Central venous catheter-related infection in adults: A diagnostic challenge

Central venous catheters are one of the main causes of bacteraemia and septicaemia in hospitalised patients and are associated with a significant morbidity and occasional mortality. Many micro-organisms are associated with catheter-related infection (CRI) and they originate from several sources. However, it is well accepted that those associated with the skin's microflora, principally the coagulase negative staphylococci (CNS) account for the majority of cases. Clinical diagnosis of CRI is challenging as infected patients frequently present with non-specific symptoms. Microbiological diagnosis is equally complex as several techniques are available to facilitate diagnosis and there is no consensus of opinion as to which one to use routinely. Traditionally, microbiological diagnosis of CRI is made by culturing the catheter following withdrawal. However, a great deal of interest now lies in establishing a diagnosis through conservative techniques which allow for catheter salvage. To confound the laboratory diagnosis of CRI further, routine tests used to identify CNS lack discrimination and do not allow for differentiation between infecting and contaminating strains to be made. To establish an accurate diagnosis precise and sensitive molecular techniques are ideally required to characterise strains of CNS recovered from patients with suspected CRI.