Staphylococcus lugdunensis.

Abstract

Historically, staphylococci are grouped as coagulase-negative or coagulase-positive, according to their ability to induce clotting of mammalian serum through the activity of a secreted coagulase. S. lugdunensis belongs to the coagulase-negative staphylococci (CoNS) but it is in many ways unusual as it shares several features with the coagulase-positive and highly invasive opportunistic pathogen Staphylococcus aureus. Like S. aureus, many S. lugdunensis strains express a cell wall-anchored molecule (Fbl) promoting adhesion to fibrinogen [ 8. Geoghegan J.A. et al. Molecular characterization of the interaction of staphylococcal microbial surface components recognizing adhesive matrix molecules (MSCRAMM) ClfA and Fbl with fibrinogen. J. Biol. Chem. 2010; 285: 6208-6216 Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar ]. This mediates clumping of fibrinogen-coated latex beads, which are frequently used for the rapid identification of S. aureus. This can lead to misidentification of S. lugdunensis in clinical samples. Furthermore, S. lugdunensis is more virulent than other CoNS, a feature especially apparent in its ability to cause infective endocarditis. In fact, S. lugdunensis encodes several putative virulence factors, including the hemolytic SLUSH peptides, which allow the release of hemoglobin (Hb) from erythrocytes [ 9. Donvito B. et al. Synergistic hemolytic activity of Staphylococcus lugdunensis is mediated by three peptides encoded by a non-agr genetic locus. Infect. Immun. 1997; 65: 95-100 Crossref PubMed Google Scholar ], sortase A [ 4. Heilbronner S. et al. Sortase A promotes virulence in experimental Staphylococcus lugdunensis endocarditis. Microbiology. 2013; 159: 2141-2152 Crossref PubMed Scopus (30) Google Scholar ], a streptolysin-like toxin [ 10. Lebeurre J. et al. Comparative genome analysis of Staphylococcus lugdunensis shows clonal complex-dependent diversity of the putative virulence factor, ess/type VII locus. Front. Microbiol. 2019; 10: 2479 Crossref PubMed Scopus (10) Google Scholar ], and an ess/type VII locus [ 10. Lebeurre J. et al. Comparative genome analysis of Staphylococcus lugdunensis shows clonal complex-dependent diversity of the putative virulence factor, ess/type VII locus. Front. Microbiol. 2019; 10: 2479 Crossref PubMed Scopus (10) Google Scholar ]. Additionally, like many bacterial pathogens, S. lugdunensis possesses systems (Isd and Lha) for the acquisition of heme that is stripped from the host Hb, enabling its cytosolic degradation and the release of nutritional iron [ 11. Jochim A. et al. An ECF-type transporter scavenges heme to overcome iron-limitation in Staphylococcus lugdunensis. eLife. 2020; 9e57322 Crossref PubMed Scopus (8) Google Scholar ]. Further factors that might promote immune evasion, killing of immune cells, or adhesion to host tissues have been suggested but they have not been experimentally validated so far [ 3. Heilbronner S. Foster T.J. Staphylococcus lugdunensis: a skin commensal with invasive pathogenic potential. Clin. Microbiol. Rev. 2021; 34e00205-20 Crossref PubMed Scopus (8) Google Scholar ]. Finally, the extracellular matrix of S. lugdunensis biofilms is not enriched in polysaccharides but in proteinaceous factors [ 12. Frank K.L. Patel R. Poly-N-acetylglucosamine is not a major component of the extracellular matrix in biofilms formed by icaADBC-positive Staphylococcus lugdunensis isolates. Infect. Immun. 2007; 75: 4728-4742 Crossref PubMed Scopus (83) Google Scholar ], and biofilm formation depends on the action of the autolysin AtlL [ 13. Hussain M. et al. The adhesive properties of the Staphylococcus lugdunensis multifunctional autolysin AtlL and its role in biofilm formation and internalization. Int. J. Med. Microbiol. 2015; 305: 129-139 Crossref PubMed Scopus (32) Google Scholar ].