Titel (eng)

Prevalence of the SigB-Deficient Phenotype among Clinical Staphylococcus aureus Isolates Linked to Bovine Mastitis

Autor*in

Anna Walzl   University of Veterinary Medicine Vienna

Tom Grunert   University of Veterinary Medicine Vienna

Simon Heilbronner   University of Tübingen

Monika Ehling-Schulz   University of Veterinary Medicine Vienna

Claus Vogl   University of Veterinary Medicine Vienna

Helene Marbach   University of Veterinary Medicine Vienna

Darya Belikova   University of Tübingen

Verlag

MDPI

Beschreibung (eng)

Phenotypic adaptation has been associated with persistent, therapy-resistant Staphylococcus aureus infections. Recently, we described within-host evolution towards a Sigma factor B (SigB)-deficient phenotype in a non-human host, a naturally infected dairy cow with chronic, persistent mastitis. However, to our knowledge, the prevalence of SigB deficiency among clinical S. aureus isolates remains unknown. In this study, we screened a collection of bovine mastitis isolates for phenotypic traits typical for SigB deficiency: decreased carotenoid pigmentation, increased proteolysis, secretion of α-hemolysin and exoproteins. Overall, 8 out of 77 (10.4%) isolates of our bovine mastitis collection exhibited the SigB-deficient phenotype. These isolates were assigned to various clonal complexes (CC8, CC9, CC97, CC151, CC3666). We further demonstrated a strong positive correlation between asp23-expression (a marker of SigB activity) and carotenoid pigmentation (r = 0.6359, p = 0.0008), underlining the role of pigmentation as a valuable predictor of the functional status of SigB. Sequencing of the sigB operon (mazEF-rsbUVW-sigB) indicated the phosphatase domain of the RsbU protein as a primary target of mutations leading to SigB deficiency. Indeed, by exchanging single nucleotides in rsbU, we could either induce SigB deficiency or restore the SigB phenotype, demonstrating the pivotal role of RsbU for SigB functionality. The data presented highlight the clinical relevance of SigB deficiency, and future studies are needed to exploit its role in staphylococcal infections.

Sprache des Objekts

Englisch

Datum

2023

Rechte

Dieses Werk bzw. dieser Inhalt steht unter einer
CC BY 4.0 - Creative Commons Namensnennung 4.0 International Lizenz.

CC BY 4.0 International

http://creativecommons.org/licenses/by/4.0/

Klassifikation

Stress Resistance; Alpha-Hemolysin; Cell-Wall; Sigma(B); Expression; Virulence; Biosynthesis; Biofilm; Rsbu; Operon

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