Nocardial Infections in Japan from 1992 to 2001, Including the First Report of Infection by Nocardia transvalensis

How an Antimicrobial Stewardship Team Treated a Nocardia farcinica-Associated Brain Abscess: A Case Report

Nocardia species, which are ubiquitous in the environment, form lesions primarily in immunocompromised patients via oral or cutaneous infection. Some of these Nocardia species, such as N. farcinica, also infect the central nervous system via hematogenous dissemination, which rarely results in brain abscesses. Notably, N. farcinica is resistant to numerous antimicrobial drugs used in empirical therapy, necessitating the intervention of an infectious disease specialist. To date, no case of antimicrobial stewardship teams (ASTs) playing a central role in community hospitals without an infectious disease specialist has been reported. Here, we describe a case of N. farcinica-associated brain abscess in a small-to-medium-sized hospital with no infectious disease department or specialist, in which the AST assisted in the identification of the causative organism and in selecting appropriate therapeutic agents, ultimately leading to a cure. The patient was an 88-year-old man with a high fever. He had been taking prednisolone (10-15 mg/day) for approximately 1 year for pemphigoid. Considering the possibility of fever owing to bacteremia of cutaneous origin, ampicillin/sulbactam antimicrobial therapy at 6 g/day was initiated. A subsequent close examination led to the diagnosis of a brain abscess. Emergency abscess drainage was performed by a neurosurgeon, and postoperative antimicrobial combination therapy comprising ceftriaxone (4 g/day), vancomycin (2 g/day), and metronidazole (1,500 mg/day) was commenced. The AST suspected Nocardia infection earlier, but further testing was difficult to perform at this facility. Therefore, by requesting assistance from Nagoya University Hospital, we performed early bacterial identification by mass spectrometry and appropriate antimicrobial susceptibility testing by a custom panel on day 11. The patient was non-responsive to all the previously used antibiotics at the time of admission. On day 13 after admission, the patient was successfully treated with trimethoprim-sulfamethoxazole (TMP-SMX) and imipenem/cilastatin sodium, and the patient was cured. The AST can be as effective as an infectious disease specialist when a strong working relationship is established between the team and clinicians. Further, the activities of the AST can improve patient survival via active medical support in collaboration with attending physicians.

Fifteen years of phenotypic and genotypic surveillance and antibiotic susceptibility pattern of Actinomycetes (Mycobacterium, Nocardia, Rhodococcus, etc.) in clinical and environmental samples of Iran

Actinomycetes, ubiquitous in the natural world, have been known to inflict infections upon both immunocompromised and healthy individuals. Interestingly enough, these species are oftentimes found residing within the microbiota of humans and animals alike. Unfortunately, these infections are frequently misdiagnosed as more sinister ailments such as malignancy or tuberculosis. Due to this issue, this review deals with 15 years of study on clinical and environmental samples to determine Actinomycetes' prevalence, isolation, identification, and antibiotic susceptibility pattern in Iran by Davood Azadi et al. According to the Davood Azadi framework, we searched the following databases: PubMed/MEDLINE, Embase, Scopus, Web of Science, SID, and Google Scholar in the period from 2007 to 2023. This review aimed to provide an overview of the most recent techniques for collecting environmental samples, cultivating them, and identifying the Actinomycetes group's members. The isolation of Actinomycetes from clinical and ecological sources is becoming more prevalent and should be a concern for health authorities in developing countries. Health centers should take action to increase awareness of diagnostic criteria and management guidelines for actinomycete diseases. Improvements in national and regional reference laboratories may also aid in accurately diagnosing these diseases.

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.

A fatal case of disseminated nocardiosis due to Nocardia otitidiscaviarum resistant to trimethoprim-sulfamethoxazole: case report and literature review

Background

Disseminated nocardiosis still causes significant morbidity and mortality and is often caused by Nocardia asteroides, N. basiliensis, and N. farcinica and are often treated with trimethoprim–sulfamethoxazole (TMP–SMX). Nocardia otitidiscaviarum (N. otitidiscaviarum) rarely causes disseminated disease and resistance to TMP–SMX is even more rare.

Case presentation

A 37-year-old woman with metastatic breast cancer and right ear deafness with recent occupational gardening and manipulating soil, presented to the hospital with first time seizure and multiple skin nodules. Magnetic resonance imaging (MRI) showed ring enhancing lesions, biopsy of the skin and brain lesions grew N. otitidiscaviarum. She was empirically treated with TMP–SMX and Imipenem–Cilastatin, however, almost three weeks into therapy, susceptibility results revealed it to be resistant to both antimicrobials, she was subsequently changed to Amikacin, Linezolid, Moxifloxacin, and Doxycycline but ultimately died.

Conclusions

This case report highlights the importance of suspecting a rare Nocardia species in patients at risk with proper occupational exposure, moreover, TMP–SMX resistance should be suspected with lack of clinical response, this may have important implications on clinical practice when facing similar infections.

Mixed Infection of Cytomegalovirus and Pulmonary Nocardiosis Caused by Nocardia elegans Diagnosed Using Nanopore Sequencing Technology

A 69-year-old woman who had undergone renal transplantation and was receiving sulfamethoxazole/trimethoprim (ST) developed pulmonary nocardiosis. To our knowledge, this is the first report of the identification of Nocardia elegans using nanopore sequencing, supported by 16S rDNA capillary sequencing findings. Chest computed tomography performed after ST initiation revealed significant improvement of the pulmonary shadows compared to previous findings. We herein report the value of nanopore sequencing for rapid identification of rare pathogens, such as Nocardia elegans. Furthermore, our findings suggest that Nocardia may infect even patients receiving ST, which is currently the most effective prophylactic drug.

Brain abscess caused by Nocardia thailandica infection in systemic lupus erythematosus patient with steroid therapy

Background:

Nocardia is an aerobic Gram-negative bacillus belonging to actinomycetes and has been reported to be an infectious disease in healthy individuals. However, more than 60% have some underlying illnesses and are said to be opportunistic infections.

Case Description:

The case was a 69-year-old man who had been on long-term steroids for systemic lupus erythematosus. He developed with nausea and gait disturbance and was suspected of having a brain abscess by imaging. Abscess drainage detects actinomycetes that appear to belong to the genus Nocardia and brain abscess by Nocardia thailandica using matrix-assisted laser desorption/ionization time-of-flight mass analysis (MALDITOFMS) I was diagnosed. He died during the course of the treatment, and his organs did not detect his N. thailandica at necropsy, so he concluded that bacterial death from long-term administration of antibiotics was the cause of death.

Conclusion:

N. thailandica is a very rare bacterium belonging to Nocardia asteroides and is said to easily form brain lesions. In immunocompromised patients, prophylaxis with antibiotics and detailed examination of lung lesions for surveillance were considered necessary. This paper is the first report of a brain abscess caused by N. thailandica, including a review of the literature.

Nocardia Infections: Ten Years Experience from a Tertiary Health Care Center in North India (2007-2016)

BACKGROUND

Nocardia species are important cause of infections in humans but are underreported due to missed diagnosis as well as misdiagnosis. Majority of the literature on these infections consists of case reports or series with few articles describing high number of cases.

OBJECTIVE

To study the epidemiology of Nocardia infections in a tertiary care center.

MATERIALS AND METHODS

This retrospective observational study was done in a tertiary care centre of North India over a period of 10 years (2007-2016). The detection of Nocardia spp. from clinical specimens was done by conventional methods viz. direct microscopy (Gram's stain, modified Ziehl -Neelsen stain [1%], KOH examination) and culture.

RESULTS

A total of 25 cases of nocardiosis were diagnosed during the study period. The mean age of the patients was 50.9 years (range 30-72 years) with a male:female ratio of 3:2. The site of disease in these patients included pulmonary (n=18), cutaneous (n=4), perinephric abscess (n=1), ocular (n=1) and bone (n=1). Risk factors associated were underlying lung disease (n=11), smoking (n=7), diabetes (n=5) and steroid therapy (n=4) in pulmonary nocardiosis, iatrogenic (n=1) and leprosy (n=1) in cutaneous nocardiosis, diabetes in perinephric abscess and cataract surgery in ocular nocardiosis. Culture was positive in 12/25 (48%) patients for Nocardia spp. Direct microscopy was positive in 22 patients. We wish to highlight that meticulous observation of KOH wet mount examination helped in clinching the diagnosis of Nocardiosis in 3 cases which were earlier missed by other methods.

CONCLUSION

Good communication with the clinician alongside a meticulous effort in the laboratory is essential for appropriate diagnosis and management of these cases.

Molecular Characterization and Antimicrobial Susceptibilities of Nocardia Species Isolated from the Soil; A Comparison with Species Isolated from Humans

Nocardia species, one of the most predominant Actinobacteria of the soil microbiota, cause infection in humans following traumatic inoculation or inhalation. The identification, typing, phylogenetic relationship and antimicrobial susceptibilities of 38 soil Nocardia strains from Lara State, Venezuela, were studied by 16S rRNA and gyrB (subunit B of topoisomerase II) genes, multilocus sequence analysis (MLSA), whole-genome sequencing (WGS), and microdilution. The results were compared with those for human strains. Just seven Nocardia species with one or two strains each, except for Nocardia cyriacigeorgica with 29, were identified. MLSA confirmed the species assignments made by 16S rRNA and gyrB analyses (89.5% and 71.0% respectively), and grouped each soil strain with its corresponding reference and clinical strains, except for 19 N. cyriacigeorgica strains found at five locations which grouped into a soil-only cluster. The soil strains of N. cyriacigeorgica showed fewer gyrB haplotypes than the examined human strains (13 vs. 17) but did show a larger number of gyrB SNPs (212 vs. 77). Their susceptibilities to antimicrobials were similar except for beta-lactams, fluoroquinolones, minocycline, and clarithromycin, with the soil strains more susceptible to the first three (p ≤ 0.05). WGS was performed on four strains belonging to the soil-only cluster and on two outside it, and the results compared with public N. cyriacigeorgica genomes. The average nucleotide/amino acid identity, in silico genome-to-genome hybridization similarity, and the difference in the genomic GC content, suggest that some strains of the soil-only cluster may belong to a novel subspecies or even a new species (proposed name Nocardia venezuelensis).

A Rare Case of Drug-Resistant Nocardia transvalensis Infection in a Renal Transplant Patient

Nocardia transvalensis is a rare species of Nocardia and is known to be a drug-resistant organism. Multiple cases have been reported of Nocardia species causing opportunistic infections in immunocompromised hosts. To our knowledge, we report the first case of successfully treated drug-resistant Nocardia transvalensis causing pulmonary nocardiosis in a renal transplant patient. Our case validates the importance of prompt identification of Nocardia species and their drug sensitivities to improve clinical outcomes and reduce mortality.

First case of fatal bacteremia due to Nocardia neocaledoniensis

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First case of bacteremia due to N.neocaledoniensis in an immunocompromised patient.

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Mass spectrometry is a discriminant technique to identify rapidly N.neocaledoniensis.

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Incubating culture media for a longer time helps to obtain definitive diagnosis and adapt antibiotics.

Nocardia neocaledoniensis is an uncommon cause of human-infections. Few cases are reported in the literature. We describe the first case of bacteremia caused by N. neocaledoniensis. This article underlines the importance of mass spectrometry for easy and rapid identification of such bacterium.

Pulmonary infection caused by Nocardia cyriacigeorgica in a patient with allergic bronchopulmonary aspergillosis: A case report

RATIONALE

Nocardia species is known as conditional pathogenic bacteria. Among Nocardia species, pulmonary infection caused by Nocardia cyriacigeorgica associated with Aspergillus fumigatus complex lung disease is rarely reported.

PATIENT CONCERNS

A 55-year-old female with a history of productive cough with recurrent expectoration for 20 years presented with increasing cough for 12 months. The patient presented complaining of respiratory symptoms including increasing cough with yellow phlegm, poor appetite, and generalized fatigue for a week prior to admission.

DIAGNOSES

Nocardia cyriacigeorgica pneumonia was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing.

INTERVENTIONS

Combined treatments (trimethoprim-sulfamethoxazole and meropenem) were administered after identification of N cyriacigeorgica.

OUTCOMES

The respiratory symptoms of the patient had improved both clinically and radiologically after 4 weeks of antibacterial therapy.

LESSONS

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

Disseminated Nocardiosis with subretinal abscess in a patient with nephrotic syndrome-a case report

Background

Nocardia infection is uncommon in clinical practice, with most cases occuring as the result of opportunistic infection in immunocompromsed patients. Here, we report a case of disseminated nocardiosis with subretinal abscess in a patient with nephrotic syndrome, and whom is receiving immunosuppressive therapy.

Case presentation

A 58-year-old male presented with decreased vision in his left eye, without redness or floaters, which had persisted for three days. The patient had previously been diagnosed with membranous nephropathy, and as such, had received systemic corticosteroid therapy for four months. Further, the patient had developed pneumonia three weeks prior to this presentation. The ocular lesion appeared as a creamy-white subretinal abscess, with overlying retinal hemorrhages. Subsequent administration of three intravitreal injections of vancomycin and ceftazidime ultimately led to eradication of the intraocular infection, however, two months later, the patient developed a brain abcess. Pathogens isolated from the blood were subsequently identified as Nocardia. The patient was successfully treated via systemic administration of imipenem and trimethoprim-sulfamethoxazole.

Conclusions

Clinicians should be aware of the possibility of Nocardia infections within all immunocompromised patients, as well as the tendency of this infection to disseminate--particularly in the brain. The early detection of Nocardia infections and prolonged treatment of the proper antibiotics may significantly improve the prognosis of this life-threatening infection.

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.

Nocardiosis from 1888 to 2017

The genus Nocardia is an aerobic bacterium, Gram-positive and catalase positive that is in Nocardiaceae family. This bacterium first described by Edmond Nocard in 1888 and is not in human commensal bacteria. To date, nocardiosis incidence is increasing due to increase population growth rate, increase in patients with immune disorder diseases and immunocompromised patients. We surveyed taxonomic position, isolation methods, phenotypic and molecular identification at the genus and species levels, antibiogram, treatment and epidemiology in the world from 1888 to 2017.

Epidemiology and susceptibility to antimicrobial agents of the main Nocardia species in Spain

Objectives

The aims of this study were to explore the clinical distribution, by species, of the genus Nocardia and to assess the antimicrobial susceptibilities of the 10 most prevalent species identified in Spain.

Methods

Over a 10 year period (2005-14), 1119 Nocardia strains were molecularly identified and subjected to the Etest. The distribution and resistance trends over the sub-periods 2005-09 and 2010-14 were also examined.

Results

Of the strains examined, 82.9% belonged to the following species: Nocardia cyriacigeorgica (25.3%), Nocardia nova (15.0%), Nocardia abscessus (12.7%), Nocardia farcinica (11.4%), Nocardia carnea (4.3%), Nocardia brasiliensis (3.5%), Nocardia otitidiscaviarum (3.1%), Nocardia flavorosea (2.6%), Nocardia rhamnosiphila (2.6%) and Nocardia transvalensis (2.4%). Their prevalence values were similar during 2005-09 and 2010-14, except for those of N. abscessus , N. farcinica and N. transvalensis , which fell significantly in the second sub-period ( P ≤  0.05). The major location of isolation was the respiratory tract (∼86%). Half (13/27) of all strains from the CNS were N. farcinica . Significant differences in MIC results were recorded for some species between the two sub-periods. According to the CLSI's breakpoints, low resistance rates (≤15%) were recorded for seven species with respect to cefotaxime, imipenem and tobramycin; five species showed similar rates with respect to trimethoprim/sulfamethoxazole. Linezolid and amikacin were the most frequently active agents.

Conclusion

The accurate identification of the infecting species and the determination of its susceptibility to antimicrobial agents, given the large number of strains with atypical patterns, are crucial if patients with nocardiosis are to be successfully treated.

Molecular analysis and species diversity of Nocardia in the hospital environment in a developing country, a potential health hazard

PURPOSE

Despite hundreds of reports on the isolation of Nocardia from clinical samples, the presence and diversity of Nocardia species that are capable of survival in a harsh and adverse condition, such as a hospital environment, have not been comprehensively studied. The aim of this study was to assess Nocardia species diversity in a hospital environment to provide a better insight into their potential threat as a reservoir for the development of nosocomial infections.

METHODOLOGY

A total of 90 samples of hospital water, dust and soil, collected from 30 hospitals, were analysed for the presence of Nocardia using standard protocols for isolation and characterization of the isolates. Conventional tests were used for preliminary identification, and PCR amplification of the 596 bp amplicon of the 16S rRNA and sequence analysis of 16S rRNA were performed for genus and species identification.

RESULTS

A total of 25 Nocardia isolates (27.7 %) from 10 species were recovered from 90 samples. The three most prevalent species were N. cyriacigeorgica, 24 %, N. asteroides, 16 % and N. kroppenstedtii, 12 %, followed by N. salmonicida-like, 8 % and single isolates of N.otitidiscaviarum, N. flavorozea-like, N. neocaledoniensis-like and N. sungurluensis-like. Thirteen out of twenty five isolates showed characteristics of six novel species.

CONCLUSION

Our study showed that the hospital environment is a potential reservoir of a diverse range of Nocardia species, due to the remarkable survival capability of these bacteria in an adverse hospital environment, which carries a threat to the health of patients.

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.

Nocardia elegans infection: a case report and literature review

A case of disseminated nocardiosis caused by Nocardia elegans in a 72-year-old man with rheumatoid arthritis, treated with tacrolimus and prednisolone, is reported herein. The patient had impaired vision and was diagnosed with endophthalmitis and an abdominal skin abscess. He was started on trimethoprim-sulfamethoxazole treatment, followed by cefepime. The patient was then switched to a combination of imipenem-cilastatin and minocycline. Although the patient survived as a result of surgery and prolonged antibiotic treatment, he eventually lost vision after the infection became resistant to antibiotic treatment. Molecular analysis of samples from the abscess and vitreous fluid confirmed the extremely rare pathogen N. elegans, which accounts for only 0.3-0.6% of infections caused by Nocardia species. This organism is almost always associated with pulmonary infection, and disseminated infections are rare. As with previously reported norcardial infections, the current case was treated successfully with trimethoprim-sulfamethoxazole, carbapenems, and aminoglycosides. However, the clinical characteristics of this organism remain unclear. Further studies are therefore required to develop more effective treatment protocols for disseminated nocardiosis caused by this problematic pathogen.

Nocardiosis in ectopic ACTH syndrome: A case report and review of 11 cases from the literature

Ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) associated with nocardiosis is rare, and little information is available regarding its clinical characteristics. In this study, the case of a 35-year-old male patient who showed significant cushingoid features and had a cough with yellow phlegm for 1 month is described. Pulmonary computed tomography (CT) scanning and ¹⁸F-fluorodeoxyglucose positron emission tomography combined with CT identified two different lesions in the mediastinum and pulmonary region, respectively. The lesion in the mediastinum was finally diagnosed as an ACTH-secreting mediastinal paraganglioma via biopsy. The sputum culture confirmed pulmonary nocardiosis. The patient was effectively treated with complete tumor resection following the treatment of nocardiosis using trimethoprim-sulfamethoxazole. Following the present case, 11 additional cases of nocardiosis in EAS were identified in the literature and their clinical characteristics were compared and evaluated. It may be concluded that, although Nocardia remains a rare opportunistic infection pathogen in EAS, it is necessary to consider nocardiosis as a diagnosis for patients with pulmonary imaging findings of cavity, consolidation or nodule, particularly when there are brain and extra-pulmonary lesions as well as a poor response to regular treatment.

Disseminated nocardiosis masquerading as metastatic malignancy

Nocardiosis is an uncommon gram-positive bacterial infection caused by aerobic actinomycetes of the genus Nocardia. It can be localized or systemic and is regarded as an opportunistic infection that is commonly seen in immunocompromised hosts. We report a case of disseminated nocardiosis caused by Nocardia cyriacigeorgica in a patient with underlying malignancy in whom the clinical presentation was highly suggestive of a metastatic disease.

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.

Nocardia transvalensisDisseminated Infection in an Immunocompromised Patient with Idiopathic Thrombocytopenic Purpura

Nocardia transvalensis complex includes a wide range of microorganisms with specific antimicrobial resistance patterns. N. transvalensis is an unusual Nocardia species. However, it must be differentiated due to its natural resistance to aminoglycosides while other Nocardia species are susceptible. The present report describes a Nocardia species involved in an uncommon clinical case of a patient with idiopathic thrombocytopenic purpura and pulmonary nocardiosis. Microbiological and molecular techniques based on the sequencing of the 16S rRNA gene allowed diagnosis of Nocardia transvalensis sensu stricto. The successful treatment was based on trimethoprim-sulfamethoxazole and other drugs. We conclude that molecular identification of Nocardia species is a valuable technique to guide good treatment and prognosis and recommend its use for daily bases diagnosis.

Cerebral nocardiosis

Cerebral Nocardiosis is a rare, challenging, opportunistic infectious disease of the central nervous system occurring in both immunocompetent and immunocompromised hosts. It often results in intraparenchymal abscess formation, which represents only 2% of all cerebral abscesses. The diagnosis of cerebral Nocardiosis is seldom based on imaging. Bacteriological diagnosis is often reached only after surgical excision of the abscess. We report a rare case of brain abscess caused by Nocardia species in a 20-year-old immunocompromised lady. Total surgical excision of the abscess, prompt bacteriological diagnosis based on smear and culture of the pus and initiation of specific antimicrobial therapy (trimethoprim and sulfamethoxazole) resulted in good clinical outcome.

Genome based analysis of type-I polyketide synthase and nonribosomal peptide synthetase gene clusters in seven strains of five representative Nocardia species

BACKGROUND

Actinobacteria of the genus Nocardia usually live in soil or water and play saprophytic roles, but they also opportunistically infect the respiratory system, skin, and other organs of humans and animals. Primarily because of the clinical importance of the strains, some Nocardia genomes have been sequenced, and genome sequences have accumulated. Genome sizes of Nocardia strains are similar to those of Streptomyces strains, the producers of most antibiotics. In the present work, we compared secondary metabolite biosynthesis gene clusters of type-I polyketide synthase (PKS-I) and nonribosomal peptide synthetase (NRPS) among genomes of representative Nocardia species/strains based on domain organization and amino acid sequence homology.

RESULTS

Draft genome sequences of Nocardia asteroides NBRC 15531(T), Nocardia otitidiscaviarum IFM 11049, Nocardia brasiliensis NBRC 14402(T), and N. brasiliensis IFM 10847 were read and compared with published complete genome sequences of Nocardia farcinica IFM 10152, Nocardia cyriacigeorgica GUH-2, and N. brasiliensis HUJEG-1. Genome sizes are as follows: N. farcinica, 6.0 Mb; N. cyriacigeorgica, 6.2 Mb; N. asteroides, 7.0 Mb; N. otitidiscaviarum, 7.8 Mb; and N. brasiliensis, 8.9 - 9.4 Mb. Predicted numbers of PKS-I, NRPS, and PKS-I/NRPS hybrid clusters ranged between 4-11, 7-13, and 1-6, respectively, depending on strains, and tended to increase with increasing genome size. Domain and module structures of representative or unique clusters are discussed in the text.

CONCLUSION

We conclude the following: 1) genomes of Nocardia strains carry as many PKS-I and NRPS gene clusters as those of Streptomyces strains, 2) the number of PKS-I and NRPS gene clusters in Nocardia strains varies substantially depending on species, and N. brasiliensis strains carry the largest numbers of clusters among the species studied, 3) the seven Nocardia strains studied in the present work have seven common PKS-I and/or NRPS clusters, some of whose products are yet to be studied, and 4) different N. brasiliensis strains have some different gene clusters of PKS-I/NRPS, although the rest of the clusters are common within the N. brasiliensis strains. Genome sequencing suggested that Nocardia strains are highly promising resources in the search of novel secondary metabolites.

Primary brain abscess caused by Nocardia otitidiscaviarum

Diagnosing primary cerebral nocardiosis is difficult. This case report describes a 79-year-old immunocompetent Japanese woman with a primary brain abscess caused by Nocardia otitidiscaviarum (IFM 11321) and reviews the findings of 11 previous patients with N. otitidiscaviarum-induced brain abscesses. Four patients survived, including ours. Beta-lactams were not effective in our patient, and the diagnosis required a pathologic analysis of the surgical specimen. Sulfamethoxazole/trimethoprim (ST) was administered to the patient. On antibiotic susceptibility testing, N. otitidiscaviarum (IFM11321) was found to be resistant to amoxicillin-clavulanic acid, ceftriaxone, cefotaxime, cefepime, imipenem and clarithromycin, but sensitive to amikacin, gentamicin, ST and linezolid. Antimicrobial susceptibility patterns differ among Nocardia species, making species identification important for treatment. Patients with suspected Nocardia infection should therefore be treated empirically with ST and/or amikacin and considered for surgical management.

Pulmonary Nocardia nova infection after allogeneic hematopoietic stem cell transplantation

We herein report the case of a 68-year-old man with a history of allogeneic hematopoietic stem cell transplantation for acute myelocytic leukemia in whom graft-versus-host disease (GVHD) developed in the gastrointestinal tract and liver five months after transplantation. In that same period, chest computed tomography showed infiltration in both upper lungs. We performed bronchoscopy to clarify the GVHD and pulmonary infection. Nocardia nova was identified in the bronchoalveolar lavage fluid, and we diagnosed the patient as having pulmonary nocardiosis. Because the differential diagnosis is important for the medical management of GVHD and pulmonary infection, performing bronchoscopy is essential for making an appropriate and rapid diagnosis.

Brain abscess caused by Nocardia cyriacigeorgica in two patients with multiple myeloma: novel agents, new spectrum of infections

OBJECTIVE AND IMPORTANCE

Introduction of high-dose chemotherapy and the novel agents including bortezomib, Lenalidomide, and Thalidomide has provided a significant progress in the treatment of multiple myeloma (MM) with an increase in median overall survival up to 6-8 years. However, the advances in myeloma treatment comes at a price with new spectrum of treatment-related infectious complications which should be taken into consideration while treating these patients.

CLINICAL PRESENTATION

We report here two patients with Ig G λ MM presenting with intracerebral mass lesions in the abscence of constitutional symptoms that would suggest an infectious etiology. Both patients had severe hypogammaglobulinemia and lymphopenia, which was attributed to treatment regimens including bortezomib. Intervention The surgical intervention-revealed abscess in both cases caused by Nocardia cyriacigeorgica, a relatively new pathogen which rarely causes infections in humans and also an unexpected pathogen in myeloma patients.

CONCLUSION

Although every aspect of immune system is known to be affected in MM, humoral immune deficiency is the hallmark of the inherent immune defect in this disease. Introduction of the novel agents, bortezomib in particular seems to have changed the characteristics of the immune dysfunction and the spectrum of the opportunistic infections by causing qualitative and quantitative changes in cellular immunity. The new spectrum of infectious agents might not be limited to hepatitis B and herpes zoster. Monitoring lymphopenia and administration of prophylactic antimicrobial agents accordingly could be considered in patients treated with bortezomib.

A case of Nocardia transvalensis pneumonia in a 19-year-old cystic fibrosis patient

Nocardia species is rarely encountered in cystic fibrosis (CF) patients. Its isolation usually implies colonization. Of all other Nocardia species, Nocardia transvalensis is very unusual and is clinically distinguishable because of its resistance to aminoglycosides, a standard antinocardial therapy. We report a case of N. transvalensis pulmonary infection in a CF patient.

Clinical isolation of Nocardia cyriacigeorgica from patients with various clinical manifestations, the first report from Iran

We herein describe five various cases of human infections by Nocardia cyriacigeorgica. The identification included conventional and molecular sequencing tests. The current study provides further evidences that N. cyriacigeorgica species is a ubiquitous organism capable of establishing long-term infection in healthy and immunocompromised patients.

Nocardia farcinica lung abscess presenting in the context of advanced HIV infection: Spontaneous resolution in response to highly active antiretroviral therapy alone

A 43-year-old man, known to be HIV-positive, presented with a six-week history of symptoms including cough, hemoptysis, anterior chest pain, fever and wasting. His CD4 cell count was 46 cells/muL, and his chest x-ray showed a cavitating lesion in the left upper lobe. Sputum culture was positive for Nocardia farcinica. His infection resolved following initiation of antiretroviral therapy. Nocardia is an uncommon opportunistic pathogen in patients with HIV infection and is usually associated with advanced CD4 depletion, cavitary pneumonia, metastatic infection and high mortality. The impact of antiretroviral therapy on Nocardia infection in the setting of HIV has not been clearly elucidated. The current report is the first to present a case in which a complete clinical cure of Nocardia pneumonia has been documented, primarily in response to highly active antiretroviral therapy alone.

Nocardia transvalensis pulmonary infection in an immunocompetent patient with radiographic findings consistent with nontuberculous mycobacterial infections

A chest roentgenogram of a 75-year-old immunocompetent woman showed disseminated micronodular densities in bilateral lung fields. Subsequent high-resolution computed tomography (CT) confirmed centrilobular micronodular densities associated with bronchial wall thickening and bronchiectatic changes. CT imaging also revealed volume loss with bronchiectatic changes in both the right middle lobe and the left lingular segment. Cytology specimens were then obtained through bronchial brushing and washes. Smears from right B2 and B4 revealed filamentous gram-positive, branched bacteria embedded among many neutrophils. Nocardia transvalensis was cultured from the bronchial wash, and no mycobacteria were identified. To our knowledge, this is the first report of a Nocardia transvalensis pulmonary infection in an immunocompetent patient, and also the first detailed description of a Nocardia transvalensis pulmonary infection in Japan. Moreover, the radiographic and CT findings in this patient were quite similar to those seen in patients with nontuberculous mycobacterial pulmonary infections, a pattern not previously reported in patients with Nocardia pulmonary infections.

Cutaneous nocardiosis: report of two cases and review of the literature

BACKGROUND

Cutaneous nocardiosis is an uncommon infectious disease that presents as a primary cutaneous infection or as a disseminated disease. It is often misdiagnosed because of its rarity and nonspecific clinical picture.

METHODS

We report a case of each type. The first case is an immunocompetent patient who was infected by Nocardia while gardening and developed a superficial skin infection--one of the three clinical manifestations of primary cutaneous nocardiosis. The second case is an immunocompromised patient with pulmonary nocardiosis that extended to the skin as part of a disseminated disease.

RESULTS

The immunocompetent patient with primary cutaneous nocardiosis had the classical features of a superficial skin infection. He had a nodular–pustular lesion on the right arm, which appeared 7 days after gardening with bare hands. Nocardia was identified in a skin culture taken from a pustule, unfortunately not to the species level. Treatment with minocycline for 3 months resulted in full remission of the lesion. The immunocompromised patient with disseminated nocardiosis had high fever, productive cough, hemoptysis, and erythematous nodules and pustules on the extremities. N. brasiliensis was isolated from bronchial samples and skin. Treatment with a high dose of trimethoprim and sulfamethoxazole for five months resulted in full recovery from cutaneous and pulmonary complaints. No relapse of the infection was found on follow-up in either patient.

CONCLUSION

These cases demonstrate the need for a high degree of suspicion, focused clinical search, and appropriate laboratory procedures in the diagnosis and management of cutaneous nocardiosis.

Unusual infections: Femoral abscess due to Nocardia abscessus in a patient suffering from metastatic peripheral bronchial carcinoma and hygienic consequences

During the course of a peripheral bronchial carcinoma with pulmonary and cerebral metastases a femoral abscess developed in a 49 year-old patient after radio- and chemotherapy. A bacterial strain, which was isolated four times from a deep wound of the left thigh was tentatively identified as a member of the genus Nocardia on the basis of selected phenotypic and chemotaxonomic characteristics. The isolate was confirmed to belong to Nocardia abscessus by 16S rRNA gene sequencing. This species had previously been described as the causative agent of soft tissue infections. Although rare, nocardia soft tissue infections as complication of systemic nocardiosis are typical air born infections of immuncompromised patients and need specific attention. Infection prevention can be realized by restriction of soil and aerosol (builder's dust) together with antibiotic intervention (oral administration of trimethoprim/sulfamethoxazole).

Homozygous triplicate mutations in three 16S rRNA genes responsible for high-level aminoglycoside resistance in Nocardia farcinica clinical isolates from a Canada-wide bovine mastitis epizootic

Nocardia farcinica strains showing high-level resistance to amikacin were isolated from clinical cases in a Canada-wide bovine mastitis epizootic. Shotgun cloning of the resistance genes in the amikacin-resistant mastitis isolate N. farcinica IFM 10580 (W6220 [Centers for Disease Control and Prevention]) using a multicopy vector system revealed that the 16S rRNA gene with an A-to-G single-point mutation at position 1408 (in Escherichia coli numbering) conferred "moderate" cross-resistance to amikacin and other aminoglycosides to an originally susceptible N. farcinica strain IFM 10152. Subsequent DNA sequence analyses revealed that, in contrast to the susceptible strain, all three chromosomal 16S rRNA genes of IFM 10580, the epizootic clinical strain, contained the same A1408G point mutations. Mutant colonies showing high-level aminoglycoside resistance were obtained when the susceptible strain N. farcinica IFM 10152 was transformed with a multicopy plasmid carrying the A1408G mutant 16S rRNA gene and was cultured in the presence of aminoglycosides for 3 to 5 days. Of these transformants, at least two of the three chromosomal 16S rRNA genes contained A1408G mutations. A triple mutant was easily obtained from a strain carrying the two chromosomal A1408G mutant genes and one wild-type gene, even in the absence of the plasmid. The triple mutant showed the highest level of resistance to aminoglycosides, even in the absence of the plasmid carrying the mutant 16S rRNA gene. These results suggest that the homozygous mutations in the three 16S rRNA genes are responsible for the high-level aminoglycoside resistance found in N. farcinica isolates of the bovine mastitis epizootic.

Resistance to rifampicin: at the crossroads between ecological, genomic and medical concerns

The first antibiotic of the ansamycin family, rifampicin (RIF), was isolated in 1959 and was introduced into therapy in 1962; it is still a first-line agent in the treatment of diseases such as tuberculosis, leprosy and various biofilm-related infections. The antimicrobial activity of RIF is due to its inhibition of bacterial RNA polymerase (RNAP). Most frequently, bacteria become resistant to RIF through mutation of the target; however, this mechanism is not unique. Other mechanisms of resistance have been reported, such as duplication of the target, action of RNAP-binding proteins, modification of RIF and modification of cell permeability. We suggest that several of these alternative resistance strategies could reflect the ecological function of RIF, such as autoregulation and/or signalling to surrounding microorganisms. Very often, resistance mechanisms found in the clinic have an environmental origin. One may ask whether the introduction of the RIF analogues rifaximin, rifalazil, rifapentine and rifabutin in the therapeutic arsenal, together with the diversification of the pathologies treated by these molecules, will diversify the resistance mechanisms of human pathogens against ansamycins.

Nocardia cyriacigeorgica: a case of endocarditis with disseminated soft-tissue infection

Nocardia cyriacigeorgica is a common environmental organism. It has been isolated from clinical samples in Europe, Asia and North America, predominantly from respiratory samples but also from samples from several other sites. We present a case report of an 85-year-old female patient in the UK who was found to have a multi-focal soft-tissue infection from which N. cyriacigeorgica was isolated. She had a background history of chronic obstructive pulmonary disease and corticosteroid use for polymyalgia rheumatica. During the course of her treatment echocardiography showed the presence of a mobile heart mass attached to a valve leaflet, a major Dukes criterion for endocarditis. We suggest that in cases of disseminated Nocardia infection, endocarditis should be tested for, particularly in cases failing to respond to treatment. We also review previous reports of both N. cyriacigeorgica infection, and of endocarditis due to Nocardia species and related genera.