Characterisation of biofilm structure: investigation and methods for developing strategies for control and prevention of infections

Scully, Ruth 2018. Characterisation of biofilm structure: investigation and methods for developing strategies for control and prevention of infections. MPhil Thesis, Cardiff University. Item availability restricted.

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Abstract

The addition of antimicrobial agents to wound dressings is used to reduce the risk of wound infection, and help manage local wound infections, thereby facilitating wound progression, but their activity is impeded by biofilm tolerance. The aim of this work was to investigate the structure and development of wound pathogen biofilm, and to design a novel, challenging in vitro simulated chronic wound biofilm model to evaluate the antimicrobial and anti-biofilm effectiveness of several current wound dressings. This study demonstrates how rapidly biofilm can form on a model wound that has been contaminated by contact with planktonic bacteria, producing structured bacterial biofilm communities with nutrient and waste channels and the dispersal of bacterial cells at the surface. Light Microscopy (LM), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) provided structural images of both biofilm formation and the presence of individual bacteria within the biofilm structure. After 24-48 hours, biofilm had become established, and dispersal of biofilm bacteria was visualised as early as 48 hours. By applying various dressings to the model and analysing representative fields of vision, biofilm was observable to varying extents beneath most of the dressings tested after 24 hours, and by 72 hours this had increased. Two dressings appeared to help prevent the growth of biofilm: a hydrated microbial cellulose dressing containing polyhexamethyl biguanidine dressing, and a next-generation antimicrobial dressing containing ionic silver in an anti-biofilm formulation. The results highlight the importance of dressing selection to manage biofilm in chronic and acute wounds, and these observations should help in the development of novel and effective control of wound infection.

Item Type:	Thesis (MPhil)
Status:	Unpublished
Schools:	Medicine
Date of First Compliant Deposit:	14 February 2018
Last Modified:	12 Apr 2021 15:25
URI:	https://orca.cardiff.ac.uk/id/eprint/109070

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