Nocardia spp

• N. abscessus
• N. asteroides
• N. beijingensis
• N. brasiliensis
• N. cyriacigeorgica
• N. farcinica
• N. nova complex
• N. otitidiscaviarum
• N. veterana

Gram Stain

• Gram positive bacilli long, branching, thin, finely beaded (aerobic)

Clinical Significance

These organisms are widely distributed in nature especially in soil, decaying vegetative matter, and aquatic environments. Inhalation is most common mode of transmission.

They are opportunistic pathogens, causing infections in immunocompromised patients, especially in setting of chronic steroid use, TNF inhibitors, malignancy, transplant recipient, chronic lung disease, diabetes, and/or HIV.

They can cause acute or chronic wounds or abscesses at various body sites including skin/soft tissue, lung, and central nervous system.

They have also been implicated in medical device related infections, post-operative wound infections, CAPD peritonitis, and endophthalmitis.

Usual Susceptibility Pattern

Although TMP/SMX is the drug of choice, susceptibility varies depending on the species.

These organisms are typically susceptible to linezolid, amikacin, and minocycline (more active than doxycycline).

Susceptibility to ceftriaxone, amoxicillin-clavulanate, imipenem, meropenem, and quinolones (moxifloxacin demonstrates best in vitro activity) is variable and species dependent. 

Daptomycin does not have activity against Nocardia spp.

Combination therapy recommended (according to susceptibility results).

Prolonged therapy is generally required, especially if patient is immunocompromised.