Computed tomography features of pulmonary nocardiosis in immunocompromised and immunocompetent patients

Lung cancer patient with Tropheryma whipplei and Nocardia co-infection

A 34-year-old male presented with lung shadow and was asymptomatic during medical examination. The patient had a prior history of thyroid tumors. Imaging manifestation showed a nodule in the medial segment of the right middle lobe, with partial obstruction of the distal bronchus within the lesion. Ground-glass and inflammatory nodules were observed in the anterior segment of the right upper lobe, as well as chronic inflammatory changes in the lower lobe of the right lung. Lung histopathological examination suggested invasive adenocarcinoma. A morphological examination of the bronchoalveolar lavage fluid revealed the presence of Tropheryma whipplei (TW) and Nocardia. Although TW infection has been reported in cancer patients, co-infection with Nocardia is a unique occurrence in this case. Opportunistic pathogens are common in immunocompromised patients but in this case, the patient was a young adult with normal immunity and an early-stage tumor with TW and Nocardia co-infection. We demonstrated the presence of rare microorganisms through imaging findings, combined with different staining methods of bronchoalveolar lavage fluid and lung tissue sections and evaluation of morphological characteristics. The aim of the present study was to provide early diagnosis and treatment of patients by improving microbial morphological detection.

Impact of immune status on the clinical characteristics, treatment outcomes and mortality of pulmonary nocardiosis: a retrospective analysis in a tertiary care hospital from a low to middle-income country

Nocardiosis is an opportunistic infection that primarily targets the immunosuppressed. We investigate the differences in demographics and characteristics between immunosuppressed and immunocompetent patients with nocardiosis in a tertiary care hospital in Pakistan. Retrospective records were reviewed for patients diagnosed with pulmonary nocardiosis between 2010 and 2020. Immunosuppressed individuals were identified as those with autoimmune diseases, hematologic diseases and malignancies, HIV, immunosuppressant therapy, etc. Data collected included basic demographics, comorbid conditions, medication history, clinical presentation, radiological and microbiological data, and nocardiosis outcomes and complications. A total of 66 patients with nocardiosis were included in this study out of which 48 were immunosuppressed while 18 were immunocompetent. Both groups were compared for a number of variables including patient characteristics, underlying conditions, radiological findings, treatment regimen and outcomes. Immunosuppressed individuals were younger, and had higher rates of diabetes, chronic renal disease, chronic liver disease, higher platelet counts, surgical intervention, and longer hospital stays. Fever, dyspnea, and sputum production were the most common presentations. Nocardia asteroides was found to be the most common species of Nocardia overall. Nocardiosis presents differently in patients with immunosuppressed and immunocompetent patients consistent with previous studies. Nocardiosis should be considered in any patient presenting with treatment-resistant pulmonary or neurological symptoms.

The Computed Tomography Findings and Follow-up Course of Pulmonary Nocardiosis

OBJECTIVE

Our study aimed to elucidate the computed tomography (CT) features and follow-up course of pulmonary nocardiosis patients to improve the understanding and diagnostic accuracy of this disease.

METHODS

The chest CT findings and clinical data of patients diagnosed with pulmonary nocardiosis by culture or histopathological examination in our hospital between 2010 and 2019 were retrospectively analyzed.

RESULTS

A total of 34 cases of pulmonary nocardiosis were included in our study. Thirteen patients were on long-term immunosuppressant therapy, among whom 6 had disseminated nocardiosis. Among the immunocompetent patients, 16 had chronic lung diseases or a history of trauma. Multiple or solitary nodules represented the most common CT feature (n = 32, 94.12%), followed by ground-glass opacities (n = 26, 76.47%), patchy consolidations (n = 25, 73.53%), cavitations (n = 18, 52.94%), and masses (n = 11, 32.35%). There were 20 cases (61.76%) with mediastinal and hilar lymphadenopathy, 18 (52.94%) with pleural thickening, 15 (44.12%) with bronchiectasis, and 13 (38.24%) with pleural effusion. Significantly higher rates of cavitations were observed among immunosuppressed patients (85% vs 29%, P = 0.005). At follow-up, 28 patients (82.35%) clinically improved with treatment, while 5 (14.71%) had disease progression, and 1 (2.94%) died.

CONCLUSIONS

Chronic structural lung diseases and long-term immunosuppressant use were found as risk factors for pulmonary nocardiosis. While the CT manifestations were highly heterogeneous, clinical suspicion should be raised upon findings of coexisting nodules, patchy consolidations, and cavitations, particularly in the presence of extrapulmonary infections such as those of the brain and subcutaneous tissues. A significant incidence of cavitations may be observed among immunosuppressed patients.

A Case of Pulmonary Nocardiosis Presenting with Multiple Cavitary Nodules in a Patient with Thrombocytopenia

Nocardiosis is an infrequent opportunistic infection that deserves more attention because of its increasing morbidity and high rate of misdiagnosis. Clinical and radiological manifestations as well as antibiograms of pulmonary nocardiosis are diverse. Herein, we report a patient with idiopathic thrombocytopenia treated with glucocorticoids, which later presented with severe pulmonary infection with widely distributed nodules on chest computed tomography. Fungal infection or tuberculosis was under initial suspicion and microbiological tests of bronchoalveolar lavage fluid eventually yielded an affirmative result of Nocardia cyriacigeorgica. The patient responded in the beginning; however, therapeutic strategies had to be altered several times due to adverse events. The patient eventually ended up with radiographic resolution at the end of six months. We wish to share some experience in dealing with this disease especially recognizing pulmonary nocardiosis in computed tomography imaging.

Detection of Nocardia by 16S Ribosomal RNA Gene PCR and Metagenomic Next-Generation Sequencing (mNGS)

In this study, the aim was to investigate the discriminatory power of molecular diagnostics based on mNGS and traditional 16S ribosomal RNA PCR among Nocardia species. A total of fourteen clinical isolates from patients with positive Nocardia cultures and clinical evidence were included between January 2017 and June 2020 in HeNan Provincial People’s Hospital. DNA extraction and 16S rRNA PCR were performed on positive cultures, and pathogens were detected by mNGS in these same samples directly. Among the 14 Nocardia isolates, four species were identified, and N. cyriacigeorgica (8 cases) is the most common species. Twelve of the 14 Nocardia spp. isolates were identified by the two methods, while two strains of N. cyriacigeorgica were not identified by mNGS. All tested isolates showed susceptibility to trimethoprim-sulfamethoxazole (SXT), amikacin and linezolid. Apart from Nocardia species, other pathogens such as Acinetobacter baumannii, Klebsiella pneumonia, Aspergillus, Enterococcus faecalis, Human herpesvirus, etc., were detected from the same clinical samples by mNGS. However, these different pathogens were considered as colonization or contamination. We found that it is essential to accurately identify species for determining antibiotic sensitivity and, consequently, choosing antibiotic treatment. 16S rRNA PCR was useful for identification of nocardial infection among species, while this technique needs the clinicians to make the pre-considerations of nocardiosis. However, mNGS may be a putative tool for rapid and accurate detection and identification of Nocardia, beneficial for applications of antimicrobial drugs and timely adjustments of medication.

Infections Are Leading Cause of In-Hospital Mortality in Indian Patients With Inflammatory Myopathy

OBJECTIVES

We explored causes of in-hospital mortality in patients with inflammatory myositis at a tertiary care center in Northern India.

METHODS

Records of adults and children diagnosed with dermatomyositis (DM), polymyositis, or anti-synthetase syndrome (ASSD) who died between 2000 and 2018 were reviewed, and causes of death were determined.

RESULTS

Of the 38 patients, 20 had DM (including 2 clinically amyopathic DM), 4 juvenile DM, 12 polymyositis, whereas 2 had ASSD. Median age at death was 42.0 (interquartile range, 32.8-52.5) years. Median disease duration at death was 18.5 (interquartile range, 2.0-23.5) months. Twenty-four (63.2%) had infection as the primary cause of death. Other causes of death included pharyngeal muscle weakness and aspiration (n = 6), myocarditis (n = 2), respiratory failure (n = 2), cerebral bleed (n = 2), and pulmonary embolism (n = 1). One patient succumbed to rapidly progressive interstitial lung disease, whereas another patient with ASSD died following respiratory distress after rituximab infusion. In post hoc analysis, although thrombocytopenia appeared to be a risk factor for early mortality (odds ratio, 13.3; 95% confidence interval, 1.4-123.8; p = 0.01), this was not supported in the multivariate analysis.

CONCLUSIONS

Infections are the most common cause of in-hospital mortality in myositis patients.

Nocardiosis in patients with nephrotic syndrome: a retrospective analysis of 11 cases and a literature review

OBJECTIVES

We evaluated the clinical manifestations and outcomes of nocardiosis, a rare opportunistic infection that occurs in patients with nephrotic syndrome.

METHODS

The records of NS patients with nocardiosis in a single hospital during 2000-2019 were retrieved and studied in detail.

RESULTS

Eleven patients were included. The mean time to develop nocardiosis after glucocorticoid therapy was 11.5 ± 14.8 months. Most patients had fever, elevated white blood cell counts and C-reactive protein, whereas procalcitonin levels were normal or slightly elevated in 91% (10/11) patients, except one patient suffered from septic shock. Nine patients were tested for CD4⁺ T-cell counts; of these, four patients had counts < 200 cells/μL. The most common site of nocardiosis involvement was lung (100%), followed by subcutaneous tissue (72.7%). Radiological findings for lungs in seven cases were characterized by isolated or scattered nodules and masses, usually located subpleural or close to the hilum. Positive smears of Nocardia were detected in 100% of samples of subcutaneous abscess and pleural fluid. Nine patients received oral trimethoprim-sulfamethoxazole, four of which received combined carbapenem, and the remaining two patients received carbapenem monotherapy. The long-term prognosis was excellent, with a treatment success rate of 100% in all patients.

CONCLUSIONS

NS patients can develop immunodeficiency after treatment with glucocorticoid and immunosuppressants. In cases where patients develop systemic multiple abscesses, or lung images reveal isolated or scattered nodules and masses that are subpleural or close to the hilum, nocardial infection should be considered. Early diagnosis and specific treatment may improve patient outcomes.

The emergence of rare nocardiosis following allogeneic hematopoietic stem cell transplantation in the era of molecular taxonomy

OBJECTIVE

The purpose of this study was to describe the clinical features of nocardiosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT), focusing on new Nocardia species.

METHODS

We retrospectively reviewed data from patients with nocardiosis after allo-HSCT treated at our hospital and documented cases in the medical literature.

RESULTS

Fifty-seven cases were identified from our institution and the literature review. Although 51 patients (89.5%) responded to initial treatment, 28 (49.1%) patients were switched over to other treatment regimens due to the recurrence of nocardiosis or adverse events of antimicrobials. Nocardiosis-attributed mortality occurred in ten patients (17.5%). Antimicrobial susceptibilities varied among intra- and inter-species except linezolid (LZD). In the present study, five species were newly discovered after 2000, including N. cyriacigeorgica, N. veterana, N. abscessus, N. aobensis, and N. mexicana. All isolates of N. cyriacigeorgica, N. veterana, N. abscessus, and N. aobensis were sensitive to trimethoprim/sulfamethoxazole, amikacin (AMK), imipenem (IPM), and LZD; however, N. mexicana was resistant to AMK and IPM.

CONCLUSION

Newly identified Nocardia species have various antimicrobial susceptibility patterns. Long-term maintenance therapy could be challenging due to the adverse events of antimicrobials, especially in the allo-HSCT setting. Prudent evaluation is crucial for selecting a second-line or further treatment options.

[Cerebral and pulmonary nocardiosis to Nocardia abscessus in an immunocompetent Algerian patient]

Nocardial brain abscess is often occurring in immunocompromised patients. It is uncommon in immunocompetent individuals. Here, the authors describe a case of cerebral and pulmonary nocardiosis mimicking a metastatic tumor in an apparently health 40-year-old Algerian male. The patient presented multiple brain abscess revealed by inaugural epileptic seizure. He was afebrile and presented with left hemiparesis. Staging imaging showed a nodular lung lesion in the apical segment of the right lower lobe. The patient underwent double craniotomy for resection of the lesion. Culture of the resected specimen isolated Nocardia abscessus. The patient was initially started on intravenous trimethoprim-sulfamethoxazole and intravenous amikacine. He was switched to oral trimethoprim-sulfamethoxazole. He finished seven months of antibiotic therapy with a good clinical response. Imaging revealed reduction in the brain abscess and a complete resolution of the lung lesion. Cotrimoxazole was stopped after twelve months of therapy. After two years, the health status of our patient improves day after day. He is however regularly under medical supervision for control exams.

Rare Multidrug-Resistant Pulmonary Nocardiosis in AIDS

Nocardiosis is an opportunistic infection in patients with depressed cell-mediated immunity. Inhalation is the primary route for exposure via dust particles. Patients with acquired immune deficiency syndrome (AIDS) are at increased risk of disseminated disease. A challenge in the diagnosis of pulmonary nocardiosis is that it can mimic other pulmonary diseases. Nocardia farcinica tends to be a more virulent, multidrug-resistant strain with an increased tendency to disseminate. This report describes a 64-year-old man with AIDS found to have pulmonary nocardiosis that did not respond to standard antibiotic therapy. Further evaluation revealed the virulent, multidrug-resistant Nocardia farcinica species. Targeted antibiotic therapy was initiated, after which the patient had an improvement in pulmonary symptoms. It is important to suspect pulmonary nocardiosis in immunocompromised patients who fail to respond to standard antimicrobial therapy. Susceptibilities should be obtained so that appropriate therapy can be promptly initiated as Nocardia farcinica is highly resistant to multiple antimicrobials.

Pulmonary Nocardiosis: A Clinical Analysis of 30 Cases

Objective Pulmonary nocardiosis frequently develops as an opportunistic infection in patients with malignant tumor and is treated with steroids. This study was performed to clarify the clinical features of pulmonary nocardiosis in Japan. Methods The patients definitively diagnosed with pulmonary nocardiosis at our hospital between January 1995 and December 2015 were retrospectively investigated. Results Nineteen men and 11 women (30 in total) were diagnosed with pulmonary nocardiosis. Almost all patients were complicated by a non-pulmonary underlying disease, such as malignant tumor or collagen vascular disease, or pulmonary disease, such as chronic obstructive pulmonary disease or interstitial pneumonia, and 13 patients (43.3%) were treated with steroids or immunosuppressors. Gram staining was performed in 29 patients, and a characteristic Gram-positive rod was detected in 28 patients (96.6%). Thirty-one strains of Nocardia were isolated and identified. Seven strains of Nocardia farcinica were isolated as the most frequent species, followed by Nocardia nova isolated from 6 patients. Seventeen patients died, giving a crude morality rate of 56.7% and a 1-year survival rate of 55.4%. The 1-year survival rates in the groups with and without immunosuppressant agents were 41.7% and 59.7%, respectively, showing that the outcome of those receiving immunosuppressants tended to be poorer than those not receiving them. Conclusion Pulmonary nocardiosis developed as an opportunistic infection in most cases. The outcome was relatively poor, with a 1-year survival rate of 55.4%, and it was particularly poor in patients treated with immunosuppressant agents. Pulmonary nocardiosis should always be considered in patients presenting with an opportunistic respiratory infection, and an early diagnosis requires sample collection and Gram staining.

Pulmonary nocardiosis in Chronic Obstructive Pulmonary Disease: A new clinical challenge

Pulmonary nocardiosis (PN) is a rare but severe disease caused by Nocardia spp. Despite the traditional description as opportunistic infection, case reports and case series of pulmonary nocardiosis have recently been reported in immunocompetent patients too, in particular among people with chronic pulmonary diseases such as advanced Chronic Obstructive Pulmonary Disease (COPD). PN is characterized by non-specific symptoms and radiological findings; bacteriological culture can be difficult. For the reasons above, diagnosis of PN is challenging, sometimes resulting in a misdiagnosis of tuberculosis. We report an interesting case of PN in a 75-year-old male with COPD. He complained a 3-months history of fatigue, evening rise in body temperature, night sweats, unexplained weight loss of 5 kg, worsening dyspnea, cough and mucopurulent sputum. The chest X-ray showed multiple nodules with cavitations bilaterally in the apical and subclavian regions. Nocardia cyriacigeorgica with 100% identity was identified in three sputum samples. Since the patient has never undergone a systemic and/or inhaled steroid therapy, and has no respiratory failure and comorbidities entailing immunodepression, it is conceivable that, in this immunocompetent patient, the COPD could represent an isolated risk factor for PN. Risk factors, clinical presentations, radiographic findings, differential diagnosis and review of the literature of PN cases in COPD, pointing out the similarities and differences, are also described.