Time-Kill Analysis of Canine Skin Pathogens: A Comparison of Pradofloxacin and Marbofloxacin.

Time-kill curves (TKCs) are more informative compared with the use of minimum inhibitory concentration (MIC) as they allow the capture of bacterial growth and the development of drug killing rates over time, which allows to compute key pharmacodynamic (PD) parameters. Our study aimed, using a semi-mechanistic mathematical model, to estimate the best pharmacokinetic/pharmacodynamic (PK/PD) indices (ƒAUC/MIC or %ƒT > MIC) for the prediction of clinical efficacy of veterinary FQs in Staphylococcus pseudintermedius, Staphylococcus aureus, and Escherichia coli collected from canine pyoderma cases with a focus on the comparison between marbofloxacin and pradofloxacin. Eight TCKs for each bacterial species (4 susceptible and 4 resistant) were analysed in duplicate. The best PK/PD index was ƒAUC24h/MIC in both staphylococci and E. coli. For staphylococci, values of 25-40 h were necessary to achieve a bactericidal effect, whereas the calculated values (25-35 h) for E. coli were lower than those predicting a positive clinical outcome (100-120 h) in murine models. Pradofloxacin showed a higher potency (lower EC50) in comparison with marbofloxacin. However, no difference in terms of a maximal possible pharmacological killing rate (Emax) was observed. Taking into account in vivo exposure at the recommended dosage regimen (3 and 2 mg/kg for pradofloxacin and marbofloxacin, respectively), the overall killing rates (Kdrug) computed were also similar in most instances.

Investigation of In Vitro Susceptibility and Resistance Mechanisms in Skin Pathogens: Perspectives for Fluoroquinolone Therapy in Canine Pyoderma.

Fluoroquinolones (FQ) are commonly used in dogs with bacterial skin infections. Their use as first choice, along with the increased incidence of FQ-resistance, represents a risk to animal and public health. Our study determined minimum inhibitory (MIC) and bactericidal (MBC) concentrations of five FQs in Staphylococcus aureus, Staphylococcus pseudintermedius, and Escherichia coli, together with FQ-resistance mechanisms. MICs, efflux pump (EP) overexpression and MBCs were measured in 249 skin infection isolates following CLSI guidelines (CLSI VET01-A4, CLSI M26-A). Chromosomal and plasmid-mediated resistance genes were investigated after DNA extraction and sequencing. FQ-resistance was detected in 10% of methicillin-susceptible (MS), 90% of methicillin-resistant (MR) staphylococci and in 36% of E. coli. Bactericidal effect was observed except in 50% of MRSA/P for ciprofloxacin and in 20% of MRSPs for enrofloxacin. Highest MICs were associated with double mutation in gyrA (Ser83Leu + Asp87Asn), efflux pumps and three PMQR genes in E. coli, and grlA (Ser80Phe + Glu84Lys) in S. aureus. EP overexpression was high among E. coli (96%), low in S. aureus (1%) and absent in S. pseudintermedius. Pradofloxacin and moxifloxacin showed low MICs with bactericidal effect. Since in vitro FQ resistance was associated with MR, FQ use should be prudently guided by susceptibility testing.

The nose is not enough: Multi-site sampling is best for MRSP detection in dogs and households.

BACKGROUND: Following recovery from meticillin-resistant Staphylococcus pseudintermedius (MRSP) infection of any type, dogs may continue to carry MRSP asymptomatically on skin and mucosae, contributing to the spread of this multidrug-resistant, veterinary hospital-associated pathogen with zoonotic potential to others and into the environment. OBJECTIVES: This study determined which canine anatomic and household environmental sites are most sensitive for sampling to identify carriage and contamination. METHODS AND MATERIALS: Fifty-one dogs and 22 households, MRSP-positive on at least one tested site, were sampled on 132 and 40 occasions over time, respectively. Dogs were swabbed at six sites (mouth, nose, conjunctiva, skin, prepuce/vulva, perianal area); household environments were sampled using contact plates (mannitol salt agar [MSA] and MSA + 6 mg/L oxacillin [MS+]) on five sites. MRSP was isolated after enrichment, grown on MSA/MS+ and was confirmed by PCR. Generalized estimating equations were used for calculation of sensitivity (95% confidence interval) for each site/combination. RESULTS: Each anatomical and environmental site yielded MRSP at least once. MRSP was isolated from only a single site in 27.3% of dogs, with the buccal mucosa showing the highest sensitivity (63.8%). Multi-site sampling of a minimum of four canine anatomical or four environmental sites, respectively, was needed to achieve >95% sensitivity. CONCLUSIONS AND CLINICAL RELEVANCE: The canine buccal mucosa should be included in MRSP sampling protocols, ideally in addition to at least three other anatomical sites. Likewise, environment sampling should be of multiple household sites in cases where it is used as a part of clinical case management.

Effect of topical antimicrobial therapy and household cleaning on meticillin-resistant Staphylococcus pseudintermedius carriage in dogs.

BACKGROUND: Meticillin-resistant Staphylococcus pseudintermedius (MRSP) is a multidrug-resistant canine pathogen with a low zoonotic potential. This study investigated MRSP carriage and clearance through topical antimicrobial therapy and household cleaning in dogs recovered from MRSP infection. METHODS: Dogs were swabbed for MRSP carriage; household contamination was assessed using contact plates. Carrier dogs were allocated randomly to receive topical fusidic acid and chlorhexidine/miconazole treatment combined with owners implementing a household hygiene protocol (H&T) or implementation of hygiene alone (H) over three weeks. Carriage-negative dogs were monitored monthly. The relatedness of isolates over time was investigated by pulsed-field gel electrophoresis (PFGE). RESULTS: At inclusion, MRSP carriage was confirmed in 31/46 (67.4%) index dogs and 16/24 (66.7%) contact dogs, and contamination was found in 18/40 (45%) environments. In dogs completing all cycles, interventions cleared carriage in 5/9 (55.6%) dogs in group H&T and 2/6 (33.3%) in group H. Environmental contamination was infrequent but associated with carrier dogs (p = 0.047). Monthly monitoring of initially negative dogs showed intermittent carriage in 9/14 dogs. PFGE-concordance was found among all 34 MRSP isolated from eight index dogs over time. CONCLUSION: MRSP carriage was common in dogs after recovery from infection. Topical antimicrobial therapy temporarily eliminated carriage but recurrence was frequent. Management efforts must include the prevention of recurrent infections and hygiene.

Malassezia otitis unresponsive to primary care: outcome in 59 dogs.

BACKGROUND: Otitis externa (OE) is a common disorder in dogs. Infection by the commensal yeast, Malassezia pachydermatis, may result in chronic disease that does not respond to standard primary care. Chronic infectious OE may be associated with otitis media (OM). HYPOTHESIS/OBJECTIVE: To report medical management, clinical outcomes and frequency of middle ear involvement, in dogs with Malassezia otitis unresponsive to primary care. ANIMALS: Fifty-nine dogs from one referral veterinary hospital from January 2007 to September 2018. METHODS AND MATERIALS: Retrospective analysis of medical records of dogs referred with chronic otitis and treated for Malassezia otitis at a referral veterinary hospital. RESULTS: Chronic Malassezia OE was treated successfully in 91% of ears, in 87% of these cases with one ear flush intervention. Median time-to-resolution was 27 days after ear flush intervention. Neither duration of otitis, presence of neutrophils in aural discharge nor administration of oral itraconazole affected clinical outcome. Malassezia OM occurred concurrently in 17% of ears. CONCLUSIONS AND CLINICAL RELEVANCE: These findings assist clinicians and carers of affected dogs in decision-making, by documenting that most cases of canine Malassezia otitis that have not resolved with standard primary care, can be treated successfully with a well-staged and intense medical treatment plan. Malassezia OM should be suspected to occur concurrently in around a fifth of affected ears.

Genes on the Move: In Vitro Transduction of Antimicrobial Resistance Genes between Human and Canine Staphylococcal Pathogens.

Transmission of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) between people and pets, and their co-carriage, are well-described. Potential exchange of antimicrobial resistance (AMR) genes amongst these staphylococci was investigated in vitro through endogenous bacteriophage-mediated transduction. Bacteriophages were UV-induced from seven donor isolates of canine (MRSP) and human (MRSA) origin, containing tet(M), tet(K), fusB or fusC, and lysates filtered. Twenty-seven tetracycline- and fusidic acid- (FA-) susceptible recipients were used in 122 donor-recipient combinations (22 tetracycline, 100 FA) across 415 assays (115 tetracycline, 300 FA). Bacteriophage lysates were incubated with recipients and presumed transductants quantified on antimicrobial-supplemented agar plates. Tetracycline resistance transduction from MRSP and MRSA to methicillin-susceptible S. pseudintermedius (MSSP) was confirmed by PCR in 15/115 assays. No FA-resistance transfer occurred, confirmed by negative fusB/fusC PCR, but colonies resulting from FA assays had high MICs (≥32 mg/L) and showed mutations in fusA, two at a novel position (F88L), nine at H457[Y/N/L]. Horizontal gene transfer of tetracycline-resistance confirms that resistance genes can be shared between coagulase-positive staphylococci from different hosts. Cross-species AMR transmission highlights the importance of good antimicrobial stewardship across humans and veterinary species to support One Health.

Isolation of dermatophytes from dogs and cats in the South of England between 1991 and 2017.

BACKGROUND: Since the epidemiology of canine and feline dermatophytosis might evolve in response to chronological, sociological and ecological factors, the authors studied the occurrence of dermatophyte pathogens over 27 years subsequent to the last major UK survey. METHODS: Dermatophyte culture submission records from dogs and cats to the Royal Veterinary College Diagnostic Laboratory in England between 1991 and 2017 were reviewed. Samples were routinely cultured aerobically at 26°C for up to four weeks on Sabouraud's dextrose agar containing cycloheximide and chloramphenicol; dermatophytes were identified using conventional phenotypic methods. RESULTS: Proportional isolation from cats (15.9 per cent of 1389) exceeded that of dogs (8.1 per cent of 2193) (P<0.001). Together, Microsporum canis and Trichophyton mentagrophytes accounted for 91.9 per cent (n=203) and 80.2 per cent (n=142) of isolations from cats and dogs, respectively. M canis was more frequently (P<0.001) isolated from cats and dogs under two years of age. Dermatophytes were more frequent (P≤0.001) in samples from first-opinion rather than referral practice, and from Jack Russell and Yorkshire terriers and from Persian and chinchilla cats (P≤0.002). CONCLUSIONS: M canis and T mentagrophytes remain the most common agents of canine and feline dermatophytosis in the South of England; continued clinical vigilance is required.

Malassezia Yeasts in Veterinary Dermatology: An Updated Overview.

Lipophilic yeasts of the genus Malassezia are important skin commensals and opportunistic skin pathogens in a variety of animals. The species M. pachydermatis was first isolated from the skin of a captive Indian rhinoceros with an exfoliative dermatitis in 1925, recognized as an important otic pathogen of dogs in the 1950's, and finally accepted, after several years of controversy, as a common cause of canine dermatitis in the 1990's. Since then, there has been considerable research into the biology of Malassezia yeasts and their interaction with their animal hosts. In dogs and cats, M. pachydermatis is associated with ceruminous otitis externa and a "seborrhoeic" dermatitis, wherein pruritic, erythematous skin lesions, often with brown/black greasy, malodourous material matting hairs, preferentially develop in intertriginous areas. Skin disease is favored by folds, underlying hypersensitivity disorders, endocrinopathies, defects of cornification, and in cats, various visceral paraneoplastic syndromes. Diagnosis is based on detecting the yeast in compatible skin lesions, usually by cytology, and observing a clinical and mycological response to therapy. Treatment normally comprises topical or systemic azole therapy, often with miconazole-chlorhexidine shampoos or oral itraconazole or ketoconazole. Management of concurrent diseases is important to minimize relapses. Historically, wild-type Malassezia isolates from dogs and cats were typically susceptible to azoles, with the exception of fluconazole, but emerging azole resistance in field strains has recently been associated with either mutations or quadruplication of the ERG11 gene. These observations have prompted increased interest in alternative topical antifungal drugs, such as chlorhexidine, and various essential oils. Further clinical trials are awaited with interest.

Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology.

BACKGROUND: The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds. OBJECTIVES: The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats. METHODS AND MATERIAL: The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document. CONCLUSIONS AND CLINICAL IMPORTANCE: There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well recognised and diagnostic approaches are well developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected.

Reduced antimicrobial prescribing during autogenous staphylococcal bacterin therapy: a retrospective study in dogs with pyoderma.

Autogenous staphylococcal bacterins are commonly mentioned as treatment for canine recurrent pyoderma but little is known about their efficacy. This retrospective study describes use and assesses efficacy of an autogenous Staphylococcus (pseud)intermedius bacterin in dogs with pyoderma. Frequency and duration of systemic antimicrobial therapy were compared 12 months before and after starting bacterin (Wilcoxon signed-rank test) with data extracted from general practice medical histories.

Opportunities for topical antimicrobial therapy: permeation of canine skin by fusidic acid.

BACKGROUND: Staphylococcal infection of the canine epidermis and hair follicle is amongst the commonest reasons for antimicrobial prescribing in small animal veterinary practice. Topical therapy with fusidic acid (FA) is an attractive alternative to systemic therapy based on low minimum inhibitory concentrations (MICs, commonly <0.03 mg/l) documented in canine pathogenic staphylococci, including strains of MRSA and MRSP (methicillin-resistant Staphylococcus aureus and S. pseudintermedius). However, permeation of canine skin by FA has not been evaluated in detail. This study aimed to define the degree and extent of FA permeation in canine skin in vitro from two sites with different hair follicle density following application of a licensed ophthalmic formulation that shares the same vehicle as an FA-betamethasone combination product approved for dermal application in dogs. Topical FA application was modelled using skin held in Franz-type diffusion cells. Concentrations of FA in surface swabs, receptor fluid, and transverse skin sections of defined anatomical depth were determined using high-performance liquid chromatography and ultraviolet (HPLC-UV) analysis. RESULTS: The majority of FA was recovered by surface swabs after 24 h, as expected (mean ± SEM: 76.0 ± 17.0%). FA was detected within 424/470 (90%) groups of serial sections of transversely cryotomed skin containing follicular infundibula, but never in 48/48 (100%) groups of sections containing only deeper follicular structures, nor in receptor fluid, suggesting that FA does not permeate beyond the infundibulum. The FA concentration (mean ± SEM) in the most superficial 240 µm of skin was 2000 ± 815 µg/g. CONCLUSIONS: Topically applied FA can greatly exceed MICs for canine pathogenic staphylococci at the most common sites of infection. Topical FA therapy should now be evaluated using available formulations in vivo as an alternative to systemic therapy for canine superficial bacterial folliculitis.

Activity In Vitro of Clotrimazole against Canine Methicillin-Resistant and Susceptible Staphylococcus pseudintermedius.

Emergence of multidrug-resistance in Staphylococcus pseudintermedius (SP) has increased interest in topical therapy as an alternative to systemic antibiotics in canine pyoderma. The antifungal imidazole, clotrimazole, is contained in numerous licensed canine ear preparations. Its in vitro activity against SP has not been evaluated, although previous studies have shown that the related imidazole, miconazole, has significant anti-staphylococcal efficacy. We therefore determined minimum inhibitory concentrations (MICs) of clotrimazole amongst 50 SP isolates (25 methicillin-resistant [MR]SP and susceptible [MS]SP) collected from dogs in Germany during 2010-2011 using an agar dilution method (CLSI VET01-A4). MICs amongst MRSP and MSSP were comparable (MIC50 and MIC90 = 1mg/L for both groups, p = 0.317); overall, 49 isolates had MIC = 1 mg/L and one had MIC = 0.5 mg/L. The relatively low MICs obtained in this study are likely to be exceeded by topical therapy and thus further clinical evaluation of clotrimazole use in canine superficial pyoderma and otitis externa caused by MRSP and MSSP is now warranted.

Interaction of chlorhexidine with trisEDTA or miconazole in vitro against canine meticillin-resistant and -susceptible Staphylococcus pseudintermedius isolates from two UK regions.

BACKGROUND: Topical therapy is an important alternative to systemic antibacterial therapy for treatment of canine superficial pyoderma in light of the emergence of multidrug-resistant staphylococci. Chlorhexidine is widely used in shampoo products alone or in combination with miconazole or tromethamine-ethylenediaminetetraacetic acid (trisEDTA). Comparisons of these combinations have not been made. HYPOTHESIS/OBJECTIVES: To determine minimum inhibitory concentrations (MICs) of combinations of chlorhexidine/miconazole and chlorhexidine/trisEDTA in vitro in a collection of Staphylococcus pseudintermedius (SP) from northern (NUK) and southeastern (SEUK) United Kingdom (UK) sources. METHODS: MICs of chlorhexidine, miconazole, trisEDTA and combinations of chlorhexidine/miconazole (1:1) or chlorhexidine/trisEDTA (80:16:1 and 80:5:1) were determined for 196 canine SP isolates from NUK [49 meticillin-resistant (MRSP), 50 meticillin-susceptible (MSSP)] and fom SEUK (48 MRSP, 49 MSSP) using agar dilution. RESULTS: TrisEDTA alone did not inhibit growth. Chlorhexidine/miconazole MICs (median = 0.5 mg/L) were lower than those of either drug alone (P < 0.05) and lower than chlorhexidine/trisEDTA MICs (median = 1 mg/L; P < 0.0005) in each bacterial type and from both regions, except for miconazole in NUK MSSP. An additive interaction was noted between chlorhexidine and miconazole or trisEDTA (80:16:1 ratio) in 79 and 43 isolates, respectively, whereas antagonism between chlorhexidine and trisEDTA was noted for three isolates. NUK isolates were more susceptible than SEUK isolates (P < 0.05), except MRSP exposed to chlorhexidine and the chlorhexidine/trisEDTA (80:16:1) combination. CONCLUSIONS AND CLINICAL IMPORTANCE: These low MICs are likely to be exceeded by topical therapy. Evaluation of the mechanisms by which chlorhexidine combinations interact to reduce MICs is warranted, in view of increasing concerns of biocide tolerance in staphylococci.

Food-specific serum IgE and IgG reactivity in dogs with and without skin disease: lack of correlation between laboratories.

BACKGROUND: Despite conflicting data on their utility and no reports on interlaboratory reproducibility, serum food-specific antibodies are commonly assayed in first-opinion canine practice. HYPOTHESIS/OBJECTIVES: To determine both the variability of test results between two laboratories and the frequencies and magnitudes of food reactivity in dogs of different disease status. ANIMALS: Sera were obtained from eight dogs with cutaneous adverse food reaction (Group A), 22 with nonfood-induced atopic dermatitis (Group B), 30 with an allergic/inflammatory phenotype (Group C), 12 with miscellaneous skin diseases (Group D) and nine healthy dogs (Group E). METHODS: Paired sera were submitted to two laboratories (A and B) for assays of food-specific IgE and IgG antibodies. RESULTS: Numbers of positive IgE and IgG tests determined by each laboratory in Groups A, B, D and E were comparable (Group C not included). Significant differences in the magnitude of IgE reactivity between groups for each allergen were seen only for lamb (Laboratory A, P = 0.003); lamb reactivity in Group D exceeded Group E (P = 0.004) but was comparable between all other groups. Agreement (kappa statistic) between the two laboratories' tests was 'moderate' for one antigen (potato IgE), 'fair' for four (corn IgE, rice IgE and IgG and soya bean IgG), 'slight' for eight (six IgE and two IgG) and 'less than chance' for the remaining six antigens (three IgE and three IgG). CONCLUSIONS AND CLINICAL IMPORTANCE: These laboratories' tests appear to have dubious predictive clinical utility because they neither correlate nor distinguish between dogs of different disease status.

Case-control risk factor study of methicillin-resistant Staphylococcus pseudintermedius (MRSP) infection in dogs and cats in Germany.

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) has emerged as a highly drug-resistant small animal veterinary pathogen. Although often isolated from outpatients in veterinary clinics, there is concern that MRSP follows a veterinary-hospital-associated epidemiology. This study's objective was to identify risk factors for MRSP infections in dogs and cats in Germany. Clinical isolates of MRSP cases (n=150) and methicillin-susceptible S. pseudintermedius (MSSP) controls (n=133) and their corresponding host signalment and medical data covering the six months prior to staphylococcal isolation were analysed by multivariable logistic regression. The identity of all MRSP isolates was confirmed through demonstration of S. intermedius-group specific nuc and mecA. In the final model, cats (compared to dogs, OR 18.5, 95% CI 1.8-188.0, P=0.01), animals that had been hospitalised (OR 104.4, 95% CI 21.3-511.6, P<0.001), or visited veterinary clinics more frequently (>10 visits OR 7.3, 95% CI 1.0-52.6, P=0.049) and those that had received topical ear medication (OR 5.1, 95% CI 1.8-14.9, P=0.003) or glucocorticoids (OR 22.5, 95% CI 7.0-72.6, P<0.001) were at higher risk of MRSP infection, whereas S. pseudintermedius isolates from ears were more likely to belong to the MSSP-group (OR 0.09, 95% CI 0.03-0.34, P<0.001). These results indicate an association of MRSP infection with veterinary clinic/hospital settings and possibly with chronic skin disease. There was an unexpected lack of association between MRSP and antimicrobial therapy; this requires further investigation but may indicate that MRSP is well adapted to canine skin with little need for selective pressure.

A review of topical therapy for skin infections with bacteria and yeast.

BACKGROUND: Cutaneous infections with bacteria and yeasts are common in small animal practice. Treatment with systemic antibiotics or antifungal agents may not be ideal, because of the increasing development of multiresistant organisms, the cost and the possible adverse effects. Topical antimicrobials may be used as adjunctive therapy to systemic treatment or as sole therapy instead of systemic treatment. OBJECTIVE: This literature review evaluated studies on topical antimicrobial treatment of skin infections. METHODS: In vitro and in vivo studies evaluating topical antimicrobial agents were identified using a number of electronic and manual searches of textbooks and articles. Studies were evaluated, and the evidence for or against the use of the topical agents was extracted. RESULTS: There is good evidence for the efficacy of chlorhexidine and, to a lesser degree, benzoyl peroxide in canine bacterial skin infections. There is limited evidence for the efficacy of silver sulfadiazine and medical honey against bacterial skin infections in the dog, and for the efficacy of hydrogen peroxide and stannous fluoride in the horse. Good evidence supports the use of a combination of chlorhexidine and miconazole in dogs with cutaneous Malassezia infections. There is insufficient evidence to recommend any other topical therapy for use in cutaneous infections. CONCLUSIONS AND CLINICAL IMPORTANCE: Although many antimicrobial topicals are marketed in veterinary dermatology, the efficacy has been reported for only a minority of agents. Randomized controlled trials evaluating various topical treatments are therefore urgently needed.

Molecular characterization of Malassezia nana isolates from cats.

Malassezia nana (M. nana) is a lipid-dependent yeast that has been isolated from cats and cows. Some sequence variability has been observed in the large subunit (LSU) and internal transcribed spacer (ITS) regions between strains isolated from cats and cows though these regions in M. nana isolates from cats alone have proven to be relatively conserved. In the present study, microsatellite PCR fingerprinting and ß-tubulin gene sequence analysis were carried out on M. nana isolates from cats to investigate the genetic diversity of this species. Although a relatively small number of isolates were available, the similarity in the sequences of the ß-tubulin and the microsatellite profiles indicate that a particular M. nana genotype colonizes cats. Moreover, all isolates obtained from animals with otitis externa had the same microsatellite fingerprinting pattern. Further studies of a wider population of M. nana isolates from other hosts and status disease are needed to establish that M. nana is a genetically homogeneous species. This is the first report of the characterization of the ß-tubulin gene in Malassezia spp.

Malassezia pachydermatis and M nana predominate amongst the cutaneous mycobiota of Sphynx cats.

Carriage of Malassezia species yeasts in healthy Sphynx cats was compared with that in Devon Rex cats (DRC), Cornish Rex cats (CRC) and domestic shorthair (DSH) cats. Swab samples from the external ear, anus and claw folds, and contact plate samples from the axillae and groins, were incubated on modified Dixon's agar at 32°C for 7 days. Malassezia species were isolated from all 18 Sphynx cats; M pachydermatis accounted for 118/140 isolates. Of 20 isolates of M nana, 16 were recovered from the ear canal. M slooffiae was isolated from the claw fold of one cat and the left groin of another. The high counts of M pachydermatis obtained from the axillae, groins and claw folds of the Sphynx cats exceeded those of healthy DSH, CRC and DRC; axillary populations were comparable to those of seborrhoeic DRC. These data support recent reports of high Malassezia species colonisation in Sphynx cats.