Investigation of daptomycin as a locking agent for line colonization with Gram-positive organisms

Abstract number: P1905

Awadel-Kariem F.M., Manzoor R.N., Jeraj H.A., Farrington K.

Background: Most line colonization, leading to bacteraemia and/or line removal, is caused by Gram-positive organisms. Line removal can have serious implication for patient management as patients may require the continuous presence on intra-vascular access (e.g. for total parental nutrition, haemodialysis and chemotherapy). Attempts to rescue precious lines especially in patients running out of sites to place central venous catheters have been an important part of line management. This is achieved by "locking" an antibiotic (to which the organism is sensitive) in the colonized lumen(s) of the central lines while the lumen is not in use. Antibiotics used for this purpose include aminoglycosides and glycopeptides. Daptomycin is a new and powerful anti-Gram-positive antibiotic that can be effective against organisms that are resistant to the other agents.

Objective: To assess the stability of daptomycin as a locking agent with heparin and anti-Gram-negative agents, and to evaluate its ability to sterilize simulated line infection with biofilm forming reference strains.

Methods: Daptomycin was prepared as recommended by the manufacturer and mixed with different anti-Gram-negative specific drugs (gentamicin and amikacin) and heparin. Various concentrations were assessed for stability. Once the ideal concentrations for all agents were identified they were employed on an in vitro line infection model against biofilm-forming reference strain of MRSA, MSSA, MRSE and VRE. Similar preparations, with Vancomycin, teicoplanin or linezolid substituted for daptomycin, were used as controls. All experiments were carried out in triplicates.

Results: The optimal concentration for daptomycin as a locking agent was identified at 5 mg/ml. The optimal concentration for heparin was 5000 U/ml, and for both gentamicin and amikacin was 5 mg/ml. At these concentrations the three agents could be combined in a stable locking solution. When this solution was tested in the in vitro line infection model sterility was achieved with all Gram-positive strains tested. However, sterility was not achieved with the other agents against all the Gram-positive reference strains.

Conclusions: This study confirms that daptomycin can be combined with different anti-Gram-negative agent and heparin in a stable manner that makes it ideal for line locking. Our line infection model has demonstrated that daptomycin is at least as effective as current anti-Gram-positive agents as a locking agent.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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