Objective—To examine the relationship between abdominal surgery and nosocomial Salmonella infections and the relationship between high caseload in combination with abdominal surgery and nosocomial Salmonella infections in hospitalized horses with signs of gastrointestinal tract disease.
Procedures—To accomplish the first objective, 1 to 4 control horses were matched with each nosocomial case horse on the basis of admission date of a primary case horse. The frequency of abdominal surgery and other investigated exposure factors were compared between nosocomial case horses and control horses. For the second objective, 4 control horses were matched with each nosocomial case horse on the basis of year of admission. The frequency of high caseload (≥ 26 inpatients), abdominal surgery, and other factors was compared between nosocomial case horses and control horses.
Results—The odds of nosocomial Salmonella infection were 8 times as high (odds ratio = 8.2; 95% confidence interval = 1.11, 60.24) in horses that underwent abdominal surgery, compared with the odds for horses that did not undergo surgery. High caseload alone or in combination with abdominal surgery was not associated with increased risk of nosocomial Salmonella infection.
Conclusions and Clinical Relevance—Abdominal surgery was identified as a risk factor for nosocomial Salmonella infections in horses. Horses that undergo abdominal surgery require enhanced infection control and preventative care. Risk of nosocomial Salmonella infections may be reduced by implementation of biosecurity measures (such as the use of plastic boots, gloves, and footbaths) immediately after surgery.
Objective—To determine the prevalence of antimicrobial resistance to macrolide antimicrobials or rifampin in Rhodococcus equi isolates and to describe treatment outcome in foals infected with antimicrobial-resistant isolates of R equi.
Sample Population—38 isolates classified as resistant to macrolide antimicrobials or rifampin received from 9 veterinary diagnostic laboratories between January 1997 and December 2008.
Procedures—For each isolate, the minimum inhibitory concentration of macrolide antimicrobials (ie, azithromycin, erythromycin, and clarithromycin) and rifampin was determined by use of a concentration-gradient test. Prevalence of R equi isolates from Florida and Texas resistant to macrolide antimicrobials or rifampin was determined. Outcome of antimicrobial treatment in foals infected with antimicrobial-resistant isolates of R equi was determined.
Results—Only 24 of 38 (63.2%) isolates were resistant to > 1 antimicrobial. Two isolates were resistant only to rifampin, whereas 22 isolates were resistant to azithromycin, erythromycin, clarithromycin, and rifampin. The overall prevalence of antimicrobial-resistant isolates in submissions received from Florida and Texas was 3.7% (12/328). The survival proportion of foals infected with resistant R equi isolates (2/8 [25.0%]) was significantly less, compared with the survival proportion in foals that received the same antimicrobial treatment from which antimicrobial-susceptible isolates were cultured (55/79 [69.6%]). Odds of nonsurvival for foals infected with resistant R equi isolates were 6.9 (95% confidence interval, 1.3 to 37) times the odds for foals infected with susceptible isolates.
Conclusions and Clinical Relevance—Interpretation of the results emphasized the importance of microbiological culture and antimicrobial susceptibility testing in foals with pneumonia caused by R equi.
To characterize transcription of profibrotic mediators in renal tissues of cats with ischemia-induced chronic kidney disease (CKD).
Banked renal tissues from 6 cats with experimentally induced CKD (RI group) and 8 healthy control cats.
For cats of the RI group, both kidneys were harvested 6 months after ischemia was induced for 90 minutes in 1 kidney. For control cats, the right kidney was evaluated. All kidney specimens were histologically examined for fibrosis, inflammation, and tubular atrophy. Renal tissue homogenates underwent reverse transcription quantitative PCR assay evaluation to characterize gene transcription of hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase (MMP)-2, MMP-7, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), transforming growth factor-β1, and vascular endothelial growth factor A. Gene transcription and histologic lesions were compared among ischemic and contralateral kidneys of the RI group and control kidneys.
Ischemic kidneys had greater transcript levels of MMP-7, MMP-9, and transforming growth factor-β1 relative to control kidneys and of MMP-2 relative to contralateral kidneys. Transcription of TIMP-1 was upregulated and that of vascular endothelial growth factor A was downregulated in ischemic and contralateral kidneys relative to control kidneys. Transcription of HIF-1α did not differ among kidney groups. For ischemic kidneys, there were strong positive correlations between transcription of HIF-1α, MMP-2, MMP-7, and TIMP-1 and severity of fibrosis.
CONCLUSIONS AND CLINICAL RELEVANCE
Transcription of genes involved in profibrotic pathways remained altered in both kidneys 6 months after transient renal ischemia. This suggested that a single unilateral renal insult can have lasting effects on both kidneys.
Objective—To create a mathematical model to assist in early prediction of the probability of discharge in hospitalized foals ≤ 7 days old.
Study Design—Prospective study.
Procedures—Medical records from 910 hospitalized foals ≤ 7 days old for which outcome was recorded as died or discharged alive were reviewed. Thirty-four variables including historical information, physical examination findings, and laboratory results were examined for association with survival. Variables associated with being discharged alive were entered into a multivariable logistic regression model. Accuracy of the model was validated prospectively on data from 163 foals.
Results—Factors in the final model included age group, ability to stand, presence of a suckle reflex, WBC count, serum creatinine concentration, and anion gap. Sensitivity and specificity of the model to predict live discharge were 92% and 74%, respectively, in the retrospective population and 90% and 46%, respectively, in the prospective population. Accuracy of an equine clinician's initial prediction of the foal being discharged alive was 83%, and accuracy of the model's prediction was 81%. Combining the clinician's prediction of probability of live discharge with that of the model significantly increased (median increase, 12%) the accuracy of the prediction for foals that were discharged and nonsignificantly decreased (median decrease, 9%) the accuracy of the predication for nonsurvivors.
Conclusions and Clinical Relevance—Combining the clinician's initial predication of the probability of a foal being discharged alive with that of the model appeared to provide a more precise early estimate of the probability of live discharge for hospitalized foals.
Objective—To estimate prevalence of and identify
risk factors for fecal Salmonella shedding among hospitalized
horses with signs of gastrointestinal tract
Animals—465 hospitalized horses with gastrointestinal
Procedure—Horses were classified as positive or
negative for fecal Salmonella shedding during hospitalization
by means of standard aerobic bacteriologic
methods. The relationship between investigated
exposure factors and fecal Salmonella shedding was
examined by means of logistic regression.
Results—The overall prevalence of fecal Salmonella
shedding was 13%. Salmonella serotype Newport
was the most commonly isolated serotype (12/60
[20%]), followed by Anatum (8/60 [13%]), Java (13%),
and Saint-paul (13%). Foals with gastrointestinal tract
disease were 3.27 times as likely to be shedding
Salmonella organisms as were adult horses with gastrointestinal
tract disease. Adult horses that had been
treated with antimicrobial drugs prior to hospitalization
were 3.09 times as likely to be shedding
Salmonella organisms as were adult horses that had
not been treated with antimicrobial drugs prior to hospitalization.
Adult horses that underwent abdominal
surgery were 2.09 times as likely to be shedding
Salmonella organisms as were adult horses that did
not undergo abdominal surgery.
Conclusions and Clinical Relevance—Results suggest
that a history of exposure to antimicrobial drugs
prior to hospitalization and abdominal surgery during
hospitalization were associated with Salmonella
shedding in adult horses with gastrointestinal tract
disease. Foals with gastrointestinal tract disease
were more likely to shed Salmonella organisms than
were adult horses with gastrointestinal tract disease.
(J Am Vet Med Assoc 2004;225:275–281)
Objective—To determine signalment, clinical findings,
results of diagnostic testing, outcome, and postmortem
findings in horses with West Nile virus
Animals—46 horses with WNV encephalomyelitis.
Procedure—Clinical data were extracted from medical
records of affected horses.
Results—On the basis of clinical signs and results of
serologic testing, WNV encephalomyelitis was diagnosed
in 46 of 56 horses with CNS signs. Significantly
more males than females were affected. Increased
rectal temperature, weakness or ataxia, and muscle
fasciculations were the most common clinical signs.
Paresis was more common than ataxia, although both
could be asymmetrical and multifocal. Supportive
treatment included anti-inflammatory medications,
fluids, antimicrobials, and slinging of recumbent horses.
Results of the IgM capture ELISA and the plaque
reduction neutralization test provided a diagnosis in
43 horses, and only results of the plaque reduction
neutralization test were positive in 3 horses. Mortality
rate was 30%, and 71% of recumbent horses were
euthanatized. One horse that had received 2 vaccinations
for WNV developed the disease and was euthanatized.
Follow-up communications with 19 owners
revealed that most horses had residual deficits at 1
month after release from the hospital; abnormalities
were resolved in all but 2 horses by 12 months after
Conclusions and Clinical Relevance—Our findings
were similar to those of previous WNV outbreaks in
horses but provided additional clinical details from
monitored hospitalized horses. Diagnostic testing is
essential to diagnosis, treatment is supportive, and
recovery rate of discharged ambulatory horses is
< 100%. (J Am Vet Med Assoc 2003;222:1241–1247)