Transport swabs from 50 dogs with otitis externa were submitted for
culture on Saboraud dextrose agar (SDA) with chloramphenicol (SDA;
Oxoid, Basingstoke, UK). After incubation for 48 h at 37 2°C in air
supplemented with 5% CO2, isolates were identified as M. pachydermatis
primarily by their ability to grow on this agar and their characteristic
colonial and microscopic morphology. The pH of each of
the nine topical ear cleaners was tested using a Jenway 3510 pH
meter (Camlab Ltd, Cambridge, UK) and is summarized with the ear
cleaner ingredients