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.

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).

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.

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.

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.

[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.

Linezolid-induced lactic acidosis in two liver transplant patients with the mitochondrial DNA A2706G polymorphism.

Mitochondrial toxicity has been recently suggested to be the underlying mechanism of long-term linezolid-associated toxicity in patients with 16S rRNA genetic polymorphisms. Here, we report for the first time two cases of lactic acidosis due to long-term linezolid exposure in liver transplant recipients who presented an A2706G mitochondrial DNA polymorphism.

Co-infection with Nocardia asteroides complex and Strongyloides stercoralis in a patient with autoimmune hemolytic anemia.

We describe an unusual case of pulmonary nocardiosis co-existing with Strongyloides stercoralis hyperinfection syndrome in a patient with autoimmune hemolytic anemia who was being treated with corticosteroids. This case highlights the importance of being aware of the possibility that infections can co-exist in immunosuppressed patients. To the best of our knowledge, this is the first report of co-infection with Nocardia asteroides and S. stercoralis.

Blood culture positive Nocardia asteroides infection: a case report.

We report a case of nocardiosis in a patient with several risk factors for this rare infection. Radiologically, the patient's multiple lung abscesses were misinterpreted as pulmonary metastases. Diagnosis was finally reached by the growth of Nocardia asteroides in two different blood culture sets. Nocardia bacteraemia is a rare clinical event. Despite initiation of an effective antibiotic therapy, the patient died. Autopsy revealed disseminated nocardial abscesses in the lungs, the kidneys and the brain.

Exploration of respiratory chain of Nocardia asteroides: purification of succinate quinone oxidoreductase.

Nocardia asteroides is a pathogenic bacterium that causes severe pulmonary infections and plays a vital role in HIV development. Its electron transport chain containing cytochromes as electron carriers is still undiscovered. Information regarding cytochromes is important during drug synthesis based on cytochrome inhibitions. In this study we explored the electron transport of N. asteroides. Spectroscopic analysis of cytoplasm and membranes isolated from N. asteroides indicates the presence of soluble cytochrome-c, complex-II and the modified a(1)c(1) complex as the terminal oxidase. The molecular weight of the respiratory complex-II isolated and purified from the given bacterium was 103 kDa and was composed of three subunits, of 14, 26 and 63 kDa. Complex-II showed symmetrical α-absorption peaks at 561 nm in the reduced state. Spectral analysis revealed the presence of only one heme b molecule (14-kDa subunit) in complex-II, which was confirmed by heme staining. Heme b content was found to be 9.5 nmol/mg in complex-II. The electron transport chain of N. asteroides showed the presence of soluble cytochrome-c, cytochrome-a(1)c(1) and cytochrome-b.

[A case of nocardiosis with associated endobronchial excavated lesions].

A case of nocardiosis with associated endobronchial excavated lesions is reported. A 79-year-old woman was diagnosed as having dermatomyositis in March, 2010. She was started on prednisolone (50mg/day) and was then switched to betamethasone due to lower limb edema and tapered to a dose of 2.5mg/day. A periodic chest X-ray examination in July, 2010, incidentally revealed nodular densities and associated cavities in the upper right lung field. On thoracoabdominal computed tomography (CT), bilateral pulmonary nodular shadows with various-sized cavities and multiple, new, intrahepatic, low-density regions were also identified. On bronchoscopy, a white, excavated lesion resembling an ulcerous lesion was observed in the left upper lobe bronchus, and a small exophytic lesion was observed in the right B6 bronchus. Nocardia asteroides complex was isolated from cultures of bronchial lavage fluid and sputum. The patient was treated with 4 weeks of intravenous imipenem (1.5g/day), followed by oral minocycline therapy (200mg/day) for 6 months, after which lesion resolution was confirmed on CT and treatment was discontinued. No recurrence has been reported in the roughly 18 months of follow-up to date. Nocardiosis results from infection with bacteria of the zoonotic, aerobic, Actinomyces genus and presents with disseminated lesions. Reported cases of human infection are increasing due to greater numbers of immunocompromised patients and improved diagnostic techniques. However, nocardiosis involving endobronchial lesions is extremely rare, and, to the best of our knowledge, the present case is the first report of endobronchial excavated lesions caused by nocardiosis.

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.

Cerebral nocardiosis.

Localized and multisystem nocardiosis is an opportunistic disease that occurs commonly in immunocompromised patients. Rarely, it is also seen in immunocompetent individuals. The most common disease sites include lung, skin and central nervous system. We report a case of 73 years old man who is a known case of rheumatoid arthritis for more than 15 years and was on Methotrexate and Prednisolone. Now presented with generalized tonic clonic seizures. His Magnetic Resonace Imaging (MRI) scan showed a ring enhancing lesion with mild surrounding oedema in right posterior parietal cortex. Based on the finding, the most probable diagnosis of cerebral abscess was suggested. Patient underwent right sided craniotomy with aspiration of abscess. Serum Gram staining showed branching Gram-positive rods, and serum culture showed colonies of Nocardia Asteroides. He was started on Sulfamethoxazole-Trimethoprim. On follow-up examination, the patient showed marked improvement clinically and was discharged in stable condition on long term antibiotic therapy. This case highlights the importance of including nocardia on the differential diagnosis especially in patients who present with abnormal MRI scan findings that mimic tuberculoma or neoplastic disease. Clinical awareness of this condition could expedite the diagnostic process and help improve morbidity and mortality.

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.

[A case of Cushing syndrome presenting after pulmonary nocardiosis with pyothorax].

A 49-year-old woman visited our clinic on July 12th, 2006, complaining of discomfort in fingers of both hands, edema of both lower limbs, and pain in the right shoulder and chest. Chest X-ray examination showed an infiltrative shadow with pleural effusion and loss of lung volume in the left lower lung field. She was treated with CTRX, but it was ineffective, and she was therefore admitted to Kurume University Hospital on July 21st, 2006. Chest CT demonstrated pyothorax and loss of lung volume in the left lung. Culture of a sample obtained by thoracentesis yielded Nocardia asteroides. The pulmonary nocardiosis improved after oral administration of trimethoprim-sulfamethoxazole, and the patient was discharged on August 25th 2006. No immunological impairment was observed, and the serum levels of ACHT and cortisol were normal. In February 2007, however, she developed facial acne, facial edema ("moon" face), centripetal obesity, and weight gain. Cushing syndrome was diagnosed on the basis of tests including a low-dose dexamethasone suppression test. To the best of our knowledge, there has been no previous report of pulmonary nocardiosis with pyothorax in a patient with Cushing syndrome. We assume that the present patient had pre-(sub-) clinical Cushing syndrome when she presented with pulmonary nocardiosis and pyothorax.