Effect of tympanic cavity evacuation and flushing on microbial isolates during total ear canal ablation with lateral bulla osteotomy in dogs.
OBJECTIVE
To evaluate differences in bacterial numbers, identity, and susceptibility in samples obtained from the tympanic cavity on entry (preflush) and after evacuation and lavage (postflush) and assess perioperative and empiric antimicrobial selection in dogs that underwent total ear canal ablation (TECA) with lateral bulla osteotomy (LBO) or reoperation LBO.


METHODS
Prospective clinical study.


METHODS
34 dogs.


METHODS
TECA with LBO or reoperation LBO was performed on 47 ears. Pre- and postflush aerobic and anaerobic samples were obtained from the tympanic cavity. Isolates and antimicrobial susceptibility patterns were compared.


RESULTS
Different isolates (31/44 [70%] ears) and susceptibility patterns of isolate pairs (6/44 [14%] ears) were detected in pre- and postflush samples from 84% of ears. Evacuation and lavage of the tympanic cavity decreased the number of bacterial isolates by 33%. In 26% of ears, bacteria were isolated from post-flush samples but not preflush samples. Only 26% of isolates tested were susceptible to cefazolin. At least 1 isolate from 53% of dogs that received empirically chosen antimicrobials postoperatively was resistant to the selected drugs. Anaerobic bacteria were recovered from 6 ears.


CONCLUSIONS
Accurate microbiologic assessment of the tympanic cavity should be the basis for selection of antimicrobials in dogs undergoing TECA with LBO. Bacteria remain in the tympanic cavity after evacuation and lavage. Cefazolin was a poor choice for dogs that underwent TECA with LBO, as judged on the basis of culture and susceptibility testing results.
Hettlich
Bianca E
BE
Department of Veterinary Small Animal Medicine, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843, USA.
Boothe
Harry W
HW
Simpson
R Bruce
RB
Dubose
Kim A
KA
Boothe
Dawn M
DM
Carpenter
Mark
M
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D015169:Colony Count, Microbial / Q000662:veterinary; D004283:Dog Diseases / Q000188:drug therapy / Q000382:microbiology / Q000601:surgery*; D004285:Dogs; D024881:Drug Resistance, Bacterial; D004424:Ear Canal / Q000601:surgery*; D004432:Ear, Middle / Q000382:microbiology / Q000601:surgery; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D008297:Male; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D010027:Osteotomy / Q000662:veterinary; D010032:Otitis Externa / Q000188:drug therapy / Q000382:microbiology / Q000601:surgery / Q000662:veterinary*; D010033:Otitis Media / Q000188:drug therapy / Q000382:microbiology / Q000601:surgery / Q000662:veterinary*; D011446:Prospective Studies
D000900:Anti-Bacterial Agents