Clinical efficacy of recombinant canine interferon-gamma therapy in dogs with cutaneous epitheliotropic T-cell lymphoma.

BACKGROUND: The antitumour effects of interferon-gamma (IFN-γ) in humans with cutaneous epitheliotropic T-cell lymphoma (CETCL) have been described; however, the efficacy of IFN-γ in dogs has not been investigated. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate the efficacy of recombinant canine IFN-γ (rCaIFN-γ) therapy in dogs with CETCL. ANIMALS: Twenty dogs with CETCL recruited from seven veterinary clinics were enrolled in the study. MATERIALS AND METHODS: Fifteen dogs were treated with rCaIFN-γ, and five control dogs were treated with prednisolone. We evaluated survival time, skin lesions (erythema, nodules, ulcers and bleeding), pruritus and general condition (sleep, appetite and body weight). In the rCaIFN-γ group, a questionnaire regarding the therapy was administered to owners after the dogs died. RESULTS: No significant differences existed in the median survival time between the rCaIFN-γ and control groups (log-rank test: p = 0.2761, Wilcoxon's rank sum test: p = 0.4444). However, there were significant differences in ulcer, bleeding, pruritus, sleep, appetite and body weight between the groups (Wilcoxon-Mann-Whitney U-test: p = 0.0023, p = 0.0058, p = 0.0005, p = 0.0191, p = 0.0306 and p = 0.0306, respectively). Two (40%) of five dogs were euthanised in the control group, compared with none in the rCaIFN-γ group. Fourteen questionnaires were collected, and owners reported that they were satisfied with the rCaIFN-γ treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Although the median survival time was not prolonged, rCaIFN-γ could be helpful in maintaining good quality of life for dogs with CETCL.

Focal cutaneous telangiectasia in a young dog of probable congenital origin.

BACKGROUND: Idiopathic cutaneous telangiectasia has been rarely described in the dog. OBJECTIVES: We present the first case of idiopathic focal cutaneous telangiectasia in a young dog of probable congenital origin. METHODS: An 18-month-old spayed female Maltese dog presented with demarcated erythema of the skin on the right thorax. The lesion consisted of scattered, florid, ramified macules with mild dermatrophia and desquamation. The lesion was examined with histopathology and immunohistochemistry using antibodies for alfa-SMA. RESULTS: Diascopy revealed a blanchable lesion. Tortuous capillary expansion was observed by dermoscopy. The histopathological examination revealed dilated but otherwise unremarkable capillaries in the superficial dermis compatible with cutaneous telangiectasia. The lesion was followed up over a 3-year period and had essentially remained stable. Other vascular anomalies displaying similarities with telangiectasia are discussed. CONCLUSIONS: In human vascular anomalies, this case would be presumably classified as 'telangiectasia' by the International Society for the Study of Vascular Anomalies. We propose that primary cutaneous telangiectasia should be included in the list of differential diagnoses for this type of lesions in dogs. We also suggest that dermoscopy would be a valuable tool for the identification of vascular anomalies in dogs.

Diode laser-assisted transcanal endoscopic removal of an aural polyp in the external auditory canal of a dog.

BACKGROUND: In humans, aural polyps comprise fibrovascular tissue covered by the respiratory epithelium. Aural polyps with ciliated epithelium are common in cats but are rarely reported in dogs. In a previous case, a mass filled the tympanic cavity alone, and it was surgically removed. OBJECTIVES: To report a case of a canine aural polyp with ciliated epithelium extending from the dorsal tympanic cavity to the external auditory canal with detailed otological features and to demonstrate the usefulness of the transcanal endoscopic procedure (TEP) with a diode laser as a less-invasive therapy. METHODS: A 12-year-old castrated male Cavalier King Charles Spaniel presented with a 6-month history of unilateral chronic otorrhoea. Video-otoscope examination revealed a protruding, reddish and soft-to-rubbery round mass in the right horizontal ear canal. Computed tomography and magnetic resonance imaging further revealed a smooth mass extending from the dorsal portion of the tympanic cavity into the horizontal part of the external auditory canal. However, it showed no lesions in the dorsal tympanic cavity. RESULTS: The mass was removed using aural forceps by a traction-torsion manoeuvre. The suspected base of the mass on the caudal side of the upper tympanic cavity was confirmed by a rigid scope, and it was completely vaporised with a diode laser. Histopathology revealed foci of columnar ciliated epithelium embedded in the connective tissue encapsulated by stratified squamous epithelium. No recurrence was observed at 3 years and 8 months. CONCLUSION: We describe a rare case of an aural polyp with ciliated epithelium extending from the upper-middle ear to the external auditory canal in a dog. The TEP using a diode laser may be a useful minimally invasive treatment option for managing external auditory canal polyps.

Outcomes and prognostic factors in canine epitheliotropic and nonepitheliotropic cutaneous T-cell lymphomas.

Canine cutaneous lymphoma is an uncommon lymphoma in dogs. Most canine cutaneous lymphoma cases have a T-cell origin. Canine cutaneous T-cell lymphoma (CTCL) is classified into epitheliotropic and nonepitheliotropic cutaneous lymphomas, and each type of lymphoma is subclassified into several histological subtypes. Limited information is available regarding the prognostic significance of clinical variables and histopathological subtypes in dogs with CTCL. This retrospective study aimed to investigate the influence of clinical variables and histopathological subtypes on the prognosis of dogs with CTCL. Forty-six dogs diagnosed with CTCL by histopathological examination were included. Histopathological specimens were reexamined and classified into CTCL subtypes. The influence of the type of skin lesion, histopathological subtype, haematological examination results and treatment response on the overall survival time (OS) was examined. Thirty-one dogs were diagnosed with epitheliotropic CTCL (mycosis fungoides in 28 dogs; pagetoid reticulosis in 3 dogs) and 15 dogs were diagnosed with nonepitheliotropic CTCL (anaplastic large T-cell lymphoma in 6 dogs; peripheral T-cell lymphoma, not otherwise specified, in 9 dogs). The OS of dogs diagnosed with epitheliotropic CTCL (141 days) was significantly shorter than that of dogs diagnosed with nonepitheliotropic CTCL (374 days). As clinical variables, the presence of neoplastic lymphocytes in peripheral blood, thrombocytopenia and initial chemotherapeutic response was related to prognosis. Our results demonstrated that histopathological subtype and several clinical variables were found to influence the prognosis of dogs with CTCL.

Narrow-band ultraviolet B therapy attenuates cutaneous T-cell responses in hapten-induced, experimental contact dermatitis in beagles.

BACKGROUND: In human medicine, narrow-band ultraviolet B (NB-UVB) phototherapy has been used to treat various T-cell-mediated skin diseases. However, the effect of NB-UVB on inflamed canine skin remains uncertain. OBJECTIVES: To investigate the effect of NB-UVB phototherapy on the skin of dogs with hapten-induced contact dermatitis. ANIMALS: Seven healthy beagles without skin problems. METHODS AND MATERIALS: Dogs were irradiated with varying doses of NB-UVB to determine the minimal erythema dose (MED). After determining the MEDs of six dogs (excluding one of the seven whose skin did not show a visible reaction), we investigated the effect of NB-UVB on their inflamed skin by topically applying 2,4-dinitrochlorobenzene (DNCB), which causes type 1 helper T cell (Th1)- and cytotoxic T-cell (Tc)1-induced skin inflammation. We then irradiated the skin with NB-UVB. We analysed the treated skin samples via histopathological and immunohistochemical methods, and TdT-mediated dUTP nick-end labelling (TUNEL) to demonstrate apoptotic cells. We also analysed the cytokine gene transcription via real-time quantitative reverse transcription PCR. RESULTS: The NB-UVB MEDs caused mild inflammatory changes yet no severe epidermal exfoliations in the irradiated skin. In DNCB-treated skin irradiated by the NB-UVB MEDs, TUNEL-positive dermal apoptotic cells were increased significantly compared with those of DNCB-treated, nonirradiated skin. INF-γ and TNF-α transcription levels in DNCB-treated, irradiated skin were significantly lower than those in the DNCB-treated, nonirradiated skin. CONCLUSION AND CLINICAL RELEVANCE: Phototherapy using NB-UVB MEDs attenuated cutaneous Th1 and Tc1 cytokine responses with minimal skin damage in a canine model of hapten-induced contact dermatitis.

Long-term follow-up of a single dose of fluralaner in nine dogs with demodicosis.

BACKGROUND: Long-term follow-up of oral fluralaner for canine demodicosis has not been demonstrated. OBJECTIVES: A multicentre prospective open trial for the efficacy of oral fluralaner for the long-term (>12 month) management of canine demodicosis. ANIMALS: Client-owned dogs diagnosed with demodicosis at nine veterinary clinics. METHODS AND MATERIALS: A single fluralaner dose was administered orally. Although shampoo was allowed to treat secondary pyoderma, no other medication or shampoo was allowed, except for medication for possible underlying disorders. Each dog underwent a thorough parasitological and dermatological assessment monthly for three months and was followed up for >12 months. RESULTS: Twenty-six dogs were enrolled. Their ages ranged from three months to 16 years. The cases were nine juvenile and 17 adult onsets; and 18 generalised and eight localised forms. Fluralaner administration resulted in 100% eradication of mites and complete resolution of all skin lesions at three months. Seventeen dogs were excluded from the one year follow-up evaluation as they had required a second dose of isoxazoline or died from causes unrelated to the fluralaner treatment. In the remaining nine cases, no relapse was observed in any of the dogs (six adult and three juvenile onsets; six generalised and three localised forms). Four dogs were monitored for over one year, one dog for over two years, and four dogs for three years. CONCLUSIONS AND CLINICAL RELEVANCE: The results indicated that a single dose of fluralaner could effectively deliver a long-term cure when combined with managing underling conditions.

Serum canine thymus and activation-regulated chemokine (TARC/CCL17) concentrations correlate with disease severity and therapeutic responses in dogs with atopic dermatitis.

BACKGROUND: Thymus and activation-regulated chemokine (TARC/CCL17) has been implicated in the pathogenesis of canine atopic dermatitis (cAD). Serum TARC concentrations are a reliable biomarker for human atopic dermatitis; however, their potential as a biomarker for cAD has not been investigated. HYPOTHESIS/OBJECTIVES: To investigate whether serum TARC concentrations correlate with disease severity and therapeutic responses for cAD. ANIMALS: Thirty-nine dogs with cAD and 42 healthy dogs were recruited. METHODS AND MATERIALS: Serum TARC concentrations in dogs with cAD and healthy dogs were measured by sandwich ELISA with anti-canine TARC antibodies. The clinical severity of cAD was scored using the validated Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04). Serum TARC concentrations were compared between dogs with cAD and healthy controls, and their relationship with CADESI-04 was examined. Serum TARC concentrations also were measured in 20 dogs with cAD treated with prednisolone or oclacitinib for four weeks. RESULTS: Serum TARC concentrations were significantly higher in dogs with cAD than in healthy dogs (P < 0.001). In dogs with cAD, serum TARC concentrations correlated with CADESI-04 scores (ρ = 0.457, P < 0.01). Furthermore, serum TARC concentrations significantly decreased in treated dogs with the attenuation of clinical signs (P < 0.001). Changes in serum TARC concentrations before and after treatment correlated with those in CADESI-04 scores (ρ = 0.746, P < 0.001). CONCLUSIONS AND CLINICAL RELEVANCE: Serum TARC concentrations have potential as a clinical and research tool for the objective evaluation of disease severity and therapeutic responses for cAD.

Clinical analysis and nonsurgical management of 11 dogs with aural cholesteatoma.

BACKGROUND: Aural cholesteatomas, also called tympanokeratomas, are destructive and expansile growths of keratinizing epithelium that develop in the middle ear. They have been reported sporadically in dogs, and surgery is usually the recommended treatment. OBJECTIVES: To describe the common clinical, radiological and histological findings of cholesteatoma; to report on the outcome of conservative management. ANIMALS: Eleven dogs (13 ears) with cholesteatomas. METHODS AND MATERIALS: Medical records were reviewed for dogs diagnosed with cholesteatoma between 2012 and 2018. All dogs had computed tomography (CT) and/or magnetic resonance imaging (MRI) followed by trans-canal endoscopic procedure (TEP) for removal and biopsy of middle ear lesions. Dogs were then treated with in-clinic flushing initially weekly tapered to monthly, as well as at-home ear cleaning and application of topical otic steroid medication, initially daily then tapered to once or twice weekly. RESULTS: Nine dogs had a history of chronic otitis externa; head tilt or facial paralysis was present in seven and four cases, respectively. Otic examination identified a protruding nodule in seven ears. CT demonstrated soft tissue-like material in 12 bullae and expansion in seven bullae. MRI revealed minimally contrast-enhancing bulla contents in 12 ears. Post-TEP and with maintenance medical treatment, nine ears had no further signs of middle ear disease during a mean follow-up of 27.9 months. CONCLUSIONS AND CLINICAL IMPORTANCE: The results suggest that otitis externa may not necessarily precede cholesteatoma in all dogs. MRI appears to be more sensitive than CT for identifying cholesteatomas. Conservative treatment of cholesteatomas could be useful before or as an alternative to surgery.

Canine non-epitheliotropic CD4-positive cutaneous T-cell lymphoma: a case report.

A 5-year-old, spayed female French Bulldog presented with multiple papules on the skin of the scapular area. Histopathological examination of punch biopsy samples revealed dense infiltration of small lymphoid cells in the superficial dermis and in areas surrounding hair follicles. Immunohistochemical analysis indicated that these cells were positive for CD3, CD4, and TCRαß, but negative for CD1c, CD8α, CD8ß, CD11c, CD20, CD45RA, CD90, MHC-II, and TCRγδ. In addition, CD45 was highly expressed, and the proliferation fraction was very low. Molecular clonality of T-cell receptor G chains yielded a clonal result. The skin lesions were surgically excised because they had progressed to the lateral front leg. Postoperative clinical course was favorable, and recurrence was not observed until the dog died in a traffic accident, approximately 1 year later.

Histopathological and electron microscopic study in dogs with patellar luxation and skin hyperextensibility.

Patellar luxation is abnormal displacement of the patella from the femoral trochlear groove. It is seen primarily in small breed dogs and causes pain and limited mobility of the stifle joint. This study aimed to investigate the relationship among patellar luxation, skin extension, and skin collagen fibril diameter. Nine dogs with patellar luxation and five clinically normal dogs were enrolled in the study. We measured the skin extension and investigated the ultrastructure of the skin and patellofemoral ligament by histopathology and transmission electron microscopy. The mean skin extension in dogs with patellar luxation was 18.5 ± 5.5% which is greater than the reference value (14.5%). Mean skin extension in controls was 8.8 ± 1.7% and was within the normal range. In dogs with patellar luxation, histopathology of the skin and patellofemoral ligament showed sparse and unevenly distributed collagen fibers. Transmission electron microscopy identified poorly organized, irregularly shaped, thin collagen fibrils. Collagen fibril thickness in dogs with patellar luxation was significantly less than fibril thickness in controls (P<0.001). There was a significant negative correlation (ρ= -0.863; P<0.001) between skin collagen fibril diameter and skin extension. Skin extension was correlated with patellar luxation and disease severity. Dogs with patellar luxation, joint dysplasia, and hyperextensible skin appear to be pathologically related. This might represent a phenotype of the Ehlers-Danlos syndrome, a hereditary connective tissue disorder in humans.

Complementary effect of oral administration of Lactobacillus paracasei K71 on canine atopic dermatitis.

BACKGROUND: Atopic dermatitis is a common skin disease encountered in dogs. Glucocorticoids are commonly recommended for symptomatic therapy and well-tolerated adjunctive therapies may help to reduce the necessary dose and associated risks of chronic glucocorticoid use. HYPOTHESIS/OBJECTIVES: The purpose of this study was to evaluate the complementary efficacy of oral administration of Lactobacillus paracasei K71 in canine atopic dermatitis (cAD). ANIMALS: Forty one dogs with mild to moderate cAD were recruited by19 animal hospitals. METHODS: Dogs were assigned to receive either the investigational agent (K71 group; n = 20) or cetirizine hydrochloride (control group; n = 21). Previously prescribed medications were allowed to be continued during the 12 week trial. Dogs were assessed by the investigators using the cAD Extent and Severity Index (CADESI) and a medication scoring system. Pet owners assessed their dogs using a visual analog scale (VAS) and pruritus scores. RESULTS: The CADESI scores, VAS and pruritus scores in both groups at 12 weeks were improved compared with their baselines. The CADESI and pruritus scores in the K71 group were slightly lower than those in the control group and the reduction of medication scores in the K71 group was significantly lower compared with the control group (P < 0.05; Student's t-test). CONCLUSIONS AND CLINICAL IMPORTANCE: Oral administration of K71 can be useful in dogs with cAD as a complementary therapy, by providing a steroid-sparing effect.

Association of cognitive dysfunction with cardiovascular disease events in elderly hypertensive patients.

OBJECTIVES: This study assesses whether presence of cognitive dysfunction can be a marker associated with the development of cardiovascular disease (CVD) events independent of ambulatory blood pressure (BP) or other indices of target organ damage (TOD) in elderly hypertensive patients. METHODS: We recruited 585 hypertensive patients (mean age, 73 years; 41% men) who were ambulatory, lived independently, and were without clinically overt dementia. Cognitive function was assessed by Mini-Mental State Examination (MMSE) at baseline, and CVD events (coronary artery disease, stroke, congestive heart failure, and sudden death) were prospectively ascertained. Cognitive dysfunction was defined as the lowest quartile of MMSE scores (n = 183, median 24 points). RESULTS: CVD events occurred in 42 people over an average of 2.8 years (1644 person-years). The prevalence of cognitive dysfunction was higher in patients with CVD events than those without (57 vs. 29%; both P <0.001) at baseline. Cognitive dysfunction was associated with CVD events, after adjustment for nocturnal SBP and evidence of TOD [i.e. albuminuria, cardiac hypertrophy, and carotid-artery intima-media thickness (IMT)], hazard ratio 2.5-2.9 (all P <0.01). Incorporation of MMSE in the risk model (including age, estimated glomerular filtration rate, and preexisting CVD) improved the C-statistics (from 0.691 to 0.741) and resulted in a net reclassification improvement of 17.6% (P = 0.02). In contrast, incorporation of albuminuria, cardiac hypertrophy, and high carotid-artery IMT added little further improvement in the risk prediction. CONCLUSION: Cognitive dysfunction is an independent marker associated with increased risk of CVD events in elderly hypertensive patients.

In vitro susceptibility of Malassezia pachydermatis isolates from canine skin with atopic dermatitis to ketoconazole and itraconazole in East Asia.

Topical or oral azole antifungals are commonly used in canine atopic dermatitis (AD), as the lipophilic yeast Malassezia pachydermatis exacerbates canine AD. To examine whether canine AD lesions harbor azole-resistant M. pachydermatis isolates in East Asia, we investigated the in vitro susceptibility of M. pachydermatis isolates to ketoconazole (KTZ) and itraconazole (ITZ) obtained from AD lesions of canines in Japan, Korea and Taiwan. The minimum inhibitory concentrations (MICs) of KTZ and ITZ were measured by the E-test using Sabouraud dextrose agar with 0.5% Tween 40. The MICs of KTZ and ITZ for isolates from canines with AD were significantly higher than the MICs for isolates from healthy canines. Our findings suggested that the clinical isolates from canine AD skin lesions were less susceptible to azoles than those from normal canine skin in East Asia.

Transcription profile of chemokine receptors, cytokines and cytotoxic markers in peripheral blood of dogs with epitheliotropic cutaneous lymphoma.

BACKGROUND: Mycosis fungoides (MF) is the most common form of canine epitheliotropic cutaneous lymphoma, which is characterized by the accumulation of neoplastic CD8(+) T cells. Given that multifocal skin lesions are commonly seen in MF, neoplastic lymphocytes may actively migrate into the blood circulation. HYPOTHESIS/OBJECTIVES: Cytotoxic T cells with a skin-homing phenotype could be increased in the blood circulation of dogs with MF. ANIMALS: Ten dogs with MF and 10 age-matched healthy dogs were included. METHODS: The transcription levels of chemokine receptors, cytokines and cytotoxic markers in peripheral blood of dogs with MF were quantified by real-time RT-PCR. RESULTS: The dogs with MF had lower transcription levels of chemokine receptors associated with skin homing (CCR4), epitheliotropism (CXCR3), lymph node homing (CCR7), a type-1 cytokine (LT-α) and cytotoxic markers (perforin and granzyme B) in the circulation than healthy control dogs (P < 0.05). CONCLUSIONS AND CLINICAL IMPORTANCE: The present results suggest that the number of peripheral cytotoxic T cells with a skin-homing phenotype could be decreased in the peripheral blood of dogs with MF, which might be due to the sequestration of cytotoxic T cells in the lesional skin.

Mastitis caused by Mycobacterium kansasii infection in a dog.

A 2-year, 7-month-old female Chihuahua was admitted for a mammary mass measuring one cm in diameter. The dog had a history of demodicosis for 4 months and showed signs of pseudopregnancy at the time of the visit. Cytologic examination of an aspirate of the mass revealed a large number of macrophages containing nonstaining bacterial rods, which were acid-fast in a Ziehl-Neelsen stain, suggesting mycobacterial infection. Histologic examination of the mass revealed a pyogranulomatous mastitis characterized by an infiltration with macrophages containing acid-fast bacteria. Mycobacterium kansasii was subsequently cultured and identified by PCR. Surgical excision of the mass resulted in the growth of other dermal masses, but antimycobacterial treatment with rifampin and clarithromycin resolved these masses within 1 month. Three months after discontinuation of the treatment, similar organisms were found in aspirates of the enlarged bilateral inguinal lymph nodes by cytologic examination. Despite antimycobacterial treatment for another 4 months, there was no improvement and demodicosis also recurred. The dog eventually died of lymphoma 5 months after the relapse of mycobacterial infection. Although M kansasii is considered an important pathogen for pulmonary and cutaneous disease in people, there is only one report in a dog with an infection in a pleural effusion. As both adult-onset demodicosis in dogs as well as mycobacterial infection in people have been associated with T-lymphocyte deficiency, the M kansasii infection in this dog may have been associated with a condition of immune compromise.

Cutaneous viral dermatoses in dogs and cats.

Cutaneous viral dermatoses are often underdiagnosed in dogs and cats because they are rare, and because it is difficult to identify an exact causative agent. Even so, practitioners in primary care may encounter some characteristic clinical features. This article reviews commonly encountered dermatoses, particularly papillomavirus-associated dermatoses in dogs and cats. It also provides a brief overview of several other dermatoses associated with feline herpesvirus, feline calicivirus, FeLV, and feline poxvirus.

Atypical canine mammary adenoma characterized by cystic ducts comprising a single layer of basaloid cells with myoepithelial differentiation.

This report describes an atypical mammary adenoma with a rare histological feature characterized by proliferating single-layered cystic ducts composed of basaloid cells with frequent myoepithelial differentiation. A 9-year-old, intact female Miniature Pinscher dog had mammary tumors on the thorax. Histologically, one of tumors comprised the proliferation of two types of tubular structures; the single-layered cystic ducts lined by flattened cells and double-layered tubules with luminal cells and outer spindle cells. The former ducts were predominant in the tumor and contained pale basophilic mucus, which was Alcian blue (pH 2.5)-positive, but periodic acid Schiff-negative. Immunohistochemical staining indicated that the cells lining single-layered cystic ducts were negative for the luminal epithelial marker, cytokeratin (CK) CAM5.2, but were constantly positive for basal cell markers CK14 and p63 and frequently positive for SMA. Electron microscopy revealed fine, parallel myofilaments within these single-layered neoplastic cells. These histological and immunohistological examinations suggested that the origin of the tumor was bipotential mammary progenitor cells with predominant differentiation into the myoepithelial progenitor linage.

[Malassezia and its presumed association with skin diseases in dogs].

Malassezia pachydermatis is the major species in Malassezia isolated from dogs, and there is a presumably Malassezia-associated skin disease,"Malassezia dermatitis" in the dog. The skin lesion is characterized by relatively demarcated erythema with some scaling at the sebum-rich areas, in which lichenification and hyperpigmentation could be involved in the chronic stage. The clinical features suggest that it corresponds to seborrheic dermatitis in humans. Hence, it might be possible to identify essential pathogenesis of the disease by clarifying its differences in humans and animals as a shared disease.

Genotyping of Malassezia pachydermatis isolates from canine healthy skin and lesional skin of atopic dermatitis in Japan, Korea and Taiwan.

Isolates of the yeast Malassezia pachydermatis obtained from skin samples of healthy dogs and of dogs with atopic dermatitis in Japan, Taiwan and Korea were molecularly characterized using intergenic pacer 1 (IGS1) region analysis. The percentage of IGS1 subtype isolates detected in healthy skin was as follows: 1A (6%), 1B (27%), 1C (11%), 2A (6%), 2B (6%), 3A (11%), 3B (6%), 3C (3%) and 3D (24%). In contrast, the most prevalent isolates detected in skin lesions of atopic dermatitis were subtype 3D in Japan and Taiwan and subtype 3C in Korea. All subtype isolates grew well on acidic medium (pH 6). However, subtype 3C and 3D isolates grew better than the other subtype isolates on medium at pH 8.

In vitro antiseptic susceptibilities for Staphylococcus pseudintermedius isolated from canine superficial pyoderma in Japan.

BACKGROUND: Topical therapy, particularly with chlorhexidine, is becoming increasingly common as a treatment option for canine pyoderma; however, there are limited studies on the susceptibility of Staphylococcus pseudintermedius to chlorhexidine compounds. OBJECTIVES: To determine the in vitro susceptibility of both meticillin-resistant and meticillin-susceptible S. pseudintermedius isolates to chlorhexidine and other antiseptic agents and the presence of multidrug efflux pump genes. SAMPLES: One hundred S. pseudintermedius isolates from 23 initial and 77 recurrent cases of canine pyoderma. METHODS: After bacterial identification and mecA testing, minimal inhibitory concentrations (MICs) of antiseptic agents were determined. Multidrug efflux pump genes, including qacA, qacB and smr, were identified. RESULTS: Of the 100 isolates, 57 were identified as meticillin-resistant S. pseudintermedius. The MIC(90) of chlorhexidine acetate, chlorhexidine gluconate, acriflavine, ethidium bromide and benzalkonium chloride were 1, 1, 2, 0.5 and 2 µg/mL, respectively. Multidrug efflux pump genes qacA, qacB and smr were not detected in any of the isolates. CONCLUSIONS AND CLINICAL IMPORTANCE: The MICs for chlorhexidine and other antiseptics remain low, and multidrug efflux pump genes were not found in the tested isolates.