Otitis In Dogs Research Articles

Antimicrobial and antibiofilm effect of promethazine on bacterial isolates from canine otitis externa: an in vitro study

Otitis externa is an inflammatory disease of the external ear canal of complex and multifactorial etiology associated with recurrent bacterial infection. This study aimed to assess the antimicrobial and antibiofilm activity of promethazine against bacterial isolates from dogs with otitis externa, as well as the effect of this compound on the dynamics of biofilm formation over 120 h. Planktonic bacterial susceptibility to promethazine was evaluated to determine the minimum inhibitory concentrations (MIC). The minimum biofilm eradication concentration (MBEC) was also determined by broth microdilution. To evaluate the effect on biofilm growth, promethazine was tested at three concentrations MIC, MIC/2 and MIC/8, with daily readings at 48, 72, 96 and 120 h. The MICs of promethazine ranged from 48.83 to 781.25 μg mL−1. Promethazine significantly (P < 0.05) reduced mature biofilm biomass, with MBECs ranging from 48.8 to 6250 μg mL−1 and reduced (P < 0.01) biofilm formation for up to the 120-h, at concentrations corresponding to the MIC obtained against each isolate. Promethazine was effective against microorganisms associated with canine otitis externa. The data suggest that promethazine presents antimicrobial and antibiofilm activity and is a potential alternative to treat and prevent recurrent bacterial otitis in dogs. These results emphasize the importance of drug repurposing in veterinary otology as an alternative to reduce antimicrobial resistance.

Clinical case of Malassezia otitis media in a dog

Dermatopathologies are pretty standard among domestic dogs and cats. Today, Malassezia occupies a leading place among fungal skin lesions. Particular attention should be paid to Malassezia otitis since fungal infections are usually a marker of low resistance, so against their background, it is natural to increase the pathogenic effect of other microflora and, as a result, damage to the eardrum, middle ear, and other destructive changes in the hearing organs. The article presents the results of the use of a bioregulatory approach in the complex therapy of malassezia otitis in dogs with the use of the drug “Traumeel”, which contains ultra-low doses of biologically active substances. The use of this drug increases the safety of treatment, which in turn protects the animal's body from complications and adverse effects of therapy. The study was conducted based on a private outpatient clinic of veterinary medicine in Ternopil during the treatment of an 11-year-old dog with chronic otitis. The clinical manifestation of Malassezia otitis was determined by characteristic clinical signs (hyperpigmentation, hyperemia, edema, pain, and increased ceruminous secretion). A cytological examination with light microscopy of adhesive strips with biomaterial fixed on a slide and stained with a modified Wright-Giemza stain, “Leukodif”, was performed to confirm the diagnosis. For therapy, initially, a generally accepted standard therapy was used using 1 % ketoconazole and 2 % chlorhexidine twice a day and preliminary cleaning of the auricles. Since no positive dynamics were observed, Traumeel 1 ml intramuscularly 1 time per day for 5 days was additionally used for therapy. The choice of bioregulatory drug was based on the components and their action. After 7 days, the dog's inflammation significantly decreased – edema, hyperemia, and itching disappeared, and there was no pathological accumulation of ceruminous gland secretion. Subsequently, three more injections of Traumeel were performed with an interval of 48 hours. 3 weeks after the diagnosis, a repeated cytological examination for the presence of Malassezia was performed – the result was negative. Subsequently, the dog underwent hygienic ear cleaning 1–2 times a week. There were no relapses. Based on the therapy results, it can be concluded that the treatment regimen for Malassezia otitis is effective.

Prevalence and genetic diversity of azole-resistant Malassezia pachydermatis isolates from canine otitis and dermatitis: A 2-year study.

Despite previous reports on the emergence of Malassezia pachydermatis strains with decreased susceptibility to azoles, there is limited information on the actual prevalence and genetic diversity of azole-resistant isolates of this yeast species. We assessed the prevalence of azole resistance in M. pachydermatis isolates from cases of dog otitis or skin disease attended in a veterinary teaching hospital during a 2-year period and analyzed the ERG11 (encoding a lanosterol 14-α demethylase, the primary target of azoles) and whole genome sequence diversity of a group of isolates that displayed reduced azole susceptibility. Susceptibility testing of 89M. pachydermatis isolates from 54 clinical episodes (1-6 isolates/episode) revealed low minimum inhibitory concentrations (MICs) to most azoles and other antifungals, but 11 isolates from six different episodes (i.e., 12.4% of isolates and 11.1% of episodes) had decreased susceptibility to multiple azoles (fluconazole, itraconazole, ketoconazole, posaconazole, ravuconazole, and/or voriconazole). ERG11 sequencing of these 11 azole-resistant isolates identified eight DNA sequence profiles, most of which contained amino acid substitutions also found in some azole-susceptible isolates. Analysis of whole genome sequencing (WGS) results revealed that the azole-resistant isolates from the same episode of otitis, or even different episodes affecting the same animal, were more genetically related to each other than to isolates from other dogs. In conclusion, our results confirmed the remarkable ERG11 sequence variability in M. pachydermatis isolates of animal origin observed in previous studies and demonstrated the value of WGS for disentangling the epidemiology of this yeast species.

THE ROLE OF YEASTS IN ETIOLOGY OF CANINE OTITIS

The article presents the results of the study of the species composition of the microbiota of the skin surface of the auditory canal for otitis in dogs, in particular the results of the study of the fungal microbiota and the frequency of associations of pathogenic fungi with bacterial pathogens. Objective Investigation of the ear microbiota in dogs with otitis with the aim of identifying microbial/fungal species composition and establishing the role of yeasts in the etiology of otitis, identifying possible associations of fungi and pathogenic staphylococci. Materials and methods Experimental animals were dogs aged from 6 months to 10 years. During the period 2018-2020, 30 dogs of various breeds weighing 5-60 kg, of both genders, with otitis symptoms were examined. During the study, sampling of clinical material from affected animals, isolation of pathogen cultures on nutrient media, the study of their cultural properties and the determination of sensitivity to the corresponding drugs were carried out. As the research results showed, among the representatives of yeast fungi in the material isolated from dogs with otitis, Malassezia pachydermatis was most often isolated - 9 cases (30%). Representatives of Candida albicans were isolated in only 1 case (3.3%), so their clinical significance requires further study. These fungi could be extraneous contaminants. It should be noted that in 9 cases (30% of the number of cases of Staphylococcus aureus isolation) associations of S. aureus were observed with Malassezia pachydermatis fungi, in 6 cases (20%) associations of Staphylococcus pseudintermedius with Malassezia pachydermatis fungi were observed; in 5 cases (16.7%) – associations of S. aureus with gram-negative Proteus spp. Conclusions 1. Among representatives of yeast fungi in the material isolated from dogs with otitis, M. pachydermatis was most often isolated – 9 cases (30%). 2. Representatives of C. albicans were isolated in only 1 case (3.3%), so their clinical significance requires further study. These agents could be extraneous contaminants. 3. It should be noted that in 9 cases (30% of the number of cases of S. aureus isolation) associations with M. pachydermatis fungi were observed, in 6 cases (20%) associations of S. pseudintermedius with M. pachydermatis fungi were observed; in 5 cases (16.7%) – associations of Malassezia with gram-negative Proteus spp.

Pseudomonas that Causes Otitis in Dogs: An Increasing Opposition

Pseudomonas that Causes Otitis in Dogs: An Increasing Opposition

Early life programming by diet can play a role in risk reduction of otitis in dogs.

Otitis in dogs is often chronic while local treatment primarily consists of flushing, antibiotics, and/or antifungals. We were interested in finding early life variables that associate with otitis later in life, preferably some that could be modified. A cross-sectional hypothesis-driven study with longitudinal data was performed to search for associations between pre- and postnatal exposures, and the incidence of owner-reported otitis in dogs at over 1 year of age. The multivariate logistic regression analysis study included data from 3,064 dogs and explored 26 different early life variables at four early life stages: prenatal, neonatal, postnatal, and puppyhood. We compared two feeding patterns, a non-processed meat-based diet (NPMD, raw) and an ultra-processed carbohydrate-based diet (UPCD, dry). We report that eating a NPMD diet significantly decreased the risk of otitis later in life, while eating a UPCD diet significantly increased the risk. This was seen in different life stages of mother or puppy: The maternal diet during pregnancy (p=0.011) and the puppies' diet from 2 to 6 months of age (p=0.019) were both significantly associated with otitis incidence later in life, whereas the puppies' first solid diet, was associated in the same way, but did not reach significance (p=0.072). Also, analyzing food ratios showed that when puppies were consuming >25% of their food as NPMD it significantly decreased their incidence of otitis later in life, while a ratio of >75% UPCD in their diet significantly increased their risk of otitis. Also, if the dog was born in the current family, was exposed to sunlight for more than 1 hour daily, and was raised on a dirt floor during puppyhood, there was a lower risk of otitis development later in life. The findings only suggest causality, and further studies are required. However, we propose that veterinarians, breeders, and owners can impact otitis risk by modifying factors such as diet and environment.

The epidemiology of canine ear diseases in Northwest China: Analysis of data on 221 dogs from 2012 to 2016.

Ear disease is relatively important in veterinary medicine as it significantly affects the quality of life of pets. Two hundred and twenty-one cases of canine ear diseases were collected and collated at the Xi'an Teaching Hospital of Northwest A&F University from 2012 to 2016. An epidemiological analysis was conducted to evaluate the prevalence and causes of various ear diseases in various breeds of dogs in Xi'an. Data were collected and statistically analyzed by reviewing previous cases and obtaining medical history data and laboratory results. This study included the following experiments: systematic examination of the animals' skin, auricular skin scraping test, ear canal endoscopy, and examination of ear canal secretion. The top three dog breeds most commonly afflicted with ear diseases in Xi'an were Toy poodles, Cocker Spaniels, and Golden Retrievers, accounting for 18.5%, 10.4%, and 9.5% of the total cases, respectively. The prevalence was the highest in August and September, with male dogs having a higher prevalence rate than female dogs. Common ear diseases were categorized as otitis externa, otitis media, otitis interna, or ear hematoma. This study determined the prevalence of external otitis, ear hematoma, otitis media, and inner otitis in dogs in the Xi'an area. These results can help expand the current understanding of the development and epidemiology of canine ear diseases and provide a reference for clinical diagnosis, treatment, and prevention.

Managing recurrent otitis externa in dogs: what have we learned and what can we do better?

Recurrent otitis externa is a common problem in dogs. Topical treatment for each flare is successful in the short term, but repeated cycles of inflammation and infection lead to chronic inflammatory changes, pain and aversion, and antimicrobial resistance. These make the flares more frequent and harder to control. Eventually, the changes become irreversible and require a total ear canal ablation/lateral bulla osteotomy or ablative laser surgery. Most ear canal surgery is avoidable if recurrent otitis is properly managed at an earlier stage. This requires a different mindset and approach to these cases, taking advantage of recent research and clinical findings. Most importantly, clinicians must appreciate that all recurrent ear infections in dogs are secondary. To achieve a good long-term outcome, it is essential that all the underlying factors in each case are diagnosed and managed using the primary, secondary, predisposing, and perpetuating framework. This means that the primary condition must be diagnosed and managed, the secondary infection treated, predisposing risks identified and corrected, and the perpetuating factors reversed. Treatment is in 2 phases: induction to get the ears in remission and then long-term maintenance therapy to prevent relapses. Treatment should be appropriate to each dog but will typically involve ear cleaning, topical antimicrobial therapy, and topical or systemic glucocorticoids. Novel treatments for infection and inflammation will offer additional options in the future. Understanding the triggers for recurrent otitis in dogs will help clinicians plan effective management regimens that will make a huge difference to the quality of life of their patients and their owners.

In Vitro Activity of Farnesol against Malassezia pachydermatis Isolates from Otitis Externa Cases in Dogs

Chronic otitis externa of dogs is a significant problem due to the prevalence and complexity of the treatment of such animals. There is evidence that in 60-80% of cases of infectious diseases microorganisms located in the biofilm phenotype play the main role. Microorganisms in the biofilm phenotype have a number of advantages, the most significant of which is considered to be increased resistance to various external factors. Among them, a special place is occupied by resistance to antibiotics. In recent decades, research has been conducted at an increasing scale on the role of biofilm infections in various pathologies in veterinary medicine. The etiology and therapy of dog otitis externa caused by Malassezia pachydermatis biofilm has not been fully studied. This is why we consider relevant the scientific and practical aspects of research on the etiology and therapy of dog otitis externa from the position of biofilm infection. In this work, it has been statistically proven that there is a relationship between the optical density of Malassezia pachydermatis biofilms and their sensitivity to drugs, and this relationship is statistically significant. In addition, we have demonstrated that Farnesol has a good antibiofilm effect at a concentration of more 1.6 μM/mL (24% OD decrease of biofilm), and its highest antibiofilm effect (71-55%-more than a half) was observed at a concentration of 200-12.5 μM/mL.

Otitis Externa in Dogs: Distribution and Antimicrobial Susceptibility Patterns of Staphylococcus Spp. Isolates

Abstract The study aimed to investigate the Staphylococcus species from dogs with chronic otitis externa in Istanbul and to determine their antibiotic susceptibility patterns. Ear swab samples were collected from 100 dogs suspected of otitis externa admitted at the clinics of Istanbul University - Cerrahpaşa, Faculty of Veterinary Medicine. The dogs were of different age, gender, and breed. The bacterial isolation was performed by conventional methods. BD Phoenix Automated Microbiology System was used to confirm bacterial identification by conventional methods and to test antimicrobial susceptibility. Staphylococcus spp. were isolated from 36% of the samples collected from the dogs. S. pseudintermedius, S. aureus, S. epidermidis, S. hyicus and S. chromogenes were identified in 41.6%, 22.2%, 11.1%, 5.5%, and 5.5%. In Staphylococcus spp. isolates, enrofloxacin, penicillin, and ampicillin-sulbactam resistance was 8.3%, marbofloxacin resistance was 11.1%, doxycycline resistance was 16.6%, amoxicillin-clavulanic acid, erythromycin, and gentamicin resistance was 19.4%, tetracycline, clindamycin, and sulphonamide resistance was 25%. Methicillin resistance was not observed in any of the isolates. However, multiple drug resistance (MDR) was detected in 11 (30.5%) of 36 isolates. In conclusion, the early detection and antimicrobial sensitivity testing of Staphylococcus spp in dog otitis externa cases that do not respond to empiric therapy could be beneficial for appropriate antibiotic selection and treatment thus preventing MDR.

The spread of dogs’ otitis in Odesa city

Inflammation of the external ear in dogs is a widespread pathology in 20 % of sick animals that come to veterinary medicine clinics. The purpose of the work was to monitor the spread of otitis in dogs for 2021 in Odesa. To solve this goal, several tasks were set: to study the spread of otitis among dogs by breed, age, and sex; to study the spread of Malassezia otitis among dogs; to determine the seasonality of otitis in dogs. The data from the journal of registration of sick animals of the veterinary clinic of Odessa (VetKOiN) served as the material. Data concerning sick animals from the logbook were entered into tables, and statistical analysis was carried out. Dogs of Pugs and Mestizo made up the most significant number of sick animals with otitis (10.4 % each); the French Bulldog breed accounts for 9.1 %, the Pekinese and Labrador breeds – 6.5 % each, the Clamber Spaniel breed – 5.2 %. Such dog breeds as Jack Russell Terrier, Chihuahua, Spitz, German Shepherd, and Cane Corso account for 3.9 %; Bull Terrier, East European Shepherd, and Retriever – 2.6 % each; Grünendal, Husky, Samoyed, Kangal, Dachshund, Scottish Shepherd, Shar-Pei, Bolonka, Beagle, American Cocker Spaniel, Shih-Tzu, Laika, Fox Terrier, Staffordshire Terrier, Pit Bull Terrier, American Bully, Breton, Bernese Mountain Dog, English Bulldog breeds – 1.3 % each. Animals between the ages of 1 and 5 years suffer mostly from canine otitis (64 %) and animals under the age of 1 year suffer less(10 %). Animals older than five years make up 26 %. The gender of dogs is not important in otitis spreading: females account for 49 % of sick animals, and males – 51 %. Malassezia otitis in dogs occurred in 38 % of cases. Dogs of Pug breeds comprised the largest percentage of sick animals (13.8 %), French bulldog and Pekingese breeds – (10.3 % each). The Bull Terrier, Jack Russell Terrier, and Chihuahua breed each account for 6.9 %. Otitis was registered every month during the year. An increase in the incidence was observed in April (9.1 %), May (13.0 %), June (7.8 %), July (15.6 %), August (13.0 %), September (10.4 % ) and November (10.4 %). So otitis was more often registered in dogs in the warm season. In the future, the spread, etiology, and most effective treatment regimens of various forms of otitis in dogs will be studied.

Pseudomonas aeruginosa susceptibility, antibiogram and clinical interpretation, and antimicrobial prescribing behaviors for dogs with otitis in the Midwestern United States.

Pseudomonas aeruginosa (P.aeruginosa) can cause otitis in dogs that is nonresponsive to empirical therapy. This study evaluated P.aeruginosa isolates (N=216) from canine ear swabs submitted to the Kansas State Veterinary Diagnostic Laboratory from 2018-2020 to create an antibiogram and minimum inhibitory concentration distributions using Clinical Laboratory Standards Institutes breakpoints. Multidrug resistance was defined as non-susceptibility to ≥1 drug from ≥3 antimicrobial classes. Submitting veterinarians (N=83) were invited to complete a survey about antimicrobial use and otitis management. Susceptibility was higher for aminoglycosides [gentamicin (82%, 177/216) and amikacin (81%, 175/216)] than fluoroquinolones [marbofloxacin (67%, 145/216), enrofloxacin (32%, 70/216), and orbifloxacin (18%, 39/216)]. Most responding veterinarians (54%, 15/28) prescribe topical aminoglycosides as first-line therapy for canine otitis, but 71% (15/21) prescribe fluoroquinolones if rods are seen cytologically. Ceftazidime, imipenem, and piperacillin-tazobactam showed high susceptibility and are used rarely. Multidrug resistance was present in 13% (28/216) of isolates. Based on in vitro susceptibility, topical aminoglycosides might be more effective than fluoroquinolones for P.aeruginosa otitis, but efficacy studies are required. Susceptibility testing is encouraged for cases not responding to empirical therapy but has limitations because topical preparations have high concentrations and otic breakpoints are not available.

Prevalence of methicillin resistance in Staphylococcus pseudintermedius isolates from dogs with skin and ear infections in South Africa

Staphylococcus pseudintermedius (SP) is an important opportunistic pathogen, frequently associated with pyoderma and otitis in dogs. The emergence and rapid expansion of methicillin-resistant Staphylococcus pseudintermedius (MRSP) is problematic due to multidrug resistance and reduced treatment options. The aim of this study was to determine i) the prevalence of MRSP in dogs with pyoderma or otitis externa, ii) the antimicrobial resistance patterns of MRSP from South African isolates, and iii) the risk factors for MRSP-associated pyoderma or otitis externa in dogs in South Africa (RSA). Sixty-eight presumptive clinical SP isolates (collected from 65 dogs) from five geographically dispersed laboratories in RSA were collected over 2 years. Possible MRSP isolates were flagged when resistance to oxacillin was observed. Thereafter, all isolates were confirmed as SP by polymerase chain reaction (PCR) and further genotyped for the mecA gene. Fifty-seven of 68 isolates were confirmed to be SP (83.8%), while 49/57 (85.9%) carried mecA. Our findings showed that preliminary phenotypic methods supplemented by genotypic methods increased the accuracy of correctly identifying SP. All isolates were resistant to at least one antimicrobial drug. There was a high incidence of amoxicillin (70.1%) and enrofloxacin (65%) resistance. Important risk factors for mecA positive carriage were previous hospital admission, pruritus, and previous antibacterial failure. This study demonstrates a high prevalence of mecA positive carriage (85.9% of samples) in MRSP pyoderma and otitis in dogs in RSA. There is an urgent need for better laboratory diagnosis of MRSP and surveillance of dogs presenting with pyoderma and otitis in South Africa.

Diversity of Monofloral Honey Based on the Antimicrobial and Antioxidant Potential.

This study aimed to investigate the antioxidant profile and the antimicrobial activity of four different types of monofloral honey (manuka (MH), brassica rapeseed (BH), acacia (AH), and linden honey (LH)) against some bacterial/fungal ATCC strains and some multidrug-resistant strains isolated from chronic otitis in dogs. For the characterisation of the antioxidant profile of each honey, we extracted the honey samples by hydroalcoholic extraction and analysed them in terms of total polyphenols (TPC), total flavonoids (TFC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) using the spectrophotometric method. The antimicrobial activity was determined using the microdilution method at concentrations of 10%, 15%, and 20%, with the results expressed in OD (optical density) calculated as BIR% (bacterial inhibition rate)/MIR% (mycelial inhibition rate). The antioxidant characterisation of the analysed honey samples showed the highest antioxidant activity and concentrations of TPC and TFC in MH, followed by LH. MH was proven to be the most effective on most clinical isolates concerning the antimicrobial activity in comparison with BH, AH, and LH. Except for B. cepacia and P. vulgaris, all the clinical isolates were sensitive to the antibacterial activity of honey. Regarding the ATCC strains, MH 10% was the most effective in inhibiting all the strains tested except for P. aeruginosa. In conclusion, the efficacy classification in our study was MH > BH > AH > LH.

Clinical and Microbiological Performances and Effects on Lipid and Cytokine Production of a Ceruminolytic Ear Cleaner in Canine Erythemato-Ceruminous Otitis Externa.

Erythemato-ceruminous otitis externa (ECOE) is the most common type of otitis in dogs and is generally associated with bacterial and/or yeast infections. The performance of an ear cleaner was assessed over two weeks in canine ECOE, associated with a mild or moderate secondary infection, in a prospective open-label study. Forty ear canals with ECOE that did not receive any type of aural treatment and were not cleaned for 7 days were included. Pruritus (PS), 0–3 Otitis Index Score (OTIS-3) and 0–4 scale cytology (CYTO) scores were assessed on Day (D) 0, D7 and D14. Concentrations of a panel of 13 cytokines on the ear canal surface and the lipid profile of the exudate were measured on D0 and D14. From D0 to D12 or D13, the dogs’ ears were cleaned daily if the secretion score (SEC) was 3/3, every second day if the score was 2/3 and every third day if the score was 1/3. PS, OTIS-3, SEC and CYTO were significantly lower on D7 compared to baseline (−40%, −31%, −36%, −34%, respectively; p < 0.0001). The same parameters decreased further on D14 (−60%, −53%, −61%, −73%, respectively; p < 0.0001) and amounts of interleukin 8 and chemokine KC-like were also reduced compared to baseline (−45%, p < 0.01; −36%, p = 0.3, respectively). The lipid profile was also modified, with a decrease in free lipids and an increase in bound lipids.

High rates of multidrug resistance in bacteria associated with small animal otitis: A study of cumulative microbiological culture and antimicrobial susceptibility

The etiology of otitis in dogs and cats is multifactorial and complex, involving bacterial and fungal pathogens. As empiric antimicrobial prescription is a common practice when treating such cases, antimicrobial resistance may represent a complicating factor. The aim of this study was to describe microbiological features and susceptibility profiles of pathogens associated with 142 cases of external otitis, comprising 138 dogs and 4 cats.. The specimens were processed to identify bacterial and fungal etiologies following standard microbiological methods. Antimicrobial susceptibility was determined in vitro against 15 antibiotics and 3 antifungals. Further, Staphylococcus spp. isolates were screened for the detection of β-lactamase enzymes using cefinase paper discs. Pseudomonas spp. and isolates from Enterobacteriaceae family were screened for colistin (Polymyxin E) resistance and for the mcr-1-mediated colistin resistance gene by PCR. The presence of mixed cultures of Enterobacteriaceae, Pseudomonas spp. and Staphylococcus spp., and co-infections with Malassezia spp., emphasizes the polymicrobial etiology of external otitis in small animals. Emerging rates of multidrug resistance observed in almost 50% of the isolates may alert for a near future of challenging veterinary cases unresponsive to first-line antimicrobials. In addition, these results highlight a potential public health concern of multidrug resistant bacteria, given the proximity of pets and their owners. This study addressed central aspects of external otitis, providing microbiologists and clinicians updated information on the etiology and treatment of challenging cases of multidrug resistant bacteria. It also provides priceless surveillance value in monitoring resistant bacteria in small animals.

In vitro and in vivo evaluation of a new phytotherapic blend to treat acute externa otitis in dogs.

Canine otitis externa is frequently encountered in veterinary practice, caused by primary factors with bacteria and yeast overgrowth acting as secondary and perpetuating factors. The pharmacological support includes anti‐inflammatory, antimicrobials, and antimycotic drugs, but therapeutic failure and antimicrobial resistance are leading to alternative strategies based on phytotherapic products. This study aimed to evaluate an essential oil blend (Otogen®) to treat otitis externa in dogs. The experimental design was divided in: (a) an in vitro approach, based on the European Normative UNI EN 1275:2006, to assess the efficacy of the product against the most frequently isolated microorganisms during otitis externa. (b) an in vivo part, 12 owned dogs presenting with acute otitis externa were enrolled. A significant growth reduction (>99.9%) of Malassezia pachydermatis and Candida albicans after 15 min of contact and Pseudomonas aeruginosa after 1 h of incubation was recorded. For Staphylococcus pseudintermedius, 50% of growth reduction were appreciated after 15 min. Results obtained in vivo after 7 days of blend administration, noted a significant improvement of all the considered parameters (most important were head shaking, erythema, and scraping). The results obtained may support the usefulness of the tested phytotherapic blend to manage acute otitis externa in dogs.

Characterization and in vitro susceptibility profile of bacterial samples harvest from canine chronic otitis

This study aimed to identify which are the most frequent bacteria evolved in cases of chronic otitis in dogs in the metropolitan region of Curitiba, as well to determine their in vitro antimicrobial susceptibility. Data of positive bacterial culture from dogs affected by chronic or recurrent otitis were compiled from the records of the veterinary hospital of Pontifícia Universidade Católica do Paraná, Curitiba, southern Brazil. In a period of 16 months, a total of 83 bacterial cultures were performed, resulting in 192 isolates. All isolates were submitted to antimicrobial susceptibility tests, based on the Kirby-Bauer technique using 17 drugs from 8 antibiotic classes (?-lactams, aminoglycosides, lincosamides, macrolides, polypeptides, quinolones, tetracyclines, and amphenicols). The five most frequent bacterial isolates were Staphylococcus spp. (58.32%), Proteus spp. (14.58%), Escherichia coli (9.90%) and Pseudomonas spp. (8.33%). The four most effective antibiotics were amikacin (13.29%), neomycin (24.47%), gentamicin (25.52%) and tobramycin (26.70%); however, these aminoglycosides may cause ototoxicity, and their use should be restricted when the tympanic membrane is intact. Quinolones also showed antimicrobial effectiveness, with 29.17% of the isolates showing resistance to ciprofloxacin and 29.69% to enrofloxacin. According to the results, it can be concluded that aminoglycosides and quinolones were effective against microorganisms of canine chronic otitis.

Efficacy assessment of PEV2 phage on Galleria mellonella larvae infected with a Pseudomonas aeruginosa dog otitis isolate

Pseudomonas (P.) aeruginosa is the most frequently isolated Gram-negative bacteria in dog otitis. Antimicrobial resistance is particularly prevalent in P. aeruginosa and phage therapy represents a promising alternative therapeutic strategy. The aim of this study was to assess the efficacy of the PEV2 phage against a clinical P. aeruginosa isolate from a canine otitis using a Galleria (G.) mellonella larvae model. The genomic DNA of PAV237 P. aeruginosa isolate was sequenced and analysed. In a first main experiment, the efficacy of PEV2 phage against PAV237 was assessed at different multiplicities of infection (MOI) (50,000, 5000, 500, 50) by analyzing the larvae survival rate during 4 days. In a second experiment, the bacterial and phage titer evolutions were assessed depending on two MOIs (50,000, 5000). No significant survival increase was observed with PEV2 therapy in the infected larvae groups. The generated Kaplan-Meier curves showed that the rate of alive larvae was significantly higher in the non-infected larvae compared to the infected-treated ones irrespective of phage MOIs. An increase of the phage titer was observed at 24 and 48 h post-inoculation (HPI) with both MOIs and the P. aeruginosa titers were lower with MOI 50,000 and 5000 compared to the infectivity control at 24 and 48 HPI. Even if an ineffectiveness of the PEV2 phage was observed on the larvae survival, PEV2 is active against P. aeruginosa in this model and PEV2 replication is correlated with a lower bacterial proliferation in the phage treated larvae.

Определение состава микрофлоры содержимого уха у собак с признаками отита с помощью микроскопического анализа

Otitis in domestic carnivores, particularly in dogs, is an important problem in veterinary science and practice. Ac-cording to various Russian and foreign authors, the spread of otitis externa in dogs varies from 12.5 to 37%. The re-search goal was to study microscopic examination as an effective method for determining the composition of ear contentmicroflora in dogs. The research objective was to conduct a microscopic analysis of the collected material for the comprehensive diagnosis of otitis in dogs. The studies were carried out at the Department of Anatomy and Physi-ology of the State Agricultural University of Northern Trans-Urals and at the veterinary clinics of the City of Tyumen. The samples from 58 dogs were examined microscopically. All animals underwent initial examination. The samples were taken from both ears. The material was applied to a microscope slide, and then dried and Gram stained. The study revealed that in 15 dogs (35%) with suspected exter-nal ear inflammation, coccal forms of bacteria were found; that was indicative of the presence of Staphylococcus spp. and Streptococcus spp. Rod-shaped bacteria were found in 10 dogs (25%), indicating the presence of Proteus spp. and Pseudomonas. Yeast fungi were found in 17 individuals (40%). Fungi were represented by Mallasezia spp and, in isolated cases, Candida. In 42 individuals (75%) with sus-pected inflammation of the external acoustic meatus, the examination revealed bacteria and yeast fungi. The studies have shown that microscopic analysis is an important diag-nostic tool to evaluate the process of inflammation and identify the causes of secondary infection. This analysis may and should be used to identify the qualitative and quantitative composition of microorganisms in the patho-logical material from the ear canal content of sick dogs