Objective—To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis.
Sample Population—Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses.
Procedures—Fungal culture of ocular samples yielded 6 Fusarium spp; 7 Aspergillus spp; and 1 isolate each of Curvularia, Scopulariopsis, Penicillium, and Chrysosporium. For each fungal isolate, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of SSD and natamycin were determined.
Results—For all 17 fungal isolates, SSD MIC distribution ranged from ≤ 1 to > 64 μg/mL; MIC50 and MIC90 (MICs at which 50% and 90% of organisms were inhibited) were 4 and 32 μg/mL, respectively. The SSD MFC distribution for all isolates was ≤ 1 to > 64 μg/mL; MFC50 and MFC90 (MFCs at which 50% and 90% of organisms were killed) were 8 and > 64 μg/mL, respectively. For all fungal isolates, natamycin MIC distribution ranged from 256 to > 1,000 μg/mL; MIC50 and MIC90 were 512 and > 1,000 μg/mL, respectively. The natamycin MFC distribution for all isolates ranged from 512 to > 1,000 μg/mL; MFC50 and MFC90 were each > 1,000 μg/mL.
Conclusions and Clinical Relevance—These in vitro data suggest that SSD is fungicidal against the fungal isolates that were obtained from eyes of horses with keratomycosis and that natamycin is fungicidal against some of the isolates at the drug concentrations evaluated. Silver sulfadiazine may be a therapeutic option for equine keratomycosis.
Objective—To develop a method for continuous infusion
of gentamicin into the tarsocrural joint of horses,
to determine pharmacokinetics of gentamicin in synovial
fluid of the tarsocrural joint during continuous
infusion, and to evaluate effects of continuous infusion
of gentamicin on characteristics of the synovial
Animals—12 healthy adult horses.
Procedure—An infusion catheter consisting of flow
control tubing connected to a balloon infuser was
used. Gentamicin solution (100 mg/ml) was infused in
the right tarsocrural joint and balanced electrolyte
solution was infused in the left tarsocrural joint for 5
days. Synovial fluid and serum gentamicin concentrations
were measured by use of a fluorescence polarization
Results—17 of the 24 (71%) infusion catheters initially
placed functioned without complications for the entire
5-day infusion period. Median gentamicin concentration
in synovial fluid from treated joints during the 5-day infusion
period ranged from 287.5 to 982 μg/ml. Median
serum gentamicin concentration during this period
ranged from 2.31 to 2.59 μg/ml. Mean (± SD) elimination
half-life and total clearance of gentamicin from the
synovial fluid were 6.25 ± 1.01 hours and
1.52 ± 0.96 ml/min, respectively.
Conclusions and Clinical Relevance—An infusion
catheter can be used for continuous infusion of gentamicin
into the tarsocrural joints of horses for up to 5
days. At a gentamicin dosage of 0.17 ± 0.02 mg/kg/h,
continuous intra-articular infusion results in synovial
fluid gentamicin concentrations greater than 100
times the minimal inhibitory concentration reported
for common equine pathogens. (Am J Vet Res 2000;61:407–412)
Objective—To compare efficacy of amoxicillin-clavulanic acid, cefovecin, and doxycycline in shelter-housed cats with clinical signs of upper respiratory tract disease (URTD).
Design—Randomized prospective clinical trial.
Animals—48 cats with URTD.
Procedures—Conjunctival and nasal swab specimens were obtained for culture and susceptibility testing, and cats were randomly assigned to 3 treatment groups (16 cats/group) on day 1: amoxicillin-clavulanic acid (12.5 mg/kg [5.68 mg/lb], PO, q 12 h, for 14 days), cefovecin (8.0 mg/kg [3.64 mg/lb], SC, once), or doxycycline (10.0 mg/kg [4.55 mg/lb], PO, q 24 h, for 14 days). Oculonasal discharge, sneezing, coughing, dyspnea, demeanor, and food intake were scored twice daily for 14 days (scale, 0 [subjectively normal] to 3 [markedly abnormal]).
Results—The most common bacterial isolates were Mycoplasma spp (n = 22) and Bordetella bronchiseptica (9). Cats treated with amoxicillin-clavulanic acid or doxycycline had significantly increased body weight by day 14. Cats that received doxycycline had significantly lower overall oculonasal discharge scores than those treated with amoxicillin-clavulanic acid or cefovecin. Cats treated with amoxicillin-clavulanic acid or doxycycline had significantly lower overall sneezing scores than those that received cefovecin. Cats that received amoxicillin-clavulanic acid had significantly decreased demeanor and food intake scores on day 2, whereas this was detected later in other groups (demeanor score on days 5 and 7 and food intake score on days 10 and 11 in the cefovecin and doxycycline groups, respectively).
Conclusions and Clinical Relevance—Oral administration of amoxicillin-clavulanic acid or doxycycline appeared to be more effective than a single SC injection of cefovecin in treating cats with clinical signs of URTD.
Objective—To identify environmental risk factors for
Animals—36 dogs with leptospirosis and 138 dogs
seronegative for leptospirosis as determined by
microscopic agglutination test for antibodies against
Procedure—Medical records of dogs evaluated for
leptospirosis from 1997 though 2002 were identified.
Owner address was used to geocode locations of
dogs, and location-specific environmental risk factor
data were obtained by use of a geographic information
system. Risk of leptospirosis was estimated by
odds ratios, controlling for potential confounding by
dog age, sex, and breed.
Results—Leptospirosis in 19 of the 30 dogs in which
an infecting Leptospira serovar could be identified
was associated with Leptospira kirschneri serovar
grippotyphosa infection. Dogs in which a diagnosis of
leptospirosis was made, and dogs with leptospirosis
caused by L kirschneri serovar grippotyphosa, were
more likely to have addresses located in areas classified
as rural in 1990 but urban in 2000. By use of information
on recent urbanization and a logistic regression
model, the status of 81.6% and 89.8% of dogs
with leptospirosis and leptospirosis caused by serovar
grippotyphosa, respectively, were correctly classified.
Other environmental variables (proximity to streams,
recreational areas, farmland, wetlands, areas subject
to flooding, and areas with poor drainage; annual rainfall;
and county cattle or pig population) did not significantly
improve accuracy of classification.
Conclusions and Clinical Relevance—Dogs in periurban
areas are at greater risk of leptospirosis.
Vaccination of dogs in these areas to protect against
leptospirosis should be considered. (J Am Vet Med
Objective—To estimate serovar-specific prevalence
of leptospirosis by use of veterinary teaching hospital
and laboratory submission data; describe annual and
seasonal patterns of leptospirosis; and identify risk
factors for age, sex, and breed.
Animals—90 dogs with leptospirosis.
Procedures—Hospital records of dogs examined at
Purdue University Veterinary Teaching Hospital with a
diagnosis of leptospirosis and laboratory records of
dogs from which sera were tested for antibodies
against Leptospira spp at Purdue University Animal
Disease Diagnostic Laboratory from 1997 through 2002
were reviewed. The likely infecting Leptospira serovar
was identified. Seasonal and annual prevalences were
calculated by use of hospital population at risk (hospital
cases) or serologic testing submissions (diagnostic laboratory
cases). Age-, sex-, and breed-specific risk factors
for hospital cases were estimated by odds ratios.
Results—Of the 39 hospitalized dogs identified, 34
had been serologically tested, and 22 of those were
infected with Leptospira kirschneri serovar grippotyphosa.
Of the 51 diagnostic laboratory cases, 59%
had a reciprocal titer ≥ 800 against serovar grippotyphosa.
Diagnostic laboratory cases were more common
in summer, whereas hospital cases of leptospirosis
were more common in fall. Male dogs were
at significantly greater risk of leptospirosis than
female dogs; and dogs 4 to 6.9 years old were at significantly
greater risk than dogs < 1 year old.
Conclusions and Clinical Relevance—L kirschneri
serovar grippotyphosa infection was associated with
most cases of leptospirosis in dogs. Use of an effective
vaccine that includes this serovar is advisable for
dogs at risk of leptospirosis. (J Am Vet Med Assoc 2004;224:1958–1963)
Objective—To determine the effects of a continuous
intra-articular infusion of gentamicin on the synovial
membrane and articular cartilage in the tarsocrural
joint of horses.
Animals—6 healthy adult horses.
Procedure—A balloon infusion system attached to a
catheter placed in the plantarolateral pouch of both
tarsocrural joints in each horse was used for continuous
gentamicin solution (GM) or balanced electrolyte
solution (BES) delivery for 5 days. Cartilage and synovial
membrane specimens were collected on day 5
from 3 horses and on day 14 from the remaining 3
horses. Both infused joints from each horse were
assessed, using gross evaluation and histologic scoring
Results—Significant differences in the histologic
scores of synovial membrane specimens between
the GM- and BES-treated joints at either 5 or 14 days
were not observed. Safranin-O-fast green staining
scores were similar between cartilage specimens
from GM- and BES-treated joints. Although the synovial
membrane histologic scores and safranin-O-fast
green staining scores improved from day 5 to 14, the
changes in scores were not significant. Loss of synovial
intimal cells from villi was found more commonly
in sections of synovial membrane from GM-treated
joints, compared with BES-treated joints.
Conclusions and Clinical Relevance—Continuous
infusion of GM into the tarsocrural joint of horses
does not have significant effects on histologic scores
of articular cartilage or synovial membrane, compared
with those infused with BES. Continuous infusion of
GM into the tarsocrural joint of horses for 5 days is an
acceptable method for the treatment of septic arthritis.
(Am J Vet Res 2002;63:683–687)
Objective—To use results of microscopic agglutination tests (MATs) conducted at a commercial veterinary diagnostic laboratory to determine temporal and demographic distributions of positive serologic test results for leptospirosis in dogs and identify correlations among results for various Leptospira serovars.
Study Population—MAT results for 33,119 canine serum samples submitted to a commercial veterinary diagnostic laboratory from 2000 through 2007.
Procedures—Electronic records of MAT results for dogs were obtained from a veterinary diagnostic laboratory. Seropositivity for antibodies against Leptospira serovars was determined by use of a cutoff titer of ≥ 1:1,600 to reduce the possible impact of postvaccinal antibodies on results. Correlations between results for all possible pairs of serovars were calculated by ordinal ranking of positive (≥ 1:100) antibody titer results.
Results—2,680 samples (8.1%; 95% confidence interval [CI], 7.8% to 8.4%) were seropositive for antibodies against Leptospira serovars. The highest percentage of positive MAT results was for the year 2007 (10.2%; 95% CI, 9.5% to 10.9%) and for the months of November and December during the study period. Antibodies were most common against serovars Autumnalis, Grippotyphosa, Pomona, and Bratislava. Seroprevalence of leptospirosis was lowest for dogs > 10 years of age but was similar across other age strata.
Conclusions and Clinical Relevance—Leptospirosis can affect dogs of small and large breeds and various ages. Although an increase in proportions of positive MAT results was evident in the fall, monthly and annual variations suggested potential exposure in all months. Because of the limitations of MAT results and the limited number of serovars used in the test, bacterial culture should be used to identify infective Leptospira serovars.
Objectives—To assess methods of detecting environmental
contamination with Salmonella organisms
and evaluate a cleaning and disinfection protocol for
horse stalls in a veterinary teaching hospital.
Sample Population—37 horses with diarrhea likely
to be caused by Salmonella infection and their stall
Procedures—Fecal samples were collected from horses
daily during hospitalization; samples were obtained
from stall sites after cleaning and application of disinfectants.
Fecal and environmental samples were cultured
for Salmonella spp and tested via polymerase
chain reaction (PCR) assay to detect Salmonella DNA.
Results—1 horse died and 2 were discharged prior to
sample collection. Fecal samples from 9 of 34 horses
yielded growth of Salmonella organisms on bacteriologic
culture, and 23 yielded positive results via PCR
assay on ≥ 1 occasion. Among environmental samples
from 21 stalls, salmonellae were detected at ≥ 1 stall
site on 6 of 78 occasions, and ≥ 1 stall site yielded positive
results via PCR assay on 69 of 77 occasions.
Salmonella DNA was detected more frequently in samples
of stall drains, cracks, and corners. Salmonella spp
were cultured from samples of 3 stalls after both initial
and second cleaning and disinfection cycles, but no
organisms were detected in samples obtained after
use of a peroxygen disinfectant.
Conclusions and Clinical Relevance—Results suggest
that stalls in which horses with salmonellosis were
housed should only be used to accommodate newly
hospitalized horses after samples (collected after 2
cycles of cleaning and disinfection) from drains, cracks,
and corners yield negative results on bacteriologic culture.
(J Am Vet Med Assoc 2003;223:1640–1644)