Central Lines and Gram-Negative Bacilli Bacteremia

Epidemiology and Causative Organisms

Gram-negative bacteria account for approximately 20-25% of catheter-related bloodstream infections (CRBSI) in patients with central venous catheters, with the most common gram-negative organisms including Escherichia coli, Pseudomonas aeruginosa, and Klebsiella species 1, 2
In patients with hematologic malignancies or solid tumors, gram-positive organisms account for 60-70% of CRBSI, while gram-negative bacteria are found in 20-25% of CRBSI cases 1, 2

Duration of catheterization beyond 1 week significantly increases infection risk 3
Catheter site selection impacts risk, with femoral and jugular sites having higher infection rates than subclavian sites 4, 5
Use of central lines for parenteral nutrition increases colonization rates and subsequent infection risk 3
High level of skin colonization at the insertion site and catheter hub/connector is a predictor for catheter-associated bloodstream infections 1
Male gender and patients with acute myeloid leukemia have increased risk for catheter-associated bloodstream infections 1
Subclinical thrombosis of the catheterized vein may be an important risk factor for subsequent catheter-related infection 1
Patients with hematologic malignancies are at higher risk for catheter-related infections than patients with solid tumors 1

Definitive diagnosis of catheter-related bloodstream infection requires either growth of the same pathogen from both peripheral blood culture and catheter tip culture, or growth of the same pathogen from both catheter blood culture and peripheral blood culture with differential time to positivity ≥2 hours 2

Select the optimal insertion site, with subclavian preferred over jugular or femoral 4, 5
Use maximal sterile barrier precautions during insertion 6
Implement proper hand hygiene before catheter insertion and maintenance 6
Use >0.5% chlorhexidine skin preparation with alcohol for antisepsis at the insertion site 6
Apply sterile, transparent dressings and change them according to protocol 6
Choose catheters with the minimum number of lumens necessary for patient management 6
Consider antimicrobial-impregnated catheters for high-risk patients 6

Klebsiella species cause approximately 3–5 % of hospital‑acquired bloodstream infections, representing a consistent component of the Gram‑negative pathogen spectrum in CLABSI. 7
Gram‑negative bacteria overall account for 20–25 % of all catheter‑related bloodstream infections, making them a substantial minority of CLABSI cases. 8
CDC surveillance data show that Klebsiella pneumoniae comprised 4 % of hospital‑acquired BSIs during 1986‑1989 and 3 % during 1992‑1999. 7
In oncology and hematology patient populations, Gram‑negative organisms (including Klebsiella) collectively cause 20–25 % of CRBSI. 8
The majority of CLABSI pathogens remain Gram‑positive cocci (60–70 % of cases), with coagulase‑negative staphylococci representing ≈ 37 % of isolates; Klebsiella contributes a smaller but notable proportion. [7][8]

Extended‑spectrum β‑lactamase (ESBL)‑producing Klebsiella strains are increasingly prevalent, conferring resistance to broad‑spectrum cephalosporins and many other commonly used agents. [7][8]
Local resistance patterns, especially the presence of ESBL production, must guide antibiotic selection for Klebsiella CLABSI. [7][8]

Empiric Gram‑negative coverage that includes Klebsiella should be considered for high‑risk patients, particularly those who are neutropenic or otherwise immunocompromised. 9
The broader recommendation from international infectious disease experts emphasizes consideration of Gram‑negative coverage in scenarios where Klebsiella infection risk is elevated, such as severe illness or ICU admission. [10][11]

Isolation of Klebsiella from central‑line blood cultures should be treated as a true infection, not a contaminant; removal of the implicated catheter is generally advised. 10
Antibiotic therapy should be continued for 10–14 days intravenously after catheter removal, with drug choice tailored to susceptibility data and local resistance trends. [7][8]