External Otitis in Dogs Caused by Pseudomonas Aeruginosa
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Transcript of External Otitis in Dogs Caused by Pseudomonas Aeruginosa
External Otitis in Dogs Caused by Pseudomonas Aeruginosa
Member’s name: Yong Mei Chan 1108-2250Khiu Poh Shyan1108-2191
PHAR 3752 Veterinary pharmacy
Introduction• External Otitis is the medical term for ear infection.• A chronic inflammation of the epithelial lining of the
external auditory canal.• Skin Disease.
Pseudomonas Aeruginosa• P Aeruginosa is a motile gram negative bacillus
ubiquitous in the environment but uncommon in the canine ear.
• It grows within moist environment.
• This predisposition makes infectious otitis caused by P Aeruginosa more common in tropical climates.
• Pseudomonas Aeruginosa is a bacterial infection that is considered “opportunistic”.
• It rarely causes disease in healthy animals but multiplies freely infecting those who are already sick or who have weakened immune systems.
Peudomonas Otitis in a cocker spaniel.
Etiopathogenesis • It is helpful to regard the outer ear as an L-shaped
dermoepidermal structure with follicles and ceruminous and sebaceous apocrine glands.
• Alteration to this anatomical structure produce a micro-environmental imbalance that can give rise to inflammation and consequent infection.
Cont.….• The following are all important factors:– The external ear conformation, which can impair
ventilation.– The vertical canal, which can impair ventilation.– The natural narrowing and bend of the canal, which favors
stenosis.– The presence of hairs, which can obliterate the canal
lumen.– The abundance of secretory glands, which produce excess
exudate.
Symptoms• One of the leading symptoms of a Pseudomonas infection is a
strong odor. Pseudomonas ear infections are extremely smelly with lots of drainage or pus.
• Other symptoms include:– Frequent scratching of the ear– Frequent shaking of the head– Pain in and around the ear– Redness and swelling inside the ear– Severe inflammation and ulceration of the canal– Yellow or green malodorous suppurative mucoid discharge
Treatment• The two most critical elements of treating
Pseudomonas otitis are:
1. Keeping the ear clean2. Administering antimicrobial therapy.
Antimicrobial TherapyAntibiotic Class Specific Example Comments
Aminoglycoside
Gentamicin Numerous otic products
AmikacinFor topical use, dilute injectable formulation to 50mg/ml with saline
Tobramycin Use ophthalmic solution
Fluoroquinolones
Marbofloxacin 2.75 to 5.5 mg/kg once a day orally
Enrofloxacin5 to 20 mg/kg once a day orally; topical otic formulation
Ciprofloxacin 22mg/kg once a day orally; human otic products
Polypeptides Polymyxin B Numerous otic productsColistin Human otic suspension
CarboxypenicillinsTicarcillin
Dilute 6g in 12ml of saline, reconstitute 2ml of solution in 40 ml saline, and freeze in 2ml aliquots (stable only for a few days if not frozen)
Carbenicillin 10 to 20 mg/kg three times a day IV3rd Generation Cephalosporin
Ceftazidime 25 to 50 mg/kg three times a day IV
Miscellaneous
Silver sulfadiazine (SSD) For topical use, mix one part 1% SSD cream with nine parts water; available in proprietary formulation with enrofloxacin
Tris- EDTA Presoak ear with Tris- EDTA for 15 to 30 minutes before applying topical antimicrobial.
ReferencesBooks:1. Gotthelf L. 2004. Small Animal Ear Diseases: An Illustrated Guide, Edition 2. Saunders.2. Harvey R, Harari J, DeLauche A. 2001. Ear Diseases of the Dog and Cat. Wiley-Blackwell.
Articles:3. Morris DO. 2004. Medical therapy of otitis externa and otitis media. Vet Clin Small Anim 34:
541–555.4. Cole LK. 2013. Topical and systemic medications for otitis externa and otitis media. Western
Veterinary Conference5. Rosser EJ, et al. 2004. Causes of otitis externa. Vet Clin Small Anim 34: 459–468.6. D. H. Lloyd- Otitis, Leon 2012 Canine Otitis Externa7. Guardabassi. L., Houser, G. A., Frank, L. A., Papich, M. G. Guidelinesfor antimicrobial use in
dogs and cats. In: Guide to Antimicrobial Use in Animals, Guardabassi, Jensen &Kruse,Blackwell Publishing, 2008, page 193.
8. Schick, A.E., Angus, J.C., Coyner, K.S., Variability of laboratory identification and antibiotic susceptibility reporting of Pseudomonas spp. isolates from dogs with chronic otitis externa, Vet. Dermatol., 2007, 18(2), 120-6.