Alyson Bexfield

Swansea University, Swansea, Wales, United Kingdom

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Publications (10)14.77 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The larvae of Lucilia sericata (the medicinal maggot) have been exploited to undertake many applications, from their use in the management of chronic, non-healing wounds (larval therapy), to their assistance in forensic investigations and analysis. This current review describes these various applications and discusses the recent scientific and clinical developments supporting their use in wound healing and management. The review includes aspects such as their role in wound debridement, disinfection properties and biofilm disruption, as well as their potential role in the acceleration of wound healing. Also considered is the study of novel therapeutic compounds and biological therapies derived from this species. From a clinical perspective, recent studies that have been concerned with the efficacy and value of maggot debridement therapy are summarised and discussed.
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    ABSTRACT: Maggot therapy, utilizing the larvae of Lucilia sericata, has been reported to reduce the bacterial load within wounds and also to enhance wound healing. Maggot excretions/secretions (ES) have been shown to have a role in the success of maggot therapy. While the protein content of ES has been investigated, to date little research has focused on the small metabolites present in ES and their potential contribution to the therapy. Study of the molecular composition of the secretions and the potential bioactivities present will allow for a more detailed evaluation of the efficacy of maggot therapy. We studied the amino acid-like compounds present in ES of L. sericata larvae in order to determine the compounds present and their potential role in the wound healing process. These included thin-layer chromatography/mass spectrometric analysis of ES to identify amino acid-like components, a turbidometric assay to investigate their potential antibacterial activity and cell proliferation studies to investigate their potential mitogenic ability. Three prominent compounds were detected and identified as histidine, valinol and 3-guanidinopropionic acid. While these amino acids were not shown to exhibit antibacterial activity, a proliferative effect on the growth of human endothelial cells, but not fibroblasts, was noted. The demonstrated proliferative effect, selectively on endothelial cells, suggests that the amino acid-like compounds present in maggot ES may have a role in wound healing, by stimulating angiogenesis.
    British Journal of Dermatology 10/2009; 162(3):554-62. DOI:10.1111/j.1365-2133.2009.09530.x · 4.10 Impact Factor
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    ABSTRACT: Chronic infections are commonly associated with biofilms formed by bacteria such as Staphylococcus epidermidis. With the increase in antibiotic resistant bacteria, maggot debridement therapy has been reintroduced for the treatment of chronic wounds. Studies have shown that the excretion/ secretions (ES) of Lucilia sericata larvae (maggots) contain many bioactive compounds which may contribute to the efficacy of maggot therapy. The present study evaluates the effect of L. sericata ES on the formation and disruption of S. epidermidis 1457 and 5179-R1 biofilms. These strains employ either polysaccharide intercellular adhesin (PIA) or accumulation associated protein (Aap) for intercellular adhesion. A semiquantitative biofilm assay was used to measure the formation/disruption of S. epidermidis 1457 and 5179-R1 biofilms by ES. ES activity was characterized according to concentration, incubation time and temperature, thermal stability, and size. Immunofluorescence microscopy was used to ascertain the effect of ES on PIA and Aap. In the presence of ES, S. epidermidis 1457 and 5179-R1 nascent biofilm formation was inhibited, and pre-formed biofilms disrupted. ES activity was temperature and time dependent, inactivated by heat treatment, and disruption depended on the mechanism of intercellular adhesion. The molecule(s) responsible was >10 kDa in size and appeared to have protease or glucosaminidase activity. ES interferes with S. epidermidis biofilm formation, specifically degrading factors employed in biofilm accumulation, which would increase bacterial susceptibility to antibiotics and the host's immune system. In purified form, ES-factors may have general applicability for the treatment or prevention of chronic biofilm infections caused by staphylococci.
    The International journal of artificial organs 09/2009; 32(9):555-64. · 1.45 Impact Factor
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    ABSTRACT: The application of Lucilia sericata larvae to chronic, infected wounds results in the rapid elimination of infecting microorganisms, including MRSA. Previously, we demonstrated in vitro antibacterial activity of native excretions/secretions (nES) from L. sericata and partially purified two low mass antibacterial compounds with masses of 0.5-10kDa and <500Da. The present study reports the antibacterial effects of the <500Da fraction (ES<500) on the growth and morphology of a range of bacteria, including 12 MRSA strains. Distinct morphological changes were observed in Bacillus cereus and Escherichia coli following exposure to ES<500. Flow cytometry and confocal microscopy analyses, in conjunction with turbidometric and CFU assays, revealed bacteriostatic activity of nES against S. aureus and E. coli. ES<500 also demonstrated bacteriostatic activity against S. aureus, however, bactericidal activity and the induction of a viable but non-culturable state were observed with ES<500-treated E. coli.
    Microbes and Infection 04/2008; 10(4):325-33. DOI:10.1016/j.micinf.2007.12.011 · 2.73 Impact Factor
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    ABSTRACT: Maggot therapy employs the use of freshly emerged, sterile larvae of the common green-bottle fly, Phaenicia (Lucilia) sericata, and is a form of artificially induced myiasis in a controlled clinical situation. Maggot therapy has the following three core beneficial effects on a wound: debridement, disinfection and enhanced healing. In part II of this review article, we discuss clinical infections and the evidence supporting the potent antibacterial action of maggot secretions. Enhancement of wound healing by maggots is discussed along with the future of this highly successful, often controversial, alternative treatment.
    Evidence-based Complementary and Alternative Medicine 10/2006; 3(3):303-8. DOI:10.1093/ecam/nel022 · 1.88 Impact Factor
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    ABSTRACT: It is now a universally acknowledged fact that maggot therapy can be used successfully to treat chronic, long-standing, infected wounds, which have previously failed to respond to conventional treatment. Such wounds are typically characterized by the presence of necrotic tissue, underlying infection and poor healing. Maggot therapy employs the use of freshly emerged, sterile larvae of the common green-bottle fly, Phaenicia (Lucilia) sericata, and is a form of artificially induced myiasis in a controlled clinical situation. In this review article, we will discuss the role of maggots and their preparation for clinical use. Maggot therapy has the following three core beneficial effects on a wound: debridement, disinfection and enhanced healing. In part I we explore our current understanding of the mechanisms underlying these effects.
    Evidence-based Complementary and Alternative Medicine 07/2006; 3(2):223-7. DOI:10.1093/ecam/nel021 · 1.88 Impact Factor
  • Alyson Bexfield · Yamni Nigam · Stephen Thomas · Norman A Ratcliffe
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    ABSTRACT: Maggot therapy is a simple and highly successful method for cleansing infected and necrotic wounds. The use of maggots has become increasingly important in the treatment of non-healing wounds, particularly those infected with the multidrug-resistant pathogen, methicillin-resistant Staphylococcus aureus (MRSA). The increasing challenge concerning the treatment of MRSA infections and the recent finding of vancomycin-resistant strains of MRSA have elicited the search for novel antibacterial compounds and, in particular, investigations into the potent antibacterial mechanism(s) behind maggot therapy. In this study, we report that excretions/secretions (ES) from the blowfly, Lucilia sericata, exhibit potent, thermally stable, protease resistant antibacterial activity against MRSA in vitro. We describe the initial characterisation of two antibacterial factors from native ES of L. sericata. A small, <500 Da factor with significant antibacterial activity against MRSA was partially isolated using ultrafiltration techniques. The potent activity of this factor was comparable to that of native excretions/secretions. A larger, 0.5-3-kDa factor with significant activity against S. aureus was also partially characterised.
    Microbes and Infection 11/2004; 6(14):1297-304. DOI:10.1016/j.micinf.2004.08.011 · 2.73 Impact Factor
  • Yamni Nigam · Alyson Bexfield
    Nursing times 104(26):24-5.
  • Alyson Bexfield · Yamni Nigam
    Nursing times 104(25):26-7.
  • Yamni Nigam · Alyson Bexfield
    Nursing times 104(23):22-3.