Infectious Disease Compendium

Nocardia

Microbiology

Gram-positive branching, filamentous rods. Includes N. asteroides, N. brasiliensis, Nocardia cyriacigeorgica, N. farcinica, N. nova, N. otitidiscaviarum, N. pseudobrasiliensis, N. transvalensis.

It is partially acid fast and it will cause a positive (1-3)-β-D-glucan. I know. I had 3 transplant patient swith a positive (1-3)-β-D-glucan brain and lung abscess I thought was fungal but grew Nocardia (Here is the case). There are twp case reports on PubMed but I have now reported 3 cases on my PubMed blog. So I have 60% of the worlds literature. Ha!

Epidemiologic Risks

Found in water and soil, it is usually acquired from trauma or inhalation. Can occur in normal but more likely the immunoincompetent. High-dose steroids, history of Cytomegalovirus disease, and high levels of calcineurin inhibitors are risk factors for infection in organ transplant recipients (PubMed).

In transplant patients it increases motrality 10 fold (PubMed).

Syndromes

Ascending nodular lymphocutaneous disease, often after trauma from wood or other organic material.

Cavitary pneumonia often with concomitant brain abscess (PubMed), especially in the immunocompetent and steroid use.

Occasional disseminated disease in the immunoincompetent.

Nocardia cyriacigeorgica caused soft tissue infections:

"All patients reported having received injections of unknown substances described as “hydrogel,” “botulinum toxin,” “silicone,” “gel filler,” or “biogel.” Six patients indicated that they had received injections from an unlicensed person, either at home, in a hotel, or at a gathering where these injections were administered to multiple persons; these patients had been referred to this provider through friends or Internet sites. (PubMed)"

Just let some random guy inject unknown material into your ass. Hard to believe.

In Mexico N. braziliensis is the most common cause mycetoma.

Treatment

Susceptibility can be variable and, as best as can be determined, should be done. Tmp/sulfa OR minocycline OR third generation cephalosporins OR imipenem OR amikacin. Often needs multiple drugs and surgical debridement for cure.

However, "93% of the N. farcinica isolates were resistant to sulfonamides. Also, during the course of our study, the resistance of N. farcinica to TMP-SMZ increased 24 percentage points (from 67% in the 1990s to 91% in the 2000s), and the resistance of N. nova to TMP-SMZ increased 24 percentage points (from 41% in the 1990s to 65% in the 2000s)(PubMed)."

For all species, "61% were resistant to sulfamethoxazole and 42% were resistant to tri- methoprim-sulfamethoxazole (PubMed)."

Resistance to sulfa may be dependent of the lab, a 2012 review found only 2% were resistant to sulfa (PubMed).

Notes

Ironically, those with cardiac transplants have increased risk. (Get it? Those with no cardia get Nocardia? My son thinks it's a lame joke).