Pathogenic bacteria can cause disease through the expression of virulence factors, most notably toxins. Toxins have different potencies and modes of action and can lead to serious complications such as septic shock and tissue necrosis. Toxicological screening analysis is one such way to analyse toxin potency and involves exposing a model organism group to toxins allowing a median lethal dose (LD50) to be obtained. Normally, mice and other small mammalian models are used to conduct this analysis however these require extensive ethical considerations and specialised staff and resources, whereas invertebrate insect models do not. Galleria mellonella larvae are one such model currently used in antimicrobial testing and disease pathogenesis studies. Due to the ability of Galleria mellonella to survive at 37°C and the similarities between their innate immune system to that of humans, there is significant potential of using this model for toxicological screening analysis of toxins produced by human pathogenic bacteria. To determine this, a meta-analysis was conducted using the Web of Science and PubMed databases and the PRISMA selection criteria. “Bacteria”, “Toxins” and “Galleria mellonella” were used as keywords in the database search resulting in 242 articles. These were initially screened based on titles and abstracts reducing the number of articles to 36 articles. The full text of each article was then screened and an inclusion criterion was adapted resulting in 9 articles being identified for the meta-analysis. These articles involved 8 studies on toxins from the insecticidal Xenorhabdus and Photorhabdus genera and 1 study on toxin supernatants from Pseudomonas aeruginosa. These studies highlight the efficacy of using the Galleria mellonella model for toxin potency analysis for a number of different toxins and present the significant possibility of using this model to use for toxicological screening analysis of toxins produced by human pathogenic bacteria.
Keywords: Bacterial toxins, endotoxins, exotoxins, toxicology screening assays, Galleria mellonella
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