Antibiotic-associated diarrhea (AAD) results from an imbalance in the colonic microbiota caused by

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

s. Microbiotal alteration changes

carbohydrate metabolism Carbohydrate metabolism is the whole of the biochemistry, biochemical processes responsible for the metabolic anabolism, formation, catabolism, breakdown, and interconversion of carbohydrates in life, living organisms. Carbohydrates are central t ...

with decreased short-chain fatty acid absorption and an osmotic diarrhea as a result. Another consequence of antibiotic therapy leading to diarrhea is an overgrowth of potentially

pathogenic In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ...

organisms such as '' Clostridioides difficile''. It is defined as frequent loose and watery stools with no other complications. __TOC__

Cause

''Clostridioides difficile'', also known more commonly as ''C. diff'', accounts for 10 to 20% of antibiotic-associated diarrhea cases, because the antibiotics administered for the treatment of certain disease processes such as inflammatory colitis also inadvertently kill a large portion of the

gut flora Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

, the normal flora that is usually present within the

bowel The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

. With this lower level of "healthy" bacteria present, the overgrowth of ''C. diff'' is then responsible "for elaborating the enterotoxin".

Treatment

Meta-analyses Meta-analysis is a method of synthesis of quantitative data from multiple independent studies addressing a common research question. An important part of this method involves computing a combined effect size across all of the studies. As such, th ...

have concluded that

probiotics Probiotics are live microorganisms that provide health benefits when consumed, generally by improving or restoring the microbiota in the Gut microbiota, gut. Probiotics are considered GRAS, generally safe to consume, but may cause bacteria– ...

may protect against antibiotic-associated diarrhea in both children and adults. Evidence is insufficient, however, regarding an effect on rates of ''C. difficile'' colitis. The efficacy of probiotic AAD prevention is dependent on the probiotic strain(s) used and on the dosage. Up to a 50% reduction of AAD occurrences has been found.

References

{{Digestive system and abdomen symptoms and signs Diarrhea