Anti-biofilm Efficacy of Liposomal Amphotericin B and Echinocandin Catheter Lock Solutions against Candida Species

Ref ID: 19259

Author:

M. Simitsopoulou, D. Kyrpitzi, A. Velegraki, T. J. Walsh, E. Roilides

Author address:

Aristotle Univ., Thessaloniki, GREECE

Full conference title:

53rd Interscience Conference on Antimicrobial Agents and Chemotherapy

Date: 10 September 2014

Abstract:

Background: Candida biofilms (BF) form on central vascular catheters and cause refractory candidemia that frequently requires catheter removal. Antifungal lock therapy may be an alternative treatment ofCandida catheter infections. Liposomal amphotericin B (LAMB) as well as anidulafungin (ANID), caspofungin (CAS) and micafungin (MFG) are differentially active against biofilms of non-albicans Candidaspp. (Simitsopoulou et al. AAC 2013). We compared the pharmacodynamic activities of LAMB and 3 echinocandins against resistant Candida spp. BF. Methods: Mature BF of C. lusitaniae (CL; n=6) and C. guillermondii (CG; n=5) blood isolates and C. albicans M61 (CA; control) were produced by shaking 106blastoconidia/mL in RPMI at 37oC for 48h. Biofilms were then incubated with no drug or with ANID, CAS, MFG and LAMB at 4-fold increasing concentrations from 0.007-2048 mg/L for 24h. BF MIC was determined as >50% fungal damage (FD) compared to controls by XTT colorimetric assay in pentaplicate on 3 separate experiments. Data from different Candida species were compared by ANOVA with Bonferroni post test. Results: While ANID and MFG at concentrations ranging from 0.007-2048 mg/L showed reduced activity against BF of CL (FD <=36% and <=42%) or CG (FD <=51% and <=43%), CAS displayed concentrationdependent anti-biofilm activity against both species (CL: 25-100% and CG: 13-100%; P<0.05), reaching complete eradication at concentrations ranging from 256-2048 mg/L. BF MICs of LAMB for CL, CG and CA were 0.06, 0.5 and 0.5 mg/L, causing FD of 51%, 60% and 52%, respectively. At 256-2048 mg/L, LAMB showed similar FD against CL (78- 89%) and CG (73-83%) without, however, reaching BF eradication of these fungi. LAMB achieved less FD than CAS against CL and CG BFs at this high range of concentrations (P<0.05). Conclusions: CAS achieves concentrationdependent anti-biofilm activity against C. lusitaniae and C. guillermondii, leading to complete elimination of BF at catheter lock concentrations. LAMB also exhibits antibiofilm activity that is, however, less than that of CAS. These findings may help in designing optimized antifungal lock therapies beneficial for catheter retainment.

Abstract Number: NULL

Conference Year: 2013

Link to conference website: NULL

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