The prevalence of Aeromonas species in feces of horses with diarrhea

Feces collected from 40 horses with diarrhea and 34 horses without diarrhea were examined to determine if an association existed between isolation of Aeromonas spp. and diarrhea. Samples were also examined for Salmonella spp. , and identification of viruses and parasite ova. Neither Salmonella spp, n or Aeromonas spp, were isolated from the feces of 34 control horses. Aeromo nas spp. were isolated from feces of 22 of 40 (55%) horses with diarrhea. S almonella spp. were isolated from feces of 8 (20%) horses, and of these, 5 (12.5%) were also positive for Aeromonas spp. Twenty-nine isolates of Aerom onas spp. were recovered from the feces of 22 diarrheic horses. Of these is olates, more than 80% were susceptible on in vitro testing to amikacin, cef tiofur, chloramphenicol, and gentamicin. All isolates were susceptible to e nrofloxacin. Diarrheic horses positive for Aeromonas were significantly (P = .04) older than diarrheic horses negative for Aeromonas spp. A significan tly greater number of fecal samples were positive for Aeromonas spp. during March through August than samples examined in other months (P = .014). Res ults of this study indicate that Aeromonas spp. should be considered as a c ause of diarrhea in horses.