Antibiotic-Associated Diarrhea Beyond C. Difficile: A Scoping Review.

Area of Science:

• Gastroenterology
• Microbiology
• Pharmacology

Background:

• Antibiotic use frequently leads to diarrheal illness.
• Antibiotic-associated diarrhea (AAD) pathogenesis involves gut microbiota alteration, pathogen overgrowth, and drug toxicity.
• Less than 33% of AAD cases are linked to *Clostridioides difficile* (CDI), indicating other causes remain poorly understood.

Purpose of the Study:

• To systematically review existing data on AAD.
• To elucidate the pathogenic mechanisms of both CDI and non-CDI AAD.
• To provide a comprehensive understanding of AAD etiology.

Main Methods:

• Systematic review of current literature on AAD.
• Analysis of data on microbial alterations and opportunistic pathogen proliferation.
• Inclusion of figures detailing pathogenic mechanisms.

Main Results:

• Established pathogenesis of *Clostridioides difficile* infection (CDI).
• Identified unclear roles and mechanisms for other putative microbial causes of AAD, including *Clostridium perfringens*, *Staphylococcus aureus*, *Klebsiella oxytoca*, and *Candida species*.
• Highlighted significant gaps in diagnosing and treating non-CDI AAD.

Conclusions:

• AAD is a complex condition with multiple potential microbial triggers beyond *C. difficile*.
• Further research is needed to clarify the pathogenesis of non-CDI AAD.
• Improved diagnostic and therapeutic strategies are required for the majority of AAD cases.