CRBSI stands for catheter-related bloodstream infection, a serious infection that occurs when bacteria or fungi enter the bloodstream through a central venous catheter (a large IV line placed in a major vein). It’s a clinical diagnosis that requires specific lab tests to confirm the catheter itself is the source of the infection, rather than some other site in the body. CRBSI is one of the most common and dangerous complications of central line use in hospitals and long-term care settings.
CRBSI vs. CLABSI: Why the Distinction Matters
You’ll often see CRBSI and CLABSI used interchangeably, but they mean different things. CRBSI is a clinical diagnosis, meaning it’s used when doctors are actively trying to figure out what’s causing a patient’s infection and how to treat it. It requires lab testing that specifically links the catheter to the bloodstream infection.
CLABSI (central line-associated bloodstream infection) is a simpler, broader surveillance term used by the CDC to track infection rates across hospitals. A CLABSI is any primary bloodstream infection in a patient who had a central line within the 48 hours before the infection developed, as long as the infection isn’t clearly linked to another source. Because some bloodstream infections get counted as CLABSIs even when the catheter wasn’t truly the cause (the infection may have originated from something like inflammation of the gut lining or pancreatitis), CLABSI numbers tend to overestimate the true rate of catheter-caused infections.
In short: CRBSI is the more precise, harder-to-prove diagnosis. CLABSI is the easier-to-track number hospitals report for quality monitoring.
How the Infection Develops
Bacteria reach the bloodstream through a central line in four main ways, and the route depends largely on how long the catheter has been in place.
For short-term catheters (those in place for days to a few weeks), the most common route is skin bacteria migrating along the outside of the catheter from the insertion site down into the vein. This is why skin preparation before insertion is so critical. For longer-term catheters, contamination of the catheter hub, the connection point where medications and fluids are administered, becomes the primary concern. Bacteria from a healthcare worker’s hands or from contaminated equipment can travel along the inside of the catheter into the bloodstream.
Less commonly, bacteria circulating from an infection elsewhere in the body can settle on the catheter. And rarely, contaminated IV fluids themselves introduce the infection.
Common Organisms Involved
The types of bacteria and fungi that cause CRBSI vary somewhat between hospitals and patient populations, but a few patterns hold. Gram-negative bacteria (a broad category that includes species resistant to many antibiotics) account for roughly 44% of cases in some studies. Gram-positive bacteria, including skin-dwelling staphylococci and enterococci, make up about 31%. Fungal infections, primarily Candida species, account for around 24%.
Coagulase-negative staphylococci, the bacteria that normally live on your skin, are among the most frequently identified culprits. This makes sense given that skin migration is the primary infection route. Other common organisms include various species of Klebsiella, Acinetobacter, and E. coli. The specific organism matters because it directly determines whether the catheter needs to come out and how long treatment will last.
How CRBSI Is Diagnosed
Diagnosing CRBSI is more involved than simply finding bacteria in a patient’s blood. The key challenge is proving the catheter is the source. One widely used method is called differential time to positivity. Blood samples are drawn simultaneously from the catheter and from a separate vein. If the catheter sample grows bacteria at least 120 minutes (two hours) faster than the sample from the vein, this strongly suggests the catheter is harboring the infection.
In practice, this testing isn’t always feasible. Many hospital labs don’t routinely perform the specialized cultures needed, and sometimes clinical circumstances (a critically ill patient, for instance) don’t allow for the ideal specimen collection. This is one reason the simpler CLABSI definition exists for tracking purposes.
Where the Catheter Is Placed Affects Risk
The vein chosen for catheter placement significantly influences infection risk. Catheters placed in the subclavian vein (beneath the collarbone) carry the lowest infection rates. In one study of patients with weakened immune systems, the rate of CRBSI was 1.2 per 1,000 catheter-days for subclavian lines compared to 5.7 per 1,000 catheter-days for internal jugular lines (in the neck). By day 15, 10% of jugular catheters had developed CRBSI versus 0% of subclavian catheters. Femoral vein catheters (in the groin) are generally considered the highest risk in adult patients due to the density of bacteria in that area.
When the Catheter Must Be Removed
Not every CRBSI requires pulling the catheter, but many do. For patients with long-term catheters (such as ports or tunneled lines used for chemotherapy or long-term IV nutrition), removal is necessary when the infection involves certain dangerous organisms: Staph aureus, Pseudomonas, any fungal species, or mycobacteria. The catheter also must come out if the patient develops severe sepsis, if the infection persists despite more than 72 hours of appropriate antibiotics, or if complications like infected blood clots or heart valve infection develop.
For short-term catheters, the threshold for removal is lower. These lines should be pulled for infections caused by most gram-negative bacteria, Staph aureus, enterococci, fungi, and mycobacteria. In hemodialysis patients, catheter removal is standard for Staph aureus, Pseudomonas, or Candida infections.
Catheter salvage, meaning treating the infection while leaving the line in place, is sometimes possible for long-term catheters when the infection is uncomplicated and caused by less dangerous organisms (typically coagulase-negative staphylococci). In these cases, antibiotics are given both through the bloodstream and directly into the catheter using a technique called antibiotic lock therapy, where a concentrated antibiotic solution sits inside the catheter between uses to kill bacteria clinging to its inner surface.
How Hospitals Prevent CRBSI
Prevention has been one of the major success stories in hospital infection control. The widely adopted “central line bundle” includes five practices that, when performed together consistently, dramatically reduce infection rates.
- Hand hygiene before and during the procedure.
- Full sterile barriers for both the operator and patient, including cap, mask, sterile gown, sterile gloves, and a full-body sterile drape over the patient with only a small opening at the insertion site.
- Chlorhexidine skin antisepsis using a 2% chlorhexidine solution in 70% isopropyl alcohol, scrubbed back and forth for at least 30 seconds and allowed to dry completely (about two minutes) before needle insertion.
- Optimal site selection, favoring the subclavian vein and avoiding the femoral vein in adults whenever possible.
- Daily review of whether the line is still needed, with prompt removal as soon as it’s no longer necessary.
That last point is deceptively simple but powerful. Every additional day a central line stays in place increases the cumulative risk of infection. The single most effective way to prevent CRBSI is to remove the catheter the moment it’s no longer serving a purpose.