Skin Lesions In Dogs Research Articles

Safety of ilunocitinib tablets (Zenrelia™) after once daily oral administration in dogs

BackgroundIlunocitinib is a new molecular entity of the Janus kinase inhibitor (JAKi) class for the treatment and control of symptoms of allergic skin disease conditions, such as pruritus and skin lesions in dogs. This laboratory study with ilunocitinib tablets (Zenrelia™, Elanco) investigated the safety in healthy dogs treated once daily for 6 months. The study was a randomized, blinded, parallel-group design examining one (1X), two (2X), three (3X) and five (5X) times the maximum recommended dose (0.8 mg/kg) compared to sham dosed control dogs.MethodsTwenty male and 20 female healthy Beagle dogs, 11 to 12-month of age, with a mean body weight ranging from 9.85 to 10.46 kg, were randomized to an untreated control group or ilunocitinib treatment groups at daily dose rates of 0.8 mg/kg (1X), 1.6 mg/kg (2X), 2.4 mg/kg (3X), or 4.0 mg/kg (5X) over six months. All animals were fed within 30 min prior to treatment. Safety assessments included general health observations, clinical observations (including complete physical and neurological examinations), ophthalmology, clinical pathology, peripheral blood immunophenotyping, body weight, food consumption, pharmacokinetic blood collections, organ macroscopic and microscopic examinations.ResultsNo effects of the treatment were noted on body weight, food consumption, physical and neurological examinations, urinalysis, peripheral blood immunophenotype, and ophthalmoscopic examinations. Clinical findings included non-exudative skin lesions, skin lesions with discharge, swollen paw(s), skin thickening, skin discoloration or scabbing of the feet (paws/digits), in both male and female dogs. Changes in clinical pathology included marginally decreased red cell mass, lower eosinophils, higher C-reactive protein, total protein and fibrinogen, lower albumin and albumin: globulin levels. Microscopic findings included skin inflammation and focal dermatitis/furunculosis.ConclusionsIlunocitinib was well tolerated when administered daily over six months at 0.8 mg/kg and multiples thereof up to 4.0 mg/kg in Beagle dogs. At the therapeutic dose, no clinically significant changes were observed. Minimal changes in hematological parameters, total protein, and fibrinogen were noted at the higher doses. All of these findings, consistent with the known pharmacology of the JAKi class at exaggerated dosing, support the safe and chronic use of Zenrelia™ tablets.Clinical trial numberNot applicable.

Comparative efficacy and safety of ilunocitinib and oclacitinib for the control of pruritus and associated skin lesions in dogs with atopic dermatitis.

Janus kinase inhibitors (JAKi) have been shown to reduce pruritus and improve associated inflammatory skin lesions in canine atopic dermatitis (cAD). To evaluate the efficacy and safety of ilunocitinib, in comparison to oclacitinib, for the control of cAD in a randomised, blinded trial. Three-hundred-and-thirty-eight dogs with cAD. Dogs were randomised to receive oclacitinib (0.4-0.6 mg/kg twice daily for 14 days; then once daily) or ilunocitinib (0.6-0.8 mg/kg once daily), for up to 112 days. Owners assessed pruritus using an enhanced Visual Analog Scale (PVAS). Investigators assessed skin lesions using the Canine Atopic Dermatitis Extent and Severity Index, 4th interaction (CADESI-04). Reduction in pruritus and CADESI-04 scores was similar for both treatment groups from Day (D)0-D14. PVAS scores increased between D14 and D28 for oclacitinib and decreased for ilunocitinib. On D28 to D112, mean PVAS and CADESI-04 scores were significantly lower for ilunocitinib compared to oclacitinib (p ≤ 0.003 and p ≤ 0.023, respectively). On D28 to D112, a greater number of ilunocitinib-treated dogs achieved clinical remission of pruritus (i.e. PVAS score <2). Subjective assessment of overall response was significantly better for ilunocitinib on D28 to D112 (p ≤ 0.002). Both drugs demonstrated similar safety throughout the study. Ilunocitinib rapidly and safely controlled signs of cAD. Ilunocitinib demonstrated significantly better control of pruritus and skin lesions compared to oclacitinib, with more dogs achieving clinical remission of pruritus.

Prospective evaluation of hospital-acquired skin lesions in dogs: A case-control study.

Hospital-related dermatological conditions are well-studied and reported in human medicine. However, studies about these dermatological disorders in veterinary medicine are lacking. To report the incidence, type and distribution of hospital-acquired skin lesions (HASL) in dogs, and to investigate risk factors that may be associated with their development. Hospitalised client-owned dogs with HASL and a control group of hospitalised dogs without skin lesions. Prospective clinical evaluation of all HASL and dermatological tests, when indicated, were performed, over 6 months. A variety of potentially predisposing factors also were recorded. Thirty-one dogs with HASL and a matched control group of 60 hospitalised dogs without skin lesions were included. The incidence of HASL was 11.2% (31 of 278). The most common lesion was erythema in 74.2% of dogs (23 of 31) and the most affected area was the abdomen in 58.1% (18 of 31) of dogs. Faecal and/or urinary incontinence was identified as an important risk factor for the development of skin lesions during hospitalisation (odds ratio 14.445, 95% confidence interval 1.444-144.479, p = 0.023). Immobilisation and changes in body temperature also may play a role in the development of such lesions in dogs. Faecal and/or urinary incontinence was found to be an important factor in the development of HASL. The impact of HASL on patient outcomes and the prevention of these lesions requires further investigation.

KRT5 in-frame deletion in a family of German Shepherd dogs with split paw pad disease resembling localized epidermolysis bullosa simplex in human patients.

Split paw pad disease is a scarcely defined phenotype characterized by skin lesions on the paw pads of dogs. We studied a family of German Shepherd dogs, in which four dogs developed intermittent paw pad lesions and lameness. The paw pads of two of the affected dogs were biopsied and demonstrated cleft formation in the stratum spinosum and stratum corneum, the outermost layers of the epidermis. Whole genome sequencing data from an affected dog revealed a private heterozygous 18 bp in frame deletion in the KRT5 gene. The deletion NM_001346035.1:c.988_1005del or NP_001332964.1:p.(Asn330_Asp335del) is predicted to lead to a loss of six amino acids in the L12 linker domain of the encoded keratin 5. KRT5 variants in human patients lead to various subtypes of epidermolysis bullosa simplex (EBS). Localized EBS is the mildest of the KRT5-related human diseases and may be caused by variants affecting the L12 linker domain of keratin 5. We therefore think that the detected KRT5 deletion in dogs represents a candidate causal variant for the observed skin lesions in dogs. However, while the clinical phenotype of KRT5-mutant dogs of this study closely resembles human patients with localized EBS, there are differences in the histopathology. EBS is defined by cleft formation within the basal layer of the epidermis while the cleft formation in the dogs described herein occurred in the outermost layers, a hallmark of split paw pad disease. Our study provides a basis for further studies into the exact relation of split paw pad disease and EBS.

Erythritol alters phosphotransferase gene expression and inhibits the in vitro growth of Staphylococcus coagulans isolated from canines with pyoderma.

Staphylococcus coagulans (SC) belongs to a group of coagulase-positive staphylococci occasionally isolated from the skin lesions of dogs with pyoderma. We recently revealed that erythritol, a sugar alcohol, inhibited the growth of SC strain JCM7470. This study investigated the molecular mechanisms involved in this growth inhibition of JCM7470 by erythritol, and determine whether erythritol inhibits the growth of SC isolated from the skin of dogs with pyoderma. Comprehensive analysis of the gene expression of JCM7470 in the presence of erythritol revealed that erythritol upregulated the expression of glcB and ptsG genes, both of which encode phosphotransferase system (PTS) glucoside- and glucose-specific permease C, B, and A domains (EIICBA), respectively, associated with sugar uptake. Moreover, erythritol suppressed in vitro growth of all 27 SC strains isolated from the skin lesions of canine pyoderma, including 13 mecA gene-positive and 14 mecA gene-negative strains. Finally, the growth inhibition of the SC clinical isolates by erythritol was restored by the addition of glucose. In summary, we revealed that erythritol promotes PTS gene expression and suppresses the in vitro growth of SC clinical isolates from dogs with pyoderma. Restoration of the erythritol-induced growth inhibition by glucose suggested that glucose starvation may contribute to the growth inhibition of SC.

Reading man flap in four dogs: a case series

BackgroundThe reading man flap is a novel technique in human medicine for the closure of cutaneous circular defects. To the best of our knowledge, no recent clinical studies have described this procedure in small animals.Case presentationIn this case series, we present four dogs in which neoplasms were reconstructed using the reading man procedure, which is a double-advancement transposition subdermal flap. The reading man flap was applied in wound revision after surgical removal of a neoplasm in two dogs and in the closure following the excision of a neoplasm in another two dogs. Successful tension-free closure of the lesion site was achieved in all four patients. The postoperative period was uneventful in all patients, and there was no flap necrosis or surgical site infection, although surgical site infection preceded in two cases. Minor complications included partial suture dehiscence in one dog and seroma formation in two dogs. Only one dog required a second anesthesia to insert an active drainage system. The follow-up examination of all four dogs revealed no further complications with the reading man flap at time of the latest wound reevaluation conducted by the surgeon.ConclusionThe reading man flap is a well-vascularized fasciocutaneous flap that provides tension-free closure owing to its asymmetrical Z-plasty. It is a simple-to-use option for the closure of circular skin lesions in dogs.

De novo transcriptome sequencing and functional annotation of Demodex canis.

Demodex canis is an important parasitic mite causing skin lesions in dogs. However, molecular studies on this species are limited because of the lack of transcriptomic data. To obtain functional genes of D. canis, mites were collected and RNA was extracted for transcriptome sequencing and functional annotation. Coding sequences (CDSs) of important functional genes were screened and identified using bioinformatics strategies. Six complete CDSs were amplified by specific primers, cloned and sequenced. Results demonstrated that the quantity of the RNA extracted from 100 mites was 12.8ng and the RNA integrity number was 5.4, indicating that it could be used to construct a cDNA library. Transcriptome sequencing yielded 263,619 unigenes, of which 151,048 (57.3%) were functionally annotated. Using bioinformatics strategies, 58 total CDSs were identified as homologous to those of closely related mite species, including 16 types of allergen genes, 13 types of protease genes, and nine types of motion-related genes. The verified CDSs were almost identical to the CDSs of unigenes. Phylogenetic analyses of tropomyosin further revealed that the verified CDSs clustered successively with those of Demodex species and Tetranychus species in Raphignathae, which agreed with the morphological classification, demonstrating the reliability of the transcriptomic data. In conclusion, this study is the first to successfully sequence transcriptome of D. canis, perform functional annotation, and verify CDSs, which will provide ample data for further studies on the functional genes and molecular pathogenic mechanism of D. canis.

Pseudomonas aeruginosa isolation from dog grooming products used by private owners or by professional pet grooming salons: prevalence and risk factors.

Background Pseudomonas aeruginosa is the most commonly isolated bacterium from skin lesions of dogs with post‐grooming furunculosis (PGF). It is frequently found in human hair and skin care products, and may pose a health risk to consumers. Information regarding the prevalence of P. aeruginosa contamination of dog grooming products is lacking.ObjectivesTo investigate the prevalence of P. aeruginosa contamination in nonmedicated dog grooming products after either home or professional use in pet grooming salons, and to identify risk factors that may be associated with contamination.Materials and methodsOf 117 bottles of grooming products sampled for bacterial culture, 97 were used by pet grooming salons and 20 were used by private individuals. The following suspected risk factors were recorded: bottle size, relative remaining volume, content dilution, expiration date and ingredient list.Results Pseudomonas aeruginosa was isolated from 14 of 117 samples [11.97%, 95% confidence interval (CI) 6.97–19.3%]. Diluted products were contaminated significantly more often compared to undiluted products (odds ratio = 15.5, 95%CI 2.05–117.23; P < 0.01). None of the other variables was significantly associated with P. aeruginosa contamination.Conclusions and clinical relevance Pseudomonas aeruginosa contamination of dog grooming shampoos and conditioners was significantly associated with product dilution. Contaminated grooming products may predispose dogs to severe bacterial skin infections such as PGF.

Efficacy and safety of lokivetmab (Cytopoint®) for the control of pruritus and skin lesions in dogs with atopic dermatitis

Background and objective: Lokivetmab is the first anti-canine interleukin-31 monoclonal antibody approved in the European Union for Canine Atopic Dermatitis (CAD) management. This study aimed to assess the lokivetmab’s efficacy and safety in treating CAD cases from a university reference service, as well as the dog’s owner’s overall opinion regarding therapy. Methods: Eighteen atopic dogs were enrolled to perform two subcutaneous injections of lokivetmab, according to the protocol. In order to determine the efficacy and safety of the treatment, skin lesions, pruritus score, blood count, liver parameters and adverse side effects were evaluated over 56 days. The overall pet owner’s satisfaction about the therapy was assessed at the end of the study, and the number of animals that maintained the treatment three months after the end of the study was considered. Results: There was a significant reduction in pruritus score over the eight weeks, with 76.5% of the dogs showing a significant clinical improvement. Regarding the lesion score, 77.8% of the dogs achieved significant clinical improvement, with 61.1% reaching it in the first 4 weeks. There were no reported adverse side effects or changes in blood tests. Pet owner’s opinion regarding the improvement of both the dog and its family’s quality of life was very positive, and three months after the end of the study, 77.8% of the dogs continued their therapy with lokivetmab. Conclusion: Lokivetmab proved to be extremely effective and safe, in addition to sparing pet owners from at home drug administrations, which also contributes to their high satisfaction degree. The great specificity of this biological therapy makes it one of the most potent and promising in the CAD field.

Canine dermatophytosis caused by Trichophyton rubrum - Case report

Trichophyton rubrum is rarely isolated from dogs with dermatophytosis. It is an anthropophilic dermatophyte commonly causing infections in humans. A 4-year-old female Shih Tzu dog was brought to the veterinary clinic with a history of circular, crusted and non-pruritic alopecia lesions located on the head. Routine blood tests, skin scrapes and bacteriological culture revealed no abnormalities. However, Trichophyton rubrum was isolated from the fungus culture. The intradomicilar condition of the dog allows contact with its frequent hosts, the man. The fungicidal treatment was implemented with shampoo (ketoconazole base 2% + chlorhexidine 2%) and oral Itraconazole at a dose of 10 mg / kg once a day, for 28 days. The lesions healed completely and the hair grew back within a month. No recurrence occurred during the 4-month follow-up. T. rubrum should be included in the differential diagnosis of crusted skin lesions in dogs.

The Detection and Association of Canine Papillomavirus with Benign and Malignant Skin Lesions in Dogs.

Papillomavirus (PV) mainly infects the squamous epithelium and may potentially lead to benign or even malignant cutaneous lesions. However, the malignant transforming ability has been identified in several types of PVs. In humans, papillomavirus (HPV) type 16 and 18 are the most prevalent causative agents of cervical cancer. Therefore, vaccines are being developed to protect against these types. For dogs, there have been limited investigations into the association of different canine papillomavirus (CPV) genotypes with malignant lesions. Understanding the high-risk CPV genotype(s) responsible for these malignant lesions would contribute to the development of interventions for preventing CPV-induced carcinomas. In the present study, a retrospective cohort of 102 pathologically confirmed papillomas and 212 squamous cell carcinomas (SCCs) were included. The viral genome and antigens in the formalin-fixed paraffin-embedded (FFPE) tissues were detected using PCR targeting pan PV E1 and COPV L1 genes and by immunohistochemistry staining (IHC), respectively. PVs were successfully detected from 11 FFPE cutaneous tissues and four oral tissues using pan PV E1- and COPV L1-based PCR, respectively. After sequencing, CPV 1, CPV 2, and CPV 6 were detected in the benign lesions using PCR and were confirmed through IHC. While CPV 9 and CPV 15 were first detected in the SCCs of dogs, CPV 16 was most often detected in SCC specimens. The association and confirmative demonstration of viral genes and intralesional antigens of CPV 9, CPV 15, and CPV 16 in SCCs highlight the potential risk of these genotypes of CPVs in malignant transformation.

Development and validation of a graphic 2D investigator's global assessment instrument for grading the overall severity of atopic dermatitis in dogs.

Clinical trials enrolling dogs with atopic dermatitis (AD) use validated instruments that aggregate the extent and severity of selected skin lesions; none of these provides a global assessment of the severity of all lesions. To validate an Investigator Global Assessment (IGA) instrument to globally evaluate the severity of skin lesions in dogs with AD. Forty dogs with AD. A 2D graphic IGA (2D-IGA) instrument was created to subjectively score, with a single dot, the overall extent and severity of all canine AD lesions. This tool was tested for its validity (content, construct and criterion), reliability (inter- and intraobserver) and sensitivity to change. The content of the 2D-IGA was first validated by a supportive vote by the International Committee of Allergic Diseases of Animals (ICADA) membership. Its construct was verified by positive correlations between the 2D-IGA scores and those of the Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04) and the Canine Atopic Dermatitis Lesion Index (CADLI) (Spearman's rank-order correlation, P<0.0001). The positive correlation (P<0.0001) between an Owner Global Assessment of Disease Severity (OGADS) and the 2D-IGA indirectly satisfied its criterion. Scores graded by the same investigator hours apart and those between investigators were positively correlated (P<0.0001), thereby validating this scale's intra- and interobserver reliabilities. Finally, the changes in 2D-IGA values during treatment were correlated positively with scores of an Owner Global Assessment of Treatment Efficacy (OGATE; P<0.0001), thus showing its sensitivity to change. This novel 2D-IGA is a simple static graphic instrument that could be useful for clinical trials testing the efficacy of interventions for canine AD.

Proactive maintenance therapy of canine atopic dermatitis with the anti-IL-31 lokivetmab. Can a monoclonal antibody blocking a single cytokine prevent allergy flares?

Once the signs of canine atopic dermatitis (AD) are controlled, the proactive application of topical glucocorticoids can delay disease flares. We wished to determine if the proactive administration of the anti-IL-31 lokivetmab would prevent or delay flares of canine AD. We tested this strategy in four Maltese-beagle atopic dogs before enrolling 21 dogs with spontaneous AD. In our acute AD model, house dust mite (HDM)-sensitized dogs were injected once with lokivetmab. After seven days, an HDM suspension was applied epicutaneously, and both skin lesions and pruritus manifestations were quantified for 24h. In a second study, 21 dogs with spontaneous AD controlled with anti-allergic drugs were treated with lokivetmab per manufacturer's recommendations; all anti-allergic drugs were discontinued within four weeks after the first injection. All dogs were followed prospectively for at least one year and the time-to-flare (TTF) of AD after the last day of anti-allergic treatment was determined. In the experimental study, one injection of lokivetmab prevented nearly all expected allergen-induced pruritus manifestations but not skin lesion development. In dogs with spontaneous AD, the median TTF after lokivetmab proactive therapy was 63days. One-fourth of dogs did not exhibit a flare for at least one year while receiving lokivetmab monotherapy. Although lokivetmab seems more effective to prevent pruritus than skin lesions in dogs with experimental AD' it also can delay disease flares in some dogs with the spontaneous disease. Studies are needed to identify those patients most likely to respond to such a proactive regimen.

Diversity of Staphylococcus pseudintermedius in carriage sites and skin lesions of dogs with superficial bacterial folliculitis: potential implications for diagnostic testing and therapy.

Staphylococcus pseudintermedius is genotypically diverse within the canine population and multiple strains may colonize individual dogs at any given time. If multiple strains with distinct antimicrobial resistance profiles are present in superficial bacterial folliculitis (SBF), sampling a single skin lesion for culture and antimicrobial susceptibility testing (AST) might be inadequate to select effective therapy. To investigate S. pseudintermedius diversity in carriage sites and lesions of dogs with SBF. Fourteen dogs with SBF. Staphylococcus pseudintermedius isolates obtained from perineum, gingiva and four to six skin lesions per dog were subjected to pulsed-field gel electrophoresis (PFGE) and AST to assess diversity between lesions. For two dogs, 14-16 isolates per lesion were included in the analysis to assess diversity within lesions. Analysis of one isolate per lesion revealed one to four strains displaying unique PFGE profiles, and up to three unique antimicrobial resistance (AMR) profiles for each dog. Multiple pustules from the same dog always harboured the same strain, whereas papules, crusts and collarettes did not. Up to four strains with distinct AMR profiles were isolated from the same lesion in two dogs. In 12 dogs, at least one carriage site strain also was represented in lesions. Lesions of SBF may harbour multiple S. pseudintermedius strains with distinct antimicrobial resistance profiles. Pustules are the best target for bacterial culture. It remains unclear whether isolation of different strains from other lesion types is a consequence of contamination or co-infection by multiple strains.

Ultramicronized palmitoylethanolamide counteracts the effects of compound 48/80 in a canine skin organ culture model.

Ultramicronized palmitoylethanolamide (PEA-um) has been reported to reduce pruritus and skin lesions in dogs with moderate atopic dermatitis and pruritus. A canine ex vivo skin model was used to investigate the ability of PEA-um to counteract changes induced by compound 48/80, a well-known secretagogue that causes mast cell degranulation. Normal skin was obtained from three donor dogs subjected to surgery for reasons unrelated to the study. Cultured skin biopsy samples in triplicate were treated with 10 and 100 μg/mL compound 48/80, without or with 30 μM PEA-um. Mast cell (MC) degranulation, histamine release into the culture medium, local microvascular dilatation, epidermal thickness, keratinocyte proliferation and epidermal differentiation markers were evaluated. Exposure of the skin organ culture to PEA-um 24 h before and 72 h concomitantly to compound 48/80 resulted in a significant decrease of degranulating MCs. PEA-um also reduced the histamine content in the culture medium by half, although the effect did not reach statistical significance. PEA-um significantly counteracted vasodilation induced by 100 μg/mL compound 48/80. Finally, PEA-um alone did not induce changes in epidermal thickness, differentiation markers, keratinocyte proliferation, MC density and/or degranulation. Collectively, these results support the protective action PEA-um on the skin of dogs undergoing allergic changes.

Cytologic features of cutaneous follicular tumors and cysts in dogs

Follicular tumors and cysts are common skin lesions in dogs. Both are distinguished based on their cellular origin (matrical, isthmus, or infundibular cells) and the type of keratin they produce. Typically, differentiation requires histopathology, as all these lesions often have similar cytologic features. The goal of this retrospective study was to identify unique cytologic features that may assist differentiation of canine benign follicular tumors and cysts at cytology, using histopathology as gold standard. Electronic medical records of the University of California-Davis Veterinary Medical Teaching Hospital were searched for diagnoses of follicular tumors and cysts in dogs that had both histopathologic and cytologic diagnoses between January 2000 and December 2013. Cytologic specimens were reassessed in a blinded manner for the presence and type of background, cells, noncellular elements, and inflammation. Forty-six samples were included in the study. Follicular cysts (n = 25) and infundibular keratinizing acanthomas (n = 5) contained sheets of keratinized anucleate to nucleated squamous cells. Trichoepitheliomas (n = 8) had 2 primary cytologic presentations: those with primarily basaloid cells that appeared to be undergoing keratinization (3/8; 38%) and those with keratinizing anucleate to nucleated squamous cells (5/8; 63%). Trichoblastomas (n = 8) had pink matrix with spindle cells and contained cohesive clusters of basaloid cells. Trichoblastomas, and to a lesser extent, trichoepitheliomas, have unique cytologic features with the potential to distinguish them from other benign follicular tumors and cysts. These results are an important first step toward improving the diagnostic specificity of cytologic examination of cutaneous follicular lesions.

Apoptosis as a Mechanism for Keratinocyte Death in Canine Toxic Epidermal Necrolysis.

In humans and dogs, toxic epidermal necrolysis (TEN) is a life-threatening dermatosis characterized by sudden epidermal death resulting in extensive skin detachment. There is little information on the pathogenesis of keratinocyte cell death in canine TEN. We studied the occurrence of apoptosis in skin lesions of dogs with TEN to determine if apoptosis contributes to the pathogenesis of this disease. Immunostaining with antibodies to activated caspase-3 and the terminal deoxynucleotidyl-transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling technique revealed positive apoptotic keratinocytes in basal and suprabasal epidermal compartments in 17 biopsy specimens collected from 3 dogs with TEN and 16 from 3 dogs with erythema multiforme (EM). There was no significant difference in the number of positively stained epidermal cells between TEN and EM. These results suggest that apoptosis of epidermal keratinocytes and lymphocytic satellitosis represent one of the early steps in the pathogenesis of canine TEN, as in the human disease counterpart.

Biofilm production and antifungal susceptibility of co-cultured Malassezia pachydermatis and Candida parapsilosis isolated from canine seborrheic dermatitis.

The yeasts Malassezia (M.) pachydermatis and Candida (C.) parapsilosis are often co-isolated in case of canine seborrhea dermatitis (SD) and also are emerging as opportunistic pathogens of immunocompromised human beings. Increased information about how their relationship results in biofilm production and an antifungal response would be useful to inform treatment and control. This study was designed to investigate biofilm production derived from co-culture of M. pachydermatis and C. parapsilosis from dog skin and to determine their in vitro antifungal susceptibility. We demonstrated that regardless of yeast strain or origin all single and dual cultures produced biofilms within 24 hours, and the greatest amount was present after 72 hours. Biofilm production from mixed cultures was greater than for single strains (P < .05). All sessile forms of the single and dual cultures were resistant to the tested antifungals itraconazole and ketoconazole, whereas planktonic forms were susceptible. The study suggests that dual cultures produce stronger biofilms that are likely to enhance persistence in skin lesions in dogs and result in greater resistance to antifungal treatment.

Identification by real‐time PCR with SYBR Green of Leishmania spp. and Serratia marcescens in canine ‘sterile’ cutaneous nodular lesions

Noninfectious, non-neoplastic, nodular to diffuse, so-called 'sterile' granulomatous/pyogranulomatous skin lesions (SGPSLs) are infrequently identified in dogs and may represent a diagnostic challenge. Their correct identification is based on history, histopathology and absence of intralesional foreign bodies and micro-organisms. The aim of this study was to investigate the presence of Leishmania spp., Mycobacterium spp., Serratia marcescens and Nocardia spp. by real-time PCR in canine nodular skin lesions histologically diagnosed as putatively sterile. Formalin-fixed skin biopsies were collected from 40 dogs. All samples were associated with an SGPSL diagnosis characterized by multifocal, nodular to diffuse, periadnexal and perifollicular pyogranulomas/granulomas. Neither micro-organisms nor foreign bodies were detected with haematoxylin and eosin staining, under polarized light. Further analyses included periodic acid Schiff, Ziehl-Neelsen, Fite Faraco, Giemsa and Gram histochemical stains; anti-Bacillus Calmette-Guérin (BCG) and Leishmania spp. immunohistochemistry; and real-time PCR analysis for Leishmania spp., Mycobacterium spp., S.marcescens and Nocardia spp. Special stains and BCG/immunohistochemistry were negative in all samples. Real-time PCR was positive for Leishmania spp. in four of 40 biopsies and for S.marcescens in two of 40 samples. Real-time PCR for Mycobacterium spp. and Nocardia spp. was negative. No correlation between real-time PCR positivity and a specific histological pattern was identified. Leishmania spp. have been previously identified as possible agents of certain SGPSLs, while the involvement of S.marcescens has not been investigated previously. According to our findings, Serratia spp. should be included in the list of agents possibly associated with a subgroup of granulomatous/pyogranulomatous skin lesions in dogs.

Expression patterns of superficial epidermal adhesion molecules in an experimental dog model of acute atopic dermatitis skin lesions.

The stratum corneum is critical for providing a functional skin barrier, especially in humans and dogs with atopic dermatitis. An effective barrier also depends upon intact corneodesmosomes and superficial epidermal tight junctions. To study the expression of selected corneodesmosome, desmosome, tight and adherens junction proteins in an experimental model of acute atopic dermatitis skin lesions in dogs. Control and house dust mite (HDM) allergen-containing patches (two types of patches) were applied to the skin of six Maltese-beagle atopic dogs hypersensitive to HDM. Patches were left on for 48h, and biopsies were collected 24h after removal. Frozen skin sections were stained by indirect immunofluorescence for corneodesmosin, desmoglein-1, desmocollin-1, claudin-1 and E-cadherin. Immunostains were assessed for their extent, intensity and patterns; they were compared between HDM and control patches on the same dogs. The immunostaining for E-cadherin, desmocollin-1 and desmoglein-1 was homogeneous, intercellular and continuous in all control and HDM patches. The immunoreactivity of corneodesmosin and claudin-1 was heterogeneous and reduced in intensity in 12 of 12 and eight of 12 HDM patches, respectively, in contrast to a normal expression seen in all control samples (Fisher's test, P<0.001). These observations suggest that HDM allergens, via proteolytic digestion and/or because of induced allergic inflammation, affect the expression and possible function of corneodesmosomal and tight junction proteins. Ensuing intercellular junction alterations might promote an abnormally increased penetration of allergens through the epidermis.