The antimicrobial effectiveness of chlorhexidine and chlorhexidine-silver sulfadiazine-impregnated central venous catheters against the emerging fungal pathogen Candida auris

Abstract

Background: Candida auris is an emerging multidrug-resistant fungus associated with catheter-related bloodstream infections. In vitro efficacy of chlorhexidine (CHX) and CHX-silver sulfadiazine-impregnated (CHX-S) antimicrobial central venous catheters (CVCs) against C auris was investigated.

Methods: Minimum inhibitory and bactericidal CHX concentrations were determined against 19 C auris isolates. To assess extraluminal efficacy, segments from CVCs impregnated externally (CHX-S1) and both externally and internally (CHX-S2) were plasma-conditioned for 1- and 6-day, and to assess intraluminal efficacy, CHX-S2 CVCs were preconditioned with saline-lock for 6days, followed by 24-hour C auris inoculation and microbial adherence determination on impregnated and nonimpregnated CVCs.

Results: CHX inhibited all C auris isolates with minimum inhibitory and bactericidal concentrations range of 8 to 128 μg/mL. C auris adherence was reduced on CHX-S1 and CHX-S2 extraluminally by 100% on day 1, 86.96% to 100% on day 7, and intraluminally on CHX-S2 by 56.86% to 90.52% on day 7.

Discussion: CHX and CHX-S CVC performance against C auris observed in this study is consistent with antimicrobial benefits observed in prior preclinical and randomized controlled clinical studies.

Conclusions: CHX showed strong inhibitory and cidal effects on C auris. CHX-S CVCs proved highly efficacious against this pathogen under in vitro conditions. Additional studies, however, are required to confirm clinical benefit.

Keywords: Antimicrobial catheters; Candida infections; Catheter colonization; Catheter-related bloodstream infections; Multidrug-resistant fungal pathogens.