Mikroorganismer och antibiotikaresistens vid otitis externa hos hund.
HundOtitis externaStaphylococcus intermediusPseudomonas aeruginosaMalassezia pachydermatis antibiotikaresistens
Canine otitis externa is a common reason for a visit to the vet. Predisposing
factors often complicate treatment and may result in a chronic disease
progression. All otic preparation for topical use in Fass Vet contain antibiotics,
corticosteroids and a fungicide. Sixty cerumen samples from dogs with external
otitis, sent to the Department of Bacteriology at SVA, were categorised according
to their profile of isolated microorganisms. Staphylococcus intermedius alone or
together with Malassezia pachydermatis were the most common organisms found.
Fifteen percent of the samples contained M. pachydermatis only. M.
pachydermatis and Pseudomonas aeruginosa in combination was also fairly
common. Combinations of S. intermedius, P. aeruginosa and M. pachydermatis
comprised about 80 % of the material.
Antimicrobial susceptibility of S. intermedius and P. aeruginosa was determined
to antibiotics used in drugs licensed for veterinary otic preparations. Resistance to
some of those antibiotics was seen as well as to some other antibiotics. A
relatively high number of penicillin-resistant isolates of S. intermedius was found
(81.5%). The antimicrobial susceptibility pattern in this study was similar to that
of other studies on S. intermedius isolates from dogs with chronic otitis and
pyodermias. The majority of bacterial isolates in this study were most likely
sampled from dogs with chronic otitis. A larger study would be required to
2
investigate a possible connection between antibiotic resistance in bacteria that can
cause chronic otitis and antibiotic treatment of the dog for other diseases.