OBJECTIVES

Otitis externa, both acute and chronic and their possible complications are very common in canine clinic. In some cases of otitis externa, the appearance of resistant germs as Pseudomonas spp or E. coli or Proteus mirabilis that acts as perpetuation factors of the pathology or yeast (Malassezia pachydermatis) constitute a difficult problem for the practitioner to treat it with effectiveness and speed.

The reason of the present study is to evaluate the effectiveness of a new eardrops solution for otitis externa in dogs: association of a fluoroquinolone (marbofloxacin), an anti-fungal (Clotrimazole) and anti-inflammatory (Dexamethasone as acetate).

The study was aimed mainly to dogs, of any race and age, affected of otitis externa with presence of secretion or extensive suppuration. All cases were identified by using cytology and bacterial culture.

MATERIALS

Seven veterinary clinics participated in the study. 51 dogs were included of both sexes, different races, ages, with acute and chronic manifestation, unilateral or bilateral otitis externa. A general dermatology examination was carried out in all animals. Pain, erythema, ceruminous or purulent secretion, ulceration were assessed in outer ear and ear canal. The alterations relationship with chronic injuries was also valuated. All cases were valued in three visits at: Do (inclusion), D8 and D15 (end). The dosage of the product was a single daily application (10 drops) in affected ears, starting from D0 and during 8 followings days (in same chronic cases was continued until 14 day).

The inclusion criteria were all dogs that presented obvious signs of acute or chronic otitis externa. The animals with otitis parasitic, otitis due to dermatosis autoimmune, neoplasms, hypersensitivity, foreign bodies or strong chronic otitis with important changes in ear canal was not included.

Dogs with systemic illness or rupture of tympanum or previous treatment a month before with systemic or topic corticoids, antibiotics or anti-fungal in the previous ten days to the beginning of the treatment was also excluded

Neither other treatment was allowed except ear cleaning on first day if it was necessary.

RESULTS

 Cultures: 84% of cases were positive. Bacteria isolated were Staphylococcus (23%), Streptococcus (14%), Pseudomonas (18%) and E. coli (4%). Malassezia pachydermatis was isolated in 25%. More than one agent was isolated in 3 cases.

 Pain assessment: Several pain degrees was considered in 42 dogs (78.5%). 36 dogs improved at D8 and only 2 cases remained with pain at D15.

 Secretion assessment: Secretions or exudations were watched in 26 dogs (50,9 %). Only three cases did not improve at D8, remaining exudation in 2 cases at D15.

 Erythema assessment: Several degrees were watched in outer ear and ear canal in 45 dogs (88.2%). All animals, except two, improved at D8 and D15. A low inflammatory reaction was observed in 5 animals.

 Ulceration assessment: Several ulceration degrees were watched in 21 cases (41.18 %). The ulceration of ear canal was so important in 7 cases. 11 dogs improved entirely at D8,7 dogs had a partial improvement and 3 animals did not respond. 14 dogs recovery at D15, 4 dogs had an obvious improvement and 3 dogs that had not reply at D8 still without it.

 Tolerance: No local or general side effect was observed in any dogs.

CONCLUSION

 The effectiveness of Marbofloxacin for pyoderma and otitis externa in dogs (wide spectre against Staphylococcus intermedius, E. coli, Proteus mirabilis and Pseudomonas aeruginosa) and of Clotrimazole against Malassezia pachydermatis has been evaluated by several authors *.

 The study was targeted towards dogs with otitis externa with bacterial or yeast implication.

 The dogs with primary cause well known (otitis parasitic or neoplasms) were refused.

 The study shows the efficacy, in mostly of the dogs affected by otitis externa of clinical signs after the application of eardrops solutions of Marbofloxacin, Clotrimazole and Dexamethasone.

 The pain degree improves in 95%, Erythema in 95.5%, secretion and exudates in 92.3% and ulceration injuries recovery or improves in 85.7%. The product was effective especially in those cases with presence of Pseudomonas spp and with intense suppuration.

 Several systemic treatments are indicated for mostly cases of severe suppurative otitis externa, however with this study, the clinical improvement is achieved without systemic treatment in an important number of cases.