نوع مقاله : مقاله پژوهشی
نویسندگان
1 مرکز تحقیقات غدد و متابولیسم اصفهان، دانشگاه علوم پزشکی اصفهان، ایران
2 گروه میکروبیولوژی، دانشکده علوم زیستی، واحد فلاورجان، دانشگاه آزاد اسلامی، فلاورجان، اصفهان، ایران
3 کلینیک دیابت سیاوش، وابسته به شرکت دانش بنیان زیست التیام سپنتا، اصفهان، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The rising resistance of bacteria to common antibiotics has underscored the urgent need to discover and develop novel antibacterial agents. One promising natural source in this regard is the secretions and extracts of Lucilia sericata larvae, which have gained attention in recent years due to their antimicrobial properties and wound-healing potential. This study aimed to evaluate and compare the antibacterial effects of the secretions and extracts derived from L. sericata larvae against Staphylococcus aureus and Escherichia coli using standard microbiological methods. In this study, larval secretions and extracts were obtained from three-day-old larvae using different solvents (70% ethanol and a mixture of methanol: water: acetic acid). The antibacterial activity of the samples was assessed using well diffusion, disk diffusion, and colony counting methods against standard strains of S. aureus and E. coli. The results indicated that larval secretions alone exhibited no significant antibacterial activity. However, the extracts from dried larvae using 70% ethanol and the mixed solvent (methanol: water: acetic acid) showed considerable inhibitory effects against pathogenic bacteria. The largest inhibition zone diameter was observed with the extract prepared using the mixed solvent. Furthermore, concentrating the extracts with Dimethyl sulfoxide (DMSO) enhanced their efficacy. This study demonstrates that L. sericata larval extracts, especially when combined with suitable solvents, possess notable potential for inhibiting pathogenic bacteria. These extracts may serve as a complementary or alternative approach in treating infections caused by antibiotic-resistant bacteria.
کلیدواژهها [English]
Extended Abstract
Introduction
The overuse of antibiotics has led to a global crisis of bacterial drug resistance, complicating infection treatment, increasing costs, and reducing drug efficacy. The World Health Organization considers this a major threat to public health. In this context, biological products from Lucilia sericata larvae, of the Calliphoridae family, have emerged as a promising alternative. Maggot therapy, an FDA-approved method, is used for debriding chronic wounds and accelerating tissue repair. The secretions and extracts of these larvae contain enzymes, antimicrobial peptides, and bactericidal compounds that disrupt bacterial membranes, inhibit enzymes, and create an unfavorable environment for pathogens. These compounds can also degrade bacterial biofilms and prevent resistant colony formation. Studies demonstrate their effectiveness against resistant strains like MRSA and Pseudomonas aeruginosa, though research on dried or frozen larval extracts and solvent comparisons is limited. Standardizing extraction methods and identifying active compounds are critical for broader clinical applications. Thus, this study aimed to prepare L. sericata secretions and extracts using multiple solvents (70% ethanol and mixed solvent including methanol: water: acetic acid mixture) and evaluate their efficacy against Staphylococcus aureus and Escherichia coli using three standard microbial methods (well plate, disk diffusion, and colony count). The study also investigated the role of DMSO in enhancing the antibacterial performance of these extracts to provide a comprehensive view of their therapeutic potential.
Materials and Methods
Three-day-old L. sericata larvae were reared and prepared under sterile conditions with strict hygiene protocols. For secretion preparation, live larvae were incubated in phosphate buffer saline (PBS), and the filtered secretion fluid was tested. For extract preparation, dried larvae were homogenized with two solvents: 70% ethanol and a mixture of methanol: water, acetic acid mixture (90:9:1 ratio). The resulting extracts were centrifuged, filtered, and concentrated for use. Antibacterial activity was assessed using three standard methods: well plate, disk diffusion, and colony count. Two standard strains, including S. aureus ATCC 25923 and E. coli ATCC 25922 strains were used as target bacteria. Negative controls included pure solvents (without extracts).
Results
The results showed that the dried larval extract with mixed solvent (DL9) exhibited the highest antibacterial activity across all tests, including well plate, disk diffusion, and colony count. In the disk diffusion method, DL9 produced inhibition zones of 22 mm against S. aureus and 16 mm against E. coli. In the colony count method, a 10-fold reduction in S. aureus colonies and a remarkable 1000-fold reduction in E. coli colonies were recorded after 24 hours of exposure to DL9, indicating significant bacteriostatic properties. Additionally, the 70% ethanol extract (DLE), while less effective than DL9, produced a 17 mm inhibition zone against S. aureus and a 10-fold reduction in bacterial count. The addition of DMSO significantly enhanced the efficacy of both extracts, particularly the ethanol extract, which showed a greater reduction in microbial load with DMSO.
Discussion
This study highlights the significant potential of L. sericata larval extracts, particularly in dried form and extracted with suitable solvents, for inhibiting pathogenic bacterial growth. The observed inhibitory effects against both Gram-positive and Gram-negative bacteria, especially S. aureus, support the potential use of these extracts as disinfectants or adjuncts to antibiotic therapies in clinical settings. The results emphasize the importance of solvent selection in extracting bioactive compounds and the effectiveness of concentration methods like DMSO in enhancing their activity. These extracts could serve as alternatives to traditional antibiotics for treating drug-resistant infections. Moreover, optimizing the extraction process could lead to standardized biological products for therapeutic applications.
Conclusion
Consistent with previous studies, our findings confirm the antibacterial activity of maggot secretions and extracts. Limitations include the focus on only two bacterial species and the lack of molecular analyses to identify active compounds. Future research should explore a broader range of pathogens, cytotoxicity, biocompatibility, and the potential for loading extracts into nanocarriers.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
The data will be made available on request.
This research was supported by the Plant Protection Department of University of Kurdistan. We thank university of Kurdistan for providing research facility and support.
The study was conducted on plant-pathogen fungus and beneficial entophy-
tic bacteria that are abundant in the environment and do not require ethical
approva
The study was conducted on plant-pathogen fungus and beneficial entophytic fungi that are abundant in the environment and do not require ethical approval.
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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