Treatment of invasive external otitis with cefsulodin.

Thirteen patients with invasive infections of the external ear were treated with cefsulodin sodium. Eleven were elderly diabetic patients with malignant external otitis, and two were nondiabetic adults with cellulitis or chondritis of the external ear. Four of 11 patients with malignant external otitis had extensive disease, with progression of infection to the petrous apex, medial base of the skull, or parapharyngeal soft tissue. Eleven patients had granulation tissue in the external auditory canal, and three presented with cranial nerve palsies (V, VII, IX, X). Pseudomonas aeruginosa was isolated from all patients. Minimal inhibitory concentrations of cefsulodin for the strains isolated were 1.56-6.25 micrograms/ml (mean, 3.37 microliter/ml) and minimal bactericidal concentrations were 1.56-25 micrograms/ml (mean, 5.59 micrograms/ml). Duration of therapy was from one to 12 weeks. Nine patients had a positive clinical response, three had recurrent disease after initial improvement, and one was lost to follow-up. A positive response was correlated with a longer duration of therapy and less extensive disease; complications were minor. Cefsulodin appears to be an effective agent for the treatment of selected patients with invasive external otitis.