title: Opportunistic pneumonia: a clinicopathological study of five cases caused by an unidentified acid-fast bacterium.
abstract: Five patients had opportunistic pulmonary infection caused by acid-fast bacilli, unusual clinical presentations and a unique pathological picture. Clinically, these cases mimicked septic pulmonary emboli or bacterial pneumonia. The infection was temporally related to high-dose corticosteroid therapy, given for renal-transplant rejection in four patients and for therapy of lymphocytic lymphoma in one. Histologic sections of lung-biopsy or autopsy material showed an acute suppurative pneumonia with dense alveolar infiltration by neutrophils, without granuloma formation or caseous necrosis. Predominantly intracellular acid-fast bacilli were present. The organism failed to grow in culture on routine bacterial, fungal and mycobacterial mediums. This unusual and possibly new acid-fast organism is a probable cause of suppurative pneumonia in impaired hosts receiving corticosteroid therapy.
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000009:adverse effects; D000907:Antibodies, Bacterial / Q000032:analysis; D001419:Bacteria / Q000302:isolation & purification*; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects; D008168:Lung / Q000382:microbiology / Q000473:pathology*; D008297:Male; D011014:Pneumonia / Q000175:diagnosis / Q000382:microbiology* / Q000473:pathology; D011650:Pulmonary Alveoli / Q000473:pathology; D011655:Pulmonary Embolism / Q000175:diagnosis
chemical_list: D000305:Adrenal Cortex Hormones; D000907:Antibodies, Bacterial; D007166:Immunosuppressive Agents