Nocardiosis in 132 patients with cancer: microbiological and clinical analyses

Disseminated Infection Caused by Nocardia cyriacigeorgica in Immunocompromised Patient Confirmed by Whole Genome Sequencing

INTRODUCTION

Nocardia spp. is an opportunistic pathogen capable of causing localized and disseminated infections in immunocompromised hosts. It is critical for serious infections to have an early and accurate identification of this pathogen in order to enable timely and focused combination antimicrobial treatment.

CASE PRESENTATION

We describe the case of an 87-year-old patient previously treated for myasthenia gravis with corticosteroids and azathioprine. Patient was admitted at the emergency department with clinical signs of sepsis with cellulitis of right hand associated with injury acquired after gardening and trimming roses and did not respond to empirical antimicrobial treatment. Computerized tomography revealed pulmonary infiltrates with inflammatory etiology. Nocardia cyriacigeorgica was cultivated from blood culture, skin swab, abscess aspirate, and endotracheal aspirate and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), 16S rRNA sequencing, and whole genome sequencing (WGS). Susceptibility testing was performed with E-test (bioMerieux, Marcy-l'Étoile, France), and corresponding resistance genes were detected by WGS. Resistance to amoxicillin-clavulanate, azithromycin, ciprofloxacin, and vancomycin was detected by both methods. Despite all interventions and the patient receiving antimicrobial treatment including imipenem-cilastatin, amikacin, and trimethoprim-sulfamethoxazole, the course and outcome of infection were unfavorable.

CONCLUSION

We would like to emphasize the need to consider the possibility of disseminated Nocardia infection in immunocompromised patients, especially in patients receiving long-term corticosteroid treatment with skin infections and/or cavitary lung lesions, especially if these do not improve with standard antimicrobial treatment. Precise species identity provides a critical guide for physicians in the choice of targeted treatment. Thanks to MALDI-TOF MS, Nocardia spp. identification is now available in routine lab work. WGS is still inevitable for the identification of uncommon and novel species due to the high sequence similarities between closely related species and the genetic diversity of that genus.

The first reported pulmonary nocardiosis caused by Nocardia gipuzkoensis resisted to trimethoprim/sulfamethoxazol (TMP-SMZ) in an immunocompetent patient

OBJECTIVES

Nocardia gipuzkoensis was first described as a novel and distinct species in 2020 by Imen Nouioui and pulmonary nocardiosis associated with N. gipuzkoensis was once reported in two bronchiectasis patients. Noteworthy, both reported N. gipuzkoensis cases showed sensitivity to trimethoprim/sulfamethoxazol (TMP-SMZ), which are usually recommended for empirical therapy.

METHODS

We reported the third case of N. gipuzkoensis infection in a 16-year-old girl with chief complaints of cough and persistent chest and back pain. No underlying immuno-suppressive conditions and glucocorticoid use was revealed. Patchy lesions next to the spine and located in the posterior basal segment of the lower lobes of the left lung were seen in thorax computed tomography (CT), but no pathogenic bacteria were detected according to routine laboratory testings.

RESULTS

Metagenomic next-generation sequencing (mNGS) combined with whole-genome sequencing (WGS) was used to classified our isolate from bronchoalveolar lavage fluid (BALF) as N. gipuzkoensis. It is worth mentioning that drug susceptibility testing of our isolate showed resistance to TMP-SMZ, which was never reported before. The patient improved remarkably both clinically and radiographically according to the treatment with imipenem-cilastatin infusion alone.

CONCLUSION

mNGS and WGS showed excellent performance in identifying the Nocardia genus to the species level and improving the detection rate of N. gipuzkoensis ignored by traditional culture. Different from previously reported cases, the N. gipuzkoensis infection case showed resistance to TMP-SMZ, which is an unprecedented finding and a crucial addition to our understanding of the antibacterial spectrum of N. gipuzkoensis. The successful treatment with imipenem-cilastatin infusion alone in this case is a testament to the importance of precise identification and tailored antibiotic therapy.

Fatal Nocardia paucivorans Lower Respiratory Tract Infection in a Tuberculosis Suspect Who Worked as Gold Miner

Nocardiosis is an opportunistic infection that affects both immunocompromised as well as immunocompetent patients. The main infections occur as soft tissue and lung infections although they might disseminate to various organs. This is a case study aimed to reflect the severity of the disease and the patient's risk factors associated with the infection. A sputum sample was collected from tuberculosis (TB) suspects for culture. Nocardia-like colonies were isolated, purified, and sent to BGI Company (Hongkong, China). Standard forward sequencing of 16S rRNA was done by ABI Genetic Analyzer (Applied Biosystems). Sequence alignment and nucleotide basic local alignment search tool (BLAST) were done using National Center for Bioinformatics (NCBI) Nucleotide BLAST. Biochemical identification to the colonies was done using an automation system (BD Phoenix™) to confirm the identification. Nocardia paucivorans was identified from the TB suspect. Risk factors were identified as extensive contact to dust, absence of primary care units with complete facilities, and old age. Since the infection of the lungs caused by Nocardia might be similar to pulmonary TB, this case report highlights the importance of accurate diagnosis and identification procedures to differentiate between the two.

Comparative Analysis of CT Findings and Clinical Outcomes in Adult Patients With Disseminated and Localized Pulmonary Nocardiosis

BACKGROUND

Pulmonary nocardiosis is a rare opportunistic infection with occasional systemic dissemination. This study aimed to investigate the computed tomography (CT) findings and prognosis of pulmonary nocardiosis associated with dissemination.

METHODS

We conducted a retrospective analysis of patients diagnosed with pulmonary nocardiosis between March 2001 and September 2023. We reviewed the chest CT findings and categorized them based on the dominant CT findings as consolidation, nodules and/or masses, consolidation with multiple nodules, and nodular bronchiectasis. We compared chest CT findings between localized and disseminated pulmonary nocardiosis and identified significant prognostic factors associated with 12-month mortality using multivariate Cox regression analysis.

RESULTS

Pulmonary nocardiosis was diagnosed in 75 patients, of whom 14 (18.7%) had dissemination, including involvement of the brain in 9 (64.3%) cases, soft tissue in 3 (21.4%) cases and positive blood cultures in 3 (21.4%) cases. Disseminated pulmonary nocardiosis showed a higher frequency of cavitation (64.3% vs. 32.8%, P = 0.029) and pleural effusion (64.3% vs. 29.5%, P = 0.014) compared to localized infection. The 12-month mortality rate was 25.3%. The presence of dissemination was not a significant prognostic factor (hazard ratio [HR], 0.80; confidence interval [CI], 0.23-2.75; P = 0.724). Malignancy (HR, 9.73; CI, 2.32-40.72; P = 0.002), use of steroid medication (HR, 3.72; CI, 1.33-10.38; P = 0.012), and a CT pattern of consolidation with multiple nodules (HR, 4.99; CI, 1.41-17.70; P = 0.013) were associated with higher mortality rates.

CONCLUSION

Pulmonary nocardiosis with dissemination showed more frequent cavitation and pleural effusion compared to cases without dissemination, but dissemination alone did not affect the mortality rate of pulmonary nocardiosis.

Clinical and Radiological Characterization of Central Nervous System Involvement in Nocardiosis: A 20-Year Experience

Background This study aimed to present the clinical and radiological characteristics and the outcomes of patients with Nocardia infection of the central nervous system (CNS). Methodology We conducted a retrospective review of patients aged 18 and older admitted between August 1998 and November 2018 with culture-proven nocardiosis and CNS involvement. Results Out of 110 patients with nocardiosis, 14 (12.7%) patients had CNS involvement. The median age was 54.5 (27, 86) years, and 12 (85.7%) patients were male. Overall, 12 (85.7%) patients were immunosuppressed on high doses of glucocorticoids; seven (50%) patients were solid organ transplant recipients. Only eight (57.1%) patients had neurological symptoms at presentation, and the rest were diagnosed with CNS involvement after imaging surveillance. Three distinct radiologic patterns were identified, namely, single or multiple abscesses, focal cerebritis, and small, septic embolic infarcts. All isolates of Nocardia were susceptible to trimethoprim/sulfamethoxazole and amikacin, with susceptibility to linezolid and carbapenems being 90.9% and 79.5%, respectively. Despite receiving antibiotic therapy, six (42.8%) patients died, most of them within weeks of initial admission. All surviving patients underwent prolonged antimicrobial therapy until the resolution of MRI abnormalities. All solid organ transplant recipients recovered. Conclusions Nocardia CNS infection was a rare condition, even among a large, immunosuppressed patient population. CNS imaging surveillance is paramount for immunosuppressed patients with nocardiosis, as CNS involvement influences the choice and duration of therapy. Nocardia antibiotic susceptibility varied widely between strains and the empiric therapy should consist of multiple classes of antimicrobials with CNS penetration. Mortality was high, but all solid organ transplant recipients recovered.

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.

Skin lesions by Scedosporium apiospermum and Nocardia pulmonary infection in an oncologic patient: a case report

BACKGROUND

Fungal infections, other than candidiasis and aspergillosis, are an uncommon entity. Despite this, emerging pathogens are a growing threat. In the following case report, we present the case of an immunocompromised patient suffering from two serious opportunistic infections in the same episode: the first of these, Nocardia multilobar pneumonia; and the second, skin infection by Scedosporium apiospermum. These required prolonged antibacterial and antifungal treatment.

CASE PRESENTATION

This case is a 71-year-old oncological patient admitted for recurrent pneumonias that was diagnosed for Nocardia pulmonary infection. Nervous system involvement was discarded and cotrimoxazole was started. Haemorrhagic skin ulcers in the lower limbs appeared after two weeks of hospital admission. We collected samples which were positive for Scedosporium apiospermum and we added voriconazole to the treatment. As a local complication, the patient presented a deep bruise that needed debridement. We completed 4 weeks of intravenous treatment with slow improvement and continued with oral treatment until the disappearance of the lesions occurs.

CONCLUSIONS

Opportunistic infections are a rising entity as the number of immunocompromised patients is growing due to more use of immunosuppressive therapies and transplants. Clinicians must have a high suspicion to diagnose and treat them. A fluid collaboration with Microbiology is necessary as antimicrobial resistance is frequent.

Design of a multi-epitope vaccine against six Nocardia species based on reverse vaccinology combined with immunoinformatics

Background

Nocardia genus, a complex group of species classified to be aerobic actinomycete, can lead to severe concurrent infection as well as disseminated infection, typically in immunocompromised patients. With the expansion of the susceptible population, the incidence of Nocardia has been gradually growing, accompanied by increased resistance of the pathogen to existing therapeutics. However, there is no effective vaccine against this pathogen yet. In this study, a multi-epitope vaccine was designed against the Nocardia infection using reverse vaccinology combined with immunoinformatics approaches.

Methods

First, the proteomes of 6 Nocardia subspecies Nocardia subspecies (Nocardia farcinica, Nocardia cyriacigeorgica, Nocardia abscessus, Nocardia otitidiscaviarum, Nocardia brasiliensis and Nocardia nova) were download NCBI (National Center for Biotechnology Information) database on May 1st, 2022 for the target proteins selection. The essential, virulent-associated or resistant-associated, surface-exposed, antigenic, non-toxic, and non-homologous with the human proteome proteins were selected for epitope identification. The shortlisted T-cell and B-cell epitopes were fused with appropriate adjuvants and linkers to construct vaccines. The physicochemical properties of the designed vaccine were predicted using multiple online servers. The Molecular docking and molecular dynamics (MD) simulation were performed to understand the binding pattern and binding stability between the vaccine candidate and Toll-like receptors (TLRs). The immunogenicity of the designed vaccines was evaluated via immune simulation.

Results

3 proteins that are essential, virulent-associated or resistant-associated, surface-exposed, antigenic, non-toxic, and non-homologous with the human proteome were selected from 218 complete proteome sequences of the 6 Nocardia subspecies epitope identification. After screening, only 4 cytotoxic T lymphocyte (CTL) epitopes, 6 helper T lymphocyte (HTL) epitopes, and 8 B cell epitopes that were antigenic, non-allergenic, and non-toxic were included in the final vaccine construct. The results of molecular docking and MD simulation showed that the vaccine candidate has a strong affinity for TLR2 and TLR4 of the host and the vaccine-TLR complexes were dynamically stable in the natural environment. The results of the immune simulation indicated that the designed vaccine had the potential to induce strong protective immune responses in the host. The codon optimization and cloned analysis showed that the vaccine was available for mass production.

Conclusion

The designed vaccine has the potential to stimulate long-lasting immunity in the host, but further studies are required to validate its safety and efficacy.

Nodular Cutaneous Lesions in Immune-Compromised Hosts as a Clue for the Diagnosis of Disseminated Nocardiosis: From Bedside to Microbiological Identification

BACKGROUND

Nocardia is a group of ubiquitous bacteria known to cause opportunistic infections in immunocompromised hosts, including those affected by malignancies and solid-organ or hematopoietic stem cell transplants. Pulmonary involvement, occurring in two-thirds of cases, is the most frequent presentation. Diagnosis might be challenging both because of microbiological technical issues, but also because of the variability of organ involvement and mimicry.

METHODS

We describe four cases of disseminated nocardiosis caused by N. farcinica observed between September 2021 and November 2021 in immune-compromised hosts presenting with nodular cutaneous lesions that had raised a high degree of clinical suspect and led to microbiological identification through MALDI-TOF MS.

RESULTS

Cutaneous involvement is typically reported in immunocompetent hosts with primary cutaneous nocardiosis with multiple forms of manifestation; nonetheless, disseminated nocardiosis rarely involves the skin and subcutaneous tissues, and this occurs as a result of metastatic spread. Our cases were disseminated nocardiosis in which the metastatic cutaneous involvement, even if rare, provided a clue for the diagnosis.

CONCLUSIONS

The pathomorphosis of disseminated nocardiosis may have changed in the current years with more rapid spread due to advanced immunosuppression. For this reason, after clinical suspicion, the prompt start of an active targeted therapy based on rapid microbiological identification might potentially open the way to hopeful results, even in the most immune-compromised patients.

Bacteremia and adrenal gland abscess due to Nocardia cyriacigeorgica: a case report and review

BACKGROUND

Nocardia cyriacigeorgica is one of the most common Nocardia species found in human infections, recently reclassified. Even though Nocardia may affect all organs by hematogenous dissemination, bacteremia are uncommon. Among all possible dissemination sites, the involvement of the adrenal glands is particularly rare.

CASE PRESENTATION

We report here a rare case of Nocardia disseminated infection with notably bacteremia and adrenal gland abscess, in a 77-years-old immunocompetent man. Adrenal gland abscess diagnosis was made by imaging (computerized tomography, magnetic resonance and positron emission tomography scan). A complete regression of all lesions including the left adrenal gland was obtained after 6 months of antibiotics. A review of literature was also performed.

CONCLUSION

Nocardia bacteremia is a rare event but blood cultures may help to improve detection of Nocardia spp. in a non-invasive way. Adrenal abscess due to Nocardia spp. is very rare with only fourteen cases reported in the literature, but it is a true cause of adrenal masses. Our report suggests that clinician should be aware of this rare location and prioritize a non-invasive diagnosis strategy.

Updated Review on Nocardia Species: 2006-2021

This review serves as an update to the previous Nocardia review by Brown-Elliott et al. published in 2006 (B. A. Brown-Elliott, J. M. Brown, P. S. Conville, and R. J. Wallace. Jr., Clin Microbiol Rev 19:259-282, 2006, https://doi.org/10.1128/CMR.19.2.259-282.2006). Included is a discussion on the taxonomic expansion of the genus, current identification methods, and the impact of new technology (including matrix-assisted laser desorption ionization-time of flight [MALDI-TOF] and whole genome sequencing) on diagnosis and treatment. Clinical manifestations, the epidemiology, and geographic distribution are briefly discussed. An additional section on actinomycotic mycetoma is added to address this often-neglected disease.

Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting

INTRODUCTION

The incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing.

MATERIAL AND METHODS

Fifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA).

RESULTS

Forty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates.

CONCLUSIONS

Routine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.

Nocardia niwae Disseminated Nocardiosis: A Novel Species Presenting Concurrently With Lung Adenocarcinoma

Nocardia includes over 90 species of filamentous gram-positive bacilli that may cause disease in immunocompromised or immunocompetent hosts. Presentations may include pulmonary, 4, cutaneous, or disseminated infections. Tissue diagnosis may be required as it may mimic alternative etiologies. There is a paucity of data regarding rarer species of Nocardia. Intraspecies variability in antimicrobial susceptibility limits many treatment regimens to in-vitro activity data and treatment regimens often must be tailored to individual patients based on microbiologic cultures. We describe the case of a 63-year-old female who presented with disseminated Nocardia niwae, a species that was previously first identified in Florida for which little clinical data is known, along with concurrent lung adenocarcinoma with pulmonary and central nervous system lesions. Typical susceptibility patterns are discussed along with potential side effects of antimicrobial therapy.

Nocardiosis in Japan: a multicentric retrospective cohort study

Background Nocardia species cause a broad spectrum of infections, especially in immunocompromised patients. Given its relative rarity, data on the prognosis and distribution of nocardiosis from a large cohort are scarce. The present study aimed to scrutinize the clinical features and outcomes of nocardiosis in Japan, including one-year mortality and microbiological data. Methods The present, multicentric, retrospective cohort study enrolled patients aged ≥ 18 years with nocardiosis diagnosed between January 2010 and December 2017 and recorded their clinical and microbiological characteristics. Factors associated with one-year mortality were also determined using Cox proportional hazard analysis. Results In total, 317 patients were identified at 89 hospitals. Almost half (155/317, 48.9%) were receiving immunosuppressive agents, and 51 had disseminated nocardiosis (51/317, 16.1%). The one-year, all-cause mortality rate was 29.4% (80/272; lost to follow-up, n = 45). The most frequently isolated species was Nocardia farcinica (79/317, 24.9%) followed by the N. nova complex (61/317, 19.2%). Selected antimicrobial agents were generally effective, with linezolid (100% susceptibility [S]) and amikacin (94% S) having the most activity against Nocardia species. In Cox proportional hazard analysis, factors independently associated with one-year mortality were a Charlson Comorbidity Index score ≥ 5 (adjusted hazard ratio [aHR], 3.61; 95% confidence interval [CI], 1.95-6.71, P < 0.001) and disseminated nocardiosis (aHR, 1.79; 95%CI, 1.01-3.18, P = 0.047). Conclusions The presence of advanced comorbidities and disseminated infection, rather than variations in antimicrobial therapy or Nocardia species, were independently associated with one-year mortality.

Treatment of Nocardial Brain Abscess in a Patient With Systemic Lupus Erythematosus and Idiopathic Thrombocytopenic Purpura: Case Report and a Review of the Literature

Brain abscesses due to Nocardia species account for 1-2% of all cerebral abscesses, often in immunosuppressed individuals, with a mortality three times higher than other cerebral abscesses. Early diagnosis and management are vital for good outcomes. We report a case of a right frontal Nocardia brain abscess in an immunosuppressed 38-year-old female. She presented with headaches, confusion, memory deficits, and personality change. She remained systemically well, with normal inflammatory markers. She underwent two open surgical drainages, with excision of the abscess wall. She made an excellent recovery with minimal edema and no contrast enhancement on imaging at eight weeks postoperatively. Management of Nocardia brain abscess includes a prompt diagnosis with direct microscopic examination and initiation of correct antibiotic therapy for good outcomes. We recommend open surgical resection, including excision of the abscess wall, followed by long-term antimicrobial therapy, to enhance the rate of recovery.

Disseminated life threatening Nocardia otitidiscaviarum infection in a young female with newly diagnosed systemic lupus erythematosus, case report and review of literature

Infection due to Nocardia is reported mainly in immunocompromised patients. It usually presents as a pulmonary or disseminated disease with a predilection for the brain. Infections are a rare etiology of intracranial vascular aneurysms. Herein we report a case of disseminated Nocardia otitidiscaviarum (N. otitidiscaviarum) in a young female newly diagnosed with systemic lupus erythematosus (SLE) complicated by the development of an infectious intracranial aneurysm. To the best of our knowledge this is the fourth case of nocardial infection-related intracranial aneurysm and the second case of N. otitidiscaviarum infection to be reported in a patient with systemic lupus erythematosus. Features of previously reported N. otitidiscaviarum related intracranial aneurysm are reviewed.

Misdiagnosed tuberculosis being corrected as Nocardia farcinica infection by metagenomic sequencing: a case report

Background

Disseminated nocardiosis is liable to be misdiagnosed owing to the non-specific clinical manifestations and laboratory/imaging findings. Metagenomic next-generation sequencing (mNGS) is a culture-independent and rapid method for direct identification of all microorganisms in clinical specimens.

Case presentation

A 72-year-old man was admitted to our hospital on February 20, 2019 with a history of recurrent cough, expectoration, fever, and diarrhea since 1 month, and unconsciousness since 1 week. Contrast-enhanced magnetic resonance imaging of head showed multiple lesions in the bilateral cerebral hemispheres, brainstem, and cerebellar hemispheres. The presumptive diagnosis was disseminated tuberculosis, although all tests for mycobacterium were negative. However, the patient did not benefit from antituberculosis treatment. Repeat MRI showed multiple abnormal signals in the brain and progression of meningeal thickening. Cerebrospinal fluid and bronchoalveolar lavage fluid specimens were subsequently sent for PMSeq metagenomics sequencing; the results indicated Nocardia. farcinica as the predominant pathogen. The anti-TB treatment was stopped and the patient was prescribed sulphamethoxazole in combination with linezolid and meropenem for nocardiosis. He showed gradual neurological improvement and was transferred to Huashan Hospital. He was discharged from the hospital on April 19, 2019, but died of persistent diarrhea on May 26, 2019.

Conclusions

Patients with suspected nocardiosis do not always respond to conventional treatment; therefore, mNGS can facilitate diagnosis and timely treatment decision-making.

The Role of 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) in Management of Nocardiosis: A Retrospective Study and Review of the Literature

Introduction

18-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is a well-established tool for managing metastatic infections. Nocardiosis, a primarily pulmonary infection, disseminates at high rates. Routine imaging includes chest CT and brain imaging. We examined the use of FDG-PET/CT in nocardiosis and assessed its contribution to diagnosis and management.

Methods

A retrospective study in two tertiary medical centers during 2011–2020. Individuals with nocardiosis for whom FDG-PET/CT was implemented for any reason were included and their medical records were reviewed. A board-certified nuclear medicine physician independently reviewed all scans. Additionally, a systematic review was conducted according to the PRISMA guidelines, to extract data from publications reporting FDG-PET/CT use for the management of nocardiosis.

Results

FDG-PET/CT contributed to the management of all seven patients who met inclusion criteria. It assisted in ruling out an underlying malignancy (29%, 2/7); establishing a wide infection extent (57%, 4/7); and affecting decisions regarding treatment (57%, 4/7), including drug regimen, oral step-down, and duration of therapy. We identified 20 published case reports on this topic. In 80% (16/20), FDG-PET/CT contributed to the management of nocardiosis similar to our study. In addition, in most of the literature cases, FDG-PET/CT guided the diagnostic biopsy.

Conclusion

FDG-PET/CT is valuable in the diagnosis and management of individuals with nocardiosis. The contribution of incorporating FDG-PET/CT to the management of individuals with nocardiosis and its role in monitoring treatment response and shortening treatment duration should be evaluated in prospective studies.

Nocardia farcinica cerebral abscess: A systematic review of treatment strategies

PURPOSE

Nocardia farcinica is an opportunistic pathogen causing mainly pneumonia in immunocompromised patients, complicated in almost one-third of the cases by a thick-walled multiloculated cerebral abscess which induces significant morbidity and mortality. This review aims to assess the optimal treatment strategy for N. farcinica cerebral abscess.

METHODS

Report of a case. Medline database was used to conduct a systematic review from inception to January 2020 looking for English-language articles focused on N. farcinica cerebral abscess, in accordance with the PRISMA guidelines.

RESULTS

The research yielded 54 articles for a total of 58 patients. N. farcinica cerebral abscess displayed three different neuroimaging patterns: a single multiloculated abscess in half of the cases, multiple cerebral abscesses, or a small paraventricular abscess with meningitis. The patients who benefited from surgical excision of the abscess showed a trend towards a lower risk of surgical revision (8% versus 31%, P=0.06) and a lower mortality rate (8% versus 23%, P=0.18) than patients who benefited from needle aspiration. Twenty-two percent of the patients benefited from microbiological documentation from another site with a mortality rate of 23%.

CONCLUSION

Urgent multimodal MRI is necessary in face with clinical suspicion of cerebral nocardiosis. In case of single or multiple small cerebral abscesses, microbiological documentation can be obtained with puncture of pseudotumoral visceral lesions. In case of large or symptomatic cerebral abscess, an aggressive surgical excision seems a reliable option and can be preferred over needle aspiration. Long-term antibiotic therapy with cotrimoxazole is necessary thereafter.

Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting

INTRODUCTION

The incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing.

MATERIAL AND METHODS

Fifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA).

RESULTS

Forty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates.

CONCLUSIONS

Routine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.

Infective endocarditis caused by Nocardia nova: A case report and literature review of nocardial endocarditis

Although a variety of microorganisms have caused infective endocarditis, Nocardia species have rarely been reported as a causative agent of the disease. We describe a case of nocardial endocarditis, occurring to a 22-year-old Japanese woman during long-term corticosteroid therapy for adult-onset Still's disease and diagnosed after the rupture of cerebral mycotic aneurysm. Echocardiography showed that the causative organism, isolated from the blood and identified as Nocardia nova with an analysis of 16S ribosomal RNA sequences, affected the posterior papillary muscle of the left ventricle. Nocardia-like organisms were also detected in the pus around the raptured aneurysm. After treatment with imipenem/cilastatin plus amikacin for 3 months followed by oral trimethoprim/sulfamethoxazole for 1 year, no relapse of nocardiosis occurred during a follow-up for 3 years. To our knowledge, the present case is the first reported endocarditis due to N. nova.

Update on Nocardia infections in solid-organ transplantation

PURPOSE OF REVIEW

Nocardia is a ubiquitous pathogen associated with life-threatening opportunistic infections. Organ transplant recipients are uniquely predisposed to Nocardia infections due to their iatrogenic cell-mediated immune deficit necessary to maintain allograft function. This review aims to address recent updates in the epidemiology, clinical presentation, diagnostics, treatment, and outcomes of Nocardia infections in solid-organ transplant recipients.

RECENT FINDINGS

The incidence of Nocardia infection depends on multiple patient and environmental factors. Among transplant recipients, lung recipients are most commonly affected. Species identification and antimicrobial susceptibility testing are critical for optimizing therapy as substantial variation occurs among and within Nocardia spp. This has been increasingly accomplished through advances in molecular methods leading to improved accuracy and wider accessibility to testing. There are emerging data applying novel therapeutics and short course therapy that may offer alternative management approaches for transplant associated nocardiosis to minimize drug toxicity and intolerance.

SUMMARY

Further prospective, multicenter studies are needed to better characterize the epidemiology of Nocardia in transplant recipients, as well as evaluate the impact of diagnostic advancements and new treatment strategies.

Invasive Nocardiosis in Transplant and Nontransplant Patients: 20-Year Experience in a Tertiary Care Center

Objective

To present the clinical characteristics and outcome of transplant and nontransplant patients with invasive nocardiosis.

Patients and Methods

We conducted a retrospective chart review of 110 patients 18 years and older diagnosed with culture-proven invasive nocardiosis (defined as the presence of clinical signs and/or radiographic abnormalities) between August 1, 1998, and November 30, 2018. Information on demographic, clinical, radiographic, and microbiological characteristics as well as mortality was collected.

Results

One hundred ten individuals with invasive nocardiosis were identified, of whom 54 (49%) were transplant and 56 nontransplant (51%) patients. Most transplant patients were kidney and lung recipients. The overall mean age was 64.9 years, and transplant patients had a higher prevalence of diabetes and chronic kidney disease. A substantial proportion of nontransplant patients were receiving corticosteroids (39%), immunosuppressive medications (16%), and chemotherapy (9%) and had chronic obstructive pulmonary disease (20%), rheumatologic conditions (18%), and malignant neoplasia (18%). A higher proportion of transplant patients (28%) than nontransplant patients (4%) received trimethoprim-sulfamethoxazole prophylaxis. In both groups, the lung was the most common site of infection. Seventy percent of all Nocardia species isolated were present in almost equal proportion: N brasiliensis (16%), N farcinica (16%), N nova (15%), N cyriacigeorgia (13%), and N asteroides (11%). More than 90% of isolates were susceptible to trimethoprim-sulfamethoxazole, linezolid, and amikacin. There was no significant difference in mortality between the 2 groups at 1, 6, and 12 months after the initial diagnosis.

Conclusion

The frequency of invasive Nocardia infection was similar in transplant and nontransplant patients and mortality at 1, 6, and 12 months was similar in both groups. Trimethoprim-sulfamethoxazole prophylaxis failed to prevent Nocardia infection.

How do I manage nocardiosis?

BACKGROUND

Nocardiosis is a rare infection that is often difficult to treat and may be life-threatening. There is no consensus on its management.

OBJECTIVES

Our aim was to provide the current evidence for the diagnosis and management of individuals with nocardiosis, and to propose a management approach for this uncommon infection.

SOURCES

We systematically searched the medical literature on nocardiosis for studies published between 2010 and 2020 and describing ten or more individuals.

CONTENT

Nocardiosis, a primarily opportunistic infection which may occur in immunocompetent persons, most commonly involves the lungs and frequently disseminates to other sites including the central nervous system. The reference standard for Nocardia species identification is molecular biology, and the preferred method for antibiotic susceptibility testing (AST) is broth microdilution. Monotherapy seems appropriate for patients with primary skin nocardiosis or non-severe pulmonary disease; we reserve a multidrug regimen for more severe infections. Species identification and AST results are often missing at initiation of antibiotics. Trimethoprim-sulfamethoxazole is the preferred agent for initial therapy, because Nocardia is very often susceptible to this agent, and because it has been the keystone of nocardiosis treatment for years. Linezolid, to which Nocardia is almost always susceptible, may be an alternative. When combination therapy is required, the repertoire of companion drugs includes third-generation cephalosporins, amikacin and imipenem. Therapeutic modifications should take into account clinical response to initial therapy and AST results. Treatment duration of 6 months is appropriate for most situations, but longer durations are preferred for disseminated nocardiosis and shorter durations are reasonable in low-risk situations. Secondary prophylaxis may be considered in selected individuals with permanent immunosuppression.

IMPLICATIONS

We hereby provide the clinician with an easy-to-use algorithm for the management of individuals with nocardiosis. We also illuminate gaps in evidence and suggest future research directions.

Infectious Disease Complications in Patients with Cancer

Critically ill patients with cancer are vulnerable to infections because of the underlying malignancy, tumor-directed therapy, immunosuppression, breaches in mucosa or skin, malnutrition, and other factors. Neutropenia remains the most important risk factor for infection. Infectious complications occurring in critically ill patients with cancer can affect the bloodstream, lungs, gastrointestinal tract, central nervous system, urinary tract, and the skin. Pneumonias are the leading cause of infection in patients with cancer admitted to the intensive care unit. Consideration of opportunistic pathogens in the differential diagnosis is important in patients with impaired cellular and/or humoral immunity or compromised splenic function.

Invasive Nocardiosis: Disease Presentation, Diagnosis and Treatment - Old Questions, New Answers?

Nocardia spp. is an environmental filamentous Gram-positive bacterium that may cause infections in humans and, despite recent progress, many challenges remain regarding the management of nocardiosis. This review aims at describing most recently published data regarding the diagnosis, treatment and follow-up of patients with invasive nocardiosis. As nocardiosis mainly affects patients with cell-mediated immunity defects, a comprehensive workup is mandatory in case of invasive nocardiosis occurring in ”apparently healthy patients”. Indeed, invasive nocardiosis might reveal an unknown primary immunodeficiency or the presence of anti-GM-CSF autoantibodies. Even if the diagnosis of nocardiosis mostly relies on direct examination and bacterial culture, a genus-specific PCR may be used for the detection of Nocardia, when directly performed on a clinical sample. Brain imaging should always be performed, even in the absence of neurological symptoms. Cotrimoxazole (trimethoprim/sulfamethoxazole), linezolid, parenteral cephalosporins, carbapenems and amikacin may be used as initial antibiotics to treat nocardiosis. Cotrimoxazole or linezolid can be used as monotherapy in selected patients without brain involvement. Although treatment duration has historically been set to at least 6 months in the absence of central nervous system involvement, shorter durations (<120 days) seem to be associated with a favourable outcome.

Nocardiosis Associated with Primary Immunodeficiencies (Nocar-DIP): an International Retrospective Study and Literature Review

PURPOSE

Nocardiosis is a life-threatening infectious disease. We aimed at describing nocardiosis in patients with primary immunodeficiency diseases (PID).

METHODS

This international retrospective cohort included patients with PID and nocardiosis diagnosed and/or published from Jan 1, 2000, to Dec 31, 2016. To identify nocardiosis cases, we analyzed PID databases from the French National Reference Center for PID (Paris, France) and the National Institute of Health (NIH, United States of America) and we performed a literature review on PubMed.

RESULTS

Forty-nine cases of nocardiosis associated with PID were included: median age at diagnosis of nocardiosis was 19 (0-56) years and most cases were observed among chronic granulomatous disease (CGD) patients (87.8%). Median time from symptoms to diagnosis of Nocardia infection was 20 (2-257) days. Most frequent clinical nocardiosis presentation was pneumonia (86.7%). Twelve-month mortality rate was 4.2%, and 11.9% of patients experienced a possible recurrence of infection. Nocardiosis more frequently led to the diagnosis of PID among non-CGD patients than in CGD patients. Non-CGD patients experienced more cerebral nocardiosis and more disseminated infections, but mortality and recurrence rates were similar. Highest incidences of nocardiosis among PID cohorts were observed among CGD patients (0.0057 and 0.0044 cases/patient-year in the USA and in France, respectively), followed by IL-12p40 deficiency.

CONCLUSIONS

Among 49 cases of nocardiosis associated with PID, most patients had CGD and lung involvement. Both mortality and recurrence rates were low.

Nocardia farcinica masquerading as intracerebral metastases in advanced metastatic prostatic cancer

A 67-year-old man with metastatic prostate cancer and underlying asymptomatic pancytopenia presented with a 1-week history of general malaise, left leg weakness and facial numbness. Initial brain imaging demonstrated two rim-enhancing lesions felt to represent intracerebral metastasis. Following neurosurgical referral, a multidisciplinary meeting decision was made for best supportive care and dexamethasone was given. He developed multiple cutaneous lesions, which on incision and drainage revealed Nocardia farcinica Repeat brain imaging showed enlargement of the existing cavitating lesions and appearance of new lesions, now typical of cerebral abscesses. A diagnosis of disseminated nocardiosis with cutaneous and intracerebral infection was reached. He started taking empirical treatment with intravenous meropenem, co-trimoxazole and subsequent addition of amikacin, with little improvement. On further review of sensitivities, moxifloxacin was added. Following over 1 month of antimicrobial treatment, his neurological symptoms, cutaneous lesions and repeat MRI of the brain had improved.

Clinical correlates of nocardiosis

Nocardia is an opportunistic pathogen that most frequently affects the lungs. Evidence is limited regarding the risk factors for nocardiosis. The current study assessed clinical correlates of nocardiosis. A retrospective study was conducted based on medical records of consecutive adult patients (N = 60) with nocardiosis hospitalized during 2007–2018 at a tertiary hospital in central Israel. A matched comparison group of 120 patients was randomly selected among hospitalized patients with community-acquired pneumonia. Multivariable conditional logistic regression models were fitted. Immunosuppressive pharmacotherapy was positively associated with nocardiosis (matched odds ratio [OR] 4.40, 95% confidence interval [CI] 2.25–8.62, p < 0.001), particularly corticosteroid therapy (matched OR 4.69, 95% CI 2.45–8.99, p < 0.001). Systemic corticosteroid therapy was strongly associated with pulmonary nocardiosis (matched OR 5.90, 95% CI 2.75–12.66, p < 0.001). The positive association between solid organ transplantation and nocardiosis was attenuated following adjustment for systemic corticosteroids in a multivariable model. The association between corticosteroid therapy and nocardiosis appeared stronger in patients with chronic pulmonary disease (OR 5.74, 95% CI 2.75–12.66, p < 0.001) than in the pooled analysis of all nocardiosis cases. In conclusion, corticosteroid therapy was strongly correlated with nocardiosis, particularly among individuals with chronic pulmonary disease and in pulmonary nocardiosis.

Nocardia Bloodstream Infection: A Retrospective Clinical Analysis of Seven Cases in a Single Centre

Objective: Nocardiosis is a rare opportunistic infection caused by the Nocardia species. Nocardia bacteremia is a life-threatening presentation of disseminated nocardiosis that presents diagnostic and therapeutic challenges. We performed this retrospective analysis in a Chinese hospital from 2010 to 2019 to describe the characteristics of this rare bloodstream infection.

Methods: We searched the database of the real-time nosocomial infection surveillance system and identified patients whose blood cultures showed Nocardia bacteria growth. The medical records of these patients were extracted and analyzed by two independent researchers. The data included age, gender, complicating disease, duration from blood drawing to reporting, clinical signs and symptoms, blood routine and C-reactive protein results, radiological examinations, sites of involvement, antibiotic treatments, and outcomes.

Results: Seven patients with Nocardia bacteremia were found. There were four male and three female patients, whose ages ranged from 41 to 75 years. Six (85.7%) patients had predisposing conditions and were administrated corticosteroids for various reasons before the identification of Nocardia infection. The most common symptom was fever (100%). Five patients presented with lung or skin involvement; meanwhile, three patients presented with brain involvement. One patient presented with pelvic and peritoneum involvement, respectively. The most common findings of chest CT imaging were consolidation, followed by nodules and cavitations. Trimethoprim/sulfamethoxazole was prescribed to all patients after the diagnosis of Nocardia bacteremia. Six patients recovered, and one patient ultimately died.

Conclusions: Nocardia bacteremia is a rare bloodstream infection that usually occurs in immunocompromised patients. Clinical manifestations of patients are nonspecific. It often causes multiple organ involvement, and early diagnosis and prompt aggressive interventions are important to improve the outcome of this disease.

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.

Nocardiosis: A Neglected Disease

Nocardiosis is a neglected tropical disease. It has varied geographical presence and a spectrum of clinical presentations. This review aims to focus on the epidemiology of nocardial infections with a systematic approach to their diagnosis and treatment. Nocardiacauses chronic infections and ailments, and may remain cryptic but progressive in its course. Unless suspected, diagnosis can be easily missed resulting in increased morbidity and mortality. Thorough knowledge of local epidemiology, demography, clinical course and presentation, diagnostic modalities, and antibiotic susceptibility patterns of the prevalent Nocardia species is essential to curb spread of this infection. This is a systematic review in which internet search has been done for citation indices (Embase, PubMed, Ovid, and other individual journals) till March 2020 utilizing the following key words "Nocardia," "taxonomy," "prevalence," "clinical features," "diagnosis," "treatment," and "susceptibility." We selected a total of 87 review articles, case series, and case reports all in English language.

Nocardia colonization in contrast to nocardiosis: a comparison of patients' clinical characteristics

Information on Nocardia colonization of the lower respiratory tract is scarce. The current study is aimed at comparing clinical characteristics between individuals with Nocardia colonization and those with nocardiosis. All patients with Nocardia isolation between 2007 and 2018 at a tertiary hospital in Israel were included. Nocardia isolation was based on biochemical tests together with phenotypic susceptibility and resistance patterns until 2011 and on matrix-assisted laser desorption/ionization time-of-flight mass spectrometer from 2012. We defined nocardiosis as a clinically evident infection related to the isolation of the bacteria, which required antibiotic therapy. We defined colonization as Nocardia isolation with no clinical evidence of disease. The medical charts of all included individuals were independently reviewed by an infectious disease specialist to ensure adequate classification. Logistic regression models were fitted to compare clinical characteristics between the groups. Fifteen (20%) of the 75 Nocardia isolations met the criteria for colonization. Of those, 13 (87%) had background illnesses. Having a chronic pulmonary disease was associated with increased likelihood of Nocardia colonization, in contrast to nocardiosis (adjusted odds ratio [OR] 4.06, 95% confidence interval [CI] 1.06-15.48, p = 0.040), while an inverse association was found with corticosteroid therapy (adjusted OR 0.21, 95% CI 0.06-0.74, p = 0.015). Nocardia colonization of the lower respiratory tract accounts for a substantial proportion of all Nocardia isolations. Individuals colonized with Nocardia typically have chronic pulmonary disease and are less frequently treated with corticosteroid than patients with nocardiosis.

Updates on Nocardia Skin and Soft Tissue Infections in Solid Organ Transplantation

PURPOSE OF REVIEW

Due to their immunocompromised status, solid organ transplant (SOT) recipients are at risk for Nocardia infections. These infections often necessitate early invasive diagnostics alongside prolonged, often combination antimicrobial therapy. This review summarizes the importance of this pathogen in skin and soft tissue infections (SSTIs) in SOT recipients inclusive of recently reported cases in the literature and an update on the epidemiology, diagnostics, and management.

RECENT FINDINGS

Six studies with 13 isolated SSTIs due to Nocardia have been published in the last 5 years in SOT recipients. The most common underlying type of transplant was kidney and time from transplantation to infection varied from 6 months to 16 years. Misdiagnosis was frequent. Available identified species included N. brasiliensis (2), N. farcinica (2), N. flavorosea (1), N. abscessus (1), N. anaemiae (1), N. asteroides (1), N. nova (1), and N. vinacea (1). Treatment choice and duration varied widely, and trimethoprim-sulfamethoxazole was utilized most often with no documented infection relapse. Nocardia SSTIs can occur both in isolation and as a component of a disseminated infection. Overall, isolated Nocardia SSTIs are uncommon in SOT recipients and are often initially misdiagnosed. They present multiple challenges to the clinician including evaluation for potential co-pathogens and/or non-infectious processes and ruling out the presence of disseminated infection. While trimethoprim-sulfamethoxazole remains the agent of choice for management of most isolated SSTIs, therapy must be tailored to the individual patient based on species-specific susceptibility patterns and formal susceptibility testing, site(s) of infection, and patient tolerability.

Nocardia infections in solid organ transplantation: Guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of Nocardia infections after solid organ transplantation (SOT). Nocardia infections have increased in the last two decades, likely due to improved detection and identification methods and an expanding immunocompromised population. The risk of developing nocardiosis after transplantation varies with the type of organ transplanted and the immunosuppression regimen used. Nocardia infection most commonly involves the lung. Disseminated infection can occur, with spread to the bloodstream, skin, or central nervous system. Early recognition of the infection and initial appropriate treatment is important to achieve good outcomes. Species identification and antimicrobial susceptibility testing are strongly recommended, as inter- and intraspecies susceptibility patterns can vary. Sulfonamide is the first-line treatment of Nocardia infections, and combination therapy with at least two antimicrobial agents should be used initially for disseminated or severe nocardiosis. Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis may be helpful in preventing Nocardia infection after SOT.

Manifestations and outcomes of nocardia infections: Comparison of immunocompromised and nonimmunocompromised adult patients

Nocardia is a ubiquitous environmental pathogen that causes infection primarily following inhalation into the lungs. It is generally thought to cause infection primarily in immunocompromised patients, but nonimmunocompromised individuals are also at risk of infection. We sought to compare risk factors, clinical manifestations, diagnostic approach, treatment, and mortality in immunocompromised and nonimmunocompromised adults with nocardiosis.We studied all adults with culture-proven Nocardia infection at a tertiary care hospital from 1994 to 2015 and compared immunocompromised with nonimmunocompromised patients. The immunocompromised group included patients who had a solid organ transplant, hematopoietic cell transplant (HCT), hematological or solid tumor malignancy treated with chemotherapy in the preceding 90 days, inherited immunodeficiency, autoimmune/inflammatory disorders treated with immunosuppressive agents, or high-dose corticosteroid therapy for at least 3 weeks before the diagnosis of nocardiosis.There were 112 patients, mean age 55 ± 17 years; 54 (48%) were women. Sixty-seven (60%) were immunocompromised, and 45 (40%) were nonimmunocompromised. The lung was the site of infection in 54 (81%) immunocompromised and 25 (55%) nonimmunocompromised patients. Pulmonary nocardiosis in immunocompromised patients was associated with high-dose corticosteroids, P = .002 and allogeneic HCT, P = .01, and in nonimmunocompromised patients with cigarette smoking, bronchiectasis, and other chronic lung diseases, P = .002.Cavitation occurred only in the immunocompromised group, P < .001. Disseminated infection was more common in the immunocompromised, P = .01, and was highest in solid organ transplant recipients, P = .007. Eye infection was more common in nonimmunocompromised patients, P = .009. Clinical signs and symptoms did not differ significantly between the 2 groups. The initial treatment for most patients in both groups was trimethoprim-sulfamethoxazole with or without a carbapenem. All-cause 1-year mortality was 19%; 18 (27%) immunocompromised and 3 (7%) nonimmunocompromised patients died, P = .01.Immunocompromised patients with nocardiosis had more severe disease and significantly higher mortality than nonimmunocompromised patients, but clinical presentations did not differ.

Pathogenic Nocardia cyriacigeorgica and Nocardia nova Evolve To Resist Trimethoprim-Sulfamethoxazole by both Expected and Unexpected Pathways

Nocardia spp. are Gram-positive opportunistic pathogens that affect largely immunocompromised patients, leading to serious pulmonary or systemic infections. Combination therapy using the folate biosynthesis pathway inhibitors trimethoprim (TMP) and sulfamethoxazole (SMX) is commonly used as an antimicrobial therapy. Not surprisingly, as antibiotic therapies for nocardiosis can extend for many months, resistance to TMP-SMX has emerged. Using experimental evolution, we surveyed the genetic basis of adaptation to TMP-SMX across 8 strains of Nocardia nova and 2 strains of Nocardia cyriacigeorgica By employing both continuous experimental evolution to provide longitudinal information on the order of changes and characterization of resistant endpoint isolates, we observe changes that are consistent with modifications of two enzymes of the folate biosynthesis pathway: dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) (FolP), with the mutations often being clustered near the active site of the enzymes. While changes to DHFR and DHPS might be expected, we also noted that mutations in a previously undescribed homolog of DHPS (DHPS2 or FolP2) that was annotated as being "nonfunctional" were also sufficient to generate TMP-SMX resistance, which serves as a cautionary tale for the use of automated annotation by investigators and for the future discovery of drugs against this genus. Additionally, folP2 overlapped glucosyl-3-phosphoglycerate synthase. Remarkably, an adaptive frameshift mutation within the overlapping region resulted in a new in-frame fusion to the downstream gene to produce a potentially new bifunctional enzyme. How a single potentially bifunctional DHPS2 enzyme might confer resistance is unclear. However, it highlights the unexpected ways in which adaptive evolution finds novel solutions for selection.

Nocardia infections in the transplanted host

BACKGROUND

Nocardia are uncommon pathogens that disproportionately afflict the immunocompromised host. Epidemiology and outcome data of Nocardia infections in transplant recipients are limited.

METHODS

We performed a retrospective chart review of all patients at Duke University Hospital with a history of solid organ transplant (SOT) or hematopoietic cell transplant (HCT) and at least one positive culture for Nocardia between 1996 and 2013. Our aim was to describe the epidemiology and outcomes of Nocardia infections in the transplanted host.

RESULTS

During the 18-year study period, 51 patients (14 HCT and 37 SOT recipients) had Nocardia infection. Nocardia incidence was stable during the study period in all populations except heart transplants, whose incidence declined. Infection occurred earlier in the HCT group than the SOT group (median time to diagnosis of 153 and 370 days, respectively). In both groups, the most common site involved was the lung. Outcomes were overall poor, especially in the HCT group with a cure rate of 29%. Heart transplant recipients had significantly better overall survival (P < .05) than other patients. Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis did not provide complete protection from Nocardia infections, nor did it appear to select for resistant Nocardia isolates.

CONCLUSIONS

Infections with Nocardia are typically a late post-transplant complication. The use of TMP-SMX prophylaxis was not associated with TMP-SMX-resistant Nocardia. Overall outcomes remain poor.

Rare case of osteomyelitis of tibial shaft caused by Nocardia cyriacigeorgica

Nocardiosis is a rare infection caused by the aerobic actinomycete of the Nocardia genus. In most cases, nocardiosis manifests as a lung infection or a bone lesion. Due to the nonspecific and mild clinical manifestations of nocardiosis, the establishment of definite diagnosis can be difficult. When antibiotic therapy is incorrectly targeted, only the symptoms of the disease are suppressed. The mainstay in the treatment of Nocardia osteomyelitis has so far been the combined surgical debridement with long-term, initially intravenous, antibiotic administration. We present the successful conservative treatment of a nocardiosis osteomyelitis of the tibia caused by the Nocardia cyriacigeorgica species in an 81-year-old female patient that manifested itself as a secondary affection on top of a primary nocardiosis infection of the lung. From microbiological examination, N. cyriacigeorgica was discovered; the identification was made using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) with an identification score of 1.9. The sensitivity was evaluated using E test. Sensitivity to trimethoprim/sulfamethoxazole, amikacin, imipenem, and linezolid was demonstrated. The bacteria were shown to be resistant to ciprofloxacin. For treatment, trimethoprim/sulfamethoxazole was used due to the value of minimum inhibitory concentration, which was 0.25 mg/L. The initial dose of 960 mg of trimethoprim/sulfamethoxazole every 8 h was reduced to 960 mg every 12 h after 3 months. The total duration of treatment was 7.5 months. Under the established treatment, the bone and lung lesions healed. Nocardiosis of the long bone is considered a rare disease and its precise diagnosis has not yet been standardized. We used the MALDI-TOF MS method for the identification of the causal organism which is a fast and reliable method according to current world literature even when compared with the rRNA genetic sequencing reference method. Our case study presents a rare case of osteomyelitis of tibial shaft caused by N. cyriacigeorgica and its successful conservative treatment.

Increasing Nocardia Incidence Associated with Bronchiectasis at a Tertiary Care Center

RATIONALE

Nocardia is a genus of pathogens that most commonly afflict immunocompromised hosts but may be an emerging infection among persons with bronchiectasis.

OBJECTIVES

To examine the epidemiology and clinical presentation of adult patients with Nocardia and bronchiectasis relative to other patient groups.

METHODS

We examined a retrospectively assembled cohort of adults at Duke University Hospital in Durham, North Carolina with at least one positive culture from a bodily fluid or tissue specimen for Nocardia between January 1996 and December 2013. Denominator data for key populations (e.g., bronchiectasis, transplant) were obtained using International Classification of Diseases, Ninth Revision codes. In addition, we performed a case-control analysis to examine the relationship between inhaled corticosteroid use and Nocardia lung infection among otherwise immunocompetent patients with bronchiectasis.

MEASUREMENTS AND MAIN RESULTS

We identified 183 patients with one or more cultures positive for Nocardia: 44 from 1996 to 2001, 64 from 2002 to 2007, and 75 from 2008 to 2013. Immune compromise was common (56%), particularly solid organ or hematopoietic cell transplant (30%). Infection usually was confined to the lungs (62%), followed by skin (10%), other sites (6%), brain (2%), and multiple sites (17%). Non-cystic fibrosis bronchiectasis was common among both immunocompetent (38%) and immunocompromised (10%) patients. Nocardia incidence in patients with bronchiectasis increased significantly over time, but there was no significant change in Nocardia incidence in hematopoietic cell or solid organ transplant recipients (our largest immunocompromised population). Among patients with bronchiectasis, Nocardia was positively but nonsignificantly associated with use of inhaled corticosteroids (odds ratio, 1.8; 95% confidence interval, 0.7-4.4).

CONCLUSIONS

The increasing incidence of Nocardia infections at our medical center appears to be driven by increased incidence in patients with bronchiectasis rather than increases in immunocompromised populations. It is unclear whether increased environmental exposures, microbiologic surveillance, or other factors account for the increased incidence of Nocardia in our patients with bronchiectasis.

Recurrent and metastatic congenital mesoblastic nephroma: where does the evidence stand?

PURPOSE

Fifty years ago, Bolande described Congenital Mesoblastic Nephroma (CMN) as a benign lesion. Unexpected aggressive clinical behaviors prompted a sub-classification based on histology. Recent molecular genetic evidence has identified the aggressive cellular variant to be the renal manifestation of congenital infantile fibrosarcoma. We submit a reappraisal and analysis of the available literature on recurrent and metastatic CMN.

METHODS

An electronic search of PubMed, MEDLINE, EMBASE, and Scopus yielded 38 children with local recurrence and/or metastases.

RESULTS

Of the 38 children with local recurrence and/or metastasis, 59% were girls. Median time to recurrence was 6 months (range 1-12 months). The commonest sites of metastases were the lung (39%) and liver (29%). Fifty percent of these children died of disease. The outcome of additional chemotherapy (p = 0.5) did not differ from that of surgery alone. The choice of chemotherapy did not influence the outcome (p = 0.6).

CONCLUSIONS

Recurrence and metastasis in cellular CMN are much more common than described earlier and carry a high mortality. Children with cellular and mixed CMN require close clinical and radiological follow-up for a minimum of 12 months after primary surgery. Surgery is the mainstay of the treatment of recurrent and metastatic lesions. Neoadjuvant chemotherapy is recommended only if the lesion is inoperable. Targeted therapy may be an option in treatment of refractory cases.

The cytopathology of Actinomyces, Nocardia, and their mimickers

Nocardia species and Actinomyces species are 2 of the most commonly diagnosed filamentous bacteria in routine cytopathology practice. These genera share many overlapping cytomorphologic features, including their thin, beaded, branching, Gram-positive, GMS-positive filamentous structures that fragment at their peripheries into bacillary- and coccoid-appearing forms. Features that help distinguish between these 2 microorganisms include the width of their filamentous structures, the angles at which they branch, and their ability or lack thereof to retain a modified acid-fast stain. In addition to cytomorphologic overlap, overlap in clinical presentation is frequent with pulmonary and mucocutaneous presentations seen in both. Differentiating between Nocardia and Actinomyces is essential because patients with these infections require different approaches to medical management. Both antibiotic susceptibilities and the need for early surgical intervention as part of the treatment plan vary greatly among these 2 groups. This review focuses on the clinical presentation, cytomorphology and staining characteristics that can be useful in identifying and distinguishing between Nocardia and Actinomyces infections, as well as their mimickers.

Disseminated Nocardia cyriacigeorgia causing pancreatitis in a haploidentical stem cell transplant recipient

We report the first published case of acute pancreatitis secondary to disseminated nocardiosis in a hematopoietic stem cell transplant (HSCT) recipient on chronic immunosuppression for graft-versus-host disease (GVHD). Nocardiosis in the HSCT population is relatively rare, and has not yet been described in haploidentical HSCT recipients. Our patient is a 28-year-old male with a history of haploidentical HSCT and GVHD of the skin and lung who was admitted to the hospital with acute pancreatitis. The workup for the etiology of his pancreatitis was initially unrevealing. He subsequently developed worsening sepsis and respiratory failure despite broad spectrum antimicrobials. After multiple bronchoscopies and pancreatic fluid sampling, he was found to have disseminated nocardiosis with Nocardia cyriacigeorgia.

Central Nervous System Infections

This chapter provides an overview of infectious syndromes, pathogens, and diagnostic testing modalities for central nervous system infections in the immunocompromised host.

Infections in Hematopoietic Cell Transplant Recipients: Results From the Organ Transplant Infection Project, a Multicenter, Prospective, Cohort Study

Background

Infection is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Our object was to better define the epidemiology and outcomes of infections after HCT.

Methods

This was a prospective, multicenter cohort study of HCT recipients and conducted from 2006 to 2011.

The study included 4 US transplant centers and 444 HCT recipients. Data were prospectively collected for up to 30 months after HCT using a standardized data collection tool.

Results

The median age was 53 years, and median follow up was 413 (range, 5–980) days. The most common reason for HCT was hematologic malignancy (87%). The overall crude mortality was 52%. Death was due to underlying disease in 44% cases and infection in 21%. Bacteremia occurred in 231 (52%) cases and occurred early posttransplant (median day 48). Gram-negative bloodstream infections were less frequent than Gram-positive, but it was associated with higher mortality (45% vs 13%, P = .02). Clostridium difficile infection developed in 148 patients (33%) at a median of 27 days post-HCT. There were 53 invasive fungal infections (IFIs) among 48 patients (11%). The median time to IFI was 142 days. Of 155 patients with cytomegalovirus (CMV) infection, 4% had CMV organ involvement. Varicella zoster infection (VZV) occurred in 13 (4%) cases and was disseminated in 2. Infection with respiratory viruses was seen in 49 patients. Pneumocystis jirovecii pneumonia was rare (1%), and there were no documented cases of nocardiosis, toxoplasmosis, endemic mycoses, or mycobacterial infection. This study lacked standardized antifungal and antiviral prophylactic strategies.

Conclusions

Infection remains a significant cause of morbidity and mortality after HCT. Bacteremias and C difficile infection are frequent, particularly in the early posttransplant period. The rate of IFI is approximately 10%. Organ involvement with CMV is infrequent, as are serious infections with VZV and herpes simplex virus, likely reflecting improved prevention strategies.