Biomedical subjects
Edmund J Rosser
Publications and source records attributed to Edmund J Rosser.
Causes of otitis externa.
Dogs with long-standing, chronic, recurrent otitis externa often represent one of the most frustrating types of problems in daily clinical practice. The important aspect of this discussion is that the clinician may be presented with a patient in which the primary chief complaint is otitis externa but a wide variety of disease processes may be causing the problem, including various combinations of the primary, predisposing, and perpetuating causes as discussed previously. The use of a thorough history and general and dermatologic physical examinations often leads the clinician to establish a systematic approach to identify the specific underlying problems. Until this is accomplished, the recurrent nature of the otitis externa will remain as a persistent problem.
Measurement of normal middle ear cavity volume in mesaticephalic dogs.
Water-filling and serial computed tomographic (CT) imaging techniques were used to measure normal middle ear cavity volume (MECV) in 18 dogs (10 live dogs, eight cadavers; 36 ears in total). The specific aims of this study were to (1) compare MECV measurements by water-filling and CT techniques and (2) define a model of MECV vs. body weight (BW) from CT values. There was a significant difference between the two techniques (P = 0.02). The volume obtained by water filling was consistently greater than that obtained by computed tomography. MECV (expressed in ml) increased with BW (expressed in kg) according to the following formula: MECV = -0.612 + 0.757 (In BW) (P<0.01, R2 = 0.74).
Frequency of isolation and antimicrobial susceptibility patterns of Staphylococcus intermedius and Pseudomonas aeruginosa isolates from canine skin and ear samples over a 6-year period (1992-1997).
Staphylococcus intermedius (S. intermedius) was isolated from 88.6% and 49.4% of skin and ear samples, respectively, during the years 1992 through 1997, and frequency of isolation remained unchanged. More than 95% of all S. intermedius isolates were susceptible to cephalothin and oxacillin, providing support for empirical treatment of canine skin and ear infections with cephalexin. Pseudomonas aeruginosa (P. aeruginosa) was isolated from 7.5% and 27.8% of skin and ear samples, respectively. The frequency of isolation from skin samples increased over the study period. Because of multidrug-resistant profiles for P. aeruginosa isolates, especially for ear isolates, empirical treatment of P. aeruginosa infections is not advisable.
Cutaneous paecilomycosis in a cat.
A cat was presented for a 2-year history of a recurrent, soft-tissue swelling of the left metacarpal region. The mass was excised and submitted for aerobic and anaerobic bacterial culture, fungal culture, and histopathological examination. Cultures revealed the organism Paecilomyces lilacinus, and histopathological examination showed a nodular mycotic granuloma. Itraconazole (10 mg/kg body weight, per os [PO], q 24 hours) was administered and continued for a total of 60 days, with a swelling of the upper lip occurring 3 months after the initial presentation. Subsequent surgical excisions and debridements along with treatment with itraconazole (20 mg/kg body weight, PO, q 24 hours) for a total of 4 months were curative.
Comparison of microbial isolates and susceptibility patterns from the external ear canal of dogs with otitis externa.
Otic exudate was obtained from 33 dogs with otitis externa for cytopathology and culture. Two samples were taken from the same location in the external ear canal, for a total of 100 samples. Thirty-six (36%) samples isolated only a single organism, of which 21 (21%) were Malassezia spp. Two organisms were present in 23 (23%) of the samples. Cultures of the two samples agreed in 40 (80%) of the 50 pairs. Cytopathology agreed with culture results only 68% of the time. Cytopathology and culture may not be as definitive as previously assumed because of apparent variability of the microbial population within the external canal.