Anemia, Aplastic/chemically induced; Anti-Bacterial Agents/adverse effects; Brain Abscess/drug therapy; Chemical and Drug Induced Liver Injury/etiology; Drug Eruptions/etiology; Nocardia Infections/drug therapy; Trimethoprim, Sulfamethoxazole Drug Combination/adverse effects; Acetamides/administration & dosage; Acetamides/therapeutic use; Aged; Anemia, Aplastic/blood; Anti-Bacterial Agents/administration & dosage; Anti-Bacterial Agents/therapeutic use; Brain Abscess/microbiology; Ceftriaxone/administration & dosage; Ceftriaxone/therapeutic use; Confusion/etiology; Drug Eruptions/diagnosis; Drug Therapy, Combination; Humans; Immunocompromised Host; Linezolid; Male; Myasthenia Gravis/complications; Myasthenia Gravis/drug therapy; Myasthenia Gravis/immunology; Oxazolidinones/administration & dosage; Oxazolidinones/therapeutic use; Prednisone/adverse effects; Prednisone/therapeutic use; Trimethoprim, Sulfamethoxazole Drug Combination/administration & dosage; Trimethoprim, Sulfamethoxazole Drug Combination/therapeutic use