Fernández-Rivero ME, Del Pozo JL, Ramírez P, Valentín E, Ruiz-Gaitán A, Pemán J, Cantón E. Time-kill assays of amphotericin B plus anidulafungin against Candida tropicalis biofilms formed on two different biomaterials.
Int J Artif Organs 2017;
41:0. [PMID:
29048702 DOI:
10.5301/ijao.5000652]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE
To determine the fungicidal activity by time-killing assays of amphotericin B (AMB) combined with anidulafungin (ANF) against biofilms of 2 clinical isolates of Candida tropicalis and the reference strain ATCC® 750, developed on polytetrafluoroethylene (PTFE) and titanium, using the CDC Biofilm Reactor (CBR) as an in vitro model.
METHODS
Biofilms were developed for 24 hours on the disk surfaces and then exposed to AMB (40 mg/L), ANF (8 mg/L), alone and combined. At predetermined time points after drug exposure, biofilms were removed from the disk surface by vortexing-sonication to quantify viable biofilm cells.
RESULTS
Drug activity was dependent on strain and time. After exposure to AMB, the mean decrease in viable cells attached to PTFE was 2.23 ± 0.89 Log10 cfu/cm2 (range 0.6-3.56 Log10), and on titanium 2.91 ± 1.04 (range 1.49-4.51 Log10). The reduction with ANF was 0.78 ± 0.5 (0.03-1.58 Log10) on PTFE and 0.8 ± 2.26 (0.42-1.16 Log10) on titanium. The reduction obtained with the combination of AMB + ANF was 1.8 ± 1.07 (0.22-3.54 Log10) on PTFE and 1.97 ± 0.49 (1.36-2.84 Log10) on titanium. The interaction was classified as indifferent with a tendency to antagonism.
CONCLUSIONS
The activity of antifungal agents depends on the biomaterial surfaces the biofilm forming capacity of the isolate. AMB + ANF is less effective than AMB alone on both surfaces. Thus, the combination of these antifungals does not seem to add additional benefits to the treatment of C. tropicalis biofilm-related infections.
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