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Limitations in the use of PSMγ, agr , RNAIII, and biofilm formation as biomarkers to define invasive Staphylococcus epidermidis from chronic biomedical device-associated infections / Llinos Harris; Ed Dudley; Holger Rohde; Lars Frommelt; Nicolaus Siemssen; Thomas S. Wilkinson; Dietrich Mack

International Journal of Medical Microbiology, Volume: 307, Issue: 7, Pages: 382 - 387

Swansea University Author: Llinos, Harris

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DOI (Published version): 10.1016/j.ijmm.2017.08.003

Abstract

Staphylococcus epidermidis is a common cause of biomedical device-associated infections. Agr is the major quorum sensing system in staphylococci and regulates virulence factors. Four agr-specificity groups exist in S. epidermidis, and chronic S. epidermidis infections are hypothesised to select for...

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Published in: International Journal of Medical Microbiology
ISSN: 14384221
Published: 2017
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URI: https://cronfa.swan.ac.uk/Record/cronfa35039
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Abstract: Staphylococcus epidermidis is a common cause of biomedical device-associated infections. Agr is the major quorum sensing system in staphylococci and regulates virulence factors. Four agr-specificity groups exist in S. epidermidis, and chronic S. epidermidis infections are hypothesised to select for agr-negative phenotypes. Therefore, we investigated S. epidermidis strains from prosthetic joint- and catheter-associated infections to establish i) whether an infection selects for an agr-negative phenotype; ii) the importance of PSMγ and iii) if the agr-specificity group is infection dependent. S. epidermidis nasal isolates from healthy volunteers were used as controls. The distribution of agr-specificity groups was significantly different between infection and control episodes, but did not distinguish between the infection types. PSMγ secretion was used to determine agr-activity and HPLC analysis showed that 44% of prosthetic and 32% of catheter-associated episodes produced no PSMγ in comparison to 8% of the control strains. However, PSMγ expression did not always correlate with RNAIII up-regulation, indicating that PSMγ synthesis is likely influenced by additional post-transcriptional control. The data suggests chronic S. epidermidis infections favour agr-specificity group 1 but the results suggest that they do not select for an agr-negative phenotype. Further studies are required to explore the mechanisms underlying the selection and survival of these S. epidermidis phenotypes isolated from biomedical device-associated infections.
Keywords: Staphylococcus epidermidis; agr; Quorum sensing; Infection; Phenol soluble modulins; Biomedical devices; Biofilm formation
College: Swansea University Medical School
Issue: 7
Start Page: 382
End Page: 387

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