Heme-iron restriction provides a selective advantage during experimental otitis media in a mixed infection model.

Restricted 86-028NP/pKM1.1 was mixed with 10 fold more 86-028NP/pGM1.1 replete for heme-iron for inoculation into the chinchilla middle ear. On days one and four post-inoculation, the total bacterial burden was enumerated from middle ear mucosal homogenates (A). The fluorescence emission spectrum was used to determine the origin of each colony. Statistical analysis was performed using a two-tailed t-test. Infected middle ear inferior bullae were analyzed by hematoxylin and eosin staining of thin sections with biofilm (Bio) as well as mucosa (M) and bone (B) highlighted (B). 86-028NP that was restricted (D) or replete (C) for heme-iron was individually inoculated into the chinchilla middle ears. Four days post inoculation, infected middle ear bullae were fixed and processed for histological examination. Scale bar = 50 µm.

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