Cerebral and mediastinal abscesses caused by Nocardia asiatica in an hiv-infected patient

We herein describe the case of a 40-year-old woman in the Central-West region of Brazil with a nine-year history of HIV infection, who was receiving stavudine, lamivudine, and efavirenz. She had a CD4 T lymphocyte count of 42/mm³, CD8 T lymphocyte count of 642/mm³, and her most recent viral load was 6,275 copies/mL. She presented with mediastinal and cerebral manifestations, characterized by a left hemithoracic tumor, left pleural effusion, evolving hypoesthesia in the phalanges of the right hand, headache, presence of a left thoracic collection, and a hypodense left parieto-temporal lesion on computed tomography, caused by Nocardia asiatica. The patient recovered after treatment with sulfamethoxazole/trimethoprim, ceftriaxone, and amikacin; thoracotomy; and drainage of the extensive thoracic collection. Nocardiosis is an uncommon infection that occurs in immunocompromised individuals, such as HIV-positive patients, patients with oncological diseases, or those receiving immunosuppressive drugs^1,2.

Analysis of pleural and cerebral secretions detected Nocardia spp., a Gram-positive (Figure A), filamentous, strictly aerobic, partially alcohol- and acid-resistant bacterium (Figure B). The laboratory identification of Nocardia spp. is difficult as it is often confused with mycobacteria². N. asiatica was also identified by direct microscopic examination with 20% potassium hydroxide (Figure C). Sequencing of the 1376 bp 16S rRNA from this isolate (GenBank accession no. KF562729) revealed 100% identity with that of the N. asiatica strain DSM 44668 (GenBank accession no. GQ217495). Furthermore, phylogenetic analysis showed the formation of a clade with N. asiatica, emphasizing the importance of genotypic analysis for the diagnosis of nocardiosis³.

FIGURE A:
Presence of Gram-positive filamentous bacteria (Nocardia spp) on Gram staining.

FIGURE B:
Presence of partially alcohol and acid resistant filamentous bacteria (Nocardia spp) on Ziehl-Neelsen staining.

FIGURE C:
Presence of filamentous bacteria (Nocardia spp), identified by direct microscopic examination with 20% potassium hydroxide.

REFERENCES

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  Steinbrink J, Leavens J, Kauffman CA, Miceli MH. Manifestations and outcomes of nocardia infections: Comparison of immunocompromised and nonimmunocompromised adult patients. Medicine (Baltimore). 2018;97(40):e12436.
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  Brown-Elliott BA, Brown JM, Conville PS, Wallace RJ Jr. Clinical and laboratory features of theNocardia spp based on current molecular taxonomy. Clin Microbiol Rev. 2006;19(2):259-82.
• ³
  Conville PS, Brown-Elliott BA, Smith T, Zelazny AM. The complexities of Nocardia taxonomy and identification. J Clin Microbiol. 2017;56(1).pi:e01419-17.

• Financial Support: This research had financial support from the Brazilian National Council for Scientific and Technological Development (CNPq), a federal agency for research support, through a research incentive grant for Francisco José Dutra Souto.

Publication Dates

• Publication in this collection
  06 June 2019
• Date of issue
  2019

History

• Received
  12 Nov 2018
• Accepted
  14 Feb 2019