Bordetella Hinzii Model of Otitis Media in the C57Bl/6J Mouse

A mouse model of otitis media (OM) was developed to study the effects of the Bordetella hinzii pathogen on the hearing sensitivity of C57BL/6J mice. This bacterial strain was recently discovered in resident mouse colonies which displayed a phenotype limited to moderate elevation of hearing thresholds. Sixteen mice were inoculated intranasally with either a high- or low-dose suspension containing B. hinzii; four mice served as uninfected controls. Serial Distortion Product Otoacoustic Emissions (DPOAEs) and Auditory Brainstem Response (ABR) measures were collected on all mice at weekly intervals. Throughout the temporal course of the infection, both DPOAEs and ABRs showed changes from baseline levels with 60% of the low-dose group and 100% of the high-dose group developing OM, while control animals did not show any significant changes during the same time period. Functional test measures were compared with histopathology results and showed DPOAEs to be more sensitive (100%) than ABRs (66%) for the low-dose group. Furthermore, ABRs were found to be more sensitive to OM infection in the high-dose group (100%) than the low-dose group (66%). Upon histological examination, a clear manifestation pattern of OM was not evident in either dosage group; various animals in both groups exhibited unilateral, bilateral, or no OM throughout the temporal course of the study