Bloodstream infections are serious, costly hospital-acquired infections and are the cause of significant morbidity and mortality and an increase in length and cost of hospitalization. Central venous catheters are associated with 90% of these hospital-acquired bloodstream infections.1 These infections are of major concern in the critical care settings for several reasons: the frequency of central venous catheter use, the susceptibility of critically ill patients, and the prevalence of high risk situations, including the presence of pathogenic and multidrug-resistant organisms.
Recently, the Infectious Diseases Society of America updated the guidelines for the diagnosis and management of intravenous catheter-related bloodstream infections (CRBSIs).2 The following are selected recommendations from this new guideline:
* For suspected CRBSI, paired blood cultures drawn, from a catheter and a peripheral vein, should be done before initiation of antimicrobial therapy, and the bottles should be appropriately marked to reflect the site the cultures were drawn from (A-II, the grading system reflects the strength of recommendation, with A being the highest and level of evidence and I being the highest; see the guideline for further explanation).
* If a blood culture cannot be drawn from a peripheral vein, it is recommended that 2 or more blood cultures should be drawn through different catheter lumens (B-III).
* A definitive diagnosis of CRBSI requires that the same organism grows from at least 1 percutaneously drawn blood culture and catheter tip (A-I) or that 2 blood cultures are to be drawn (1 from a catheter hub and 1 from a peripheral vein) and meet the CRBSI criteria for quantitative blood cultures or differential time to positivity (DTP; A-II). Differential time to positivity uses a continuous blood culture monitoring for growth (eg, radiometric methods), and DTPS are compared for qualitative blood cultures drawn from a catheter and a peripheral vein. The greater the number of microbes inoculated into blood culture bottles, the shorter the DTP.
* Most microbiology laboratories do not perform quantitative blood cultures, but many laboratories will be able to determine DTP. Differential time to positivity may not discriminate between CRBSI and non-CRBSI in patients already receiving antibiotics.
* For quantitative blood cultures, a colony count of microbes grown from blood obtained through a catheter hub that is at least 3-fold greater than the colony count from blood obtained from a peripheral vein best defines CRBSI (A-II).
* Empiric combination antibiotic coverage for multidrug-resistant gram-negative bacilli, such as Pseudomonas aeruginosa, should be used when CRBSI is suspected in neutropenic patients, severely ill patients with sepsis, or patients known to be colonized with such pathogens, until the culture and sensitivity data are available and de-escalation can be done (A-II).
* In addition to coverage for gram-positive pathogens, empiric therapy for suspected CRBSI involving femoral catheters in critically ill patients should include coverage for gram-negative bacilli and Candida spp (A-II).
* Antibiotic lock therapy should be used for catheter salvage (B-II); however, if antibiotic lock therapy cannot be used in this situation, administration of systemic antibiotics should be done through a colonized catheter (C-III).
* Four to 6 weeks of antibiotics should be administered in patients with persistent fungemia or bacteremia after catheter removal (ie, ≥72 hours; A-II for Staphylococcus aureus and C-III for other pathogens) and in patients found to have infective endocarditis or suppurative thrombophlebitis and pediatric patients with osteomyelitis; and 6 to 8 weeks of therapy should be used for the treatment of osteomyelitis in adults.
* Long-term catheter use should be removed in patients with CRBSI associated with any of the following conditions: severe sepsis, suppurative thrombophlebitis, endocarditis, bloodstream infection that continues despite 72 hours of antimicrobial therapy or longer to which the infecting microbes are susceptible, or infections due to S. aureus, P. aeruginosa, fungi, or mycobacteria (A-II). Short-term catheter use should be removed in patients with CRBSI due to Gram-negative bacilli, S. aureus, enterococci, fungi, and mycobacteria (A-II).
* For patients with CRBSI in whom catheter salvage is attempted, repeated blood cultures should be obtained, and the catheter should be removed if blood cultures (eg, 2 sets of blood cultures on a given day; 1 set in neonates is acceptable) remain positive for a microorganism when drawn 72 hours after initiation of appropriate therapy (B-II).
* In uncomplicated CRBSI involving long-term catheter use due to pathogens other than S. aureus, P. aeruginosa, Bacillus, Micrococcus, Propionibacteria, fungi, or mycobacteria, given limited access sites in many patients who require long-term intravascular access for survival (eg, hemodialysis and short-gut syndrome), treatment should be attempted without catheter removal using both systemic and antimicrobial lock therapy (B-II).
For other recommendations, refer to the guideline.