Nocardia ignorata Infection in Heart Transplant Patient

To the Editor: We read with interest the recent description of pulmonary Nocardia ignorata infection (1). We report a similar infection in an orthotopic heart transplant recipient, which likely began as a pulmonary infection with dissemination to soft tissue, without known exposure. Risk factors included tacrolimus, steroids, older age, and posttransplant intensive care unit admission (2). The patient was a 66-year-old African American man with a history of ischemic cardiomyopathy. After implantation of a left ventricular assist device, infectious complications included Enterococcus faecalis device infection and extended spectrum β-lactamase–producing (ESBL) Klebsiella urosepsis. The course after left ventricular assist device explantation and orthotopic heart transplant was complicated by tamponade requiring a pericardial window and an ESBL Klebsiella urinary tract infection treated with meropenem. Because of leukopenia, Pneumocystis prophylaxis was changed from trimethoprim/ sulfamethoxazole to atovaquone 2 weeks posttransplant. ESBL Klebsiella bacteremia recurred 6 weeks later, again treated with meropenem. The patient returned 6 months posttransplant with 10 days of cough and dyspnea. Chest computed tomography demonstrated bilateral nodules with cavitation, bronchiectasis, and spiculation. We initially treated the patient with meropenem and doxycycline. Results from severe acute respiratory syndrome coronavirus 2 swab test, respiratory pathogen panel, fungal studies, and sputum culture were nondiagnostic. We obtained no additional pulmonary samples. Due to severe left calf pain, venous duplex was performed, revealing a nonvascular mass. The patient reported no trauma, soil contact, or recent travel. The abscess was aspirated, demonstrating branching gram-positive beaded rods. The isolate was identified by a reference laboratory (Mycobacteria and Nocardia Laboratory, University of Texas Health Center at Tyler, Tyler, TX, USA) by partial 16S rRNA sequencing as a 99.51% match with Nocardia ignorata, with susceptibilities identical to the isolate in Rahdar et al. (1). Brain magnetic resonance imaging results were unremarkable. The patient’s respiratory status and leg pain quickly COMMENT LETTERS Her current research investigates the impact of Social Determinants of Health needs and interventions on severe maternal morbidity and maternal mortality in an attempt to improve parity in maternal/neonatal health outcomes.


Nocardia ignorata Infection in Heart Transplant Patient
To the Editor: We read with interest the recent description of pulmonary Nocardia ignorata infection (1). We report a similar infection in an orthotopic heart transplant recipient, which likely began as a pulmonary infection with dissemination to soft tissue, without known exposure. Risk factors included tacrolimus, steroids, older age, and posttransplant intensive care unit admission (2).
The patient was a 66-year-old African American man with a history of ischemic cardiomyopathy. After implantation of a left ventricular assist device, infectious complications included Enterococcus faecalis device infection and extended spectrum β-lactamase-producing (ESBL) Klebsiella urosepsis. The course after left ventricular assist device explantation and orthotopic heart transplant was complicated by tamponade requiring a pericardial window and an ESBL Klebsiella urinary tract infection treated with meropenem. Because of leukopenia, Pneumocystis prophylaxis was changed from trimethoprim/ sulfamethoxazole to atovaquone 2 weeks posttransplant. ESBL Klebsiella bacteremia recurred 6 weeks later, again treated with meropenem.
The patient returned 6 months posttransplant with 10 days of cough and dyspnea. Chest computed tomography demonstrated bilateral nodules with cavitation, bronchiectasis, and spiculation. We initially treated the patient with meropenem and doxycycline. Results from severe acute respiratory syndrome coronavirus 2 swab test, respiratory pathogen panel, fungal studies, and sputum culture were nondiagnostic. We obtained no additional pulmonary samples.
Due to severe left calf pain, venous duplex was performed, revealing a nonvascular mass. The patient reported no trauma, soil contact, or recent travel. The abscess was aspirated, demonstrating branching gram-positive beaded rods. The isolate was identified by a reference laboratory (Mycobacteria and Nocardia Laboratory, University of Texas Health Center at Tyler, Tyler, TX, USA) by partial 16S rRNA sequencing as a 99.51% match with Nocardia ignorata, with susceptibilities identical to the isolate in Rahdar et al. (1). Brain magnetic resonance imaging results were unremarkable. The patient's respiratory status and leg pain quickly

COMMENT LETTERS
Her current research investigates the impact of Social Determinants of Health needs and interventions on severe maternal morbidity and maternal mortality in an attempt to improve parity in maternal/neonatal health outcomes.

T he genus Nocardia is named in honor of Edmond
Isidore Etienne Nocard (1850-1903), a French veterinarian and microbiologist who discovered the bacteria in 1888 from a bovine farcy case. He named this filamentous, branching bacteria Streptothrix farcinica (Greek streptós-"twisted" and thrix "hair"). Farcy (old French farcin), is a form of cutaneous glanders, characterized by superficial lymph node swelling and ulcerating nodule formation under the skin (Late Latin farcīminum "glanders," from Latin farcīmen "a sausage," from farcīre "to stuff").
One year later, Trevisan characterized and termed the bacteria Nocardia farcinica, creating the genus Nocardia. In 1890, Eppinger isolated a similar organism from a brain abscess and called it Cladothrix asteroides (Greek kládos-"branch" and -thrix "hair") because of its star-shaped colonies (Greek asteroeidēs "starlike"). Blanchard renamed the organism Nocardia asteriodes in 1896. Additional taxonomic work in 1962 resulted in Nocardia asteroides replacing Nocardia farcinica as the type species for the genus Nocardia.

Figure.
Twisted hair bacteria (Nocardia spp.) described by Edmond Nocard, from a bronchial alveolar lavage sample. Nocardiosis is an opportunistic infection, commonly associated with pulmonary disease. Nocardia are partially acid-fast, filamentous, branching bacilli (modified Kinyoun acid-fast stain using weak acid [0.5% sulfuric acid] for decolorization and methylene blue counterstain, original magnification x1,000.) Photograph courtesy of the author.
improved and he was discharged on long-term trimethoprim/sulfamethoxazole and doxycycline. Because of renal insufficiency, trimethoprim/sulfamethoxazole was switched to moxifloxacin after 2 weeks. Chest radiograph results were improving 3 months later.