forms of L. major. Also, the ES exert both topical and systemic effects on mice experimentally infected with L. major.

Graphical abstract

Effectiveness of broad-spectrum antiseptics in production of disinfected maggots of Lucilia sericata for use in wound debridement therapy

The establishment of low-cost, effective, safe and practical methods is necessary to increase the use of larval therapy in wound care. Although studies on external disinfection of calliphorid eggs have been reported, many studies lack data on the effect of disinfection on egg viability and the microorganisms found before disinfection. Therefore, the main objective of this study was to compare three antiseptic solutions, that is, chlorhexidine (5%), Dakin's solution (0.5% NaOCl) and povidone-iodine (10%), in terms of their ability to disinfect Lucilia sericata eggs. Egg viability after disinfection and microorganisms present on the eggs and larvae before and after treatment were also examined. None of the antiseptics had a significant effect on egg viability. Disinfection of L. sericata eggs with 0.5% NaOCl was the best method, as sterility tests showed no contamination. Escherichia coli, Bacillus subtilis and Proteus mirabilis were present in all cultures isolated from the non-disinfected eggs and larvae, while Enterococcus faecium, Enterococcus faecalis, Morganella morganii, Corynebacterium spp. and Providencia stuartii were isolated from more than half of the same cultures. Sterility testing of medicinal maggots after disinfection is crucial to prevent secondary infections and achieve a positive therapeutic outcome.

Bacterial association observations in Lucilia sericata and Lucilia cuprina organs through 16S rRNA gene sequencing

Blowfly (Diptera: Calliphoridae) species Lucilia sericata (Meigen) and related species Lucilia cuprina (Wiedmann) are important agricultural pests, assist in forensic fields and also have a therapeutic role in medicine. Both species (though predominantly L. sericata) are utilised in a clinical setting for maggot debridement therapy (MDT) where the larvae ingest necrotic tissue and bacteria from non-healing wounds. Conversely, larvae of L. cuprina feed invasively, as major initiators of sheep myiasis in Australia, New Zealand, and the UK, among other regions. Both species exhibit larval and adult interactions with bacterially rich environments, but the significance of this in the composition of their microbiome has yet to be considered. This study utilised dissected samples of digestive and reproductive organs from both disinfected and non-disinfected adults and larvae of both species for bacterial DNA extraction, followed by 16S rRNA gene sequencing. Sequencing data indicated unsurprisingly that digestive tracts of both genders and female salivary glands from all non-disinfected samples carry the most concentrated amounts of bacteria. Genera Pseudomonas and Corynebacterium were also highly represented within all organs and species analysed. Comparison of bait lures to sample sequence read output of insect specimens showed no correlation with genera such as Pseudomonas present in insects, while absent from wild bait, and in reduced amounts from fleece bait profiles. With this information, future work can focus on key organs such as the spermathecae and salivary glands, while also providing the potential to identify the role these bacteria may play in the blowfly life cycle. KEY POINTS: Genera Pseudomonas appears consistently in the microbiome of Lucilia species. Female spermathecae and salivary glands show the highest microbial diversity. Bacterial profiles of L. sericata and L. cuprina have similar composition.

The maggot therapy supply chain: a review of the literature and practice

Maggot therapy (MT) is the clinical application of living fly larvae for the treatment of non-healing wounds and wounds that require debridement. This systematized and expanded literature review is the first study to investigate MT through the conceptual and disciplinary framework of supply chain management. The review of 491 selected academic papers was expanded to include the grey literature and online information resources to construct a first-pass theory of the medicinal maggot supply chain. It shows that the literature to date has focused on isolated discussions of echelon-specific issues such as diet improvement and sterilization protocols in the production echelon, and the relative effectiveness of medicinal maggot application methods in the treatment echelon. There is little knowledge in the public domain regarding the transport and distribution of medicinal maggots, but existing supply chains for vaccines, blood and pathology specimens may provide learning and supply chain integration opportunities. Maggot therapy knowledge across the treatment echelon is generally substantive but there is still insufficient knowledge regarding patients' and health care providers' attitudes toward the therapy, and their experiences of receiving and administering MT. Moreover, there is no research concerned with the humane disposal of medicinal flies during production and after treatment.