In vivo effectiveness of several antimicrobial locks to eradicate intravascular catheter coagulase-negative staphylococci biofilms

Tunneled central venous catheter (TCVC) related infection remains a challenge in the care of hemodialysis patients. We aimed to determine the best antimicrobial lock therapy (ALT) to eradicate coagulase-negative staphylococci (CoNS) biofilms. We studied the colonization status of the catheter every 30 days by quantitative blood cultures (QBC) drawn through all catheter lumens. Those patients with a significant culture (i.e.,100 to 1,000 CFU/mL) of a CoNS were classified as patients with a high risk of developing catheter-related bloodstream infections (CRBSI). They were assigned to receive daptomycin, vancomycin, teicoplanin lock solution, or the standard of care (SoC) (i.e., heparin lock). The primary endpoint was to compare eradication ability (i.e., negative QBC for 30 days after ending ALT) rates between different locks and the SoC. A second objective was to analyze the correlation between ALT exposure and isolation of CoNS with antimicrobial resistance. Daptomycin lock was associated with a significant higher eradication success than with the SoC: 85% versus 30% (relative risk [RR] = 14, 95% confidence interval [CI] = 2.4 – 82.7); followed by teicoplanin locks with a 83.3% success (RR = 11.7; 95% CI = 2 – 70.2). We observed CoNs isolates with a higher teicoplanin MIC in patients with repeated teicoplanin locks exposure (coefficient = 0.3; 95% CI = 0.11 – 0.47). However, teicoplanin MICs decreased in patients treated with vancomycin locks (coefficient = 20.56; 95% CI = 20.85 – 20.02). Methicillin-resistance decreased with accumulative ALT (RR = 0.82; 95% CI = 0.69 – 0.98). In this study, daptomycin locks achieve the highest eradication rate of CoNS from hemodialysis catheters in viv