Surveillance of susceptibility profile to antiseptics in ITU isolates of Staphylococcus aureus, including MRSA

Cheeseman, Keely 2010. Surveillance of susceptibility profile to antiseptics in ITU isolates of Staphylococcus aureus, including MRSA. PhD Thesis, Cardiff University.

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Abstract

Hand hygiene is the most important measure for reducing healthcare associated infections. Previous in-vitro testing of alcohol hand rubs AHR has not reflected conditions found in practice therefore little is known about their true efficacy. This study aimed to discover how effective AHRs are when used in local intensive therapy Units ITU against Staphylococcus aureus clinical isolates and their mode of action. The AHRs were unable to achieve significant bactericidal effect 4 log reduction against S. aureus within the time healthcare workers HCW took to rub AHR into their hands, particularly when tested against bacterial cells on the surface of excised skin. The AHRs had no residual effect and the mechanical action of hand rubbing only increased bacterial cell death by approximately 1 log. The AHRs demonstrated varying efficacies against the isolates and variation in susceptibility to the AHRs was also observed among the isolates. AHR damaged the cytoplasmic membrane, but this was not the cause of the bactericidal effect, nor a reason for the differences in susceptibility observed among the strains. The cell wall and/or outer layers of the bacterial cell were found to most likely be the main target of AHR, most likely due to protein denaturation, although this study was unable to confirm this hypothesis. Virulence gene expression, cell surface charge and cell surface hydrophobicity was not affected by exposure of bacterial cells to AHR and were not responsible for varying AHR susceptibility among the isolates. This study determined the quality of AHR application amongst HCWs in the ITU and the potential cross-contamination resulting from failure to perform hand hygiene before and after certain activities. It can be concluded from this study that AHRs are unlikely to kill all microbial flora on HCWs hands. Recommendations have been made to improve hand hygiene practices and the efficacy of AHRs used in ITUs.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Pharmacy
ISBN:	9781303191336
Date of First Compliant Deposit:	30 March 2016
Last Modified:	09 Jan 2018 23:19
URI:	https://orca.cardiff.ac.uk/id/eprint/55896

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