Lk. Cole et al., MICROBIAL-FLORA AND ANTIMICROBIAL SUSCEPTIBILITY PATTERNS OF ISOLATEDPATHOGENS FROM THE HORIZONTAL EAR CANAL AND MIDDLE-EAR IN DOGS WITH OTITIS-MEDIA, Journal of the American Veterinary Medical Association, 212(4), 1998, pp. 534
Objective-To compare microbial flora and antimicrobial susceptibility
patterns of isolated pathogens from the horizontal ear canal and middl
e ear in dogs with otitis media. Design-Prospective study. Animals-23
dogs with chronic bilateral otitis externa. Procedures-Swab specimens
of the horizontal ear canal and middle ear were obtained for cytologic
analysis, bacterial culture, and antimicrobial susceptibility testing
, integrity of the tympanic membrane was observed. if the tympanic mem
brane was intact, myringotomy was performed to collect specimens. Resu
lts-Otitis media was diagnosed in 38 of 46 (82.6%) ears evaluated. The
tympanic membrane was intact in 71.1% of the ears with otitis media.
The 3 most common organisms isolated from the horizontal ear canal and
middle ear were Staphylococcus intermedius, yeast, and Pseudomonas sp
p. A difference in total isolates or susceptibility patterns between t
he horizontal ear canal and middle ear was found in 34 (89.5%) ears. C
ompared with results of bacterial culture, cytologic examination of sw
ab specimens was not as effective for detection of rods and cocci from
the middle ear. Clinical Implications-In dogs with chronic otitis ext
erna, otitis media often exists even when there is an intact tympanic
membrane. In our study, the same isolates were rarely found in the hor
izontal ear canal and middle ear. Therefore, to choose appropriate ant
imicrobial agents, in addition to cytologic examination, bacterial cul
ture and susceptibility testing of swab specimens from the horizontal
ear canal and middle ear should be performed.