AUTHOR=Dahyot Sandrine , Lebeurre Jérémie , Laumay Floriane , Argemi Xavier , Dubos Charline , Lemée Ludovic , Prévost Gilles , François Patrice , Pestel-Caron Martine 

TITLE=fbl-Typing of Staphylococcus lugdunensis: A Frontline Tool for Epidemiological Studies, but Not Predictive of Fibrinogen Binding Ability

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.01109

DOI=10.3389/fmicb.2019.01109

ISSN=1664-302X

ABSTRACT=<p><italic>Staphylococcus lugdunensis</italic> is increasingly recognized as a potent pathogen, responsible for severe infections with an outcome resembling that of <italic>Staphylococcus aureus</italic>. Here, we developed and evaluated a tool for <italic>S. lugdunensis</italic> typing, using DNA sequence analysis of the repeat-encoding region (R-domain) in the gene encoding the fibrinogen (Fg)-binding protein Fbl (<italic>fbl</italic>-typing). We typed 240 <italic>S. lugdunensis</italic> isolates from various clinical and geographical origins. The length of the R-domain ranged from 9 to 52 repeats. <italic>fbl</italic>-typing identified 54 unique 18-bp repeat sequences and 92 distinct <italic>fbl</italic>-types. The discriminatory power of <italic>fbl</italic>-typing was higher than that of multilocus sequence typing (MLST) and equivalent to that of tandem repeat sequence typing. <italic>fbl</italic>-types could assign isolates to MLST clonal complexes with excellent predictive power. The ability to promote adherence to immobilized human Fg was evaluated for 55 isolates chosen to reflect the genetic diversity of the <italic>fbl</italic> gene. We observed no direct correlation between Fg binding ability and <italic>fbl</italic>-types. However, the lowest percentage of Fg binding was observed for isolates carrying a 5′-end frameshift mutation of the <italic>fbl</italic> gene and for those harboring fewer than 43 repeats in the R-domain. qRT-PCR assays for some isolates revealed no correlation between <italic>fbl</italic> gene expression and Fg binding capacity. In conclusion, this study shows that <italic>fbl</italic>-typing is a useful tool in <italic>S. lugdunensis</italic> epidemiology, especially because it is an easy, cost-effective, rapid and portable method (<ext-link ext-link-type="uri" xlink:href="http://fbl-typing.univ-rouen.fr/" xmlns:xlink="http://www.w3.org/1999/xlink">http://fbl-typing.univ-rouen.fr/</ext-link>). The impact of <italic>fbl</italic> polymorphism on the structure of the protein, its expression on the cell surface and in virulence remains to be determined.</p>