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Program

WSU Medical School

Training Level

Medical Student

Institution

Wayne State University

Abstract

Nocardia species are gram-positive, aerobic, partially acid-fast organisms with a beaded branching growth pattern. This species is commonly found in soil, dust, decomposing vegetation, salt and fresh water. Nocardia species are opportunistic bacteria, acquired either through inhalation of airborne spores or direct skin inoculation. The typical patient population includes cases of neoplasms, solid organ and hematopoietic stem cell transplant on immunosuppression, HIV infection, and long-term steroid use. Of all the nocardiosis cases, 22-39% of patients are immunocompetent. Although rare, Nocardia bacteremia, in conjunction with disseminated disease, has a 50% mortality rate. The usual clinical tableau consists of severe pulmonary disease, a frequent mimicker of lung tumors and tuberculosis, and central nervous system infections, such as brain abscess or meningitis. Here we present a case of Nocardia bacteremia with systemic nocardiosis in an HIV/AIDS patient. The patient is a 48 year-old African American male with a history of untreated HIV due to lack of insurance. He presented to the ED with worsening cough, shortness of breath, generalized weakness and fatigue over the past two months along with a left axillary abscess. The patient was in septic shock on arrival with hypotension, tachycardia, leukocytosis and blood cultures positive for Nocardia farcinica. An X-ray of the chest revealed a left lower lobe pneumonia with positive sputum cultures for the same species. The axillary abscess was excised with cultures returning positive for Nocarida farcinica as well. In addition, the infection also manifested with skin lesions and bilateral ring enhancing brain lesions on MRI. The patient was started on Vancomycin, Cefepime, Bactrim and Azithromycin upon arrival. After cultures returned, he was switched to IV Amikacin, Bactrim and Meropenem for a duration of one-year total.The most common Nocardia spp. responsible for infections in humans are N. asteroides (80-90%) followed by N.brasiliens, N. farcinica and N. nova. Nocardiosis usually affects the lungs, followed by the central nervous system, with skin, soft tissue and pleura, less commonly involved. Nocardia farcinica is known to be multi-drug resistant and more prone to dissemination. AIDS patients with a CD4 count <200 cells/uL and those not on HAART or Bactrim for PCP prophylaxis are at a higher risk for dissemination. Diagnosing these patients can be cumbersome due to the length of time it takes for Nocardia to grow in blood cultures: median incubation time is four days. The median total duration of treatment is 75 days with sulfonamide-based antibiotics, such as Bactrim, followed by carbapenems.

Presentation Date

5-2020

Nocardia farcinica: No Farce Bacteremia

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