Occurrence of genes of putative fibrinogen binding proteins and hemolysins, as well as of their phenotypic correlates in isolates of S. lugdunensis of different origins

Abstract

BackgroundStaphylococcus lugdunensis is an important human pathogen that causes potentially fatal endocarditis, osteomyelitis and skin and soft tissue infections similar to diseases caused by Staphylococcus aureus. Nevertheless, in contrast to S. aureus, data on pathogenicity factors of S. lugdunensis is scarce. Two adhesins, a fibrinogen and a von Willebrand factor binding protein, and a S. lugdunensis synergistic hemolysin (SLUSH) have been previously described. Moreover, the newly sequenced genome of S. lugdunensis revealed genes of other putative fibrinogen binding adhesins and hemolysins. The aim of this study was to gain more insight into the occurrence of genes likely coding for fibrinogen binding adhesins and hemolysins using clinical strains of S. lugdunensis.FindingsMost of the putative adhesin genes and hemolysin genes investigated in this study were highly prevalent, except for the SLUSH gene cluster. In contrast to previous reports, binding to fibrinogen was detected in 29.3% of the S. lugdunensis strains. In most strains, hemolysis on blood agar plates was weak after 24 h and distinct after 48 h of incubation. The fibrinogen binding and hemolysis phenotypes were also independent of the type of clinical specimen, from which the isolates were obtained.ConclusionIn this study we described a pyrrolidonyl arylamidase negative S. lugdunensis isolate. Our data indicate that a matrix-assisted laser desorption ionisation time-of-flight MS-based identification of S. lugdunensis or species-specific PCR's should be performed in favour of pyrrolidonyl arylamidase testing. In contrast to the high occurrence of putative fibrinogen binding protein genes, 29.3% of the S. lugdunensis strains bound to fibrinogen. Putative hemolysin genes were also prevalent in most of the S. lugdunensis strains, irrespective of their hemolysis activity on Columbia blood agar plates. Similar to a previous report, hemolysis after 48 h of incubation is also indicative for S. lugdunensis. The SLUSH gene cluster was detected in an estimated 50% of the strains, indicating that this locus is different or non-prevalent in many strains.

Multi-Virulence-Locus Sequence Typing of Staphylococcus lugdunensis Generates Results Consistent with a Clonal Population Structure and Is Reliable for Epidemiological Typing

“…This result confirms that fbl is a good PCR target for the S. lugdunensis identification (61). The slush operon was also detected in all the strains of our collection, unlike in Svabados et al (35), who detected it only in 28 strains of 58 with the same primers. Shown to mediate the synergistic ␦-like hemolytic activity of S. lugdunensis (27) and to stimulate human leukocytes via interaction with the formyl-peptide receptor 2 (29) as phenol-soluble modulin peptides, the SLUSH peptides display an important role in the virulence of this species.…”

“…Interestingly, the genome sequencing of two strains of S. lugdunensis, N920143 (30) and HKU09-01 (33), revealed genes encoding putative virulence factors, such as adhesins, toxins, and hemolysins. Among them is a gene denoted SLUG_16930 in the N920143 genome that encodes a putative fibrinogen/fibronectin binding adhesin named FbpA homologue, which is homologous to FbpA of S. aureus (30,34,35). The hlb gene encodes a putative sphingomyelinase ␤-toxin of 329 amino acids (aa), which shares 85% identity with that of S. aureus (30,36), and a putative hemolysin III (denoted SLUG_09050 in the N920143 genome [30]) is encoded as well.…”

Implementation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry in Routine Clinical Laboratories Improves Identification of Coagulase-Negative Staphylococci and Reveals the Pathogenic Role of Staphylococcus lugdunensis

“…S. lugdunensis is the second cause of endocarditis due to CoNS, with a poor prognosis in 40% of cases (36). Putative virulence factors have been described in S. lugdunensis that may explain its pathogenicity, including a fibrinogen binding protein, a von Willebrand factor binding protein, and possibly a delta-like hemolysin and a beta-hemolysin, although these hemolysins have not been correlated with any clinical type or severity of infection (37)(38)(39). The fibrinogen binding protein, also called the clumping factor, yields a positive result in slide coagulase and rapid latex agglutination tests, leading to its misidentification as S. aureus.…”

Late Periprosthetic Joint Infection due toStaphylococcus lugdunensisIdentified by Matrix-Assisted Laser Desorption/Ionisation Time of Flight Mass Spectrometry: A Case Report and Review of the Literature

“…In addition, the reaction with pyrrolidonyl arylamidase (PYR) and ornithine decarboxylase (ODC) has been described to distinguish S. lugdunensis from other staphylococci [2]. In contrast to this, a PYR-negative S. lugdunensis isolate has recently been reported [3], indicating that a significant amount of stains will be misidentified using the latter strategy. An ODC-negative S. lugdunensis has not been reported yet, but it is likely that such isolates also exit.…”