Antimicrobial properties of Ascaris suum body cavity fluid

Abstract

Parasitic helminth infections pose a huge threat to human health and agricultural productivity worldwide. This threat is set to grow in the coming years due to global warming increasing the range of parasites and their hosts, growing global populations requiring more intensive farming, and increasing human migration resulting in further parasite spread. The current control of helminths relies on anthelmintic drug administration however the overuse of such drugs is resulting in the rise of anthelmintic resistance. Novel control mechanisms, including anthelmintics with original modes of action, are necessary to regain control over parasitic nematode infections. A lack of understanding of nematode parasite biology hinders the production of new control mechanisms, and so research now turns to better understanding parasite biology. Additionally, intestinal parasitic nematodes are an attractive model organism to investigate how the nematode survives in a microbe-rich environment with the view to discovering new antimicrobial peptides which might be used as a template for novel antibiotics.


This thesis employs a range of microbial and molecular assays to better understand the dynamic environment of Ascaris suum pseudocoelomic fluid (PCF) and its role in worm health and immune response. The assays described in this thesis exploit the experimental tractability of A. suum and reveal that the antimicrobial properties of PCF are bacterial species-specific and influenced by abiotic and biotic factors outside of the worm. The data presented here attempt to identify the specific mode of action of the antimicrobial effectors and again reveal that PCF possesses antimicrobial responses that are species specific. Finally, this thesis describes efforts to begin identifying to a genus level bacteria isolated from the PCF, which marks the beginning of classifying members of the A. suum microbiota.

Date of Award	Dec 2022
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy
Supervisor	Angela Mousley (Supervisor), Linda Stewart (Supervisor) & Nikki Marks (Supervisor)