A retrospective study of the relationship between bacterial numbers from central venous catheter tip cultures and blood cultures for evaluating central line-associated bloodstream infections]

Catheter-related bloodstream infection (CRBSI) is an infectious disease requiring special attention. It is a common cause of nosocomial infections; catheter insertion into the central veins particularly increases the risk of infection (CLA-BSI: central line-associated bloodstream infection). We examined the relationship between the number of bacterial colonies cultured from shredded central venous catheter (CVC) tips and from blood cultures in our hospital from 2011 to 2012. Coagulase-negative staphylococci topped the list of microbe isolated from the CVC tip culture, followed by Pseudomonas aeruginosa, Staphylococcus aureus, and Candida spp. S. aureus and Candida spp., with growth of over 15 colony-forming units in the CVC tip culture, were also detected at high rates in the blood culture. However, gramnegative bacilli (Enterobacteriaceae and P. aeruginosa) did not show a similar increase in colony number in the CVC tip culture. Because microbes adhering to shredded catheter tips are readily detected by culture, this method is useful as a routine diagnostic test. In addition, prompt clinical reporting of the bacterial number of serious CLA-BSI-causing S. aureus and Candida spp. isolated from CVC tips could contribute to earlier CLA-BSI diagnosis.