ABSTRACT
Coagulase-negative staphylococci (CoNS), particularly Staphylococcus epidermidis, are the species most frequently isolated from infections associated with the use of vascular catheters. The propensity of these species to cause invasive disease, frequently manifestating as primary bacteremia, has for a long time been a conundrum in modern medicine: In contrast to their highly pathogenic coagulase-positive counterpart, Staphylococcus aureus, for a long time CoNS have been considered avirulentmicroorganisms that form amajor component of the cutaneous microflora. Since the 1980s, however, it has been recognized that these organisms are readily able to colonize and infect various devices used for diagnostic and therapeutic procedures such as intravascular catheters, cerebrospinal fluid shunts, prosthetic heart valves, orthopedic devices, pacemakers, peritoneal dialysis catheters, vascular grafts, and ventricular assist devices (1). In fact, CoNS are now the leading organism for nosocomial bacteremia (2), and it is suggested that most of these cases are a consequence of infection of intravascular catheters. Bacteremia due to CoNS is associated with considerable hospital expenditures, morbidity, and also
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an increased mortality rate (3-5), yet treatment options are increasingly narrowed by emerging resistance against previously active antimicrobials (6). Over the last decades, important insight into the pathogenesis of these low-virulence microorganisms has been gained, particularly with respect to their interaction with a polymer surface, and it has now become clear that the intimatemultifactorial interactionwith the artificial surface is the basis for the role of these organisms in catheter-related infection (7). However, at this time it is not possible to translate the enhanced understanding of the pathogenic mechanisms in preventive or prophylactic measures specifically directed against this group of microorganisms, and additional efforts have to be made to introduce innovative, pathogen-directed strategies in clinical application.
