Pulmonary infection with Nocardia species: a report of 10 cases and review

Formulation and clinical translation of inhalable nanomedicines for the treatment and prevention of pulmonary infectious diseases

Pulmonary infections caused by bacteria, viruses and fungi are a significant global health issue. Inhalation therapies are gaining interest as an effective approach to directly target infected lung sites and nanoparticle-based pulmonary delivery systems are increasingly investigated for this purpose. In this review, we provide an overview of common pulmonary infectious diseases and review recent work on the application of inhalable nanoparticle-based formulations for pulmonary infectious diseases, the formulation strategies, and the current research for delivering inhalable nanomedicines. We also evaluate the current clinical development status, market landscape, and discuss challenges that impede clinical translation and propose solutions to overcome these obstacles, highlighting promising opportunities for future advancements in the field. Despite advancements made and products reaching the market, notable gap persists in translational research, with challenges in achieving the target product profile, availability of appropriate in vivo disease models, scale-up, and market related questions, likely hindering research translation to the clinic.

Nocardia Isolation in People with Cystic Fibrosis and Non-CF Bronchiectasis: A Multicenter Italian Study

Background:Nocardia species are an emergent pathogen in people with CF (pwCF) or bronchiectasis. Their clinical role and management remain unclear, and their isolation is a challenge. In this paper, we describe four cases of Nocardia detection, in two pwCF and two patients with non-CF bronchiectasis or primary ciliary dyskinesia (PCD). Methods: We conducted a multicenter retrospective study, involving pwCF and non-CF people with bronchiectasis who presented with a Nocardia detection and were followed at three CF Italian centers (Florence, Verona, and Cerignola). Results:Nocardia detection was associated with clinical and radiological respiratory exacerbation and decline in lung function. In one CF patient, Nocardia was not detected in sputum cultures after starting Elexacaftor-Tezacaftor-Ivacaftor therapy. Conclusions: Managing Nocardia detection in patients with underlying lung diseases such as CF, PCD, or bronchiectasis presents significant challenges for clinicians.

Unveiling the Unexpected: An Intriguing Case of Neonatal Nocardial Pneumonia

Nocardial infections in neonates are exceptionally rare, posing significant diagnostic challenges due to their atypical presentations and the rarity of such cases. This case report delves into a unique instance of nocardial pneumonia in a neonate, initially misdiagnosed due to its unconventional clinical presentation and the absence of traditional risk factors for opportunistic infections. The neonate exhibited worsening respiratory distress, misleadingly suggestive of more common neonatal conditions or congenital anomalies such as an infected congenital pulmonary airway malformation, as per radiological imaging and initial clinical assessments. The diagnosis of nocardial pneumonia was eventually established on histopathology, highlighting the critical need for heightened clinical suspicion and consideration of uncommon etiologies in neonatal respiratory distress beyond the conventional differential diagnoses.

Exposing the Masquerade of Nocardia otitidiscaviarum Pneumonia: A Case Report

We present a rare case of an immunocompetent 49-year-old male agriculturalist from India diagnosed with Nocardia otitidiscaviarum pneumonia. Nocardia species are ubiquitous gram-positive, partially acid-fast bacilli that predominantly infect immunocompromised individuals. Only 0.3% to 2.9% of all nocardiosis cases are attributed to N. otitidiscaviarum. The patient presented with a 25-day history of wet cough and high-grade fever, with bilateral bronchial breath sounds on chest auscultation and findings consistent with pneumonia on chest X-ray. During hospitalization, multiple treatment revisions were made. On admission, empiric antibiotic therapy against community-acquired pneumonia was initiated. Later, GeneXpert sputum testing for Mycobacterium tuberculosis complex (MTBC) was positive for MTBC DNA. Suspected tuberculosis with a secondary infection prompted a treatment switch to antitubercular therapy (ATT) along with meropenem. Despite changes to treatment, the patient continued to deteriorate with no signs of clinical improvement. ATT with meropenem was discontinued when a repeat GeneXpert for MTBC was negative, ruling out tuberculosis. Slow-growing bronchial wash culture identified the rare pathogen N. otitidiscaviarum, prompting an urgent referral to a specialized Infectious Diseases team. Treatment was then tailored according to antibiotic resistance-sensitivity testing. Targeted multidrug antibiotic therapy with trimethoprim-sulfamethoxazole and amikacin against N. otitidiscaviarum facilitated gradual clinical improvement. This case underscores the importance of considering uncommon pathogens in differential diagnosis and highlights the critical role of microbiological diagnostics in guiding effective treatment. Drug resistance and changing bacterial pathogenicity trends must not be overlooked. The round-about antibiotic treatment changes in this case point to the necessity for faster diagnostic methods in identifying Nocardia species. Further research into rapid diagnostic methods and up-to-date treatment guidelines are warranted to optimize outcomes in nocardiosis management.

Silent Manifestations of Disseminated Nocardia in a Renal Transplant Patient

This case report describes a unique presentation of disseminated nocardiosis in a 45-year-old male transplant recipient who initially presented with acute left hip pain. Despite being asymptomatic for respiratory symptoms, the patient developed a fever and subsequently exhibited hypoxia. A diagnostic workup revealed a cavitary mass in the right upper lobe and multiple pulmonary nodules, confirming silent pulmonary nocardiosis. Concurrently, an MRI identified myositis and a possible abscess in the left hip musculature. Treatment involved a regimen including imipenem-cilastatin and linezolid, tailored for Nocardia species farcinica. This case underscores the importance of vigilant evaluation for metastatic infections in immunocompromised patients presenting with atypical symptoms, highlighting the necessity of imaging studies such as CT of the thorax for early detection of silent pulmonary involvement.

Disseminated nocardiosis presenting as a superinfected thyroglossal duct cyst in a patient with diabetes

We introduce the case of a male patient in his 60s who was admitted to our emergency department with a persisting sore throat for the last 3 weeks and dysphagia. Fibre-endoscopic evaluation revealed an asymmetry at the base of the tongue. In combination with elevated white cell count and C reactive protein, a computerized tomography showed a superinfected thyroglossal duct cyst. Intravenous antibiotics were initiated, and the patient was taken to the operating room for cervicotomy. The microbiological swab taken intraoperatively detected Nocardia paucivorans Additional imaging revealed disseminated nocardiosis with cerebral and pulmonary manifestations.The patient was treated with oral trimethoprim/sulfamethoxazole and, over time, showed complete remission of central nervous system lesions and improvement of pulmonary involvement. Following this, the treatment was stopped 8 months after the initial diagnosis. In this report, we discuss treatment standards and outcomes of nocardiosis based on our management strategies of our patient.

Unintended Consequences: Risk of Opportunistic Infections Associated With Long-term Glucocorticoid Therapies in Adults

Glucocorticoids are widespread anti-inflammatory medications used in medical practice. The immunosuppressive effects of systemic glucocorticoids and increased susceptibility to infections are widely appreciated. However, the dose-dependent model frequently used may not accurately predict the risk of infection in all patients treated with long-term glucocorticoids. In this review, we examine the risks of opportunistic infections (OIs) in patients requiring glucocorticoid therapy by evaluating the influence of the glucocorticoid dose, duration, and potency, combined with biological and host clinical factors and concomitant immunosuppressive therapy. We propose strategies to prevent OIs, which involve screening, antimicrobial prophylaxis, and immunizations. While this review focuses on patients with autoimmune, inflammatory, or neoplastic diseases, the potential risks and preventative strategies are likely applicable to other populations. Clinicians should actively assess the benefit-harm ratios of systemic glucocorticoids and implement preventive efforts to decrease their associated infections complications.

Unusual Presentation of Nocardiosis With Pleural Effusion in an Immunocompetent Host

Nocardiosis is a disease caused by gram-positive, catalase-positive, rod-shaped bacteria that stain weakly on a Gram stain. It usually affects the lungs and skin but can cause disseminated infections. Nocardia has 85 species, ranging from nonpathogenic to pathogenic. Nocardia is an opportunistic organism that causes infections in the immunocompromised; however, 7% of the immunocompetent population has suffered from Nocardia infection. This case report highlights an unusual occurrence of pulmonary nocardiosis in a 31-year-old woman with a normal immune system. She was initially treated as an outpatient for what appeared to be community-acquired pneumonia. However, her condition deteriorated, ultimately revealing a substantial right pleural effusion with loculation and adjacent compressive atelectasis affecting a significant portion of her right middle and lower lung lobes, as detected by a CT scan followed by pleural fluid analysis which confirmed the infection. By sharing this experience, we aim to contribute to the collective knowledge of medical professionals and improve the accuracy of diagnosis and treatment.

TB or Not TB: Lung Nocardiosis, a Tuberculosis Mimicker

Nocardia, a gram-positive bacterium found in soil and water, rarely causes infections in immunocompetent patients. Diagnosing and treating nocardiosis can be challenging due to its infrequency and the similarity of its symptoms to other diseases. We describe the case of a middle-aged male with a history of latent tuberculosis who presented with hemoptysis. Imaging revealed a persistent lung mass, and pathology and microbiology studies confirmed Nocardia infection. The patient was treated with antibiotics and discharged home. Pulmonary nocardiosis can mimic tuberculosis, fungal infections, or malignancies. Immunocompetent patients make up one-third of the cases. Diagnosis can be difficult, as the organism takes time to grow in culture, but molecular techniques and histology can aid in diagnosis. Treatment often involves a six- to 12-month course of trimethoprim-sulfamethoxazole (TMP-SMX). Prompt identification of the etiological agent is essential for effective treatment, especially for immunocompetent patients who may not exhibit typical risk factors.

Nocardia farcinica infection presenting as a solitary bronchial neoplasm in an immunocompetent adult: a case report

Nocardia species are gram-positive, acid-fast, saprophytic, aerobic bacilli, predominantly resulting in opportunistic infections in immunocompromised individuals. Here, we reported a case of Nocardia infection in a 27-year-old woman with normal immunocompetence, who presented as a solitary neoplasm in the left principal bronchus with a chief complaint of postural dyspnea. By electrotomy via bronchoscopy, the neoplasm was successfully removed, and it was further identified as Nocardia farcinica by metagenomic next-generation sequencing.

Case report: Nocardia gipuzkoensis infection in an immunocompetent patient diagnosed by metagenomic next-generation sequencing and whole genome sequencing

The infection of Nocardia gipuzkoensis is a relatively uncommon form of pulmonary nocardiosis seen in clinical patients. In general, nocardiosis tends to occur in patients with immune deficiency. Here, we report a 23-year-old female who was admitted to the hospital due to cough and sputum production over 10 years, diagnosed with bronchiectasis. The N. gipuzkoensis infection was identified by metagenomic next-generation sequencing and whole genome sequencing. Imipenem/cilastatin and compound sulfamethoxazole tablets were used to control the infection and the pulmonary inflammation subsided gradually.

Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency?

Nocardiosis is an infectious disease caused by the gram-positive bacterium Nocardia spp. Although it is commonly accepted that exposure to Nocardia is almost universal, only a small fraction of exposed individuals develop the disease, while the vast majority remain healthy. Nocardiosis has been described as an "opportunistic" disease of immunocompromised patients, suggesting that exposure to the pathogen is necessary, but a host predisposition is also required. Interestingly, increasing numbers of nocardiosis cases in individuals without any detected risk factors, i.e., without overt immunodeficiency, are being reported. Furthermore, a growing body of evidence have shown that selective susceptibility to a specific pathogen can be caused by a primary immunodeficiency (PID). This raises the question of whether an undiagnosed PID may cause nocardiosis affecting otherwise healthy individuals. This review summarizes the specific clinical and microbiological characteristics of patients with isolated nocardiosis published during the past 30 years. Furthermore, it gives an overview of the known human immune mechanisms to fend off Nocardia spp. obtained from the study of PIDs and patients under immunomodulatory therapies.

Incidental Finding of Nocardia: A Case Series from a Tertiary Care Centre in Uttarakhand

Nocardiosis is a rare bacterial infection that may lead to a severe disease. These infections are rare among normal population and are showing an increasing trend worldwide attributable to the increase in the immunosuppressed population. Most of these patients present with nonspecific clinical features such as fever, productive cough, and exertional dyspnoea as seen in our series of patients which makes it difficult to be diagnosed. Pulmonary nocardiosis is rarely clinically suspected and often diagnosed very late in the course of disease resulting in high mortality. A similar observation was made in one of our cases where the patient was being treated on the lines of pneumonia, and in the end she was diagnosed with pulmonary nocardiosis. In view of the limited literature available, we report here a case series of pulmonary nocardiosis in immunosuppressed patients diagnosed incidentally by fungal KOH mount. The most common conditions causing immunosuppression were type II DM, COPD, and pulmonary tuberculosis.

A multicentre analysis of Nocardia pneumonia in Spain: 2010-2016

OBJECTIVE

To analyse all cases of Nocardia pneumonia occurring between 2010 and 2016 in five Spanish hospitals.

METHODS

This was a retrospective observational analysis of clinical and microbiological data collected from 55 cases of Nocardia pneumonia.

RESULTS

There were one to 20 cases per hospital and six to nine cases per year. Chronic obstructive pulmonary disease, bronchiectasis, and asthma were the main predisposing underlying respiratory conditions. Thirty-four patients were receiving systemic and/or inhaled corticosteroids prior to infection, eight had neoplasia, and six had haematological malignancies. Clinical and radiological findings were common to pneumonia of other infectious aetiologies, except for the frequent presence of nodules and cavitation. Overall, the 1-year mortality was high (38.2%), and mortality was directly related to the pulmonary disease in 15 patients (27.3%). The most frequently identified species were N. cyriacigeorgica (n=21), N. abscessus (n=8), and N. farcinica (n=5). All Nocardia isolates were susceptible to linezolid and all but two were susceptible to amikacin and trimethoprim-sulfamethoxazole.

CONCLUSIONS

Nocardia pneumonia-associated mortality remains high, probably because of the debilitated status of patients in whom this pathogen is able to cause pulmonary infection.

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.

Pulmonary Nocardiosis Presenting as Exacerbation of Chronic Pulmonary Disease

BACKGROUND

Pulmonary nocardiosis (PN) occurs in chronic pulmonary disease (CPD) in the absence of traditional risk factors. Clinical features that differentiate bacterial exacerbations (AE-CPDb) from PN-related exacerbations (AE-CPDPN) are not well described.

OBJECTIVES

To describe a series of AE-CPDPN without traditional risk factors and compare clinical features, radiology and outcomes with age, gender and CLD-type matched AE-CPDb.

MATERIALS AND METHODS

Single-center retrospective review and case-control study.

RESULTS

AE-CPDPN had longer duration of symptoms and more leukocytosis at hospitalization. AE-CPDb patients were sicker with more chronic respiratory failure (OR 33.3, p = 0.01), cardiac disease and pulmonary hypertension (OR 6.2, p = 0.008) at diagnosis. More patients with AE-CPDb were discharged on domiciliary oxygen (OR 5.27, p = 0.01). On logistic regression, AE-CPDPN was independently associated with mechanical ventilation (OR 22.3, p = 0.01), length of hospital stay (median difference, 4 days, p = 0.016) but not to hospital mortality. 22.7% of AE-CPDPN died. Respiratory failure requiring oxygen, NIPPV or mechanical ventilation was associated with mortality in AE-CPDPN.

CONCLUSION

PN is a rare cause of AE-CPD and can be suspected by longer symptom duration, more leukocytosis, consolidation and cavitation. AE-CPDPN is associated with longer hospital stay and mechanical ventilation. Respiratory failure is associated with mortality in AE-CPDPN.

KEY MESSAGES

Pulmonary nocardiosis can present in advanced chronic lung disease as an exacerbation in the absence of traditional risk factors like immunosuppression.Bronchiectasis, followed by chronic obstructive pulmonary disease are the most common chronic lung disease risk factors.Pulmonary nocardiosis is a rare cause of acute exacerbation of chronic pulmonary disease (CPD).Compared to exacerbations of CPD due to bacterial infections, nocardiosis-related exacerbations (CPDPN) were independently related to need for mechanical ventilation and length of hospital stay.Respiratory failure requiring oxygen, noninvasive ventilation and mechanical ventilation are associated with mortality in AE-CPDPN.

HOW TO CITE THIS ARTICLE

Kancherla R, Ramanathan RM PL, Appalaraju B, Srinivas R. Pulmonary Nocardiosis Presenting as Exacerbation of Chronic Pulmonary Disease. Indian J Crit Care Med 2019;23(10):467-474.

Nocardia lung abscess in an immunocompetent adolescent

The authors report a case of a lung abscess caused by Nocardia sp. in a previously healthy adolescent. A 17-year-old young man presented with tonsillitis that did not respond to β-lactamic antibiotic, dyspnoea and thoracic pain. The X-ray revealed a cavitation in the right pulmonary upper lobe. He was admitted and completed a 14-day empirical antimicrobial therapy for a pulmonar abscess, although no clinical recovery was observed. He then underwent pulmonary biopsy of the lesion and PCR analysis of the collected pulmonary tissue, which revealed the presence of Nocardia This case emphasises the importance of considering nocardiosis in the differential diagnosis of a lung abscess, particularly if no response to empirical therapy is obtained.

Pulmonary Nocardiosis: Unusual Presentation in Intensive Care Unit

Pulmonary nocardiosis is a rare disease, which mainly affects immunocompromised hosts such as uncontrolled diabetics; HIV patients; and patients on immunosuppressive therapies such as anticancer drugs, systemic steroids, and transplant recipients. The diagnosis is often missed and delayed, resulting in inappropriate treatment and thus higher mortality. We are reporting a case of pulmonary nocardiosis with acute presentation in an immune-competent host, who presented with community-acquired pneumonia to the Intensive Care Unit. Clinical expertise with multiple high-end and interventional investigations timely confirmed the case as pulmonary nocardiosis. Conservative management with medications led to her complete recovery.

Isolation, biochemical and molecular identification of Nocardia species among TB suspects in northeastern, Tanzania; a forgotten or neglected threat?

BACKGROUND

Pulmonary nocardiosis mimic pulmonary tuberculosis in most clinical and radiological manifestations. In Tanzania, where tuberculosis is one of the major public health threat clinical impact of nocardiosis as the cause of the human disease remains unknown. The objective of the present study was to isolate and identify Nocardia isolates recovered from TB suspects in Northeastern, Tanzania by using biochemical and molecular methods.

METHODS

The study involved 744 sputum samples collected from 372 TB suspects from four periphery diagnostic centers in Northeastern, Tanzania. Twenty patients were diagnosed as having presumptively Nocardia infections based on microscopic, cultural characteristics and biomèrieux ID 32C Yeast Identification system and confirmed using 16S rRNA and hsp65 gene specific primers for Nocardia species and sequencing.

RESULTS

Biochemically, the majority of the isolates were N. asteroides (n = 8/20, 40%), N. brasiliensis (n = 4/20, 20%), N. farcinica (n = 3/20, 15%), N. nova (n = 1/20, 5%). Other aerobic actinomycetales included Streptomyces cyanescens (n = 2/20, 10%), Streptomyces griseus, Actinomadura madurae each (n = 1/20, 5%). Results of 16S rRNA and hsp65 sequencing were concordant in 15/17 (88. 2%) isolates and discordant in 2/17 (11.8%) isolates. Majority of the isolates belonged to N. cyriacigeorgica and N. farcinica, four (23.5%) each.

CONCLUSIONS

Our findings suggest that Nocardia species may be an important cause of pulmonary nocardiosis that is underdiagnosed or ignored. This underscores needs to consider pulmonary nocardiosis as a differential diagnosis when there is a failure of anti-TB therapy and as a possible cause of human infections.

Pulmonary and cutaneous infection caused by Nocardia farcinica in a patient with nephrotic syndrome: A case report

RATIONALE

Nocardia species is known as conditional pathogenic bacteria. Disseminated infection caused by Nocardia species is rare and occurs primarily in immunosuppressed patients. Signs and symptoms of this infection are frequently nonspecific making early diagnosis and treatment difficult.

PATIENT CONCERNS

We report a case of subcutaneous and pulmonary nocardiosis due to Nocardia farcinica (N farcinica) in a patient with nephrotic syndrome who is undergoing long-term corticosteroid therapy. In this patient, systemic and pulmonary symptoms (usually found in nocaria infection) such as fever, cough, and expectoration were absent.

DIAGNOSES

Early diagnosis was made by pus culture from subcutaneous abscesses and 16S rRNA gene sequencing, which confirm the diagnosis of N farcinica infection.

INTERVENTIONS

The patient was treated with combination therapy of cefatriaxone and trimethoprim-sulfamethoxazole (TMP-SMX) for 2 weeks, and the treatment with TMP-SMX continued to 6 months.

OUTCOMES

The abscesses were cured in 4 weeks and a lesion in the upper lobe of left lung resolved in 3 months.

LESSONS

This case indicates that disseminated infection due to N farcinica could occur in patients with nephrotic syndrome, even during the period of maintenance therapy with a low-dose corticosteroid and common signs and symptoms of infections could be absent.

Severe pneumonia due to Nocardia otitidiscaviarum identified by mass spectroscopy in a cotton farmer: A case report and literature review

RATIONALE

Nocardia species are aerobic saprophytic bacilli. Among Nocardia species, Nocardia otitidiscaviarum (N otitidiscaviarum) is rarely reported in pulmonary infection.

PATIENT CONCERNS

We reported a case of N otitidiscaviarum pneumonia in a cotton farmer.

DIAGNOSES

N otitidiscaviarum pneumonia was identified by mass spectroscopy.

INTERVENTIONS

Combined treatments (amikacin, imipenem and trimethoprim-sulfamethoxazole) were administered after identification of N otitidiscaviarum.

OUTCOMES

The patient eventually died from severe respiratory insufficiency in the hospital.

LESSONS

Early precise diagnosis and prompt combined therapy are of vital importance in severe Nocardia pulmonary infection.

Clinical spectrum and outcome of pulmonary nocardiosis: 5-year experience

Background:

Pulmonary nocardiosis is a rare but a life-threatening infection caused by Nocardia spp. The diagnosis is often missed and delayed resulting in delay in appropriate treatment and thus higher mortality.

Aim:

In this study, we aim to evaluate the clinical spectrum and outcome of patients with pulmonary nocardiosis.

Methods:

A retrospective, 5-year (2009–2014) review of demographic profile, risk factors, clinical manifestations, imaging findings, treatment, and outcome of patients with pulmonary nocardiosis admitted to a tertiary care hospital.

Results:

The median age of the study subjects was 54 years (range, 16–76) and majority of them (75%) were males. The risk factors for pulmonary nocardiosis identified in our study were long-term steroid use (55.6%), chronic lung disease (52.8%), diabetes (27.8%), and solid-organ transplantation (22.2%). All the patients were symptomatic, and the most common symptoms were cough (91.7%), fever (78%), and expectoration (72%). Almost two-third of the patients were initially misdiagnosed and the alternative diagnosis included pulmonary tuberculosis (n = 7), community-acquired pneumonia (n = 5), lung abscess (n = 4), invasive fungal infection (n = 3), lung cancer (n = 2), and Wegener's granulomatosis (n = 2). The most common radiographic features were consolidation (77.8%) and nodules (56%). The mortality rate for indoor patients was 33% despite treatment. Higher mortality rate was observed among those who had brain abscess (100.0%), HIV positivity (100%), need for mechanical ventilation (87.5%), solid-organ transplantation (50%), and elderly (age > 60 years) patients (43%).

Conclusion:

The diagnosis of pulmonary nocardiosis is often missed and delayed resulting in delay in appropriate treatment and thus high mortality. A lower threshold for diagnosing pulmonary nocardiosis needs to be exercised, in chest symptomatic patients with underlying chronic lung diseases or systemic immunosuppression, for the early diagnosis, and treatment of this uncommon but potentially lethal disease. Despite treatment mortality remains high, especially in those with brain abscess, HIV positivity, need for mechanical ventilation, solid-organ transplantation, and elderly.

Specific clinical manifestations of Nocardia: A case report and literature review

Nocardiosis is a rare bacterial infection of either the lungs (pulmonary) or body (systemic) that usually affects immunocompromised individuals. It is caused by Gram-positive, aerobic actinomycetes of the Nocardia genus. Multiple high-density sheet shadows in both lungs along with nodules or cavities are the most common presentations of nocardiosis, whereas a large pulmonary mass is considered to be rare. However, there is no specificity in the clinical manifestation of the disease. Therefore, isolation and identification of Nocardia strains is the only reliable diagnostic method. The present study describes the cases of two male patients of Asian descent with nocardiosis. Chest computed tomography scans showed a suspected tumor mass in both patients. Microscopic analysis and culturing of tissue samples obtained using a bronchoscope detected the presence of Nocardia wallacei. Neither patient showed signs of immunosuppression. The present study aimed to improve the understanding of lung nocardiosis and demonstrated that pulmonary nocardiosis should be suspected in the case of non-immunocompromised patients with a large mass in the lung. Furthermore, a review of the literature on infection with Nocardia was conducted.

Experimental Granulomatous Pulmonary Nocardiosis in BALB/C Mice

Pulmonary nocardiosis is a granulomatous disease with high mortality that affects both immunosuppressed and immunocompetent patients. The mechanisms leading to the establishment and progression of the infection are currently unknown. An animal model to study these mechanisms is sorely needed. We report the first in vivo model of granulomatous pulmonary nocardiosis that closely resembles human pathology. BALB/c mice infected intranasally with two different doses of GFP-expressing Nocardia brasiliensis ATCC700358 (NbGFP), develop weight loss and pulmonary granulomas. Mice infected with 10⁹ CFUs progressed towards death within a week while mice infected with 10⁸ CFUs died after five to six months. Histological examination of the lungs revealed that both the higher and lower doses of NbGFP induced granulomas with NbGFP clearly identifiable at the center of the lesions. Mice exposed to 10⁸ CFUs and subsequently to 10⁹ CFUs were not protected against disease severity but had less granulomas suggesting some degree of protection. Attempts to identify a cellular target for the infection were unsuccessful but we found that bacterial microcolonies in the suspension used to infect mice were responsible for the establishment of the disease. Small microcolonies of NbGFP, incompatible with nocardial doubling times starting from unicellular organisms, were identified in the lung as early as six hours after infection. Mice infected with highly purified unicellular preparations of NbGFP did not develop granulomas despite showing weight loss. Finally, intranasal delivery of nocardial microcolonies was enough for mice to develop granulomas with minimal weight loss. Taken together these results show that Nocardia brasiliensis microcolonies are both necessary and sufficient for the development of granulomatous pulmonary nocardiosis in mice.

Nocardiosis following hematopoietic stem cell transplantation

BACKGROUND

Nocardia species are ubiquitous environmental organisms that can cause a diverse spectrum of disease. Clinical manifestations range from localized skin and soft tissue infections to life-threatening pulmonary, central nervous system, and/or disseminated infections. Patients with hematologic malignancies undergoing hematopoietic stem cell transplantation (HSCT) are at risk for nocardiosis, and further data in regard to characteristics of disease in this population are warranted.

METHODS

We performed retrospective chart review of patients post allogeneic HSCT at Moffitt Cancer Center in Florida diagnosed with nocardiosis from 2003 to 2013.

RESULTS

In a decade, 15 cases of nocardiosis were identified. The majority of patients were men (11/15). The median age was 55 years (range 25-65). The most common type of transplant was matched-related donor (n = 8), followed by matched-unrelated donor (n = 3), mismatched-unrelated donor (n = 3), and double umbilical cord (n = 1). Ten received myeloablative conditioning (MAC) regimens. Twelve of 15 patients were on prednisone, 10 of which were on a total daily dose ≥20 mg. The median time from transplant to first positive culture was 10 months (range 1.5-93). Pulmonary nocardiosis was the most prevalent manifestation at 87%. Disseminated disease (2 or more sites of infection) was seen in 47%, whereas blood cultures were positive in 27% of the total cohort. The most common species was Nocardia nova (n = 4). At the time of diagnosis, 20% of the patients were receiving prophylaxis for Pneumocystis jirovecii pneumonia (PJP) with trimethoprim-sulfamethoxazole (TMP-SMX). Susceptibility data were available for 8 patients: all 8 samples were susceptible to TMP-SMX. Nocardiosis was treated with 2 or more active drugs in 93% of the patients. Overall mortality was 53%, with nocardiosis attributed as the cause in 62.5% (5/8). The absolute lymphocyte count at time of diagnoses was significantly lower in patients who ultimately experienced treatment failure.

CONCLUSION

Infection with Nocardia species in allogeneic HSCT recipients appears to be a late complication of transplantation and most commonly involves the lung. Two-thirds of the cohort received a MAC regimen and the majority of the patients were receiving steroids at the time of diagnosis. Most patients were not receiving TMP-SMX for PJP prophylaxis at the time of nocardiosis diagnosis, and TMP-SMX may therefore have a protective effect.

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.

High-resolution Computed Tomography Findings in Patients with Pulmonary Nocardiosis

RATIONALE AND OBJECTIVES

Nocardiosis is difficult to diagnose, and the diagnosis is thus frequently delayed. High-resolution computed tomography (HRCT) findings of patients with pulmonary nocardiosis have been documented in few reports. Our study objective was to assess HRCT findings of patients with pulmonary nocardiosis.

MATERIALS AND METHODS

This was a retrospective study of 20 consecutive patients with pulmonary Nocardia infections who underwent HRCT of the chest at our institutions from January 2011 to August 2014. After the exclusion of two patients with concurrent infections, the study group comprised 18 patients (11 men, 7 women; age range, 39-83 years; mean, 67.9 years) with pulmonary Nocardia infections. Parenchymal abnormalities, enlarged lymph nodes, and pleural effusion were evaluated on HRCT.

RESULTS

Underlying conditions included respiratory disease (n = 6, 33.3%), collagen diseases (n = 5, 27.8%), and diabetes mellitus (n = 4, 22.2%). All patients showed abnormal HRCT findings, including the presence of a nodule/mass (n = 17, 94.4%), ground-glass opacity (n = 14, 77.8%), interlobular septal thickening (n = 14, 77.8%), and cavitation (n = 12, 66.7%). Pleural effusion was seen in two patients. There were no cases of lymph node enlargement.

CONCLUSIONS

Among the HRCT findings in patients with pneumonia, a nodule/mass with interlobular septal thickening and/or cavitation are suggestive of pulmonary nocardiosis.

Pleural Nocardiosis in an Immunocompetent Patient: A Case Report

Nocardiosis is a rare infection that has attracted attention with its increased rate of occurrence in the recent years. In India there is a rare documentation of the pleural involvement in nocardiosis. We report here a case of pleural nocardiosis caused by Nocardia brasiliensis in an immunocompetent patient. This case highlights the importance of considering nocardiosis as a differential diagnosis in patients with pleural lesions.

Pulmonary Nocardiosis in the Immunocompetent Host: Case Series

Pulmonary nocardiosis is commonly recognized as an opportunistic infection in patients with predisposing immunosuppressive conditions. However, reports of pulmonary nocardiosis in the immunocompetent host are rare. Here, we report a case series of four patients with pulmonary nocardiosis without a predisposing condition.

An unusual case of pulmonary nocardiosis in immunocompetent patient

Pulmonary nocardiosis is a subacute or chronic necrotizing pneumonia caused by aerobic actinomycetes of the genus Nocardia and rare in immune-competent patients. A 35-year-old male, who had treated with antituberculosis drugs, presented with cough, dyspnea, and expectoration with episodes of hemoptysis with purulent sputum. The diagnosis of nocardiosis was made by microscopic examination of the surgically resected portion of the lung and revealed filamentous Gram-positive bacteria.

Long-term treatment of persistent disseminated Nocardia cyriacigeorgica infection

In this paper a disseminated persistent Nocardia cyriacigeorgica infection in an immunocompetent patient is described. The patient's long-term treatment, as well as its implications for managing similar cases in the future, is emphasized. Presenting with high fever, multiple nodules, and ulcerative cutaneous lesions of body sites, the patient was treated with various antimicrobials. Under combined therapy, empyema and arthritis, leading to disseminated nocardiosis, were seen. The overall treatment course was 28 months. It can be concluded that the choice of the antibiotics and optimal duration of treatment are uncertain; therefore the treatment of nocardiosis requires expertise.

Pulmonary nocardiosis: a clinical analysis of 59 cases

BACKGROUND

Pulmonary nocardiosis is a rare but severe infection caused by Nocardia species. This study aimed at describing the clinical characteristics and prognosis of pulmonary nocardiosis.

METHODS

An observational, retrospective study was undertaken of patients diagnosed with pulmonary nocardiosis over a 13-year period at the Kinki-Chuo Chest Medical Center, Osaka, Japan.

RESULTS

Seven patients with airway nocardial colonization and 59 patients with pulmonary nocardiosis were identified, one of whom had disseminated nocardiosis. Patients with pulmonary nocardiosis were predominantly male patients (73%), with a mean age of 66 (range, 15-88) years. New-onset cough and dyspnea were the most common manifestations (76%). Although 52 (88%) patients had at least one underlying pulmonary disease, most patients did not appear to be systemically immunocompromised. The predominant abnormality on chest computed tomography in pulmonary nocardiosis was airspace consolidation (52%), sometimes associated with cavitation. Multivariate Cox proportional-hazards analysis revealed the following significant and independent risk factors for overall mortality: age >68 years (hazard ratio [HR], 4.7; 95% confidence interval [CI], 1.6-14; p=0.05), pulmonary aspergillosis (HR, 8.8; 95% CI, 2.4-33; p=0.01), and trimethoprim/sulfamethoxazole (TMP-SMZ) resistance (HR, 4.3; 95% CI, 1.6-11; p=0.04).

CONCLUSIONS

Clinicians should be aware that pulmonary nocardiosis can occur even in immunocompetent patients, especially those with an underlying pulmonary disease. In pulmonary nocardiosis, older age, pulmonary aspergillosis, and TMP-SMZ resistance are associated with increased risk of mortality.

Coinfection by Nocardia beijingensis and Nocardia arthritidis in an immunocompromised patient diagnosed by endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA)

2 different strains of Nocardia were isolated from a lung mass in a post kidney-pancreas transplant patient through convex endobronchial ultrasound transbronchial needle aspiration (EBUS-TNBA). TBNA cultures (16S rRNA gene-targeted PCR sequencing) subsequently grew Nocardia beijingensis and Nocardia arthritidis.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Nocardiosis: a 15-year experience in a tertiary medical center in Israel

OBJECTIVES

The objective of this study is to characterize the common risk factors, clinical presentation, imaging findings, treatment and outcome of nocardial infection.

DESIGN AND SETTINGS

A retrospective cohort study. We reviewed the charts of all patients with nocardiosis in the Chaim Sheba Medical Center, a tertiary medical center in Israel, between the years 1996 and 2011.

RESULTS

A total of 39 patients who had positive culture of Nocardia were analyzed. The majority of our patients were immunocompromised (74.5%), mostly due to corticosteroid therapy. None had HIV/AIDS. The clinical presentation was either acute or a chronic smoldering illness. The three major clinical syndromes were pleuropulmonary, neurological and skin/soft tissue infection about 20.5% each. Pathology in the lungs was seen in most of the patients by CT scan; discrete nodules and wedge shaped pleural based consolidations were the most frequent findings. Brain lesions consistent with abscesses were detected in 10 patients by brain imaging. Some cases had relapsing disease in spite of antimicrobial treatment. 25% of examined isolates were resistant to trimethoprim/sulfamethoxazole. The duration of intravenous antimicrobial treatment ranged from one month to over a year in the severe cases. One year mortality rate was 32%.

CONCLUSION

Nocardiosis requires a high clinical index of suspicion in order to diagnose and treat promptly. Disease extent and bacterial susceptibility have important implications for prognosis and treatment.

Functional diversity of Nocardia in metabolism

Bacteria affiliated in the genus Nocardia are aerobic and Gram-positive actinomycetes that are widely found in aquatic and terrestrial habitats. As occasional pathogens, several of them cause infection diseases called 'nocardiosis' affecting lungs, central nervous system, cutaneous tissues and others. In addition, members of the genus Nocardia exhibit an enormous metabolic versatility. On one side, many secondary metabolites have been isolated from members of this genus that exhibit various biological activities such as antimicrobial, antitumor, antioxidative and immunosuppressive activities. On the other side, many species are capable of degrading or converting aliphatic and aromatic toxic hydrocarbons, natural or synthetic polymers, and other widespread environmental pollutants. Because of these valuable properties and the application potential, Nocardia species have attracted much interest in academia and industry in recent years. A solid basis of genetic tools including a set of shuttle vectors and an efficient electroporation method for further genetic and metabolic engineering studies has been established to conduct efficient research. Associated with the increasing data of nocardial genome sequences, the functional diversity of Nocardia will be much faster and better understood.

Pulmonary nocardiosis in an immunocompetent patient with COPD: the role of defective innate response

OBJECTIVES

Pulmonary nocardiosis is an uncommon opportunistic infection affecting mainly immunocompromised patients. We herein present a case of nocardiosis without profound underlying immunodeficiency.

BACKGROUND

A female, 84-years' old patient with stage IV chronic obstructive pulmonary disease (COPD) is presented. No profound causes of immunodeficiency existed, such as HIV infection, diabetes mellitus, malignancy, alcoholism, chemotherapy or previous corticosteroid intake. The patient recovered after treatment with trimethoprim/sulfamethoxazole for 6 months.

RESULTS

One year after infection resolution, stimulation of the patient's blood monocytes with Nocardia antigens revealed defective production of tumor necrosis factor-alpha, interleukin (IL)-6 and IL-17.

CONCLUSION

We provide preliminary evidence for a link between defective innate immune responses and predisposition for Nocardia infections. Further studies must be conducted in order to fully investigate this mechanism of infection acquisition.

HIV-associated bacterial pneumonia

Community-acquired bacterial pneumonia (CAP) remains one of the most common opportunistic infections in patients who are infected with the human immunodeficiency virus (HIV). The risk of CAP increases as the CD4 cell count decreases. The common bacterial pathogens that cause CAP in HIV-infected persons are similar to those in HIV-uninfected individuals, with the pneumococcus being the most common pathogen. Prevention of CAP remains critical and necessitates a comprehensive approach addressing, among many other factors, cigarette smoking cessation strategies, antiretroviral therapy adherence, and immunization against those infections for which effective vaccinations are available.

High-resolution CT findings of patients with pulmonary nocardiosis

BACKGROUND

Opportunistic pulmonary infection with Nocardia species is rare in humans, and only a few studies have radiologically analyzed patients with pulmonary nocardiosis using high-resolution computed tomography (HRCT).

METHODS

We retrospectively reviewed the medical records of patients with pulmonary nocardiosis at our hospital between April 2006 and December 2011 to assess HRCT and clinical findings. We also searched the medical literature for pulmonary nocardiosis reported in Japan between 2002 and 2011 for comparison.

RESULTS

We identified seven patients at our institution and 33 reported infections in Japan. Four of our patients were immunocompetent, whereas the other three had impaired cellular immunity due to type 2 diabetes mellitus or having been inappropriately treated with steroid. Thoracic HRCT revealed no zonal predominance, but tropism for distribution from the middle to the peripheral area, and radiological findings of nodules, cavitation, mass, consolidations, bronchial wall thickening, septal line thickening and ground glass opacity (GGO) were evident. The main HRCT finding in our study comprised nodules (n=5, 71.4%) <30 mm and four patients had multiple nodules as described in other reports. Furthermore, we discovered a crazy paving appearance (CPA) around nodules, cavities, masses or consolidations in five patients (71.4%).

CONCLUSIONS

Multiple nodules distributed from the middle to the peripheral area on HRCT might reflect pulmonary nocardiosis, and CPA seemed to be a worth paying attention to the diagnosis.

Bird fancier's lung complicated by pulmonary nocardiosis

We report the case of an 84-year-old male who was admitted to the hospital with persistent cough and dyspnea. An initial chest X-ray revealed pulmonary infiltrates. Nocardia asteroides was detected in sputum, and the patient was treated with antibiotics. However, his symptoms did not completely resolve. He was admitted multiple times, and his symptoms relapsed after every discharge. He was finally suspected of having hypersensitivity pneumonitis and was diagnosed with bird fancier's lung. Pulmonary nocardiosis is likely to develop in patients with chronic pulmonary disorders, such as COPD, as well as in immunosuppressed hosts. To our knowledge, this is the first report of a case of bird fancier's lung complicated by pulmonary nocardiosis.

[Bacterial pneumonia in HIV-infected patients (excluding mycobacterial infection)]

Respiratory infections are the most common complications in HIV patients, regardless of the degree of immunosuppression. Even though antiretroviral therapy has a protective effect on the risk of bacterial pneumonia, this still remains high (including those with CD(4)>500/mm(3)). The most frequently isolated bacteria are Streptococcus pneumoniae and Haemophilus influenzae. The clinical and radiological presentations of lower respiratory tract infections in HIV patients are quite variable. The clinical presentation is more severe and the radiological presentation is more atypical if the immunosuppression is severe. The first-line antibiotic therapy is an injectable third-generation cephalosporin (ceftriaxone or cefotaxime) or co-amoxiclav. Pneumococcal vaccination (as well as influenza vaccine) is recommended. Although rare, Nocardia spp. and Rhodococcus equi seem more common among AIDS patients.