Corynebacterium accolens Has Antimicrobial Activity against Staphylococcus aureus and Methicillin-Resistant S. aureus Pathogens Isolated from the Sinonasal Niche of Chronic Rhinosinusitis Patients.

Martha Alemayehu Menberu,Sarah Vreugde,Alkis James Psaltis,Sha Liu,Clare Cooksley,Peter-John Wormald,Andrew James Hayes

doi:10.3390/pathogens10020207

Abstract

Corynebacterium accolens is the predominant species of the healthy human nasal microbiota, and its relative abundance is decreased in the context of chronic rhinosinusitis (CRS). This study aimed to evaluate the antimicrobial potential of C. accolens isolated from a healthy human nasal cavity against planktonic and biofilm growth of Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) clinical isolates (CIs) from CRS patients. Nasal swabs from twenty non-CRS control subjects were screened for the presence of C. accolens using microbiological and molecular techniques. C. accolens CIs and their culture supernatants were tested for their antimicrobial activity against eight S. aureus and eight MRSA 4CIs and S. aureus ATCC25923. The anti-biofilm potential of C. accolens cell-free culture supernatants (CFCSs) on S. aureus biofilms was also assessed. Of the 20 nasal swabs, 10 C. accolens CIs were identified and confirmed with rpoB gene sequencing. All isolates showed variable antimicrobial activity against eight out of 8 S. aureus and seven out of eight MRSA CIs. Culture supernatants from all C. accolens CIs exhibited a significant dose-dependent antibacterial activity (p < 0.05) against five out of five representative S. aureus and MRSA CIs. This inhibition was abolished after proteinase K treatment. C. accolens supernatants induced a significant reduction in metabolic activity and biofilm biomass of S. aureus and MRSA CIs compared to untreated growth control (p < 0.05). C. accolens exhibited antimicrobial activity against S. aureus and MRSA CIs in both planktonic and biofilm forms and holds promise for the development of innovative probiotic therapies to promote sinus health.

Highlights

IntroductionDisruption of the human nasal microbiome homeostasis is found in patients with chronic rhinosinusitis (CRS)
Our results show that C. accolens strains isolated from the sinonasal cavities of non-chronic rhinosinusitis (CRS) control patients have antimicrobial activity against methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains isolated from the sinonasal cavities of CRS patients
Both MSSA and MRSA planktonic cells and biofilms were sensitive to C. accolens and our results indicate a secreted protein to likely be responsible for this activity

Summary

Introduction

Disruption of the human nasal microbiome homeostasis is found in patients with chronic rhinosinusitis (CRS). CRS is an inflammatory disorder of the mucosa of the nasal cavity and paranasal sinuses, characterized by various clinical manifestations including sinus/facial pain, nasal congestion, rhinorrhoea, post-nasal discharge, and a reduced sense of smell for a minimum of 12 weeks duration [1]. Whilst the aetiology of CRS is thought to be multifactorial, disruption of the microbial community residing in the sinuses, termed dysbiosis, has recently been implicated in CRS pathophysiology, in particular in more severe patients [2]. In CRS patients, the microbiome is characterised by a decrease in the relative abundance of Corynebacterium and an expansion of pathogenic bacteria including Staphylococcus, Haemophilus, Moraxella and Enterobacteriacea [5]. Staphylococcus aureus is the most frequently isolated species in patients with CRS [6]. Exacerbations of CRS due to S. aureus and methicillin-resistant

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