Factors associated with survival of neonatal foals with bacteremia and racing performance of surviving Thoroughbreds: 423 cases (1982-2007).
OBJECTIVE
To identify factors associated with short-term survival in bacteremic neonatal foals, evaluate the racing performance of Thoroughbred survivors, and evaluate changes in causative organisms and their antimicrobial susceptibility.


METHODS
Retrospective case series.


METHODS
423 bacteremic foals.


METHODS
Medical records of foals that were hospitalized in 1982 through 2007 were reviewed, and those with bacteremia were included in the study. Data retrieved included signalment, physical examination and clinicopathologic findings at admission, localized infections, concurrent illnesses, duration of hospitalization, and outcome (survival to discharge from the hospital vs nonsurvival). The number, identity, and antimicrobial susceptibility of organisms isolated from blood samples were also obtained. Racing records for surviving Thoroughbred foals and maternal siblings were examined.


RESULTS
Of 423 bacteremic foals, 254 survived. Odds of survival were negatively associated with age at admission, septic arthritis, band neutrophil count, and serum creatinine concentration and positively associated with year of admission, diarrhea, rectal temperature, neutrophil count, and arterial blood pH. Overall, microbial culture of blood samples yielded 554 isolates; Escherichia coli was consistently isolated most frequently. Percentage of isolates susceptible to enrofloxacin, but no other antimicrobial, decreased over time. Surviving Thoroughbred foals did not differ from siblings with regard to percentage of starters, percentage of winners, or number of starts; however, surviving foals had significantly fewer wins and total earnings.


CONCLUSIONS
During the study period, microbial resistance to antimicrobials commonly used to treat bacteremic foals did not develop. Surviving bacteremic Thoroughbred foals were as likely to start races as their siblings but earned less money.
Sanchez
L Chris
LC
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0136, USA.
Giguère
Steeve
S
Lester
Guy D
GD
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001170:Arthritis, Infectious / Q000401:mortality / Q000503:physiopathology / Q000662:veterinary; D016470:Bacteremia / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology / Q000662:veterinary*; D003404:Creatinine / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality* / Q000503:physiopathology; D006736:Horses; D008297:Male; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D009504:Neutrophils; D016017:Odds Ratio; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013177:Sports / Q000706:statistics & numerical data*; D016019:Survival Analysis; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D003404:Creatinine