Disseminated nocardiosis due to Nocardia farcinica: diagnosis by thyroid abscess culture

Fever of unknown origin revealing testicular nocardiosis: a case report and literature review

BACKGROUND

Nocardia is an ubiquitous soil organism. As an opportunistic pathogen, inhalation and skin inoculation are the most common routes of infection. Lungs and skin are the most frequent sites of nocardiosis. Testis is a highly unusual location for nocardiosis.

CASE PRESENTATION

We report the case of an immunocompromised 75-year-old-man admitted for fever of unknown origin. He presented with skin lesions after gardening and was first suspected of Mediterranean spotted fever, but he did not respond to doxycycline. Then, physical examination revealed new left scrotal swelling that was compatible with a diagnosis of epididymo-orchitis. The patient's condition did not improve despite empirical antibiotic treatment with the onset of necrotic scrotal abscesses requiring surgery. Nocardia brasiliensis yielded from the removed testis culture. High-dose trimethoprim-sulfamethoxazole and ceftriaxone were started. Multiple micro-abscesses were found in the brain and spinal cord on imaging studies. After 6 weeks of dual antibiotic therapy for disseminated nocardiosis, slight regression of the brain abscesses was observed. The patient was discharged after a 6-month course of antibiotics and remained relapse-free at that time of writing these lines. Trimethoprim-sulfamethoxazole alone is meant to be pursued for 6 months thereafter. We undertook a literature review on previously reported cases of genitourinary and urological nocardiosis; to date, only 36 cases have been published with predominately involvement of kidney, prostate and testis.

CONCLUSIONS

To the best of our knowledge, this is the first case of Nocardia brasiliensis simultaneously infecting skin, testis, brain and spinal cord in an immunocompromised patient. Knowledge on uncommon forms of nocardiosis remains scarce. This case report highlights the difficulty of diagnosing atypical nocardiosis and the importance of prompt bacteriological sampling in case of empirical antibiotics failure.

Disseminated nocardiosis caused by Nocardia farcinica in a patient with colon cancer: A case report and literature review

RATIONALE

Nocardiosis is an uncommon and potentially life-threatening infection that usually affects immunocompromised hosts. No clinical guidelines have been established for managing this rare disease, and the optimal treatment modality remains unclear. Nocardia farcinica, a relatively infrequent pathogen of nocardiosis, causes a clinically aggressive infection. In addition to our patient data, our search of the literature for patients who presented with empyema caused by N. farcinica will provide fundamental information for optimal treatment modalities.

PATIENT CONCERNS

A 64-year-old man was diagnosed with empyema, 4 days following surgery for sigmoid colon cancer. Brain lesions were evaluated only after N. farcinica was isolated and identified as the causative pathogen through repeated culture tests.

DIAGNOSES

N. farcinica was isolated from the pleural effusion and confirmed as the pathogen through 16S rRNA sequencing.

INTERVENTIONS

The patient was successfully treated with tube thoracotomy, neurosurgical evacuation, and a combination of trimethoprim/sulfamethoxazole plus imipenem. Long-term antibiotic therapy was required to prevent recurrence.

OUTCOMES

Pyothorax showed a good clinical response to antimicrobial therapy and drainage of pleural effusion, whereas brain abscess did not respond to medical therapy and required surgery. The patient eventually recovered and continued chemotherapy as treatment for sigmoid colon cancer.

LESSONS

Although extremely rare, this report demonstrates the importance of considering Nocardia infection as the differential diagnosis in immunocompromised patients who present with empyema. In particular, because of the N. farcinica infection's tendency to spread and the resistance of the organism to antibiotics, aggressive evaluation of metastatic lesions and standardized support from microbiological laboratories are important. Surgery may be required in some patients with brain abscesses to improve the chance of survival.

Pleural Infection Caused by Nocardia farcinica: Two Cases and Review of the Literature

Nocardia farcinica is a rare Nocardia species causing localized (lung, brain, skin) and disseminated infections. Predisposing factors include the chronic use of corticosteroids, organ transplantation and other immunocompromise conditions. Pleural empyema caused by this microorganism has scantily been reported. We describe two cases of pleural infection by N. farcinica that occurred in patients with a kidney transplant and cirrhosis, respectively. The first patient died soon after hospitalization, while the second survived nocardiosis (despite having significant adverse events to antibiotics) but eventually succumbed to other infectious complications. In this infectious disease, in which the duration of therapy is typically long and pleural space drainage is frequently required, bacterial susceptibility to antimicrobial agents should be tested.

Thyroid nocardiosis: Case report and review of the literature

Disseminated nocardiosis is a rare but growing concern in immunocompromised patients. Typical localizations include the lung, brain and/or soft tissues, but laboratory confirmation of nocardiosis usually requires sampling of infected organs by invasive procedures such as bronchoalveolar lavage or brain biopsy. We report a case of disseminated nocardiosis occurring in a hematopoietic stem-cell transplant recipient, with clinical lung and brain localizations. Examination of the thyroid gland was suggestive of a unilateral abscess. A culture of thyroid pus sampled by fine-needle aspiration was positive for Nocardia farcinica and therefore avoided a more invasive procedure. The patient recovered after a six-month antibiotic therapy without thyroid surgery. We reviewed other ten cases of thyroid nocardiosis published in the medical literature. Among the ten cases of disseminated nocardiosis established during the patient's lifetime including ours, six (60%) were asymptomatic and seven (70%) were confirmed by culture of the aspiration of thyroid pus. When disseminated nocardiosis is suspected, systematic examination for a thyroid abscess may help establish a microbiological diagnosis and prevent further invasive procedures.

Nocardia bacteremia: A single-center retrospective review and a systematic review of the literature

OBJECTIVES

Nocardia bacteremia is a rare but severe disease associated with high mortality. This systematic review is the largest and most comprehensive review performed over the past 20 years.

METHODS

A single-center retrospective review of Nocardia bacteremia was performed using hospital microbiology records from January 1, 2010 to December 31, 2017. A systematic literature review was also performed to identify cases of Nocardia bacteremia described in the NCBI PubMed database in English between January 1, 1999 and December 31, 2018.

RESULTS

Four new cases of Nocardia bacteremia are described. The systematic review identified 134 cases with sufficient information available for analysis. Of the total 138 cases, the median age was 58 years (interquartile range (IQR) 44-69 years) and 70% were male. Eighty-one percent were immunocompromised (corticosteroid use (49%), hematological malignancy (20%), solid organ transplant (20%), solid organ malignancy (19%), and hematopoietic stem cell transplantation (15%)) and 29% had endovascular devices. Pulmonary infection was the most common concurrent site of clinical disease (67%). The median incubation time to the detection of Nocardia bacteremia was 4 days (IQR 3-6 days). Blood cultures were the only positive microbiological specimen in 38% of cases. The median total duration of treatment was 75 days (IQR 25-182 days). Thirty-day all-cause mortality was 28% and overall all-cause mortality was 40%.

CONCLUSIONS

Nocardia bacteremia is most frequently identified in immunocompromised patients and those with intravascular devices. Although rare, it represents a serious infection with high associated overall mortality.

Detection of high serum levels of β-D-Glucan in disseminated nocardial infection: a case report

Background

β-D-glucan (BDG) is a helpful diagnostic marker for many invasive fungal infections, but not for nocardiosis. Here, we reported the first case of nocardial infection with high serum level of BDG.

Case presentation

A 73-year-old man was hospitalized because of fever, headache, and appetite loss after 10 months of steroid and immunosuppressive therapy for cryptogenic organizing pneumonia. With a diagnosis of bacterial pneumonia, treatment with ampicillin/sulbactam was initiated. There was improvement on chest radiograph, but fever persisted. Further work-up revealed multiple brain abscesses on cranial magnetic resonance imaging (MRI). Serum galactomannan and BDG were elevated at 0.6 index and 94.7 pg/ml, respectively. Voriconazole was initiated for presumed aspergillus brain abscess. However, fever persisted and consciousness level deteriorated. Drainage of brain abscess was performed; based on the Gram stain and Kinyoun acid-fast stain, disseminated nocardiosis was diagnosed. Voriconazole was then shifter to trimethoprim/sulfamethoxazole. The presence of Nocardia farcinica was confirmed by the 16S rRNA gene sequence. Treatment course was continued; BDG level normalized after 1 month and cranial MRI showed almost complete improvement after 2 months.

Conclusion

BDG assay is widely used to diagnose invasive fungal infection; therefore, clinicians should be aware that Nocardia species may show cross-reactivity with BDG assay on serum.

A case of community-acquired pneumonia due to influenza A virus and Nocardia farcinica co-infection

Nocardia spp. has not been reported previously as a cause of post-influenza pneumonia. Here we present a first case of post-influenza bacterial pneumonia due to Nocardia farcinica. Initial reason for hospitalization of the 90 year old female patient was a pneumonia with the symptoms of fever and productive cough. A rapid test for influenza antigen was positive for influenza A virus. Treatment with Zanamivir and piperacillin was initiated. However, after 1 week of treatment, the infiltration shadows on chest X-ray had worsened. Because the expectorated sputum collected on admission for culture was found to be positive for Nocardia spp., piperacillin was replaced with trimethoprim/sulfamethoxazole, and a chest X-ray showed some improvement. Although pulmonary nocardiosis with co-infection with influenza A is extremely rare, clinicians should be alert to the possibility.

Molecular identification of nocardia isolates from clinical samples and an overview of human nocardiosis in Brazil

BACKGROUND

Nocardia sp. causes a variety of clinical presentations. The incidence of nocardiosis varies geographically according to several factors, such as the prevalence of HIV infections, transplants, neoplastic and rheumatic diseases, as well as climate, socio-economic conditions and laboratory procedures for Nocardia detection and identification. In Brazil the paucity of clinical reports of Nocardia infections suggests that this genus may be underestimated as a cause of human diseases and/or either neglected or misidentified in laboratory specimens. Accurate identification of Nocardia species has become increasingly important for clinical and epidemiological investigations. In this study, seven clinical Nocardia isolates were identified by multilocus sequence analysis (MLSA) and their antimicrobial susceptibility was also determined. Most Nocardia isolates were associated to pulmonary disease.

METHODOLOGY/PRINCIPAL FINDINGS

The majority of Brazilian human isolates in cases reported in literature were identified as Nocardia sp. Molecular characterization was used for species identification of Nocardia nova, Nocardia cyriacigeorgica, Nocardia asiatica and Nocardia exalbida/gamkensis. Data indicated that molecular analysis provided a different Nocardia speciation than the initial biochemical identification for most Brazilian isolates. All Nocardia isolates showed susceptibility to trimethoprim-sulfamethoxazole, the antimicrobial of choice in the treatment nocardiosis. N. nova isolated from different clinical specimens from one patient showed identical antimicrobial susceptibility patterns and two distinct clones.

CONCLUSIONS/SIGNIFICANCE

Although Brazil is the world's fifth-largest country in terms of land mass and population, pulmonary, extrapulmonary and systemic forms of nocardiosis were reported in only 6 of the 26 Brazilian states from 1970 to 2013. A least 33.8% of these 46 cases of nocardiosis proved fatal. Interestingly, coinfection by two clones may occur in patients presenting nocardiosis. Nocardia infection may be more common throughout the Brazilian territory and in other developing tropical countries than is currently recognized and MLSA should be used more extensively as an effective method for Nocardia identification.

Disseminated Nocardia farcinica: literature review and fatal outcome in an immunocompetent patient

BACKGROUND

Nocardia farcinica is a gram-positive, partially acid-fast, methenamine silver-positive aerobic actinomycete. Nocardia spp. are opportunistic pathogens, and N. farcinica is the least common species of clinical importance.

METHODS

Review of the recent literature and description of a immunocompetent patient with no known risk factors who contracted fatal N. farcinica sepsis.

RESULTS

Positive pre-mortem and post-mortem cultures from the lung and synovium correlated with acute bronchopneumonia and synovitis at autopsy. Colonies of filamentous bacteria, which were not apparent in conventional hematoxylin and eosin-stained sections, were observed with gram and methenamine silver stains, but acid-fast stains were negative. A literature review revealed that disseminated N. farcinica often is associated with an underlying malignant tumor or autoimmune disease (88% of patients). Chemotherapy or corticosteroid treatments are additional risk factors.

CONCLUSIONS

Trimethoprim-sulfamethoxazole typically is the first-line therapy for N. farcinica; treatment with amikacin and imipenem-cilastatin is used less often (7% of patients). Despite aggressive therapy, we observed that the death rate (39%) associated with N. farcinica in recent publications was eight percentage points higher than reported in a review from 2000.