Clinical failure of an extended-pulsed fidaxomicin regimen associated with emergence of a Clostridioides difficile isolate with reduced fidaxomicin susceptibility in an elderly man

Antimicrobial Agents and Chemotherapy 2026 Open access

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Authors: Claire E. Kaple, Sarah N. Redmond, Jennifer L. Cadnum, Bryan Hausman, Munok Hwang, Hosoon Choi, Piyali Chatterjee, Chetan Jinadatha, Curtis J. Donskey
DOI: 10.1128/aac.00130-26
Cited by: 3
References: 10

Abstract

ABSTRACT The clinical significance of Clostridioides difficile isolates with reduced fidaxomicin susceptibility is uncertain. We report treatment failure of extended-pulsed fidaxomicin treatment during every other day pulsing associated with emergence of a C. difficile isolate with reduced fidaxomicin susceptibility and a novel rpoC gene mutation, resulting in a novel amino acid substitution (R89K). The reduced susceptibility isolate had no reduction in growth or ability to colonize mice, but in vitro sporulation and toxin production were reduced.

Fields of Study & Subjects

Clostridium difficile and Clostridium perfringens research Antibiotic Use and Resistance Nosocomial Infections in ICU

Publication details

Journal / source
Antimicrobial Agents and Chemotherapy
Publisher
American Society for Microbiology
Volume
70
Issue
9
Pages
e0013026–e0013026
Publication date
4 May 2026
Language
EN