Salmonella enterica shedding in hospitalized horses and associations with diarrhea occurrence among their stablemates and gastrointestinal-related illness or death following discharge.

ABSTRACT

OBJECTIVE: To evaluate the potential association between Salmonella enterica shedding in hospitalized horses and the risk of diarrhea among stablemates, and to characterize gastrointestinal-related illness and death following discharge among horses that shed S. enterica while hospitalized. DESIGN: Retrospective cohort study [corrected]. ANIMALS 221 horses (59 that shed S. enterica during hospitalization and 162 that tested negative for S. enterica shedding ≥ 3 times during hospitalization). PROCEDURES Information from medical records (signalment, results of microbial culture of fecal samples, clinical status at the time of culture, and treatment history) was combined with data collected through interviews with horse owners regarding formerly hospitalized horses and their stablemates. Data were analyzed to investigate risk factors for death and diarrhea. RESULTS: Occurrence of diarrhea among stablemates of formerly hospitalized horses was not associated with S. enterica shedding in hospitalized horses but was associated with oral treatment with antimicrobials during hospitalization. Salmonella enterica shedding during hospitalization was not associated with risk of death or gastrointestinal-related illness in study horses ≤ 6 months after discharge, but shedding status and history of gastrointestinal illness were associated with increased risk of death during the preinterview period. CONCLUSIONS AND CLINICAL RELEVANCE Stablemates of horses that shed S. enterica during hospitalization did not appear to have an increased risk for diarrhea, but comingling with horses that receive orally administered antimicrobials may affect this risk. Salmonella enterica shedding during hospitalization may be a marker of increased long-term risk of death after discharge. Risks are likely influenced by the S enterica strain involved and biosecurity procedures used.