Emergence of coagulase-negative staphylococci

ABSTRACT

Introduction: Compared to Staphylococcus aureus, coagulase-negative staphylococci (CoNS) are characterized by a lower capacity to cause acute, live-threatened infections. CoNS are, however, of ever increasing importance as pathogens causing infections in immunocompromised patients and after foreign-material implantation. Typically, antibiotics fail to cure foreign body-related infections and removal of the implanted device is inevitable.

Areas covered: This review focuses on the emergence of CoNS species, their pathogenic potential in particular due to their ability to form therapy-refractory biofilms on biotic and abiotic surfaces and evasion strategies to resist host response and antibiotic treatment. Their medical significance and proven and novel therapy strategies are discussed.

Expert opinion: CoNS contribute significantly to morbidity and socio-economic costs. The anticipated developments in modern medicine, in particular the increasing use of foreign materials and the rising numbers of immunocompromised patients, as well as the changing demographic and hospital-related factors will inevitably contribute to further emergence of CoNS infections. Increasing rates of (multi-)resistant CoNS strains will limit the therapeutic armamentarium and aggravate treatment strategies. Increased research is necessary to understand their role as resistance and virulence gene reservoir and to reduce CoNS infections by the development of innovative colonization-preventing materials and other CoNS-tailored treatment strategies.

KEYWORDS:

• Biofilm
• coagulase-negative staphylococci
• device-related infection
• foreign body-associated infection
• methicillin resistance

Article highlights

• The term “coagulase-negative staphylococci (CoNS)“comprises a heterogeneous, still expanding group of species of the genus Staphylococcus colonizing the skin and mucous membranes of human and animal hosts.

• The emergence of CoNS is linked to the medical progress characterized by an increased number of immunocompromised patients and foreign body-related medical procedures.

• CoNS are not able to produce the S. aureus-associated virulence factor ‘coagulase,’ but own species- and strain-dependently various virulence factors enabling many of them to act as notorious opportunistic pathogens.

• CoNS biofilm formation comprises surface adherence and subsequent biofilm accumulation and main bacterial factors involved include various surface proteins, exopolysaccharides (e.g. PIA/PNAG), teichoic acids, and eDNA.

• Whole-genome analysis of invasive and colonizing S. epidermidis populations and identification clones exhibiting augmented invasive potential has significantly improved our understanding of CoNS epidemiology.

• Biofilm formation as a principal pathogenic strategy in device-associated CoNS infections demands specific treatment requirements, including device removal, combination therapy, and prolonged treatment courses.

• The availability of novel cell wall active compounds significantly broadens therapeutic options to treat methicillin-resistant CoNS.

Declaration of interest

K Becker has acted as speaker for Pfizer Pharma and Holger Rohde acted as a speaker for Pfizer Pharma, Merck Sharp & Dohme, Infectopharm, and Accelerate Diagnostics and consultant for Pfizer and Merck & Sharp Dohme. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The EU/INTERREG (VA-681377, ‘EurHealth-1Health’) supports in part the work of Karsten Becker and the Interdisciplinary Center for Clinical Research Münster (IZKF, project Hei2/027/18) supports the work of Christine Heilmann. The work of Holger Rohde is supported by the Damp Foundation (2013-2019).