Phenotypic Characterisation of Staphylococcus aureus and Escherichia coli Clinical Isolates and their Susceptibility to Targeted Bacteriophages

ORCID

0009-0002-3124-5388

Department

Biological Sciences

Year of Study

PhD

Full-time or Part-time Study

Full-time

Level

Postgraduate

Presentation Type

Poster

Supervisor

Laura O'Connell

Supervisor

Michael Callanan

Supervisor

Aidan Coffey

Abstract

Abstract:

Antibiotic resistance (AMR) is the one of the biggest threats facing humans and animals in the 21st century. This has been caused by the overuse and misuse of antibiotics leading to the desperate need for innovative therapeutic alternatives. Research is ongoing regarding the use of bacteriophages as a possible viable antimicrobial agent. However, various limitations exist which hinder their use including their narrow host range. This limitation poses a significant threat to the development of phage therapies as it requires phenotypic characterisation of clinical isolates to ensure compatibility between strains and phage. This study outlines phenotypic characterisation of clinical isolates of 20 S. aureus strains and 19 E. coli from the Bons Secures Hospital, Cork. This includes antibiotic susceptibility, biofilm formation assays, and motility assays which provide information on the virulence and resilience of these strains. Results reveal a range of biofilm forming and motile capabilities, with resistance to common antibiotics. A notable correlation was observed between moderate biofilm formers and higher motility in E. coli strains, whilst S. aureus strains demonstrated moderate to strong biofilm formation. Worryingly, high levels of AMR were detected is both species, E. coli especially to Beta Lactams while S. aureus strains were resistant to six classes of antibiotics, Fluoroquinolones (CIP), Macrolides (CLR + E), Oxazolidinones (FD), Nitroimidazoles (MET), Beta Lactams (OXE + PN), and Streptogramins (OCSF). However, several isolates demonstrated clear zones of lysis when tested against targeted phage, indicating and supporting phage’s possible use in the fight against AMR.

Keywords:

Bacteriophage, phage, phage therapy, endolysins, clinical isolates, antimicrobial resistance

Start Date

16-6-2025 11:00 AM

End Date

16-6-2025 12:00 PM

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Jun 16th, 11:00 AM Jun 16th, 12:00 PM

Phenotypic Characterisation of Staphylococcus aureus and Escherichia coli Clinical Isolates and their Susceptibility to Targeted Bacteriophages

Abstract:

Antibiotic resistance (AMR) is the one of the biggest threats facing humans and animals in the 21st century. This has been caused by the overuse and misuse of antibiotics leading to the desperate need for innovative therapeutic alternatives. Research is ongoing regarding the use of bacteriophages as a possible viable antimicrobial agent. However, various limitations exist which hinder their use including their narrow host range. This limitation poses a significant threat to the development of phage therapies as it requires phenotypic characterisation of clinical isolates to ensure compatibility between strains and phage. This study outlines phenotypic characterisation of clinical isolates of 20 S. aureus strains and 19 E. coli from the Bons Secures Hospital, Cork. This includes antibiotic susceptibility, biofilm formation assays, and motility assays which provide information on the virulence and resilience of these strains. Results reveal a range of biofilm forming and motile capabilities, with resistance to common antibiotics. A notable correlation was observed between moderate biofilm formers and higher motility in E. coli strains, whilst S. aureus strains demonstrated moderate to strong biofilm formation. Worryingly, high levels of AMR were detected is both species, E. coli especially to Beta Lactams while S. aureus strains were resistant to six classes of antibiotics, Fluoroquinolones (CIP), Macrolides (CLR + E), Oxazolidinones (FD), Nitroimidazoles (MET), Beta Lactams (OXE + PN), and Streptogramins (OCSF). However, several isolates demonstrated clear zones of lysis when tested against targeted phage, indicating and supporting phage’s possible use in the fight against AMR.