Distribution of pathogens in central line-associated bloodstream infections among patients with and without neutropenia following chemotherapy: evidence for a proposed modification to the current surveillance definition.

OBJECTIVE: Many bloodstream infections (BSIs) occurring in patients with febrile neutropenia following cytotoxic chemotherapy are due to translocation of intestinal microbiota. However, these infections meet the National Healthcare Safety Network (NHSN) definition of central line-associated BSIs (CLABSIs). We sought to determine the differences in the microbiology of NHSN-defined CLABSIs in patients with and without neutropenia and, using these data, to propose a modification of the CLABSI definition.
DESIGN: Retrospective review.
SETTING: Two large university hospitals over 18 months.
METHODS: All hospital-acquired BSIs occurring in patients with central venous catheters in place were classified using the NHSN CLABSI definition. Patients with postchemotherapy neutropenia (500 neutrophils/mm(3) or lower) at the time of blood culture were considered neutropenic. Pathogens overrepresented in the neutropenic group were identified to inform development of a modified CLABSI definition.
RESULTS: Organisms that were more commonly observed in the neutropenic group compared with the nonneutropenic group included Escherichia coli (22.7% vs 2.5%; P < .001) but not other Enterobacteriaceae, Enterococcus faecium (18.2% vs 6.1%; P = .002), and streptococci (18.2% vs 0%; P < .001). Application of a modified CLABSI definition (removing BSI with enterococci, streptococci, or E. coli) excluded 33 of 66 neutropenic CLABSIs and decreased the CLABSI rate in one study hospital with large transplant and oncology populations from 2.12 to 1.79 cases per 1,000 line-days.
CONCLUSIONS: Common gastrointestinal organisms were more common in the neutropenia group, suggesting that many BSIs meeting the NHSN criteria for CLABSI in the setting of neutropenia may represent translocation of gut organisms. These findings support modification of the NHSN CLABSI definition.