Objective—To determine the functionality of canine
anti- Malassezia IgE via the passive transfer of immediate
hypersensitivity localized to the skin (ie, cutaneous
anaphylaxis) from atopic dogs with dermatitis
attributable to overgrowth of Malassezia pachydermatis
( Malassezia dermatitis [MD]) to healthy recipient
dogs by use of the Prausnitz-Küstner (P-K) technique.
Animals—7 clinically normal dogs, 32 atopic dogs
with MD, serum from 11 atopic dogs with MD, and 3
healthy dogs without prior sensitization to M pachydermatis.
Procedure—Serum from atopic dogs with MD was
used for P-K tests in 3 clinically normal recipient
dogs. Serial dilutions of untreated, heat-inactivated,
IgE-absorbed, and bovine serum albumin (BSA)-
absorbed (control) aliquots of serum were injected
ID in triplicate for dermal sensitization. Twenty-four,
48, and 72 hours later, a crude extract of M pachydermatis
was injected ID into the sites used for
sensitization injections, and immediate hypersensitivity
reactions were graded on a 4-point scale.
Results—Untreated serum caused P-K reactivity
beginning 24 hours after passive sensitization and
persisting through 72 hours (titers, 1:32 to 1:64).
Heat inactivation and IgE-absorption of serum
eliminated P-K reactivity, whereas treatment of
serum with BSA did not.
Conclusions and Clinical Relevance—Analysis of
P-K test results supports the passive transfer of cutaneous
anaphylaxis by anti-Malassezia IgE and indicates
it is functional in type-1 hypersensitivity reactions
of atopic dogs with MD. Reduction or blockade
of anti-Malassezia IgE in atopic dogs with MD may
provide better clinical control of the disease.
(Am J Vet Res 2003;64:262–266)
Objective—To characterize skin lesions and causative
infections in diabetic dogs and evaluate other potential
causes of dermatologic disorders, including concurrent
endocrinopathies, allergic skin disease, and
long-term corticosteroid administration.
Animals—45 dogs with diabetes mellitus (DM) that
were examined by dermatologists.
Procedure—Medical records were reviewed for signalment;
allergic conditions prior to development of
DM; prior corticosteroid administration; and results of
dermatologic examinations, ear and skin cytologic
examinations, skin scrapings for parasites, bacteriologic
and fungal culturing of ear and skin specimens,
histologic examinations, and endocrine testing.
Results—Bacterial skin infection was the most common
dermatologic disorder (n = 38 [84%]), followed by
otitis (26 [58%]) and Malassezia-induced dermatitis
(19 [42%]). Twenty-two (49%) dogs had pruritic skin
disease consistent with allergic dermatitis, which preceded
diagnosis of DM. Prior corticosteroid administration
was reported in 21 (47%) dogs. Concurrent
hyperadrenocorticism was diagnosed in 13 (29%)
dogs, and concurrent hypothyroidism was diagnosed
in 5 (11%) dogs. Iatrogenic hyperadrenocorticism was
diagnosed in 1 additional dog. Only 10 (22%) dogs did
not have a documented concurrent endocrinopathy or
allergic disease that could have caused the dermatitis.
Conclusions and Clinical Relevance—Bacterial and
yeast-induced dermatitis and otitis develop in dogs with
DM. Many diabetic dogs with dermatologic problems
have a preexisting allergic condition, history of prior corticosteroid
administration, or concurrent endocrinopathy
that may be a more likely cause of dermatologic problems
than DM alone. (J Am Vet Med Assoc 2001:219:
Objective—To define clinical differences between coagulase-positive and coagulase-negative Staphylococcus schleiferi infections in dogs and to identify risk factors for the isolation of oxacillin-resistant S schleiferi.
Design—Retrospective case series.
Animals—225 dogs (yielding 225 S schleiferi isolates).
Procedures—Information obtained from affected dogs' medical records included isolate body site source, antimicrobial treatments, and primary disease. For each dog, the S schleiferi isolate was characterized and antimicrobial susceptibility data were recorded. Risk factors for infection based on coagulase status and for S schleiferi oxacillin resistance were investigated.
Results—Allergic dermatitis was the most common underlying disease (111/225 dogs). Ears (102 [45%]) and skin (95 [42%]) were sources of most of the 225 isolates. Isolate coagulase status was not significantly associated with any patient-level factors. Of the 225 isolates, 129 (57%) were oxacillin resistant. Coagulase-negative isolates were more likely to be oxacillin resistant than were coagulase-positive isolates (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1 to 3.0). Administration of penicillin-based or first-generation cephalosporin drugs (OR, 3.0; 95% CI, 1.8 to 5.9) and third-generation cephalosporins (OR, 3.7; 95% CI, 1.1 to 12.3) within 30 days prior to culture were risk factors for oxacillin resistance.
Conclusions and Clinical Relevance—Results suggested that coagulase-negative and coagulase-positive S schleiferi are potential pathogens in dogs and are often oxacillin resistant. Recent patient treatments with penicillin or cephalosporin were risk factors for oxacillin resistance. In clinical cases, full speciation of all Staphylococcus isolates should be performed and microbial treatments should be selected on the basis of results of susceptibility testing.
Objective—To compare clinical information obtained from medical records of cats with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S aureus (MSSA) infections, evaluate antibiograms of MRSA and MSSA for multiple-drug resistance (MDR), and characterize the strain type and staphylococcal chromosome cassette (SCC)mec type of each MRSA.
Sample Population—70 S aureus isolates obtained from 46 cats.
Procedures—Clinical information obtained from medical records, including signalment, clinical signs, histologic examination of affected tissues, and outcomes, was compared between the 2 groups. Composite antibiograms of MRSA and MSSA were compared statistically. The MRSA strains were characterized by use of pulsed-field gel electrophoresis and SCCmec typing.
Results—No statistical differences in signalment or subjective differences in clinical signs or outcomes were detected between groups with MRSA or MSSA infection. Significant differences in antimicrobial resistance were detected, with MRSA having complete resistance to fluoroquinolone and macrolide antimicrobials, whereas MSSA maintained a high frequency of susceptibility. Seven pulsed-field patterns were observed in 15 MRSA strains; all but 1 were highly related. All MRSA isolates contained a type II SCCmec element.
Conclusions and Clinical Relevance—Because MDR cannot be predicted in staphylococcal infections in cats on the basis of clinical signalment, culture and susceptibility testing are recommended whenever initial empirical treatment is unsuccessful. Molecular characterization of MRSA strains suggests that there has been reverse-zoonotic transmission from humans.
Impact for Human Medicine—The SCCmec type II element is typically associated with nosocomial MRSA infections of people. Cats may serve as reservoirs for MRSA infections in humans.
Objective—To assess the degree of biological similarity (on the basis of genotype determined via pulsed-field gel electrophoresis [PFGE]) between isolates of 2 Staphylococcus schleiferi subspecies (S schleiferi subsp coagulans and S schleiferi subsp schleiferi) in clinical samples obtained from dogs.
Sample Population—161 S schleiferi isolates from 160 canine patients.
Procedures—A commercial microbiology identification system was used to identify each isolate as S schleiferi. Isolates underwent slide and tube coagulase testing and antimicrobial susceptibility testing. A mecA PCR assay and a latex agglutination test for penicillin-binding protein 2a (PBP2a) were also performed on each isolate. Clonal clusters with a similarity cutoff value of 80% were identified via PFGE.
Results—Of the 161 isolates, 61 (38%), 79 (49%), and 21 (13%) were obtained from cutaneous sites, ears, and other sites, respectively; 110 (68%) were coagulase negative, and 51 (32%) were coagulase positive. Among the coagulase-negative and coagulase-positive isolates, 65% (71/110) and 39% (20/51) were oxacillin resistant, respectively. All oxacillin-resistant isolates yielded positive results via mecA PCR assay and PBP2a latex agglutination testing. Via PFGE, 15 major clusters and 108 individual pulsed-field profiles were identified. Oxacillin-resistant and oxacillin-susceptible isolates clustered separately. Clonal clusters were heterogeneous and contained representatives of both subspecies.
Conclusions and Clinical Relevance—Coagulase-positive and coagulase-negative isolates were not genotypically distinct and may represent a single S schleiferi sp with variable coagulase production, rather than 2 biologically distinct subspecies. Further studies are needed to characterize clinical or epidemiological differences associated with infections with coagulase-positive and coagulase-negative S schleiferi in dogs.
Objective–To investigate the potential cell-mediated
immune response of atopic dogs to the yeast
Malassezia pachydermatis and to correlate it with the
type-1 hypersensitivity (humoral) response of the
same population of dogs.
Animals–16 clinically normal dogs, 15 atopic dogs
with Malassezia dermatitis, 5 atopic dogs with
Malassezia otitis, and 7 atopic control (ie, without
Malassezia dermatitis or otitis) dogs.
Procedure–A crude extract of M pachydermatis was
extracted for use as an intradermal allergy testing
reagent and for stimulation of isolated peripheral
blood mononuclear cells in vitro. Flow cytometry was
also used to assess cell surface antigenic determinants
(CD3, CD4, CD8, CD14, CD21, CD45RA, surface
immunoglobulin) on peripheral blood mononuclear
Results–Atopic dogs with cytologic evidence of
Malassezia dermatitis had an increased lymphocyte
blastogenic response to crude M pachydermatis
extract, compared with clinically normal dogs and
dogs with Malassezia otitis. Atopic control dogs did
not differ significantly in their responses from atopic
dogs with Malassezia dermatitis or otitis. A significant
correlation was not found between the lymphocyte
blastogenic response and the type-1 hypersensitivity
response to M pachydermatis within any of the
Conclusions and Clinical Relevance–Cell-mediated
and humoral reactivities to M pachydermatis contribute
to the pathogenesis of atopic dermatitis in
dogs but are not directly correlated. Modification of
the dysregulated immune response toward M pachydermatis
may assist in the reduction of pathologic
changes associated with an atopic dermatitis phenotype
in dogs. (Am J Vet Res 2002;63:358–362)
Objective—To evaluate the outcome of otitis media
in dogs after video-otoscopic lavage of the tympanic
bulla and long-term antimicrobial drug treatment.
Animals—44 dogs with otitis media treated in an academic
Procedure—Medical records were reviewed for signalment,
duration of ear canal disease, previous medical
treatments, dermatologic diagnosis, results of
cytologic examination and microbial culture of ear
canal exudate, findings during video-otoscopy, medical
treatment, days to resolution, and maintenance treatments
prescribed. Four independent variables (age,
duration of ear canal disease prior to referral, use of
corticosteroids in treatment regimens, and infection
with Pseudomonas aeruginosa) were evaluated statistically
for potential influence on time to resolution.
Results—Mean ± SD (range) duration of ear canal disease
prior to referral was 24.9 ± 21.6 (3 to 84) months.
Otitis media in 36 dogs resolved after lavage of the tympanic
bulla and medical management; mean ± SD
(range) time to resolution was 117 ± 86.7 (30 to 360)
days. Time to resolution was not significantly influenced
by any variable evaluated. Three dogs were lost to follow-up, and 4 dogs eventually required surgical intervention.
Seven of 36 dogs in which otitis had resolved
relapsed; 4 required additional lavage procedures.
Conclusions and Clinical Relevance—Results indicate
that lavage of the tympanic bulla combined with
medical management is an effective and viable option
for treatment of otitis media in dogs. (J Am Vet Med Assoc 2004;225:548–553)
Objective—To identify factors affecting prognosis,
outcome, and complications associated with pemphigus
foliaceus in dogs.
Animals—43 dogs with pemphigus foliaceus.
Procedure—Medical records were reviewed for signalment,
age at diagnosis, duration to diagnosis, body
area affected, initial immunosuppressive regimens
and concurrent use of antimicrobials and sucralfate or
histamine receptor 2 blocking agent, adverse effects
of treatment, duration of treatment, number of visits
for follow-up care, cause of death, and credentials of
the veterinarians responsible for continued care.
Results—The case fatality rate was 60.5%. Factors
significantly correlated with survival time included
concurrent use of antimicrobials during initiation of
immunosuppressive treatment and a lower number
of adverse effects to treatment. Treatment times lasting
more than 10 months from diagnosis correlated
significantly with survival.
Conclusions and Clinical Relevance—Treatment with
or prophylactic use of antimicrobials may be warranted
during initial immunosuppressive treatment. The inverse
correlation between survival time and number of
adverse treatment effects was not unexpected because
it was reflective of the owners' decision to euthanatize
their dogs and of corticosteroid-related secondary diseases.
Survival beyond the tenth month of treatment
predicted long-term survival, which suggests that dogs
require careful management during the early months of
treatment. (J Am Vet Med Assoc 2004;224:1312–1316)
Objective—To ascertain whether Malassezia organisms can be detected via cytologic examination and fungal culture of samples from the skin surface of psittacine birds and determine whether the number of those organisms differs between unaffected psittacines and those that have chronic feather-destructive behavior or differs by body region.
Animals—50 unaffected psittacines and 53 psittacines that had feather-destructive behavior.
Procedure—Samples were collected by use of acetate tape strips from the skin of the head, neck, proventer, propatagium, inguinal region, and preen gland area of each bird; 0.5-cm2 sample areas were examined microscopically for yeast, and samples were also incubated on Sabouraud dextrose agar. Polymerase chain reaction assays specific for Malassezia spp, saprophytic fungi, and Candida albicans were performed on DNA prepared from cultured colonies; nested PCR evaluation for Malassezia pachydermatis was then performed.
Results—Microscopically, 63 of 618 (10%) tape-strip samples contained yeast. Thirty cultured colonies were assessed via PCR assays, and all yielded negative results for Malassezia spp; C albicans was identified in 2 colony samples. The numbers of yeast identified microscopically in psittacines with feather-destructive behavior and in unaffected birds did not differ significantly, and numbers did not differ by body region.
Conclusions and Clinical Relevance—Yeast were identified infrequently via cytologic examination of samples from the skin surface of unaffected psittacine birds or those that had chronic feather-destructive behavior. If yeast are identified on the skin of birds with feather-destructive behaviors, fungal culture of skin samples should be performed to identify the organism.
Objective—To survey 2 populations of psittacines to characterize Staphylococcus spp isolated from commensal cutaneous microflora.
Design—Prospective cross-sectional study.
Animals—107 psittacine birds from a sanctuary and 73 psittacine birds in private households or a pet store.
Procedures—Gram-positive, catalase-positive cocci isolated from mucosal and seborrheic sites were speciated, and pulsed-field gel electrophoresis was performed on coagulase-positive isolates. A bird was classified as having positive results when at least 1 sample site yielded positive results for at least 1 staphylococcal species.
Results—89 of 180 (49.4%) birds had positive results for staphylococci at the carriage sites sampled. Privately owned birds were twice as likely to have positive results for staphylococci as were sanctuary birds (71% vs 35%). Coagulase-positive staphylococci were significantly more common in the sanctuary birds (47% vs 1%). Staphylococcus intermedius was significantly more common in the sanctuary birds (46% vs 2%). Staphylococcus hominis subsp hominis and Staphylococcus epidermidis, coagulase-negative staphylococci associated with humans, were significantly more common in pet birds. Cockatoos were twice as likely to have positive results for staphylococci as were other genera.
Conclusions and Clinical Relevance—Results suggested that staphylococcal colonization in captive psittacines was less common than in other species studied. Staphylococci isolated from a pet psittacine may reflect that of the humans and other animals with which the bird lives in close proximity; however, further studies are needed to evaluate the effects exposure to humans may have on the microflora of these birds.