Abstract
Bacterial infections remain a significant global health concern, contributing to millions of deaths annually. Among the most critical bacterial pathogens to human health cases are Escherichia coli and Pseudomonas aeruginosa, both of which are responsible for severe infections, particularly in immunocompromised individuals and neonates. Traditional mammalian models, such as mice, are widely used to study bacterial virulence due to their genetic similarity to humans. However, ethical concerns, high costs, and logistical strains, like having access to large sample sizes, have driven interest in alternative invertebrate models. This study explores the potential of the tobacco hornworm, Manduca sexta, as a novel invertebrate host model for bacterial virulence research. The larval tobacco hornworm has been used in a laboratory setting for physiological studies and fungal pathogen virulence studies. This moth larvae offers a much larger size than the commonly used wax moth larvae (Galleria mellonella), and it can thus be used for a greater variety of assays, such as repeated sampling of the same individual, growth measurements, and tissue sampling. To facilitate further adoption of this insect model, I expanded on previously reported protocols and developed our own rearing methods. M. sexta possesses a well-characterized innate immune system with parallels to mammalian innate immune responses and offers advantages such as large body size, ease of handling, and the ability to sustain chronic infections. I developed an infection protocol that allows for monitoring bacterial load, survival, and treatment responses over time. These findings demonstrate that M. sexta is a viable alternative model for studying bacterial pathogenesis, with the potential to enhance our understanding of host-pathogen interactions and antimicrobial interventions.