Efficacy and Antimicrobial Properties of Different Locking Solutions in Hemodialysis Patients to Prevent Catheter-Related Bloodstream Infection

Abstract

Background: Dialysis and infection remain challenging despite ongoing updates to measures, approaches, and preventive protocols. Particularly, vascular access- related infections, which are associated with catheters that are often unavoidable due to late referrals or patients' poor vascular condition. Bloodstream infections and related complications continue to be the second leading cause of morbidity and mortality among hemodialysis patients. Antimicrobial locking solutions have been proposed to reduce the risk of infection, but data from Georgia remain limited. Objectives: To evaluate the effectiveness of different catheter locking solutions—including unfractionated heparin, sodium bicarbonate, and gentamicin/citrate— in reducing the incidence of catheter-related bloodstream infections (CRBSIs) and catheter removal in hemodialysis patients with long-term tunneled central venous catheters in Georgia. Methods: We performed a retrospective study at a high-volume HD center in Tbilisi, Georgia, including adult patients with long-term tunneled CVCs. Two study periods were compared: the Pre-Lock Period (2019–2020; n = 80) when unfractionated heparin (UFH) was the only locking solution, and the Lock Period (2022– 2024; n = 241) when three different agents were used: UFH (5000 U/mL), sodium bicarbonate (8.4%), and gentamicin/citrate (0.5 mg gentamicin in 2.2% citrate). CRBSIs were defined according to the KDOQI-2019 criteria, with incidence rates expressed per 1,000 catheter days. Pathogens were identified and tested for antimicrobial susceptibility using VITEK 2 and EUCAST standards. Results: The CRBSI incidence declined from 3.53 per 1,000 catheter-days in the Pre-Lock Period to 0.80 per 1,000 catheter-days in the Lock Period. Among locking solutions, sodium bicarbonate showed the lowest incidence (0.56), followed by gentamicin/citrate (0.72) and UFH (1.2). Catheter removals due to infection were also reduced (11.11/1,000 catheter-days with UFH vs. 3.89, 2.38, and 4.49 for sodium bicarbonate, gentamicin/citrate, and UFH during the Lock Period). Gram- positive bacteria predominated (59–64%), especially Staphylococcus aureus, while gram-negatives (36–37%) included Klebsiella pneumoniae and Escherichia coli. No MRSA, ESBL, or gentamicin resistance was observed. Conclusions: Antimicrobial locking solutions were more effective than UFH in preventing CRBSIs and reducing catheter removal. Sodium bicarbonate was the most effective agent. These findings support the adoption of antimicrobial locks for CVC maintenance in HD patients, with future studies needed to directly assess biofilm colonization.