Torticollis in mice intravenously infected with Mycobacterium tuberculosis

Female BALB/cAnNCrl (n = 170; age, 6 to 9 wk) mice were infected by intravenous inoculation of 5 × 10(6) cfu Mycobacterium tuberculosis strain Erdman (ATCC 35801). Between day 52 and 5 mo after infection, 10 of the 170 mice infected according to this protocol developed torticollis, including mice in treatment groups that received combination antibiotic therapy of rifampin-pyrazinamide or moxifloxacin-rifampin-pyrazinamide. Torticollis did not develop in mice receiving isoniazid- rifampin-pyrazinamide therapy, nor was it present in the cohort of aerogenically infected mice. Affected mice were euthanized, and complete necropsy evaluation was performed on 4 mice. Gross necropsy evaluation revealed typical tuberculosis lesions in lungs of infected mice. Histologic evaluation of tissues revealed granulomatous otitis media with intralesional acid-fast bacilli consistent with Mycobacterium tuberculosis. These cases represent an unusual finding specific to the intravenous mouse model of Mycobacterium tuberculosis and may represent a model of a similar condition in humans that is known as tuberculous otitis media.