Activity of Cysteamine against the Cystic Fibrosis Pathogen Burkholderia cepacia Complex

Abstract

There are no wholly successful chemotherapeutic strategies against Burkholderia cepacia complex (BCC) colonization in cystic fibrosis (CF). We assessed the impact of cysteamine (Lynovex) in combination with standard-of-care CF antibiotics in vitro against BCC CF isolates by the concentration at which 100% of bacteria were killed (MIC100) and checkerboard assays under CLSI standard conditions. Cysteamine facilitated the aminoglycoside-, fluoroquinolone- and folate pathway inhibitor-mediated killing of BCC organisms that were otherwise resistant or intermediately sensitive to these antibiotic classes. Slow-growing BCC strains are often recalcitrant to treatment and form biofilms. In assessing the impact of cysteamine on biofilms, we demonstrated inhibition of BCC biofilm formation at sub-MIC100s of cysteamine.

FIG 1

Cysteamine inhibits adherence of BCC strains at concentrations below the MIC₁₀₀ as detected by crystal violet assay. One-way analysis of variance with Tukey's posttest analysis showed significant differences as follows: *, P < 0.05; **, P < 0.01; and ***, P < 0.001 (compared to untreated medium-only controls [n = 6]).