Disseminated Nocardia Paucivorans in an immunocompetent pati
Nocardia paucivorans can cause disseminated infection in immunocompetent hosts in rare occasions. Nocardia paucivorans is usually susceptible to many antibiotics including Trimethoprim/Sulfamethoxazole. Duration of treatment is usually 6–12 months.

73-year-old male patient was admitted to hospital in Houston, Texas, USA, for right lung mass evaluation and mild intermittent headache. Two months ago, patient was treated for pneumonia with a short course of oral levofloxacin. Then, the symptoms recur in one week after finishing the antibiotic course. His past medical and past surgical history are unremarkable. Two months ago, he received a 5-day course of oral levofloxacin and currently he denied taking any medications. Chest X-ray and CT chest were performed by his primary care doctor and revealed right middle lobe mass. Six months ago, patient was in Alaska and Argentina for hunting ducks and fishing. Patient smokes 30 pack-year. He denied drug abuse, sick contact, pets, or tick bites.

On physical examination, his blood pressure was 130/70 mmHg, his temperature was 99.2 F, his pulse was 80 beats per minute, and his respiratory rate was 16 breath per minute. Respiratory examination revealed decreased breath sounds on the right middle lobe. Rest of cardiovascular, neurological, abdominal, and skin examinations were unremarkable. At this point, neoplastic disease was on top of our differential diagnosis list followed by other diseases such as infections or autoimmune disorders.

Initial complete blood count and complete metabolic panel were normal. Serum interferon gamma release assay (IGRA), serum Beta-d-Glucan, serum aspergillus galactomannan antigen, serum coccidioides antibodies, and urine histoplasma antigen were negative. CT chest revealed 3.6 cm right middle lobe mass. Patient underwent excisional lung biopsy which showed branching gram-positive rods consistent Nocardia species. We started intravenous imipenem and oral Trimethoprim/Sulfamethoxazole. CT head with contrast was unremarkable. For intermittent headache, MRI brain was performed and showed 0.8 cm ring-enhancing lesion in left frontal cortex and 0.6 cm ring-enhancing lesion in left temporal lobe.

In the sixth day of hospitalization, patient started to complain of posterior right knee pain and lump. MRI of right knee revealed 2.5 X 2.4 cm ill-defined mass involving the distal gastrocnemius muscle. Right posterior knee mass fine needle aspiration was performed and resulted as fibroadipose tissue with granulation tissue, plasma cells, macrophages, and neutrophils. Culture of the aspirated fluid showed no growth. HIV test was negative, and CD4 count was normal.

Later, the culture of the lung mass grew Nocardia paucivorans by using 16S ribosomal sequencing and the susceptibility is reported. Patient was discharged on IV imipenem and TMP/SMX until resolution of the headache (8 weeks). Then, the treatment course was continued for at least one year with oral TMP/SMX alone with close monitoring to the major side effects such as agranulocytosis, thrombocytopeneia, electrolytes abnormalities, and renal impairment. Patient is following up with an infectious disease specialist at his home town. Patient reported complete resolution of his symptoms at the 8th week of treatment no side effects were reported.

Source: https://onlinelibrary.wiley.com/doi/10.1002/ccr3.4659?af=R
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