Pulmonary Nocardiosis: Risk Factors, Clinical Features, Diagnosis and Prognosis

Raquel Martínez; Soledad Reyes; Rosario Menéndez


Curr Opin Pulm Med. 2008;14(3):219-227. 

In This Article


Nocardia is not a commensal bacillus of the human body, so positive cultures from tissue or normally sterile body fluids should never be ignored. Therefore, after the isolation of Nocardia, we must begin antibiotic treatment while waiting for the antibiogram, which must be individually evaluated. In addition to the clinical response of the patient after receiving the empirical treatment, this antibiogram will be useful, especially in patients resistant to the initial treatment.

The choice of therapy depends on the severity and localization of the infection, whether there is dissemination, the host's immune status, potential drug interactions and toxicity, and the Nocardia species involved.

Historically, the sulfonamides have been the treatment of choice, and currently the TMP-SMX combination is a good choice, as a high percentage of Nocardia isolates are sensitive to it; however, it should be kept in mind that resistance to sulfonamides is most common among N. farcinica and N. ostitidiscaviarium isolates.[48,49,50*]

Amikacin, imipenem,[51,52,53] third-generation cephalosporins, minocycline, netilmicin and amoxicillin-clavulanic acid are drugs that are active in vitro against a large percentage of Nocardia isolates.

In patients with pulmonary nocardiosis and dissemination to other organs, especially the CNS, combined treatment is recommended including a sulfonamide and a bactericidal primary agent, or a combination of imipenem and amikacina. Experimental studies have shown in-vitro synergy with imipenem-cefotaxime, cefotaxime-amikacin and imipenem-amikacin[54,55] with good clinical results. When the CNS is involved, treatment with cefotaxime or ceftriaxone is also recommended.[56] Linezolid, approved in 2000 by the Food and Drug Administration, has shown excellent in-vitro activity against all of the clinically relevant species of Nocardia; moreover, the mechanism of action is unique, so that cross-resistance with other antimicrobials is unlikely. Unfortunately, the high cost and serious toxicities associated with prolonged use of the drug, such as bone marrow suppression, lactic acidosis, peripheral neuropathy and optic neuritis, appear to limit its use and relegate it to salvage therapy, alone or in combination with other antimicrobials.[57,58,59**]

Immunocompetent patients with pulmonary nocardiosis or disseminated nocardiosis outside the CNS should be treated for 6-12 months. In the case of immunodepressed patients, treatment should continue for 1 year[60] and, if possible, the dose of the immunodepressant drug should be reduced. Likewise, the duration of treatment must be at least 1 year for patients with CNS involvement.


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