In vivo emergence of fidaxomicin resistance, a yet infrequent but worrying resistance in the urgent antimicrobial resistance threat Clostridioides difficile

Clostridioides difficile is considered by the CDC as an urgent antimicrobial resistance threat. This strictly anaerobic, Gram-positive, spore-forming bacillus is indeed a leading worldwide pathogen causing potentially fatal healthcare-associated (HA) and community-associated infections of the digestive tract. Fidaxomicin is now considered as a first-line treatment of C. difficile infections (CDI) and resistance has only been reported twice previously. The aim of the project was to report on clinical data and C. difficile strain characteristics associated to a case of in vivo emergence of fidaxomicin resistance.