Central-line-associated bloodstream infections secondary to anaerobes: Time for a definition change?

Primary central-line–associated bloodstream infection (CLABSI) pathogenesis occurs via 1 of 2 mechanisms: bacteria on the skin migrate along the external surface of the catheter from the catheter exit site toward the intravascular space or bacteria are directly inoculated by contamination of the hub. In contrast, anaerobic bacteria, which commonly colonize mucous membranes of the mouth, gastrointestinal tract, and genital tract, lack detoxifying enzymes to break down oxygen-reduction products and cannot survive in the presence of oxygen. The National Health Safety Network (NHSN) established the mucosal barrier injury–laboratory confirmed bloodstream infection (MBI-LCBI) definition in 2013 to acknowledge that some patients have BSIs due to mucosal barrier translocation. Based on current National Healthcare Safety Network (NHSN) definitions, mucosal barrier translocation of anaerobic bacteria in the MBI-LCBI definition only applies to immunocompromised patients. A nonimmunocompromised patient with a central catheter and a blood culture growing an anaerobic organism can still meet the CLABSI criteria despite both primary mechanisms of CLABSI requiring bacterial exposure to atmospheric oxygen. Here, Dr. Jessie Seidelman and other members of the DICON faculty have described the epidemiology of anaerobic CLABSI, and evaluated the impact of modifying the MBI-LCBI definition to include CLABSI caused by obligate anaerobic bacteria in nonimmunocompromised patients with central catheters.

This article was published in Infection Control & Hospital Epidemiology