Dermatologic Manifestations of Nocardiosis Medication

Updated: Dec 09, 2016
  • Author: Brent A Shook, MD; Chief Editor: Dirk M Elston, MD  more...
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Medication

Medication Summary

Sulfonamides have been the antimicrobial agents of choice for more than 50 years and are recommended based on accumulated clinical experience because results from in vitro studies have been less than impressive. TMP-SMZ is used most commonly. Other sulfonamides used include (1) sulfadiazine, which is not recommended as first-line therapy because of significant risk of oliguria, azotemia, and crystalluria in patients who do not maintain a high fluid intake, and (2) sulfisoxazole, which is as equally effective as sulfadiazine and much less likely to cause oliguria, although no parenteral form is available (2 g PO q6h in adults).

Potassium iodide is an older therapy active against lymphocutaneous nocardiosis and is not recommended for severe infections or systemic disease.

Newer antimicrobials such as linezolid have been used successfully in combination with more traditional agents in more resistant or severe cases of nocardiosis. [22] Linezolid is the only antimicrobial that has been shown to be active against all Nocardia species in vitro. [23]

A case report demonstrated successful use of oral minocycline in a patient who did not respond to intravenous cephalosporin therapy for primary cutaneous nocardiosis caused by N brasiliensis. [24]

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Antibiotics

Class Summary

Empiric antimicrobial therapy must be comprehensive and cover all likely pathogens in the clinical setting. Imipenem is consistently active in vitro, although 18-36% of Nocardia farcinica strains are not susceptible and 70% of Nocardia brasiliensis strains are resistant. Because most primary cutaneous nocardiosis is caused by N brasiliensis, imipenem is mostly used to treat systemic disease. The parenteral drug of choice for initial therapy in persons with systemic disease is amikacin in combination with imipenem. Tobramycin is an aminoglycoside to which many nocardial strains are resistant, especially N farcinica.

A case report demonstrated successful use of oral minocycline in a patient who did not respond to intravenous cephalosporin therapy for primary cutaneous nocardiosis caused by N brasiliensis.

Trimethoprim/sulfamethoxazole (Bactrim DS; Septra DS)

This is first-line treatment for both cutaneous and systemic nocardiosis. It inhibits bacterial growth by inhibiting the synthesis of dihydrofolic acid. It has maximal efficacy against N brasiliensis. More than 90% of N asteroides and N transvalensis isolates are sensitive. It is not effective against N otitidiscaviarum.

Minocycline (Dynacin, Minocin)

Minocycline is the second drug of choice because of excellent in vitro activity against most pathogenic nocardial species. It is especially effective in pulmonary nocardiosis and N farcinica (4% resistance). Only Nocardia transvalensis isolates are significantly resistant (46%). A case report demonstrated successful use of oral minocycline in a patient who did not respond to intravenous cephalosporin therapy for primary cutaneous nocardiosis caused by N brasiliensis.

Amikacin (Amikin)

Amikacin irreversibly binds to the 30S subunit of bacterial ribosomes; it blocks the recognition step in protein synthesis and causes growth inhibition. Along with imipenem, amikacin is currently the most active parenteral drug in vitro against nocardiosis (90-95% of all strains). N transvalensis has up to an 18% resistance. Amikacin is extremely effective against N farcinica (0% resistance) and in immunocompromised patients. Unfortunately, potential adverse effects may limit its usefulness for the long courses needed for cure.

Check peak (20-35 mcg/mL) and trough (< 5 mcg/mL) levels.

Cefotaxime (Claforan)

Cefotaxime arrests bacterial cell wall synthesis, which, in turn, inhibits bacterial growth. It is a third-generation cephalosporin with a gram-negative spectrum. It has lower efficacy against gram-positive organisms. High levels of resistance are seen against third-generation cephalosporins by N farcinica. Cefotaxime is recommended in combination with amikacin or imipenem in acutely ill patients.

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