RESUMEN
BACKGROUND: Antimicrobial resistance is a growing threat to public health. Pseudomonas aeruginosa is a relevant pathogen causing human and animal infections, frequently displaying high levels of resistance to commonly used antimicrobials. The increasing difficulty to develop new effective antibiotics have discouraged investment in this area and only a few new antibiotics are currently under development. An approach to overcome antibiotic resistance could be based on antimicrobial peptides since they offer advantages over currently used microbicides. METHODS: The antimicrobial activity of the synthetic peptide AMP2041 was evaluated against 49 P. aeruginosa clinical strains with high levels of antimicrobial resistance, isolated from humans (n = 19) and animals (n = 30). In vitro activity was evaluated by a microdilution assay for lethal dose 90% (LD90), while the activity over time was performed by time-kill assay with 12.5 µg/ml of AMP2014. Evidences for a direct membrane damage were investigated on P. aeruginosa ATCC 27853 reference strain, on animal isolate PA-VET 38 and on human isolate PA-H 24 by propidium iodide and on P. aeruginosa ATCC 27853 by scanning electron microscopy. RESULTS: AMP2041 showed a dose-dependent activity, with a mean (SEM) LD90 of 1.69 and 3.3 µg/ml for animal and human strains, respectively. AMP2041 showed microbicidal activity on P. aeruginosa isolates from a patient with cystic fibrosis (CF) and resistance increased from first infection isolate (LD90 = 0.3 µg/ml) to the mucoid phenotype (LD90 = 10.4 µg/ml). The time-kill assay showed a time-dependent bactericidal effect of AMP2041 and LD90 was reached within 20 min for all the strains. The stain-dead assay showed an increasing of membrane permeabilization and SEM analysis revealed holes, dents and bursts throughout bacterial cell wall after 30 min of incubation with AMP2041. CONCLUSIONS: The obtained results assessed for the first time the good antimicrobial activity of AMP2041 on P. aeruginosa strains of human origin, including those deriving from a CF patient. We confirmed the excellent antimicrobial activity of AMP2041 on P. aeruginosa strains derived from dog otitis. We also assessed that AMP2041 antimicrobial activity is linked to changes of the P. aeruginosa cell wall morphology and to the increasing of membrane permeability.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple , Péptidos/farmacología , Infecciones por Pseudomonas/microbiología , Infecciones por Pseudomonas/veterinaria , Pseudomonas aeruginosa/efectos de los fármacos , Animales , Membrana Celular/efectos de los fármacos , Membrana Celular/ultraestructura , Pared Celular/efectos de los fármacos , Pared Celular/ultraestructura , Perros , Humanos , Viabilidad Microbiana/efectos de los fármacos , Microscopía Electrónica de Rastreo , Pseudomonas aeruginosa/aislamiento & purificaciónRESUMEN
BACKGROUND: Pseudomonas aeruginosa (PA) may cause suppurative otitis externa with severe inflammation and ulceration in dogs. Multidrug resistance is commonly reported for this organism, creating a difficult therapeutic challenge. OBJECTIVE: The aim of this study was to evaluate the in vitro antimicrobial activity of a gel containing 0.5 µg/mL of antimicrobial peptide AMP2041, 0.07% chlorhexidine digluconate (CLX), 0.4% Tris and 0.1% EDTA on 30 clinical isolates of PA from canine otitis externa. MATERIALS AND METHODS: Antimicrobial activity was evaluated through minimal bactericidal concentration (MBC). Standardized bacterial suspensions were incubated with different concentrations of the gel at 37°C for 30 min and plated for colony forming unit (CFU) counts. Time-to-kill kinetics were evaluated with the undiluted product and at MBC for each PA strain at 30 s, 1, 5, 10, 15, 30 min, 24 and 48 h. RESULTS: The MBC was 1:64 for two of 30 strains, 1:128 for 15 of 30 strains and 1:256 for 13 of 30 strains. The geometric mean was 1:165, equivalent to a concentration of 0.003 µg/mL AMP2041 + 0.0004% CLX + 0.0024%Tris + 0.0006% EDTA. Time-to-kill assays with the undiluted product showed complete bactericidal effect within 30 s for all isolates, whereas at the MBC this effect was reached within 5 min for 20 of 30 isolates and within 30 min for all isolates. Bactericidal activity was maintained after 48 h for all isolates. CONCLUSION: This gel has shown rapid, complete and long-lasting activity against a panel of 30 PA isolates from cases of canine otitis externa.
Asunto(s)
Antibacterianos/uso terapéutico , Péptidos Catiónicos Antimicrobianos/uso terapéutico , Clorhexidina/análogos & derivados , Enfermedades de los Perros/microbiología , Ácido Edético/análogos & derivados , Ácido Edético/farmacología , Otitis Externa/veterinaria , Pseudomonas aeruginosa/efectos de los fármacos , Trometamina/análogos & derivados , Trometamina/farmacología , Animales , Clorhexidina/administración & dosificación , Clorhexidina/uso terapéutico , Perros , Geles , Otitis Externa/microbiologíaRESUMEN
BACKGROUND: Canine subcutaneous dirofilariosis caused by Dirofilaria repens is an important cause of human dirofilariosis in the Old World. OBJECTIVES: To describe the clinical and pathological features of infestation by D. repens in dogs with cutaneous nodules and to discuss key diagnostic procedures. ANIMALS: Sixteen privately owned dogs of different breeds, ages and genders with subcutaneous nodules were positive for D. repens on at least one diagnostic test. METHODS: Diagnostic tests included cytological examination of fine-needle aspiration biopsies, detection of circulating larvae by Knott's test, morphological and molecular identification of adult parasites and microfilariae, and histopathological examination of excised nodules. RESULTS: Twelve animals were positive for D. repens microfilariae, using cytology and at least one other diagnostic test. Four of twelve dogs screened by Knott's test had circulating D. repens microfilariae, and three of them were co-infected with Dirofilaria immitis. In eight dogs, adult nematodes were morphologically identified as D. repens. Nodular panniculitis was observed in all cases, with nodules containing either one or several cross-sections of nematodes and microfilariae. The nematodes extracted were identified as D. repens by an RT-PCR on the second internal transcribed spacer (ITS-2). CONCLUSIONS AND CLINICAL IMPORTANCE: Adults and larvae of D. repens can induce skin nodules in dogs, and these lesions should be carefully evaluated in endemic areas. Clinicians should be aware that correct tissue sampling (including the storage of part of a sample in ethanol instead of formalin) is pivotal to achievement of a specific diagnosis. Cytology of fine-needle tissue aspirates was shown to be useful.
Asunto(s)
Dirofilaria repens/aislamiento & purificación , Dirofilariasis/parasitología , Enfermedades de los Perros/parasitología , Enfermedades Cutáneas Parasitarias/veterinaria , Animales , Dirofilariasis/epidemiología , Dirofilariasis/patología , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/patología , Perros , Femenino , Italia/epidemiología , Masculino , Enfermedades Cutáneas Parasitarias/epidemiología , Enfermedades Cutáneas Parasitarias/parasitología , Enfermedades Cutáneas Parasitarias/patologíaRESUMEN
A previously validated 15-item questionnaire on dogs' life quality (QoL1) and that of their owners (QoL2) was applied in a multicentre study to owners of 200 dogs with different dermatological conditions, together with a question on the owner-perceived disease severity (S). Factor analysis was applied to the whole questionnaire. The correlation of S with QoL1 and QoL2 scores was evaluated using Spearman's rank correlation tests. Owner sex, age, educational level and willingness to pay for a potential definitive cure of the disease were recorded, and compared with quality of life (QoL) scores. In 23 atopic dogs, CADESI-03, pruritus Visual Analogue Scale and QoL scores were obtained before and after therapy, and their correlation was evaluated with linear regression. Factor analysis revealed that three factors (S, QoL1 and QoL2) explained 75% of the variance. Owner-perceived severity correlated significantly with QoL1 and QoL2 (P = 0.002 and P = 0.015, respectively). The five diseases with the worst QoL scores were scabies, pododermatitis, complicated atopic dermatitis, pemphigus foliaceus and endocrine alopecia. Pruritic diseases did not give significantly higher QoL1 or QoL2 scores compared with nonpruritic diseases (P = 0.19, Kruskall-Wallis test). Owner sex, age or educational level did not influence QoL scores. Female sex, a younger age and a higher educational level were significantly associated with more willingness to pay. In atopic dogs, all the scores decreased after therapy, but post-treatment CADESI-03 and Visual Analogue Scale scores did not correlate with QoL1 and QoL2. Questions related to the burden of maintenance therapy showed the lowest improvements in score.
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Enfermedades de los Perros/psicología , Calidad de Vida/psicología , Enfermedades de la Piel/veterinaria , Adulto , Anciano , Envejecimiento , Animales , Enfermedades de los Perros/economía , Enfermedades de los Perros/terapia , Perros , Análisis Factorial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Propiedad , Enfermedades de la Piel/psicología , Enfermedades de la Piel/terapia , Encuestas y CuestionariosRESUMEN
Aspergillus ochraceus, a widely distributed filamentous fungus, was isolated and identified by cytology and culture as the cause of unilateral ceruminous purulent otitis in a 4-year-old male mixed-breed dog. The pathogenic role of the fungal isolate was confirmed by a good response to antifungal therapy and the absence of other pathogens. No underlying diseases were identified and the dog recovered after 3 weeks of therapy with oral itraconazole and topical miconazole.
Asunto(s)
Aspergilosis/veterinaria , Aspergillus ochraceus/aislamiento & purificación , Otitis Externa/veterinaria , Administración Tópica , Animales , Antifúngicos/uso terapéutico , Aspergilosis/tratamiento farmacológico , Aspergilosis/microbiología , Enfermedad Crónica , Perros , Itraconazol/uso terapéutico , Masculino , Miconazol/administración & dosificación , Miconazol/uso terapéutico , Otitis Externa/tratamiento farmacológico , Otitis Externa/microbiologíaRESUMEN
Minimum bactericidal concentrations (MBCs) of a commercial ear antiseptic containing chlorhexidine 0.15% and Tris-EDTA (Otodine) were determined by broth microdilution for 150 isolates representing the most common pathogens associated with canine otitis. The microorganisms were classified into three groups according to their levels of susceptibility. The most susceptible group included Staphylococcus pseudintermedius, Malassezia pachydermatis, Streptococcus canis and Corynebacterium auriscanis, which were generally killed by 1 : 64 dilution of the antiseptic product (MBC = 23/0.8 microg/mL of chlorhexidine/Tris-EDTA). The most resistant organism was Proteus mirabilis, which survived up to 1 : 8 dilution of the product (MBC = 375/12 microg/mL). Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus displayed intermediate MBCs ranging between 188/6 and 47/1.5 microg/mL. Interestingly, S. pseudintermedius was more susceptible than S. aureus, and no significant difference was observed between meticillin-resistant and meticillin-susceptible isolates within each species, indicating that antiseptic use is unlikely to co-select for meticillin resistance. Although the concentrations required for killing (MBCs) varied considerably with microorganism type, the combination of chlorhexidine 0.15% and Tris-EDTA was active against all the pathogens most commonly involved in canine otitis.