2117. Catheter-related Bacteremia in Hemodialysis Patients on Antibiotic Lock Therapy: Are Antibiotic Locks Ineffective?

Antibiotic lock therapy (ALT) is used to prevent catheter-related bacteremia (CRB) associated with use of tunneled/nontunneled hemodialysis (HD) catheters. ALT exerts its action by preventing intraluminal biofilm formation, a common source of infection with long-term catheters. However, catheters that are in place for <2 weeks are most often infected extraluminally. ALT is unlikely to have any impact on extraluminal infection. Our study aims to define the characteristics of CRB in HD patients receiving prophylactic ALT (HD-ALT patients) and investigate for possible lack of efficacy of ALT ALT project was implemented in all HD patients with tunneled/nontunneled catheters in 3 tertiary care hospitals in Detroit from June 2016 to October 2017. ALT containing Gentamicin (5 mg/2 mL) in 4% sodium citrate was instilled into each catheter lumen after HD. National Healthcare Safety Network (NHSN) criteria were used to define CRB. Retrospective chart review was done in HD-CRB patients. Out of 3,384 ALT,13 CRB were recorded (eight tunneled and five nontunneled). Nine of 13 patients received all ALT doses. Median duration from catheter insertion to CRB occurrence in these nine patients was 7 days (range 2–380 days) with six (67%) patients having catheter duration of ≤8 days. Three of nine patients had catheters longer than 8 days (154, 194 and 380 days, respectively). The mean time to development of CRB after beginning ALT were 3.22 (SD ± 1.85). The three patients with prolonged duration of catheterization had catheters inserted long before the ALT project was implemented. Additional details of the 13 HD-CRB patients are as follows: Mean age 61 years (± 10.7), 54% were male, 77% had catheters removed or replaced, one patent died. Most predominant organisms isolated were Staphylococcus aureus 6 (4/6 methicillin-resistant) and Pseudomonas aeruginosa 3. Two of 14 isolated organisms had gentamicin resistance. A large proportion of ALT patients had catheters for short duration before CRB episode, therefore an intraluminal source of bacteremia due to biofilm formation is unlikely to have occurred. In those HD-CRB patients with long periods of catheterization, ALT duration might not have been sufficient to eradicate biofilm. Therefore, CRB occurrence in our population is probably not due to ALT failure. All authors: No reported disclosures.