Inhibition of Nocardia asteroides by neutrophils

Neutrophils are found in lesions of Nocardia asteroides infection, but neutrophils kill few nocardiae in vitro. For determination of neutrophil inhibition of nocardiae, neutrophils and nocardiae were incubated together. Filament formation and amino acid uptake by nocardiae were inhibited for 7.5 hr. Thereafter, nocardiae extended long filaments from within neutrophils to the outside and increased their rate of amino acid uptake. Addition of freshly isolated neutrophils at 7.5 hr of incubation prolonged the inhibition. Electron micrographs revealed that neutrophils phagocytosed nocardiae but that most nocardiae did not appear damaged. Formalin and 2-deoxy-D-glucose abrogated the inhibition by neutrophils. Lysozyme and granule-cationic proteins inhibited amino acid uptake under some conditions. Lactoferrin and lactic acid had no effect, and the oxidative metabolic burst was not required. These findings and clinical observations suggest that inhibition of N. asteroides by neutrophils may be important in vivo.     

Contribution of neutrophils and cell-mediated immunity to control of Nocardia asteroides in murine lungs

To distinguish between the contributions of neutrophils and cell-mediated immunity to defense against Nocardia asteroides in the lung, we induced pneumonia in BALB/c mice by intranasal inoculation. We studied the course of pneumonia by histology, bronchoalveolar lavage, and quantification of colony-forming units in lungs. Mice with intact host defenses had an initial inflammatory response, consisting mostly of neutrophils, followed by a mononuclear cell infiltrate. Nocardiae were eradicated during the seven days after inoculation. Mice in which the early, predominantly neutrophil inflammatory response was prevented with mechlorethamine or antiserum to neutrophils had little inflammation, and nocardiae grew extensively. Mice in which cell-mediated immunity was impaired with cyclosporin A or cortisone acetate developed abscesses; neutrophils were abundant, but nocardiae proliferated. The occurrence of these three separate and distinct patterns suggested that both neutrophils and cell-mediated immunity are necessary for optimal control of N. asteroides infection.     

Superior vena cava syndrome caused by Nocardia asteroides

A patient developed the superior vena cava syndrome from Nocardia asteroides pneumonia with mediastinitis. Specific treatment was dangerously delayed because malignancy was primarily suspected, and nocardial infection was not initially considered. The correct diagnosis was eventually made by appropriate stains and culture of a lung aspirate. Specific therapy with sulfonamide resulted in a cure of the infection, disappearance of facial swelling, and a long-term state of clinical well-being. Active nocardial pneumonia with mediastinitis is a treatable cause of the superior vena cava syndrome and should be considered in the differential diagnosis.     

Nocardia asteroides infection complicating neoplastic disease

During the decade 1960–1969, Nocardia asteroides was isolated from sputum, abscesses or exudates in twenty-two patients at Memorial Hospital. These patients could be divided into two groups. Group I consisted of thirteen patients with underlying neoplasms receiving radiation or chemotherapy in whom unequivocal evidence of nocardial infection developed. Clinical manifestations included bronchopneumonia, lobar pneumonia, necrotizing pneumonia with single or multiple abscesses, and brain, hepatic or scrotal abscesses. Ten patients had either leukemia or lymphoma. The simultaneous presence of tumor and nocardial infection in the lung was noted in five cases. Sputums or exudates from the patients in group I were positive for organisms simultaneously in both culture and smear in only a third of examinations; this stresses the need for multiple bacteriologic examinations when the diagnosis of nocardiosis is suspected. Although the underlying disease was usually progressively fatal, an excellent response to sulfonamides with resolution of pulmonary disease was noted in several patients who were maintained on anticancer therapy.     

Nocardia asteroides infection complicating rheumatoid arthritis

We describe a case of pulmonary nocardiosis in a patient with rheumatoid arthritis (RA) receiving treatment with combined immunosuppressive agents and prednisone. This infection is still considered rare, hard to diagnose, and difficult to treat. To the best of our knowledge, such a case has not been described in a patient with RA.     

Nocardia asteroides native valve endocarditis.

A 39-year-old man with a history of injection drug abuse was given a diagnosis of Nocardia asteroides native aortic valve endocarditis, and he required valve replacement therapy, despite having received potent antimicrobial therapy. This is the first reported proven case of native valve endocarditis due to Nocardia species.     

Apparent cure of intracranial Nocardia asteroides infection by minocycline.

Currently preferred therapy for CNS Nocardia infection is high-dose sulfonamide coupled with surgical drainage. Neither of these could be used in our patient; this led to therapy with minocycline alone. Several months after completion of minocycline therapy, the patient apparently is cured. His favorable outcome probably resulted from a combination of susceptibility of the organism to minocycline coupled with good CNS penetration of the agent resulting in CNS levels of drug 16 to 22 times higher than the Nocardia inhibitory concentration.     

Lung infection caused by Nocardia asteroides in a renal-transplant patient

A 65-yr-old man developed an acute lung infection while being treated for a rejection episode 2 months after renal transplantation. A chest X-ray revealed a pulmonary infiltrate. Nocardia asteroides was cultured from a percutaneous lung aspirate. The patient was successfully treated with trimethoprim/sulfamethoxazole.