Topical erythritol combined with L-ascorbyl-2-phosphate inhibits staphylococcal growth and alleviates staphylococcal overgrowth in skin lesions of canine superficial pyoderma.

Erythritol (ERT) and L-ascorbyl-2-phosphate (APS) are bacteriostatic, but their effects on staphylococcal skin infections remain unknown. We aimed to determine whether ERT combined with APS inhibits the growth of staphylococci that are commonly isolated from pyoderma skin lesions in dogs. We investigated the individual and combined effects of ERT and APS on the growth of Staphylococcus pseudintermedius, S. schleiferi, and S. aureus using turbidity assays in vitro. Skin lesions from 10 dogs with superficial pyoderma were topically treated with 5% ERT and 0.1% APS for 28 days, and swabbed skin samples were then analyzed using 16S rRNA amplicon sequencing and quantitative real-time PCR (qPCR). Results showed that ERT inhibited S. pseudintermedius growth regardless of harboring the mecA gene, and APS increased the inhibitory effects of ERT against S. pseudintermedius, S. schleiferi, and S. aureus in vitro. Moreover, combined ERT and APS decreased the prevalence of staphylococci on canine skin lesions at the genus level. The combination slightly increased the α-diversity but did not affect the ß-diversity of the microbiota. The qPCR results revealed that the combination significantly decreased S. pseudintermedius and S. schleiferi in skin lesions. Topical administration of EPS combined with APS can prevent staphylococcal colonization on the surface of mammalian skin. The results of this study may provide an alternative to systemic antibiotics for treating superficial pyoderma on mammalian skin surfaces.

Rifampicin treatment of canine multidrug-resistant meticillin-resistant staphylococcal pyoderma: A retrospective study of 51 cases.

BACKGROUND: Rifampicin (RFP) is a potential treatment for canine multidrug-resistant (MDR) meticillin-resistant staphylococci (MRS), yet the use of lower doses based on recent MIC data has not been evaluated in vivo. HYPOTHESIS/OBJECTIVES: To provide information on the efficacy and safety of low-dose range RFP (≤6 mg/kg/day) for the treatment of canine MDR MRS pyoderma. ANIMALS: Fifty-one client-owned dogs. MATERIALS AND METHODS: Retrospective review of dogs medical records. Dogs were from 11 US dermatology referral practices and had oral RFP at ≤6 mg/kg/day. Data evaluated included response to treatment, adverse events, and serum changes in alanine aminotransferase (ALT) and alkaline phosphatase (ALP). RESULTS: Complete resolution of pyoderma occurred in 39 of 51 dogs (76.5%). Topical antimicrobials were used concurrently in most cases (47 of 51; 92.2%). ALP elevation >1.5-fold of baseline or the high end of the reference range occurred in nine of 37 (24.3%) dogs, while ALT elevation above baseline and the high end of the reference range occurred in two of 36 (5.6%). Only six of 51 (11.8%) had clinical adverse events during treatment; five of six (83.3%) were mild reactions consisting of lethargy and gastrointestinal signs, while one dog had a possible cutaneous adverse drug reaction. Of those that experienced clinical adverse events, four of six (66.7%) did not have concurrent increased liver enzyme activity, while two of six (33.3%) had elevations in ALP alone. CONCLUSIONS AND CLINICAL RELEVANCE: Low-dose RFP (≤6 mg/kg/day) appears to be a relatively safe and effective single-agent systemic antibiotic in combination with topical antimicrobials for canine MDR MRS pyoderma.

CONTEXTE: La rifampicine (RFP) est un traitement potentiel des staphylocoques canins multirésistants (MDR) résistants à la méticilline (MRS), mais l'utilisation de doses plus faibles sur la base de données récentes sur la CMI n'a pas été évaluée in vivo. Hypothèse/Objectifs : Fournir des informations sur l'efficacité et l'innocuité des RFP à faible dose (≤ 6 mg/kg/jour) pour le traitement de la pyodermite MDR-MR canine. Animaux : Cinquante et un chiens de propriétaires. Matériels et méthodes : Revue rétrospective de chiens ayant reçu RFP par voie orale à des doses ≤ 6 mg/kg/jour provenant des dossiers médicaux de 11 centres de référés en dermatologie aux États-Unis. Les données évaluées comprenaient la réponse au traitement, les événements indésirables et les modifications sériques de l'alanine aminotransférase (ALT) et de la phosphatase alcaline (ALP). Résultats : Une résolution complète de la pyodermite s'est produite chez 39 des 51 chiens (76,5 %). Des antimicrobiens topiques ont été utilisés simultanément dans la plupart des cas (47 sur 51 ; 92,2 %). Une élévation de l'ALP> 1,5 fois la ligne de base ou l'extrémité supérieure de la plage de référence s'est produite chez neuf des 37 (24,3%) chiens, tandis qu'une élévation de l'ALT au-dessus de la ligne de base et de l'extrémité supérieure de la plage de référence s'est produite chez deux des 36 (5,6%). Seuls six sur 51 (11,8 %) ont eu des événements indésirables cliniques pendant le traitement ; cinq des six (83,3 %) étaient des réactions bénignes consistant en une léthargie et des signes gastro-intestinaux, tandis qu'un chien a eu un possible effet indésirable cutané au médicament. Parmi ceux qui ont subi des événements indésirables cliniques, quatre sur six (66,7 %) n'ont pas eu d'augmentation simultanée de l'activité des enzymes hépatiques, tandis que deux sur six (33,3 %) ont présenté des élévations de l'ALP seule. Conclusions et pertinence clinique : La RFP à faible dose (≤ 6 mg/kg/jour) semble être un antibiotique systémique à agent unique relativement sûr et efficace en association avec des antimicrobiens topiques pour la pyodermite MDR MRS canine.

Introducción- la rifampicina (RFP) es un tratamiento potencial para los estafilococos resistentes a múltiples fármacos (MDR) y meticilina (MRS), sin embargo, el uso de dosis más bajas basado en datos recientes de MIC no se ha evaluado in vivo. Hipótesis/Objetivos- Proporcionar información sobre la eficacia y seguridad de RFP en el rango de dosis bajas (≤6 mg/kg/día) para el tratamiento de la pioderma canina MDR MRS. Animales- Cincuenta y un perros propietarios particulares. Materiales y métodos- revisión retrospectiva de perros que recibieron RFP oral a dosis ≤6 mg/kg/día obtenida de historiales clínicos de 11 prácticas de referencia de dermatología de los Estados Unidos. Los datos evaluados incluyeron la respuesta al tratamiento, los eventos adversos y los cambios séricos en la alanina aminotransferasa (ALT) y la fosfatasa alcalina (ALP). Resultados- una resolución completa de la pioderma ocurrió en 39 de 51 perros (76,5 %). Antimicrobianos tópicos se usaron al mismo tiempo en la mayoría de los casos (47 de 51; 92,2%). En nueve de 37 (24,3 %) perros se produjo una elevación de ALP >1,5 veces respecto al valor inicial o el extremo superior del rango de referencia, mientras que en dos de 36 (5,6 %) se produjo una elevación de ALT por encima del valor inicial y en el límite superior del rango de referencia. Solo seis de 51 (11,8%) tuvieron eventos adversos clínicos durante el tratamiento; cinco de seis (83,3 %) fueron reacciones leves que consistieron en letargo y signos gastrointestinales, mientras que un perro tuvo una posible reacción cutánea adversa al medicamento. De los que experimentaron eventos adversos clínicos, cuatro de seis (66,7 %) no tuvieron un aumento simultáneo de la actividad de las enzimas hepáticas, mientras que dos de seis (33,3 %) tuvieron elevaciones en la ALP por sí sola. Conclusiones y relevancia clínica- la dosis baja de RFP (≤6 mg/kg/día) parece ser un antibiótico sistémico de uso único relativamente seguro y efectivo en combinación con antimicrobianos tópicos para la pioderma canina MDR MRS.

Contexto - A rifampicina (RFP) é um tratamento potencial para estafilococos resistentes à meticilina (MRS) multirresistentes (MDR) e a utilização de doses mais baixas baseado em dados recentes de MIC não foi avaliada in vivo. Hipótese/Objetivos: Fornecer informações sobre a eficácia e segurança de RFP em menor dosagem (≤6 mg/kg/dia) para o tratamento de piodermite canina por MRS MDR. Animais: Cinquenta e um cães de clientes. Materiais e métodos: Uma revisão retrospectiva dos prontuários de cães que receberam RFP oral na dose de ≤6 mg/kg/dia em 11 clínicas dermatológicas nos Estados Unidos. Os dados avaliados incluíram resposta ao tratamento, eventos adversos, alterações séricas de alanina aminotransferase (ALT) e fosfatase alcalina (FA). Resultados: Resolução completa da piodermite ocorreu em 39 de 51 dos cães (76,5%). Antimicrobianos tópicos foram utilizados concomitantemente na maioria dos casos (47 de 51; 92,2%). Elevação de mais de 1,5 vezes na FA ou para o limite superior do intervalo de referência ocorreu em nove de 37 cães (24,3%), enquanto a elevação de ALT acima do valor inicial e o limite superior do valor de referência ocorreu em dois de 36 (5,6%). Apenas cinco de 51 (11,8%) apresentaram efeitos adversos durante o tratamento; cinco de seis (83,3%) tiveram reações leves caracterizadas por letargia e sinais gastrointestinais, enquanto um cão apresentou uma possível farmacodermia. Dos que apresentaram eventos adversos, quatro de seis (66,7%) não apresentaram aumento concomitante de enzimas hepáticas, enquanto dois de seis (33,3%) tiveram aumento de FA isoladamente. Conclusões e relevância clínica - RFP em baixa dosagem (≤6 mg/kg/dia) aparenta ser relativamente segura e eficaz em monoterapia no tratamento da piodermite canina por MRS MDR por via sistêmica, associada a antimicrobianos tópicos.

Evidence of new sequence types of methicillin-resistant Staphylococcus pseudintermedius in Italy.

Staphylococcus pseudintermedius (SP) and methicillin-resistant SP (MRSP) is one of the most important veterinary pathogens in the dog. Herein, from a total of 126 S. pseudintermediusstrains, 23 MRSP (18%) were identified. Multi-Locus Sequence Typing (MLST) revealed that most of MRSP strains belonged to ST71 (26%), which have been already reported in Italy and other countries. Interestingly, nine new sequence types (39%), from 1053 up to 1061, were described for the first time. Moreover, the isolated MRSP strains showed relevant antibiotic resistance profiles. This report highlights the circulation of new sequence types of MRSP in Italy and underlines the need of a global epidemiological surveillance to limit the increasing spread of multidrug-resistant MRSPstrains worldwide, since they may represent a considerable concern for dog's health.

Antibody levels to Malassezia pachydermatis and Staphylococcus pseudintermedius in atopic dogs and their relationship with lesion scores.

BACKGROUND: Elevated immunoglobulin E (IgE) levels to Malassezia or Staphylococcus species in human atopic dermatitis are related to the skin severity index; a similar association has not been reported in atopic dogs. OBJECTIVES: To investigate serum levels of allergen-specific IgE, total specific IgG and IgG subclasses (IgG1 and IgG2) for M. pachydermatis and S. pseudintermedius, and to correlate them with the severity of dermatitis in dogs. ANIMALS: Serum samples were collected from dogs categorized by age and disease status. Groups 1 and 2: <3-year-old healthy (n = 9) and atopic dogs (n = 9), respectively; and groups 3 and 4: ≥3-year-old healthy (n = 11) and atopic dogs (n = 14), respectively. METHODS AND MATERIALS: Antibody levels were measured by ELISA. The Canine Atopic Dermatitis Lesion Index (CADLI) was analyzed in relation to antibody levels. RESULTS: Specific IgE and total IgG against M. pachydermatis and S. pseudintermedius were significantly increased in atopic dogs of all ages. Although differences between atopic and healthy dogs, with regard to specific IgG1 and IgG2 levels to each microbe, varied in significance within age groups. No significant relationships were found between the CADLI and any specific immunoglobulin levels for both microbe types. CONCLUSIONS AND CLINICAL IMPORTANCE: In dog skin, microbes may act as allergens triggering inflammatory responses via IgE- and IgG-dependent pathway(s). The affinity of the IgG subclass produced may vary according to antigen type. Specific IgE levels may be related to clinical disease in dogs and not to skin lesion severity.

Recovery of meticillin-resistant Staphylococcus species from pet-grooming salons.

BACKGROUND: Meticillin-resistant (MR) staphylococcal species have been cultured from veterinary hospital environments and veterinary instruments. Pet-grooming salon environments and grooming tools may pose a risk for dissemination of MR staphylococcal bacteria into the pet population. OBJECTIVE: The objectives of this study were to investigate the frequency of MR staphylococcal colonization of pet-grooming salons and to collect information regarding cleaning procedures in grooming salons. METHODS AND MATERIALS: A nonrandomized, observational study was performed in 2018. Locations inside 19 grooming salons near Tacoma, WA, USA, were sampled and selectively cultured for MR, coagulase-positive staphylococci. Sampled sites included clipper blades and handles, leashes, rims of bathtub drains, insides of shampoo caps, and bathtub spray hoses or faucet handles. Grooming salons were asked to complete surveys regarding their cleaning practices. RESULTS: Meticillin-resistant coagulase-positive staphylococci were isolated from 12 of 19 grooming salons and 25 of 112 total samples. Meticillin-resistant S. pseudintermedius, S. aureus and S. schleiferi were isolated from multiple salons, most commonly from electric clipper blades, clipper handles and grooming leashes. No statistically significant correlations were identified between cleaning practices and the isolation of MR coagulase-positive staphylococci. CONCLUSIONS AND CLINICAL IMPORTANCE: Clipper blades, clipper handles and leashes are potential fomites for MR staphylococci in a grooming salon; increased disinfection practices for these items are indicated. A prospective, controlled, large-scale study is warranted to examine the effect of grooming salon hygiene practices on the isolation of MR staphylococci in salons.

Carriage of Staphylococcus schleiferi from canine otitis externa: antimicrobial resistance profiles and virulence factors associated with skin infection.

The recent emergence of Staphylococcus schleiferi in dogs with otitis externa or skin and soft tissue infections has become a significant zoonotic issues. In the current study, we investigated 1) the carriage rates of S. schleiferi among major staphylococci in healthy dogs and dogs with otitis externa, 2) antibiotic susceptibility profiles of S. schleiferi, particularly methicillin resistance (MR), and 3) virulence factors associated with skin and soft tissue infections such as ability to form biofilm, resistance to cationic antimicrobial peptides (CAMPs), and carriage of staphylococcal enterotoxin genes. Among the 21 S. schleiferi isolates, 5 isolates (24%) were determined to be methicillin-resistant (MRSS). Staphylococcal cassette chromosome mec (SCCmec) typing revealed the presence of SCCmec type V in 4 MRSS isolates and type VII in one MRSS. Higher levels of antibiotic resistance, especially multidrug resistance, were observed in MRSS isolates compared to the methicillin-susceptible S. schleiferi (MSSS) isolates. In addition, MRSS isolates exhibited enhanced ability to form biofilm under static condition and all the 5 MRSS isolates carried three or more enterotoxin genes. However, there were no significant differences in resistance to CAMPs between MRSS and MSSS isolates. These findings suggest that coagulase-negative S. schleiferi is becoming more prevalent in canine otitis externa cases. Our results also highlight the presence of multidrug-resistant MRSS isolates with enhanced biofilm production and carriage of multiple enterotoxins.

Sodium Hypochlorite/Salicylic Acid Shampoo for Treatment of Canine Staphylococcal Pyoderma.

The emergence of methicillin-resistant Staphylococcus pseudintermedius has increased the interest in topical therapy for treating canine pyoderma. Shampooing with chlorhexidine followed by dilute bleach rinses are often recommended, but household bleach can dry the skin and is unpleasant to use. A shampoo formulated with sodium hypochlorite and salicylic acid was evaluated as sole therapy for dogs with superficial pyoderma associated with S. pseudintermedius, including methicillin-resistant strains. Client-owned dogs were recruited based on positive culture for methicillin-resistant staphylococci or prior failure of pyoderma to respond to antibiotics. This prospective, open-label pilot study assessed the efficacy of the shampoo when used three times weekly for 4 wk. Dogs were evaluated at baseline and at 2 and 4 wk by cytology, clinical examination, and owner assessment. Digital images were also obtained. Baseline bacterial counts, clinical assessments and owner scores were significantly improved at 2 and 4 wk. Clients completing the study reported excellent lathering and dispersion, reduction in odor, and brightening of white and light coats. No owners reported skin dryness or other adverse events during the study. We conclude that this shampoo containing sodium hypochlorite in a vehicle that avoids skin drying is an effective treatment for canine pyoderma.

Residual antibacterial activity of canine hair treated with five mousse products against Staphylococcus pseudintermedius in vitro.

BACKGROUND: Topical therapy alone can be effective in the treatment of canine pyoderma. Topical products are commercially available as shampoos, sprays, wipes and mousses. To date, no studies have evaluated the efficacy of commercially available mousse products in the treatment of canine pyoderma. OBJECTIVE: To determine the residual antibacterial activity of canine hairs treated with mousse products containing different active ingredients. ANIMALS: Fifteen client-owned dogs with no history of dermatological disease. METHODS AND MATERIALS: Dogs were treated once with five mousse products [(i) 2% chlorhexidine and 1% ketoconazole, (ii) 2% chlorhexidine and 2% miconazole, (iii) 3% chlorhexidine and 0.5% climbazole, (iv) 2% salicylic acid 10% ethyl lactate and (v) phytosphingosine HCl 0.05%; control]. Hair samples were collected from each treatment area before application, one hour after application and on days 2, 4, 7, 10 and 14 post-treatment. Collected hairs were weighed and plated on Mueller-Hinton agar plates streaked with a Staphylococcus pseudintermedius isolate showing no antimicrobial resistance. Plates were incubated for 24 h and bacterial growth inhibition zones around the hairs were measured. RESULTS: Mousses 1, 2 and 3 created significant inhibition zones up to Day 10 when compared to pre-treatment samples. On Day 14, only mousse 3 produced a significant zone of inhibition when compared to the pre-treatment sample. Mousses 4 and 5 showed no statistical difference between any of the samples. CONCLUSIONS AND CLINICAL IMPORTANCE: These results suggest that three of the mousse products had residual activity in inhibiting S. pseudintermedius growth in vitro for at least 10 days.

Characterization, mechanism of action and optimization of activity of a novel peptide-peptoid hybrid against bacterial pathogens involved in canine skin infections.

Integumentary infections like pyoderma represent the main reason for antimicrobial prescription in dogs. Staphylococcus pseudintermedius and Pseudomonas aeruginosa are frequently identified in these infections, and both bacteria are challenging to combat due to resistance. To avoid use of important human antibiotics for treatment of animal infections there is a pressing need for novel narrow-spectrum antimicrobial agents in veterinary medicine. Herein, we characterize the in vitro activity of the novel peptide-peptoid hybrid B1 against canine isolates of S. pseudintermedius and P. aeruginosa. B1 showed potent minimum inhibitory concentrations (MICs) against canine S. pseudintermedius and P. aeruginosa isolates as well rapid killing kinetics. B1 was found to disrupt the membrane integrity and affect cell-wall synthesis in methicillin-resistant S. pseudintermedius (MRSP). We generated 28 analogues of B1, showing comparable haemolysis and MICs against MRSP and P. aeruginosa. The most active analogues (23, 26) and B1 were tested against a collection of clinical isolates from canine, of which only B1 showed potent activity. Our best compound 26, displayed activity against P. aeruginosa and S. pseudintermedius, but not the closely related S. aureus. This work shows that design of target-specific veterinary antimicrobial agents is possible, even species within a genus, and deserves further exploration.

Combining MALDI-TOF and genomics in the study of methicillin resistant and multidrug resistant Staphylococcus pseudintermedius in New Zealand.

Staphylococcus pseudintermedius is an opportunistic and emerging zoonotic pathogen that primarily colonises the skin of dogs. Many common variants are methicillin resistant (MRSP) or multidrug resistant (MDR), and drug resistance is increasingly reported across the globe. In New Zealand, MRSP isolation remains rare in clinics. To pre-emptively inform diagnostic and antimicrobial stewardship practices, we examine isolates of S. pseudintermedius, MRSP and MDR-MRSP from New Zealand dogs using a combination of methodologies. Genetic and genomic data combined with antimicrobial susceptibility screening identify common drug-resistance profiles and their genetic determinants. We demonstrate that sensitive and specific species-level identification of S. pseudintermedius can be achieved using Bruker MALDI-TOF MS and, further, that this technique can be used to identify some common subtype variants, providing a level of categorical precision that falls somewhere between single-locus and multi-locus sequence typing. Comparative genomics analysis of global S. pseudintermedius data shows that MRSP moves frequently across the globe, but that horizontal gene transfer events resulting in the acquisition of the SCCmec cassette (responsible for beta-lactam antibiotic resistance) are infrequent. This suggests that biosecurity and surveillance in addition to antibiotic stewardship should play important roles in mitigating the risk of MRSP, especially in countries such as New Zealand where MRSP is still rare.

Ceftaroline resistance in Staphylococcus pseudintermedius gene mecA carriers / Resistência à ceftarolina em Staphylococcus pseudintermedius portadores do gene mecA

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) being a constant concern, ceftaroline fosamil has been recently approved as a new cephalosporin, active against MRSA, for use in humans; only rare cases of resistance have been reported till date. There is no report of resistance to ceftaroline in Staphylococcus pseudintermedius, which is the main bacterium causing dermatitis and otitis in dogs. To evaluate staphylococcal resistance to ceftaroline, 35 isolates of methicillin-resistant S. pseudintermedius (MRSP), carrying the mecA gene, from 26 dogs with folliculitis and nine dogs with external otitis, underwent disk diffusion test with cefoxitin, oxacillin, and ceftaroline. Tests with cefoxitin and oxacillin showed > 90% sensitivity in methicillin resistance detection. In the disk diffusion test, 97.14% (34/35) were resistant to cefoxitin, 94.29% (33/35) to oxacillin, and 31.43% (11/35) to ceftaroline. Of the ceftaroline-resistant strains, 27.27% (3/11) were obtained from the ears of dogs while the rest (8/11) were from the skin. The current report is the first description of MRSP resistance to ceftaroline.(AU)

Infecções causadas por Staphylococcus aureus resistente à meticilina (MRSA) são uma preocupação médica constante. A ceftarolina fosamila é uma nova cefalosporina ativa contra Staphylococcus aureus resistente à meticilina recentemente aprovada para uso em humanos e raros casos de resistência relatados até agora. Não há relatos de resistência à ceftarolina em Staphylococcus pseudintermedius, principal bactéria causadora de dermatite e otite em cães. Com o objetivo de avaliar a resistência estafilocócica à ceftarolina, 35 amostras de S. pseudintermedius resistentes à meticilina (MRSP), portadoras do gene mecA, provenientes de 26 cães com foliculite e 9 com otite externa foram submetidos ao teste de disco-difusão com cefoxitina, oxacilina e ceftarolina. Os testes realizados com cefoxitina e oxacilina mostraram mais de 90% de sensibilidade na detecção da resistência à meticilina em ambas. No teste da disco-difusão, 97,14% (1/35) foram resistentes à cefoxitina, 94,29% (3/35) à oxacilina e 31,43% (11/35) à ceftarolina. Das cepas resistentes às ceftarolina, 27,27 (3/11) foram provenientes de ouvido de cães e as demais (8/11), provenientes da pele, sendo essa primeira descrição de resistência de MRSP à ceftarolina na literatura atual.(AU)

What has changed in canine pyoderma? A narrative review.

Canine pyoderma is a common presentation in small animal practice and frequently leads to prescription of systemic antimicrobial agents. A good foundation of knowledge on pyoderma was established during the 1970s and 1980s, when treatment of infection provided relatively few challenges. However, the ability to treat canine pyoderma effectively is now limited substantially by the emergence of multidrug-resistant, methicillin-resistant staphylococci (MRS) and, in some countries, by restrictions on antimicrobial prescribing for pets. The threat from rising antimicrobial resistance and the zoonotic potential of MRS add a new dimension of public health implications to the management of canine pyoderma and necessitate a revisit and the search for new best management strategies. This narrative review focusses on the impact of MRS on how canine pyoderma is managed and how traditional treatment recommendations need to be updated in the interest of good antimicrobial stewardship. Background information on clinical characteristics, pathogens, and appropriate clinical and microbiological diagnostic techniques, are reviewed in so far as they can support early identification of multidrug-resistant pathogens. The potential of new approaches for the control and treatment of bacterial skin infections is examined and the role of owner education and hygiene is highlighted. Dogs with pyoderma offer opportunities for good antimicrobial stewardship by making use of the unique accessibility of the skin through cytology, bacterial culture and topical therapy. In order to achieve long term success and to limit the spread of multidrug resistance, there is a need to focus on identification and correction of underlying diseases that trigger pyoderma in order to avoid repeated treatment.

Use of a Compounded Poloxamer 407 Antibiotic Topical Therapy as Part of the Successful Management of Chronic Ulcerative Dermatitis in a Congo African Grey Parrot ( Psittacus erithacus).

A 23-year-old, 425-g male African grey parrot ( Psittacus erithacus) was evaluated for chronic ulcerative dermatitis of the axillary regions under both wings. Initial swab cultures of the sites had revealed a coagulase-positive methicillin-resistant Staphylococcus aureas (MRSA) with marked antibiotic resistance. A second swab culture obtained 8 weeks after the initial culture showed heavy growth of a coagulase-positive Staphylococcus species, which could not be speciated, but showed the same sensitivity as the previous culture. Previous treatment included systemic antibiotics and a topical antimicrobial cream, with variable response and only temporary resolution. On examination, full-thickness, ulcerative, necrotic dermatitis was present under both wings with intermittent bleeding and subdermal tissue exposure. Initial treatment included wound debridement, oral antibiotics, topical therapy, analgesics, and bandages. After a relapse, a poloxamer gel containing 2% doxycycline, 1% chloramphenicol, and 0.5% mupirocin was used in combination with oral antibiotics and analgesics. On follow-up examination, the skin lesions had completely resolved and the patient was doing well and remains normal 4 years later. This report emphasizes the importance of prompt, aggressive multi-modal therapy for MRSA and other dermal bacterial infections in pet birds that may represent zoonoses or have carrier-state zoonotic potential. Preparation by a compounding pharmacy of a transdermal poloxamer gel containing antibiotics shows promise for severe, infected, ulcerative skin lesions in birds when other therapies fail to achieve a cure.

Low prevalence of mupirocin resistance in Staphylococcus pseudintermedius isolates from canine pyoderma in Korea.

BACKGROUND: Mupirocin is a topical antibacterial drug used for the treatment of staphylococcal infections, including meticillin-resistant Staphylococcus pseudintermedius (MRSP). The recent emergence of resistance to mupirocin is a major concern in many countries. OBJECTIVES: This study investigated the prevalence and genotype of mupirocin-resistant S. pseudintermedius isolated from pet dogs with pyoderma. SAMPLES: A total of 110 clinical isolates of S. pseudintermedius were collected from dogs with pyoderma (n = 110) between July 2010 and September 2016. All animals were client-owned dogs. METHODS: Low- and high-level mupirocin resistance were evaluated with both the broth microdilution and disk diffusion tests. Mupirocin resistance in S. pseudintermedius isolates was confirmed by genetic analysis of the ileS-2 and naïve ileS genes. RESULTS: MRSP and meticillin-susceptible S. pseudintermedius were detected in 69 and 41 dogs, respectively. One MRSP strain was highly resistant to mupirocin and contained the high-level mupirocin resistance gene ileS-2. There were no low-level mupirocin-resistant isolates. CONCLUSION AND CLINICAL IMPORTANCE: Mupirocin is a useful topical antibacterial for MRSP, but a clinical MRSP isolate that had not previously been exposed to mupirocin exhibited the high-level mupirocin resistance in phenotype and genotype. Therefore, continuous monitoring for mupirocin resistance is important in small animal practice.

Characterization of a Polymicrobial Dermal Infection in a Peninsular Pronghorn ( Antilocapra americana peninsularis) in Baja California, Mexico.

In situ conservation efforts are assisting the recovery of free-ranging populations of the endangered peninsular pronghorns ( Antilocapra americana peninsularis) at the Vizcaino Biosphere Reserve, Baja California Sur, Mexico. We detected a polymicrobial dermal infection. Etiologic agents were identified as a keratinophilic dermatomycete and opportunistic pathogenic bacteria.

Effect of prophylactic cefalexin treatment on the development of bacterial infection in acute radiation-induced dermatitis in dogs: a blinded randomized controlled prospective clinical trial.

BACKGROUND: Acute radiation-induced dermatitis (ARID) is a common sequela of radiation therapy and carries the risk of secondary bacterial skin infection. No standard of care exists for managing canine ARID and evidence-based guidelines are lacking; however, prophylactic use of antibiotics is common. HYPOTHESIS/OBJECTIVES: To evaluate the impact of prophylactic cefalexin on the prevalence and severity of bacterial infection in canine ARID. ANIMALS: Seventeen dogs treated with definitive-intent radiotherapy. METHODS: All dogs were treated with definitive-intent radiation therapy (48-57.5 gray) targeted to the skin surface. Dogs were randomized to receive either prophylactic cefalexin (22 mg/kg twice daily) beginning halfway through the prescribed radiotherapy course (cohort A) or to serve as controls (cohort B). Aerobic skin cultures and surface cytological evaluation were performed at first onset of moist desquamation and one week following completion of radiation therapy. Skin toxicity grading and owner quality of life (QoL) questionnaires were performed weekly. The rate of infection, multidrug resistance status, toxicity severity and QoL between cohorts were compared. RESULTS: Staphylococcus schleiferi and S. pseudintermedius were the most frequent bacterial agents isolated in both cohorts. There was no significant difference in prevalence of bacterial infection or overall QoL between cohorts at either time point; however, multidrug-resistant infections were significantly increased in cohort A versus cohort B. Clinician- and client-perceived severity of toxicity was significantly greater and median duration of moist desquamation was significantly longer in cohort A than cohort B. CONCLUSIONS AND CLINICAL IMPORTANCE: Prophylactic use of cefalexin for management of canine ARID is not recommended.

Severe Dermatitis Associated with Spontaneous Staphylococcus xylosus Infection in Rag-/-Tpl2-/- Mice.

Staphylococcus xylosus is a commensal bacterium found on the skin and mucosal surfaces of SPF mice. S. xylosus is rarely pathogenic, most often causing skin lesions and dermatitis in immunocompromised mice, particularly those with impaired NADPH oxidase function. Here we report spontaneous infection with S. xylosus in Rag1-/-Tpl2-/- mice. Infection was characterized by the presence of alopecia, crusts, and scaly skin. S. xylosus was detected in the feces, skin, lymph nodes, and lungs of Rag1-/-Tpl2-/- mice and led to mortality or euthanasia due to humane endpoints. C57BL/6 mice were culture-positive for S. xylosus on the skin, and Rag1-/- and Tpl2-/- mice were culture-positive on the skin and occasionally in the feces. However, S. xylosus did not cause clinical symptoms in C57BL/6, Rag1-/-, or Tpl2-/- mice. Compared with those in Rag1-/- mice, relative concentrations of circulating monocytes, but not neutrophils or lymphocytes, were increased in Rag1-/-Tpl2-/- mice, consistent with their increased incidence of clinical symptoms. Overall, this case study suggests a novel role for Tpl2 in T-cell-independent host resistance to the otherwise commensal organism S. xylosus.

In vitro bactericidal activity of blue light (465 nm) phototherapy on meticillin-susceptible and meticillin-resistant Staphylococcus pseudintermedius.

BACKGROUND: Staphylococcus pseudintermedius is the most common cause of bacterial skin infections in dogs. Meticillin-resistant infections have become more common and are challenging to treat. Blue light phototherapy may be an option for treating these infections. HYPOTHESIS/OBJECTIVES: The objective of this study was to measure the in vitro bactericidal activity of 465 nm blue light on meticillin-susceptible Staphylococcus pseudintermedius (MSSP) and meticillin-resistant Staphylococcus pseudintermedius (MRSP). We hypothesized that irradiation with blue light would kill MSSP and MRSP in a dose-dependent fashion in vitro as previously reported for meticillin-resistant Staphylococcus aureus (MRSA). METHODS: In six replicate experiments, each strain [MSSP, n = 1; MRSP ST-71 (KM1381) n = 1; and MRSA (BAA-1680) n = 1] were cultivated on semisolid media, irradiated using a 465 nm blue light phototherapeutic device at the cumulative doses of 56.25, 112.5 and 225 J/cm2 and incubated overnight at 35°C. Controls were not irradiated. Colony counts (CC) were performed manually. Descriptive statistics were performed and treatment effects assessed using the Wilcoxon-Mann-Whitney rank-sum test. Bonferroni-corrected rank-sum tests were performed for post hoc analysis when significant differences were identified. RESULTS: There was a significant decrease in CC with blue light irradiation at all doses for MRSA (P = 0.0006) but not for MSSP (P = 0.131) or MRSP (P = 0.589). CONCLUSIONS: Blue light phototherapy significantly reduced CC of MRSA, but not of MSSP or MRSP. The mechanism for the relative photosensitivity of the MRSA isolate is unknown, but is hypothesized to be due to an increased concentration of porphyrin in S. aureus relative to S. pseudintermedius, which would modulate blue light absorption.