Antibiotics and Diarrhea

Newsdate: Fri, 4 Feb 2011 - 09:00 am
Location: LEXINGTON, Kentucky

Antibiotics are commonly used in veterinary medicine to treat a number of infectious diseases. There are many different types of antibiotics, each targeting different pathogens and having different side effects.

Dr. Bonnie Barr, VMD, DACVIM, along with internal medicine clinicians at two large equine referral practices in Florida and New Jersey, studied the association between antibiotic administration on the farm for non-diarrheic cases and the prevalence of diarrhea. The particular antibiotics associated with these cases were identified as well as any pathogens found. The results were presented at the 2010 AAEP convention in Baltimore, MD and Pfizer Animal Health provided the funds to enable this research project.

Dr. Barr’s study evaluated 5251 horses that were treated with various antibiotics on the farm for non-gastrointestinal problems during 2009. Only 32 of these horses developed diarrhea, which is a prevalence of 0.6%. The most common antibiotics used were: oxytetracycline, trimethoprim-sulfa (TMS/SMZ), gentamicin, penicillin and doxycycline. These antibiotics all had less than 1% incidence of causing diarrhea. The highest occurrence was seen with enrofloxacin (Baytril®), 5.4%, and the combination of penicillin/gentamicin, 3.2%. Out of those 32 horses, 6 died or were euthanized (18.8%).

Infectious pathogens were identified in 7 of the 32 cases, an incidence of 22%. Clostridium difficile was identified in fecal samples from 4 horses, and Salmonella in samples from 3 horses. Clostridium difficile was found in 2 of the 6 horses that died. No other pathogens were found in the remaining 25 horses.

While this study found the risk for antibiotic associated diarrhea to be very low (0.6%), it emphasizes that antibiotics should be used only when necessary.

About the Author

Flossie Sellers

As an animal lover since childhood, Flossie was delighted when Mark, the CEO and developer of EquiMed asked her to join his team of contributors.

She enrolled in My Horse University at Michigan State and completed a number of courses in everything related to horse health, nutrition, diseases and conditions, medications, hoof and dental care, barn safety, and first aid.

Staying  up-to-date on the latest developments in horse care and equine health is now a habit, and she enjoys sharing a wealth of information with horse owners everywhere..