Edmund J. Rosser

Frequency of isolation and antimicrobial susceptibility patterns of Staphylococcus intermedius and Pseudomonas aeruginosa isolates from canine skin and ear samples over a 6-year period (1992-1997)

Staphylococcus intermedius (S. intermedius) was isolated from 88.6% and 49.4% of skin and ear samples, respectively, during the years 1992 through 1997, and frequency of isolation remained unchanged. More than 95% of all S. intermedius isolates were susceptible to cephalothin and oxacillin, providing support for empirical treatment of canine skin and ear infections with cephalexin. Pseudomonas aeruginosa (P. aeruginosa) was isolated from 7.5% and 27.8% of skin and ear samples, respectively. The frequency of isolation from skin samples increased over the study period. Because of multidrug-resistant profiles for P. aeruginosa isolates, especially for ear isolates, empirical treatment of P. aeruginosa infections is not advisable.

Comparison of Microbial Isolates and Susceptibility Patterns From the External Ear Canal of Dogs With Otitis Externa

Otic exudate was obtained from 33 dogs with otitis externa for cytopathology and culture. Two samples were taken from the same location in the external ear canal, for a total of 100 samples. Thirty-six (36%) samples isolated only a single organism, of which 21 (21%) were Malassezia spp. Two organisms were present in 23 (23%) of the samples. Cultures of the two samples agreed in 40 (80%) of the 50 pairs. Cytopathology agreed with culture results only 68% of the time. Cytopathology and culture may not be as definitive as previously assumed because of apparent variability of the microbial population within the external canal.

German shepherd dog pyoderma: a prospective study of 12 dogs.

Twelve German shepherd dogs, each diagnosed as having a recurrent or refractory deep pyoderma (i.e., German shepherd dog pyoderma [GSP]), were evaluated for several parameters over a six-year period. Results indicated that GSP could be associated with flea allergy dermatitis, atopic dermatitis, food allergy, cell-mediated immunodeficiency, or hypothyroidism, or could be an idiopathic disease. The combination of diseases present for a given dog varied from case to case. Adequate control of the pyoderma was achieved only after each identified underlying disease was treated specifically, along with aggressive concurrent medical therapy using systemic antibiotics and medicated baths.

Multi-drug and methicillin resistance of staphylococci from canine patients at a veterinary teaching hospital (2006-2011).

Background: Over the past 10 years, an increase in methicillin and multi-drug resistant staphylococcal species has been identified worldwide and anecdotally reported within our veterinary teaching hospital. Objective: To determine the methicillin resistance (MR) and multi-drug resistance (MDR) patterns of staphylococcal species isolated from canine patients between 2006 and 2011. Animals and Methods: Staphylococcal isolates (n = 1069) were cultured from the canine patient population of the veterinary teaching hospital. The susceptibility reports of Staphylococcus pseudintermedius, S. aureus, S. schleiferi v. coagulans, S. schleiferi v. schleiferi, and other coagulase-negative staphylococci (CoNS) were assessed. Isolates were organized into five site categories. Isolates were scored on a 0–10 scale based on resistance to antimicrobial classes, with MDR classified as an isolate scoring a value ≥3. Statistical analysis included χ2, Fishers exact test, and ANOVA with mean square and post hoc analysis; p < 0.05 was significant. Results: S. pseudintermedius (76.6%), S. aureus (15.5%), S. schleiferi v. coagulans (5.7%), S. schleiferi v. schleiferi (1.2%), and CoNS (0.9%) isolation was observed. MR occurred in 11.4% of all combined isolates, with no difference between sites and years. Of the S. pseudintermedius isolates, 4.5% were methicillin resistant. Of all the isolates, 27.5% were MDR. The mean resistance score of S. pseudintermedius isolates increased significantly comparing 2006 and 2008 (p = 0.0006) and 2006 and 2009 (p = 0.0009). The mean score of all combined isolates increased significantly comparing 2006 and 2008 (p = 0.001). Conclusion: MR staphylococci isolation is similar when compared to other studies. However, increased MDR isolation is of greater concern and high-scoring MDR staphylococci will limit our future antimicrobial choices.

Investigation on the effects of ciclosporin (Atopica) on intradermal test reactivity and allergen-specific immunoglobulin (IgE) serology in atopic dogs

The ability to use ciclosporin (Atopica®: Novartis Animal Health, Greensboro, NC, USA) prior to intradermal testing (IDT) would help avoid exacerbation of clinical disease that can be associated with drug withdrawal. This study evaluated the effects of 30 days of administration of ciclosporin at a dose of 5 mg/kg once daily on IDT reactivity (immediate phase reactions) in a group of dogs with atopic dermatitis (AD) with initial positive IDT reactions. 16 dogs diagnosed with AD were included in the study. Eight dogs (group A) were treated with ciclosporin orally at 5 mg/kg once daily for 30 days. Eight dogs (group P) were treated with a placebo orally once daily for 30 days. IDT was performed at day 0 and day 30 on all dogs enrolled using a standardized panel of 45 aqueous allergens (Greer Laboratories, Lenoir, NC, USA) appropriate to our geographical region. IDT reactivity was assessed by both subjective and objective methods at 15 min post-intradermal injection. Serum for allergen-specific immunoglobulin (IgE) serology was obtained at day 0 and day 30. The study was designed as a double-blinded, placebo-controlled, cross-over study. Data were analysed using a split-plot analysis of variance with the grouping factor of treatment and the repeat factor of time (SAS System for Windows). At week 4, ciclosporin did not have a statistically significant effect on IDT reactivity or serology results. It therefore appears that, no withdrawal is recommended to evaluate immediate phase reactions.

Comparison of hair follicle histology between horses with pituitary pars intermedia dysfunction and excessive hair growth and normal aged horses

BACKGROUND Pituitary pars intermedia dysfunction (PPID) in older equids is commonly recognized by a long hair coat that fails to shed. OBJECTIVE The aim of this study was to compare hair follicle stages in PPID-affected horses with excessively long hair coats with the stages of normal aged horses (controls) and to compare hair follicle stages in PPID-affected horses after 6 months of treatment with pergolide mesylate with those of control horses. ANIMALS Eight PPID-affected horses and four normal, age-matched, control horses. METHODS Skin biopsies were collected from the neck and rump of PPID-affected and control horses. A diagnosis of PPID was established based on hair coat changes and supportive overnight dexamethasone suppression test results. Skin biopsies were repeated after 6 months of treatment with pergolide. The number of hair follicles in anagen (A) or telogen (T) was counted for each skin biopsy using transverse sections. RESULTS Pretreatment biopsies had a greater percentage of A follicles (neck 96%, rump 95%) and a lower percentage of T follicles (neck 4%, rump 5%) in PPID-affected horses than in control horses (A, neck 15%, rump 25%; and T, neck 85%, rump 75%). After treatment with pergolide, all PPID-affected horses had improved shedding, and the percentages of A follicles (neck 69%, rump 70%) and T follicles (neck 31%, rump 30%) were not different from untreated control horses (A, neck 68%, rump 82%; and T, neck 32%, rump 18%). CONCLUSIONS These findings document that excessive hair growth (hypertrichosis) in PPID-affected horses is due to persistence of hair follicles in A. Furthermore, treatment with pergolide improved shedding and reduced the percentage of A follicles in PPID-affected horses.

Cutaneous paecilomycosis in a cat.

A cat was presented for a 2-year history of a recurrent, soft-tissue swelling of the left metacarpal region. The mass was excised and submitted for aerobic and anaerobic bacterial culture, fungal culture, and histopathological examination. Cultures revealed the organism Paecilomyces lilacinus, and histopathological examination showed a nodular mycotic granuloma. Itraconazole (10 mg/kg body weight, per os [PO], q 24 hours) was administered and continued for a total of 60 days, with a swelling of the upper lip occurring 3 months after the initial presentation. Subsequent surgical excisions and debridements along with treatment with itraconazole (20 mg/kg body weight, PO, q 24 hours) for a total of 4 months were curative.

Efficacy of once-daily clindamycin hydrochloride in the treatment of superficial bacterial pyoderma in dogs

Twenty-one dogs with canine superficial bacterial pyoderma were treated with clindamycin at a dosage of approximately 11 mg/kg body weight, q 24 hours, given orally for 14 to 42 days. All dogs were reexamined on days 14, 28, and, if necessary, 42 and given a clinical score of excellent (i.e., complete remission), good (i.e., primary lesions resolved but secondary lesions evident), fair (i.e., partial improvement but primary lesions still evident), or poor (i.e., no improvement or worsening of the lesions). A clinical score of excellent was obtained in 71.4% (15/21) of the dogs in this study within 14 to 28 days.

Advances in the diagnosis and treatment of atopy.

Regarding the diagnosis of atopy, the emphasis in this article has been on how to use the initial history and physical examination findings to lead the clinician towards this diagnosis. After a systematic approach to the differential diagnosis of pruritus in the dog has been completed, the diagnosis of atopy can be further evaluated using one of the specific allergy tests available. The authors preference is the IDST to aid in the confirmation of the presence of atopy. Regarding the treatment of atopy, the emphasis in this article has been on the use of immunotherapy as the specific treatment for this disease. Careful monitoring of dogs on immunotherapy is essential to obtain optimum results, and response rates to treatment may be significantly improved by implementing various modifications in the standard hyposensitization protocol being used by the clinician.

Group 1 and 2 Dermatophagoides house dust mite allergens in the microenvironment of cats

House dust mite allergens (HDMAs) are some of the most common allergens associated with allergic diseases in humans and dogs. The purpose of this study was to determine whether HDMAs could be detected in cat-associated household microenvironments. From 50 cat-only households with 95 cats, dust samples were collected by vacuuming for 2 min m(-2) from three areas where cats slept or rested regularly from September to October 2006. Relative humidity and temperature were measured in each household using a data logger. Each owner completed a questionnaire on potential factors that might influence the prevalence of house dust mites (HDMs). Dust samples were analysed utilizing an ELISA for Der p 1, Der f 1 and HDM group 2 allergens. In 38 of 50 households there was greater than 2 microg g(-1) of dust for at least one HDMA. Using stepwise logistic regression, factors associated with increased HDMA levels included: free-standing houses, number of humans in household, longhaired cats and age of the cat. Factors associated with decreased HDMA concentrations included: forced air heating and central air conditioning, less than 50% carpeting of the home, use of flea control, cats suffering from dermatological disease and the average temperature of the household. Many sleeping/resting areas utilized by cats contain sufficiently high levels of HDMAs to be potential sources of sensitization. This finding should lead to further determination of the role of HDMs in cats suffering from putative allergic conditions such as atopic dermatitis or asthma.