Antibiotic-associated diarrhea
Encyclopedia
Antibiotic-associated diarrhea (AAD) results from an imbalance in the colonic microbiota
caused by antibiotic
therapy. Microbiota alteration changes carbohydrate metabolism
with decreased short-chain fatty acid absorption and an osmotic diarrhea
as a result. Another consequence of antibiotic therapy leading to diarrhea is overgrowth of potentially pathogenic organisms such as Clostridium difficile
. It is defined as frequent loose and watery stools
with no other complications.
Several meta-analyses indicated that probiotics may protect against AAD. However, these studies produced conflicting data, and the use of probiotics has failed thus far to meet the standard of medical care required for evidence-based medicine
. Demonstration of the efficacy of probiotics is needed by randomized
, double blind, placebo-controlled trials.
Efficacy of probiotic AAD prevention is dependent on the probiotic strain(s) used and on the dosage. Up to a 50% reduction of AAD occurrence has been found. No side-effects have been reported in any of these studies. Caution should, however, be exercised when administering probiotic supplements to immunocompromised individuals or patients who have a compromised intestinal barrier
.
Clostridium difficile
, also known more commonly as C. diff, is known to account for 10 to 20 percent of antibiotic-associated diarrhea cases. The reasoning for this, is that the antibiotics administered for the treatment of certain diseases processes such as inflammatory colitis also inadvertently kills a large portion of the gut flora
, the normal flora that is usually present within the bowel. With this lower amount of "healthy" bacteria present, the overgrowth of C. diff is then responsible "for elaborating the enterotoxin
."
Gut flora
Gut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....
caused by antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
therapy. Microbiota alteration changes carbohydrate metabolism
Carbohydrate metabolism
Carbohydrate metabolism denotes the various biochemical processes responsible for the formation, breakdown and interconversion of carbohydrates in living organisms....
with decreased short-chain fatty acid absorption and an osmotic diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
as a result. Another consequence of antibiotic therapy leading to diarrhea is overgrowth of potentially pathogenic organisms such as Clostridium difficile
Clostridium difficile
Clostridium difficile , also known as "CDF/cdf", or "C...
. It is defined as frequent loose and watery stools
Human feces
Human feces , also known as a stool, is the waste product of the human digestive system including bacteria. It varies significantly in appearance, according to the state of the digestive system, diet and general health....
with no other complications.
Several meta-analyses indicated that probiotics may protect against AAD. However, these studies produced conflicting data, and the use of probiotics has failed thus far to meet the standard of medical care required for evidence-based medicine
Evidence-based medicine
Evidence-based medicine or evidence-based practice aims to apply the best available evidence gained from the scientific method to clinical decision making. It seeks to assess the strength of evidence of the risks and benefits of treatments and diagnostic tests...
. Demonstration of the efficacy of probiotics is needed by randomized
Randomized controlled trial
A randomized controlled trial is a type of scientific experiment - a form of clinical trial - most commonly used in testing the safety and efficacy or effectiveness of healthcare services or health technologies A randomized controlled trial (RCT) is a type of scientific experiment - a form of...
, double blind, placebo-controlled trials.
Efficacy of probiotic AAD prevention is dependent on the probiotic strain(s) used and on the dosage. Up to a 50% reduction of AAD occurrence has been found. No side-effects have been reported in any of these studies. Caution should, however, be exercised when administering probiotic supplements to immunocompromised individuals or patients who have a compromised intestinal barrier
Leaky gut
Leaky gut is a name used to describe intestinal or bowel hyperpermeability. Tight junctions represent the major barrier within the pathway between intestinal epithelial cells that line the digestion tract...
.
Clostridium difficile
Clostridium difficile
Clostridium difficile , also known as "CDF/cdf", or "C...
, also known more commonly as C. diff, is known to account for 10 to 20 percent of antibiotic-associated diarrhea cases. The reasoning for this, is that the antibiotics administered for the treatment of certain diseases processes such as inflammatory colitis also inadvertently kills a large portion of the gut flora
Gut flora
Gut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....
, the normal flora that is usually present within the bowel. With this lower amount of "healthy" bacteria present, the overgrowth of C. diff is then responsible "for elaborating the enterotoxin
Enterotoxin
An enterotoxin is a protein toxin released by a microorganism in the intestine. Enterotoxins are chromosomally encoded exotoxins that are produced and secreted from several bacterial organisms. They are often heat-stable, and are of low molecular weight and water-soluble...
."