Serum and tissue protein binding and cell surface properties of Staphylococcus lugdunensis

Abstract

Summary. Eleven strains of Staphylococcus lugdunensis from different clinical sources were investigated for their ability to bind 12'I-labelled collagen (Cn) type I and IV, fibronectin (Fn), vitronectin (Vn), laminin (Lm), fibrinogen (Fg), thrombospondin, plasminogen (glu-and lysform) and human IgG. All the strains bound these proteins, although a higher degree of binding was obtained for Cn types I and IV and IgG with mean values of 36 YO, 32 YO and 26 YO binding. respectively. In tests with proteins immobilised on latex beads in a particle agglutination assay, eight of the 11 strains bound Cn type I and seven bound Fg, whereas no strain bound immobilised IgG. Binding to immobilised Cn-I, Fg, Lm and Vn was abolished when the bacterial cells were treated with proteases or heat, indicating cell-surface receptors with protein characteristics. Cell-surface extracts of S . lugdunensis 2342 were able to totally inhibit binding of the homologous strain and S . aureus Cowan 1 to latex-immobilised proteins Cn-I, Lm, Vn, Fn and Fg. The binding of '"I-labelled Cn IV by S. lugdunensis 2342, was heat sensitive, whereas the binding to S. auieus Cowan 1 was heat resistant. The strains gave negative results in tests for the presence of protein A with a S. aureus protein A gene probe and with sensitised red blood cells. No production of heat-stable nuclease (TNase) could be detected by monoclonal antibodies against TNase or by the polymerase chain reaction with an oligonucleotide sequence from S . aureus TNase as primer. When the cell surface characters of the S. lugdunensis strains were studied, five were found to be hydrophobic and negatively charged. four hydrophilic and positively charged and two hydrophobic with positive net charge. lntroduc tionCoagulase-negative staphylococci (CNS) are well recognised as opportunist pathogens causing infections in neonates and neutropenic patients.' They are the most important pathogens in infections associated with intravascular catheters and grafts, peritoneal catheters and prostheses in various organs.' With the recent description of two new species of CNS, Staph?.-lo~~occ~us luqduimsis and S. sclde !'fc.ri,3 there are at present 24 species of CNS. S . epidemviiclis, S. huernolyficws and S. .s~~?rc~~~12.ticIrs are the species isolated most frequently from human infections.' C'ougufase-positive staphylococci, i.e., S. mreus, are more virulent than CNS.' Numerous studies have focused on presumptive virulence factors of S . aureus, and latterly on those of CNS.' Of these factors, only protein A and coagulase are consistently absent in CNS. The presence of heat-stable nuclease is characteristic: of coagulase-positive staphylococci but has not been ascribed any role in pathogenicity.' All other toxin>. enzymes and outer-membrane proteins of S. U14Wli.S have been detected in CNS strains with varying

Poly- N -Acetylglucosamine Is Not a Major Component of the Extracellular Matrix in Biofilms Formed by icaADBC -Positive Staphylococcus lugdunensis Isolates

“…However, our present comprehension of the virulence factors involved in S. lugdunensis pathogenesis is relatively limited (17,43,50,52,53,57). In our experience working with S. lugdunensis (in accordance with Mitchell et al [50]), we have been unable to introduce DNA and perform genetic analyses with any of the clinical isolates in our collection.…”

From Clinical Microbiology to Infection Pathogenesis: How Daring To Be Different Works forStaphylococcus lugdunensis

“…In addition to human plasma, there exist a large number of commercially available latex agglutination kits containing fibrinogen-coated particles to facilitate visible clumping reactions mediated by clumping factor (5 (135). Six of 11 strains were positive under all four conditions tested.…”

“…1A), but a variable percentage of strains are positive for clumping factor (bound coagulase) when tested in a slide agglutination test with human plasma or various commercial latex agglutination kits (discussed further below) (5,68). S. lugdunensis does not possess protein A (68,135). Isolates are positive for acetoin production, nitrate reduction, and ornithine decarboxylase and pyrrolidonyl arylamidase (PYR) activities ( (5,68).…”

The N-terminal of thrombospondin-1 is essential for coagulase-negative staphylococcal binding

“…TSP was labelled with Na 125 I according to a modi®ed chloramine-T method with Iodo-beads [21]. The speci®c activity was 1:2 3 10 6 cpm=ìg of TSP.…”

“…S. aureus has also been shown to bind TSP [20]. There have been a few reports on the binding of TSP by CNS but the mechanism of the interaction has not been demonstrated clearly [9,20,21].…”