Coagulase-negative staphylococci species affect biofilm formation of other coagulase-negative and coagulase-positive staphylococci

Abstract

Coagulase-negative staphylococci (CNS) are considered to be commensal bacteria in humans and animals, but are now also recognized as etiological agents in several infections, including bovine mastitis. Biofilm formation appears to be an important factor in CNS pathogenicity. Furthermore, some researchers have proposed that CNS colonization of the intramammary environment has a protective effect against other pathogens. The mechanisms behind the protective effect of CNS have yet to be characterized. The aim of this study was to evaluate the effect of CNS isolates with a weak-biofilm phenotype on the biofilm formation of other staphylococcal isolates. We selected 10 CNS with a weak-biofilm phenotype and 30 staphylococcal isolates with a strong-biofilm phenotype for this study. We measured biofilm production by individual isolates using a standard polystyrene microtiter plate assay and compared the findings with biofilm produced in mixed cultures. We confirmed the results using confocal microscopy and a microfluidic system with low shear force. Four of the CNS isolates with a weak-biofilm phenotype (Staphylococcus chromogenes C and E and Staphylococcus simulans F and H) significantly reduced biofilm formation in approximately 80% of the staphylococcal species tested, including coagulase-positive Staphylococcus aureus. The 4 Staph. chromogenes and Staph. simulans isolates were also able to disperse pre-established biofilms, but to a lesser extent. We also performed a deferred antagonism assay and recorded the number of colony-forming units in the mixed-biofilm assays on differential or selective agar plates. Overall, CNS with a weak-biofilm phenotype did not inhibit the growth of isolates with a strong-biofilm phenotype. These results suggest that some CNS isolates can negatively affect the ability of other staphylococcal isolates and species to form biofilms via a mechanism that does not involve growth inhibition.

Nonconventional starter cultures of coagulase-negative staphylococci to produce animal-derived fermented foods, a SWOT analysis

“…Alternatively, mechanisms different from direct growth inhibition can be at play, for instance by interfering with the biofilm formation of S. aureus (Goetz et al . ).…”

“…; Goetz et al . ). For instance, it has been described for isolates from cured meats or naturally fermented sausages belonging to S. equorum , Staphylococcus vitulinus and Staphylococcus warneri (Leroy et al .…”

“…Antimicrobial activity has also been attributed to human-and animal-associated strains, belonging to the species Staphylococcus capitis, S. chromogenes, S. epidermidis, S. hominis and Staphylococcus lugdunensis (Iwase et al 2010;Sung et al 2010;Zipperer et al 2016;Carson et al 2017). Alternatively, mechanisms different from direct growth inhibition can be at play, for instance by interfering with the biofilm formation of S. aureus (Goetz et al 2017).…”

Biofilm Producing Staphylococcus epidermidis (RP62A Strain) Inhibits Osseous Integration Without Osteolysis and Histopathology in a Murine Septic Implant Model

“…Staphylococci species are responsible for the majority of implant‐associated osteomyelitis, and account for ~80% of the cases . Historically, Staphylococci were distinguished by their ability to produce coagulase; a virulent enzyme that causes fibrin to clot . Examples of this are Staphylococcus epidermidis ( S. epidermidis ), which is a representative species of coagulase‐negative Staphylococci (CNS), and Staphylococcus aureus ( S. aureus ), which is the most common coagulase‐positive organism in implant‐associated infection.…”

“…1,2 Historically, Staphylococci were distinguished by their ability to produce coagulase; a virulent enzyme that causes fibrin to clot. 3 Examples of this are Staphylococcus epidermidis (S. epidermidis), which is a representative species of coagulase-negative Staphylococci (CNS), and Staphylococcus aureus (S. aureus), which is the most common coagulase-positive organism in implant-associated infection. Clinically, Staphylococci strains are further defined by their resistance to methicillin, and the methicillin-resistant S. aureus (MRSA) strain USA300 is known to be the most challenging to treat.…”