A 52-year-old man has a fever and cough productive of thick, gelatinous sputum that worsens over 4 days. On physical examination, his temperature is 38.2deg C. On auscultation of the chest, diffuse crackles are heard at the right lung base. Laboratory studies show WBC count, 13,240/mm3 with 71% segmented neutrophils, 8% bands, 15% lymphocytes, and 6% monocytes. A sputum gram stain shows gram-negative bacilli with mucoid capsules. His condition improves after a course of gentamicin therapy. Which of the following complications of this infection is he most likely to develop?