Objective—To determine efficacy of a commercially
available hyperimmune plasma product for prevention
of naturally acquired pneumonia caused by
Rhodococcus equiin foals.
Design—Randomized clinical trial.
Procedure—Foals were randomly assigned to 1 of 2
groups (hyperimmune plasma or nontreated controls).
Foals with failure of passive transfer (FPT) of immunity
were treated with hyperimmune plasma and evaluated
as a third group. Foals that received plasma were
given 950 ml between 1 and 10 days of age and
between 30 and 50 days of age. A tracheobronchial
aspirate was obtained from foals with clinical signs of
respiratory tract disease for bacteriologic culture.
Results—A significant difference in incidence of
pneumonia caused by R equi in foals with adequate
passive transfer was not detected between foals that
received plasma (19.1%) and nontreated foals (30%).
Of 13 foals without FPT that received plasma and
developed pneumonia caused by R equi, 12 developed
disease prior to administration of the second
dose of hyperimmune plasma. Incidence of undifferentiated
pneumonia of all causes was not different
Conclusion and Clinical Relevance—Intravenous
administration of the commercially available hyperimmune
plasma was safe, and the product contained
high concentrations of anti-R equi antibodies.
However, within this limited foal population, the difference
in incidence of pneumonia caused by R equi
observed between foals that received plasma and
control foals was not significant. (J Am Vet Med
Objective—To evaluate WBC concentration, plasma
fibrinogen concentration, and an agar gel immunodiffusion
(AGID) test for early identification of Rhodococcus
Animals—162 foals from a farm with enzootic R equi
Procedure—Blood samples were obtained from
each foal at 4-week intervals for measurement of
WBC and plasma fibrinogen concentrations and at
2-week intervals for detection of anti-R equi antibody
by an AGID assay. Diagnostic performance of
WBC and fibrinogen concentrations was assessed
by use of receiver operating characteristic curve
analysis. For each assay, sensitivity, specificity, and
predictive values were calculated at various cutoff
points; bacteriologic culture of R equi from a tracheobronchial
aspirate was used as the reference
Results—Diagnostic performance of WBC concentration
was significantly higher than that of fibrinogen
concentration. Sensitivity and specificity of measurement
of WBC concentration at a cutoff of 13,000
cells/µL were 95.2 and 61.2%, respectively; at a cutoff
of 15,000 cells/µL, sensitivity was 78.6% and
specificity was 90.8%. When a positive test result
was used as the cutoff, sensitivity of the AGID assay
was 62.5% and specificity was 53.8%.
Conclusion and Clinical Relevance—Monitoring WBC
concentration is a useful approach for early detection of
infected foals on farms with a high prevalence of R equi
pneumonia. In contrast, serologic surveillance by use of
an AGID assay is of little benefit for that purpose. (J Am
Vet Med Assoc 2003;222:775–781)
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 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)