Brain Abscess Caused by Nocardia asteroides in a Diabetic Patient: A Rare Case Report.

Nocardial brain abscess is usually associated with immunodeficiency, but can sometimes emerge in healthy individuals. This infection can be acquired through inhalation or direct inoculation of the bacteria, followed by dissemination to various organs, including the brain, through blood circulation. Mortality rate due to nocardial cerebral abscess is three times higher than that associated with cerebral abscess caused by other types of bacteria. Moreover, patients with Nocardia asteroides-associated brain abscess show poorer prognosis compared to patients with brain abscess caused by other Nocardia species, which is probably due to the high tendency of N. asteroides to become resistant to numerous antibiotics. It is, therefore, of paramount importance to diagnose and treat N. asteroides cerebral abscess in patients as soon as possible. The current paper is a rare report of a brain abscess caused by N. asteroides in a diabetic patient who failed to respond to multiple antibiotics (trimethoprim/sulfamethoxazole and amikacin), but improved by receiving imipenem and linezolid, and was finally successfully treated by surgical operation and long-term antibiotic therapy (imipenem and linezolid).

Efficient biodegradation of di-(2-ethylhexyl) phthalate by a novel strain Nocardia asteroides LMB-7 isolated from electronic waste soil.

The di-2-ethylhexyl phthalate (DEHP) degrading strain LMB-7 was isolated from electronic waste soil. According to its biophysical/biochemical characteristics and 16S rRNA gene analysis, the strain was identified as Nocardia asteroides. Optimal pH and temperature for DEHP degradation were 8.0 and 30 °C, respectively, and DEHP removal reached 97.11% after cultivation for 24 h at an initial concentration of 400 mg/L. As degradation intermediates, di-butyl phthalates, mono-2-ethylhexyl phthalate and 2-ethylhexanol could be identified, and it could be confirmed that DEHP was completely degraded by strain LMB-7. To our knowledge, this is a new report of DEHP degradation by a strain of Nocardia asteroides, at rates higher than those reported to date. This finding provides a new way for DEHP elimination from environment.

Micetoma por Nocardia asteroides / Nocardia Asteroids Mycetoma

Introducción: En 1860 Henry Van Carter introdujo la definición del micetoma y desde 1884 se reportan los primeros casos en África (Sudán, Senegal). Estas infecciones afectan la piel, el tejido celular subcutáneo y, en ocasiones, los músculos, los huesos, y pueden diseminarse por la cavidad torácica, la abdominal, y por otras regiones del cuerpo. Objetivo: Presentar un caso de micetoma por Nocardia asteroides con evolución desfavorable y tratamiento. Presentación del caso: Paciente masculino de 47 años de edad que sufrió hace 18 años un trauma en la rodilla izquierda con herida avulsiva y evolución desfavorable por infección. Diez años después presentó en el mismo sitio múltiples lesiones fistulosas con drenaje activo, secreción serohemática escasa y no fétida. En varias ocasiones fue llevado al salón de operaciones para realizarle debridamientos quirúrgicos y toillete y recibió múltiples tratamientos antibióticos y antifúngicos. Se concluyó el caso como un micetoma y se aisló una Nocardia asteroides. El paciente estuvo en desacuerdo con la amputación de la extremidad como tratamiento quirúrgico definitivo. Llegó a nuestro centro en octubre del 2020 con mal estado general y extensión severa del proceso infeccioso en toda la extremidad. Se planificó una hemipelvectomía como tratamiento definitivo, pero desafortunadamente el paciente falleció antes, debido a complicaciones generales. Conclusiones: Ante la aparición del micetoma es importante definir el alcance de la infección para determinar el tipo de tratamiento a utilizar, ya que bien empleado y de forma oportuna, puede salvar la vida al paciente sin dejar graves secuelas(AU)

Introduction: In 1860, Henry Van Carter introduced the definition of mycetoma and since 1884 the first cases have been reported in Africa (Sudan, Senegal). These infections affect the skin, the subcutaneous cellular tissue and, sometimes, the muscles, the bones, and it can spread throughout the thoracic cavity, the abdominal cavity, and other regions of the body. Objective: To report a case of mycetoma due to nocardia asteroides with unfavorable evolution and treatment. Case report: We report the case of a 47-year-old male patient who suffered a left knee trauma 18 years ago with an avulsive wound and unfavorable evolution due to infection. Ten years later, he presented, in the same site, multiple fistulous lesions with active drainage, scant serohematic, non-fetid secretion. On several occasions he was taken to the operating room for surgical debridement and toilette and he received multiple antibiotic and antifungal treatments. The case was concluded as a mycetoma. Nocardia asteroides was isolated. The patient disagreed with limb amputation as definitive surgical treatment. He came to our treatment center in October 2020 with poor general condition and severe extension of the infectious process throughout the limb. A hemipelvectomy was planned as definitive treatment, but unfortunately the patient deceased before due to general complications. Conclusions: Before the appearance of mycetoma, it is important to define the extent of the infection to determine the type of treatment to use, since it can save the patient's life if properly used and in a timely manner without leaving serious sequelae(AU)

Mini-mycetoma due to Nocardia asteroides: a short report from Mexico.

An illustrative case of mini-mycetoma in a 54-year-old female agricultural worker from Mexico.

Development of a SYBR Green Multiplex Real Time PCR for Simultaneous Detection of Mycobacterium Tuberculosis and Nocardia Asteroides in Respiratory Samples.

BACKGROUND: Nocardia asteroides and Mycobacterium tuberculosis are worldwide-distributed bacteria. These infectious agents can cause many infections in humans, especially in immunocompromised individuals. Pulmonary infections are more common and have similar clinical symptoms. Proper diagnosis and treatment of these patients are important for accurate treatment and could be lifesaving. METHODS: In this study, a multiplex real-time PCR assay was established for the simultaneous detection of the N. asteroides and M. tuberculosis. Both this homemade multiplex real time PCR and routine commercial tuberculosis tests were performed on 150 pulmonary specimens collected from individuals suspected to have tuberculosis. RESULTS: From 150 specimens, 20 samples were acid fast positive, 14 positives for M. tuberculosis by singleplex real time PCR, 10 positives for N. asteroides by singleplex real time PCR and 2 positives for M. tuberculosis and N. asteroides by multiplex real time PCR whereas 14 samples were positive for M. tuberculosis with commercial test. Differential diagnosis of pulmonary tuberculosis is useful for their proper treatment. CONCLUSION: Our test had good performance for differential diagnosis of tuberculosis and nocardiosis. Therefore, it is recommended to be used to diagnose such patients.

Métodos de identificación polifásica aplicados a la búsqueda de microorganismos con potencial industrial / Polyphasic identification methods applied in searching for microorganisms with industrial potential

Introducción: La bioprospección de metabolitos de interés antropogénico emplea métodos de recolección de microorganismos en ecosistemas extremófilos o endémicos. La microbiota aislada en estos lugares puede o no incluir microorganismos patógenos. Es imprescindible un enfoque interdisciplinario que permita abordar la búsqueda de las especies de interés mientras se preserva la buena salud de los investigadores. Objetivo: Identificar molecular, bioquímica y morfológicamente microorganismos patógenos humanos en cepas celulolíticas de importancia industrial almacenadas en el banco de cepas del Laboratorio de Investigación de la Facultad de Ingeniería Química de la Universidad Central del Ecuador, procedentes del Yasuní, la Antártida y Balzapamba. Métodos: Se realizó un estudio de bioprospección de bacterias celulolíticas empleando técnicas de microbiología ambiental. Se evaluaron las características morfológicas mediante tinciones, como por ejemplo Gram. Además, se realizaron pruebas bioquímicas y antibiogramas para bacterias Gram-negativas y Gram-positivas. Las pruebas moleculares utilizaron extracción de ADN bacteriano para la secuenciación Sanger del gen 16S. Resultados: Se encontraron las especies Klebsiella pneumoniae (Y2 y Y3r) y Nocardia asteroides (Y1 y Y3p) en las muestras de material lignocelulósico recolectadas en Yasuní, mientras que las especies aisladas en la Antártida y en Balzapamba corresponden a Bacillus subtillis. Conclusiones: Se identificaron cepas pertenecientes a diferentes géneros bacterianos. Las bacterias del género Klebsiella, en las muestras colectadas en Yasuní, podrían tener un potencial patógeno. Eso se puede corroborar con técnicas de genotipificación. Por lo tanto, puede existir riesgo para los seres humanos que realizan bioprospección en ese ecosistema y se deben tomar medidas de bioseguridad.

Abstract Background: The bioprospection of metabolites of anthropogenic interests employs methods of collecting microorganisms in extremophile or endemic ecosystems. The microbiota isolated in these places may or may not include pathogenic microorganisms. Therefore, an interdisciplinary approach is essential to address the search of the species of interest while the good health of the researchers is preserved. Objective: To identify in molecular, biochemical and morphologically ways some human pathogenic microorganisms in cellulolytic strains of industrial importance stored in the strain bank of the Research Laboratory of the Faculty of Chemical Engineering at the Central University of Ecuador, from Yasuní, Antarctic and Balzapamba. Methods: IA bioprospecting study of cellulolytic bacteria was performed using environmental microbiology techniques. Morphological characteristics were assessed by Gram staining. In addition, biochemical tests and antibiograms were performed for Gram-negative and Gram-positive bacteria. The molecular tests used extraction of bacterial ADN for 16S gene Sanger sequencing. Results: The species Klebsiella pneumoniae (Y2 and Y3r) and Nocardia asteroides (Y1 and Y3p) were found in samples of lignocellulosic material collected in Yasuni, while the isolated species in Antarctica and Balzapamba correspond to Bacillus subtillis. Conclusions: Strains belonging to different bacterial genera were identified. The bacteria of the genus Klebsiella from the samples collected in Yasuní could have a potential pathogen. This can be corroborated with genotyping techniques. Therefore, there could be a risk to humans who perform bioprospecting in that ecosystem and biosecurity measures should be taken.

Identification of common antigens of three pathogenic Nocardia species and development of DNA vaccine against fish nocardiosis.

Fish nocardiosis is a chronic granulomatous bacterial disease and three pathogens have been reported so far, including Nocardia asteroids, N. seriolae and N. salmonicida. However, the absence of antigen markers is a bottleneck for developing effective vaccines against fish nocardiosis. In this study, the antigenicity of whole-cell protein of these three pathogenic Nocardia species were profiled by immunoproteomic analysis and 7 common immunogenic proteins were identified as follows: molecular chaperone DnaK (DnaK), molecular chaperone GroEL (GroEL), 30 S ribosomal protein S1 (RpsA), TerD family protein (TerD), FHA domain-containing protein (FHA), 50 S ribosomal protein L7/L12 (RplL) and PspA/IM30 family protein (PspA). Furthermore, the DNA vaccine encoding FHA gene against fish nocardiosis was developed and its efficacy was investigated in hybrid snakehead. The results suggested that it needed at least 7 d to transport pcDNA-FHA DNA vaccine from injected muscle to head kidney, spleen and liver and stimulate host's immune system for later protection. In addition, non-specific immunity paraments (serum lysozyme (LYZ), peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) activities), specific antibody (IgM) titers production and immune-related genes (MHCIα, MHCIIα, CD4, CD8α, IL-1ß and TNFα) were used to evaluate the immune response induced in pcDNA-FHA vaccinated hybrid snakehead, it proved that all these mentioned immune activities were significantly enhanced after immunization. The results also showed hybrid snakehead vaccinated with pcDNA-FHA had higher survival rate (79.33%) compared with the controls after challenge with N. seriolae, indicating that the pcDNA-FHA DNA vaccine can supply immune protection against N. seriolae infection. Taken together, this study may warrant further development of these common immunogenic proteins as the antigens for vaccine or diagnosis and facilitate the prevention and treatment of fish nocardiosis.

Nocardiosis in Kidney Disease Patients under Immunosuppressive Therapy: Case Report and Literature Review.

The increased use of novel and powerful immunosuppressive drugs in kidney diseases may concomitantly expose the patients to higher risk of opportunistic infections, some of which still remain underdiagnosed thus mishandled. As such, we recently had a less prepared encounter of pulmonary nocardial infection in an ANCA-associated renal vasculitis patient under steroid therapy. Despite the use of broad-spectrum antimicrobials including micafungin, the infection was still unbridled and eventually culminated in lethal brain abscess. We thus chose to renew the knowledge of the clinical features, imaging manifestations, differential diagnosis, specific laboratory tests and unique treatment about this rare infection in kidney diseases patients under immunosuppressive therapy. In addition, CT images of easily confused pulmonary lesions superimposed on kidney diseases were also retrieved from our depository. Moreover, impaired renal function as a risk factor for infection and pharmacological options for the treatment were also focused. By sharing our hard-learnt experience and reviewing the literatures, our report may contribute to the awareness among the clinicians in general and nephrologists in particular of this rare disease in susceptible patients and facilitate a swift thus life-saving treatment.

Management of Nocardia Interface Keratitis After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To report the clinical course and management of graft-host interface Nocardia keratitis after Descemet membrane endothelial keratoplasty (DMEK). METHODS: A 70-year-old man presented with a corneal epithelial defect, stromal edema, graft infiltrate, and graft-host interface infection 5 months after an uneventful DMEK performed for bullous keratopathy in the left eye. Corneal scrapings from the margin of epithelial defect showed gram-positive bacillus, and the organism was identified as Nocardia asteroides. RESULTS: Intensive and appropriate topical and systemic antibiotic therapy resulted in complete resolution of infection. Three months later, the patient underwent a repeat DMEK, which resulted in clearing of corneal edema and improvement in visual acuity. CONCLUSIONS: Nocardia interface keratitis is a rare entity, which can occur after DMEK. Proper clinical evaluation and microbiological workup helped us in accurate diagnosis and management. Repeat DMEK after complete resolution of the infection resulted in good outcomes regarding corneal clarity and vision improvement.

Isolation of Nabscessin C from Nocardia abscessus IFM 10029T and a Study on Biosynthetic Pathway for Nabscessins.

A new aminocyclitol derivative, designated nabscessin C (1), was isolated from Nocardia abscessus IFM 10029T. Nabcessin C is an isomer of nabscessins A (2) and B (3) with different positioning of the acyl group. Absolute configuration of nabscessin A was determined by conversion into the 2-deoxy-scyllo-inosamine pentaacetyl derivative (4) by hydrolysis and acetylation of 2. The biosynthetic pathway of nabscessins is proposed based on gene expression analysis.

Catch Me If You Can.

Nocardia is a genus of anaerobic gram-positive bacteria that most commonly infect persons with compromised immunity. Pneumonia and soft tissue infections are seen most frequently; osteomyelitis is an uncommonly reported manifestation of nocardiosis. We report a case of pelvic osteomyelitis due to Nocardia asteroides in a patient with unrecognized acquired immune deficiency syndrome (AIDS) without evidence of concomitant pulmonary or skin infection.

The Complexities of Nocardia Taxonomy and Identification.

Nocardia species are a complex group of organisms considered to belong to the aerobic actinomycetes. Of the validly described species, many have been implicated as the cause of serious human infections, especially in immunocompromised patients. The genus has a complicated taxonomic history; this is especially true for Nocardia asteroides, the type species of the genus and previously the most frequently reported nocardial taxon from human specimens. We provide background on the current taxonomy of Nocardia, with a focus on clinically relevant species, and discuss the currently available methods used to accurately identify isolates to the species, complex, or group level.

[Native Aortic Valve Endocarditis Caused by Nocardia asteroides;Report of a Case].

Infection by Nocardia sp. is rare and usually affects immuno-depressed patients, such as those receiving chemotherapy and long-term steroid therapy. Cardiac involvement is uncommon and usually occurs as endocarditis. We present a case of native aortic valve endocarditis caused by Nocardia asteroides. Aortic valve translocation method was chosen because of extensive root infection with major disruption of the aortic annulus. Over 2 years after the surgery, there is no recurrence and no enlargement of the aortic annulus.

Nocardia Arthritidis Keratitis: Case Report and Review of the Literature.

INTRODUCTION: Keratitis due to Nocardia infection is not commonly encountered in clinical practice and may therefore be mistaken for fungal or viral keratitis leading to delayed treatment and increased risk of permanent visual impairment. CASE: An otherwise healthy 27 years old Caucasian Active Duty military member presented to the clinic with three days of light sensitivity and irritation of his right eye. He carried a history of PRK in both eyes six years prior and admitted to recent contact lens overuse. With empiric treatment for typical bacterial keratitis including corticosteroids, his condition worsened on close follow-up. While awaiting cultures, a shift to fortified topical antibiotics tobramycin, moxifloxacin and ciprofloxacin showed improvement with closure of the epithelial defect. Ulcerative relapse occurred with withdrawal of therapy. Culture proven Nocardia arthritidis prompted successful treatment with topical antibiotic amikacin. On follow-up at three months, the patient was doing well with a small peripheral anterior stromal scar without permanent visual sequelae. Visual acuity returned to baseline of 20/20 in the affected eye. CONCLUSION: Keratitis caused by Nocardia species, including arthritidis, responds well to amikacin. Late diagnosis and early treatment withdrawal may lead to a prolonged recovery. Current literature indicates that corticosteroids may be harmful in the treatment of Nocardia keratitis. Increased awareness of Nocardia as an ocular pathogen has the potential to reduce unnecessary morbidity related to delayed diagnosis, inadequate therapy and inappropriate use of corticosteroids.