Nocardia beijingensis sp. nov., a novel isolate from soil

Persistent Nocardia beijingensis infection in a patient with postoperative abscess and misuse of antibiotics in China

Here we describe the first case of abscess infection caused by Nocardia beijingensis in China. The patient was immunocompetent but suffered from postoperative abscess for 6 years. This study highlights the necessity of long-term infected foci to be thoroughly examined to identify the pathogen, as well as the importance of accurate Nocardia identification and antimicrobial susceptibility tests for understanding the pathogen's epidemiology, clinical significance, and treatment strategy.

Nocardia sputi sp. nov. isolated from the sputum of patients with pulmonary infection

Two Gram-stain-positive, aerobic and rod-shaped actinomycetes (strains CY18T and CY8) were isolated from the sputum of two patients with pulmonary infections, and their taxonomic status was investigated. The 16S rRNA gene sequences and the results of phylogenetic analyses indicated that CY18T and CY8 were identical (100 %) and were most closely related to Nocardia beijingensis CGMCC 4.1521T (99.9 %) and Nocardia araoensis NBRC 100135T (99.5 %). The predominant cellular fatty acids of CY18T and CY8 were C16 : 0, C18 : 0, C18 : 1ω9c and summed feature 3 (comprising C16 : 1ɷ7c and/or C16 : 1ɷ6c), and the major menaquinone was MK-8(H4ω-cycl).The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The whole-cell hydrolytic sugar pattern consisted of arabinose and glucose. The polar lipid profile contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, two unidentified phospholipids, three unidentified glycolipids and two unidentified lipids.The DNA G+C contents of CY18T and CY8 were 67.9 and 68.0 % respectively. The digital DNA–DNA hybridization and average nucleotide identity values between the two novel strains and closely related species were well under the 70 % and 95–96 % thresholds, respectively, but these values between the two novel strains were 95.5 % and 99.5 %, respectively. On the basis of morphological and chemotaxonomic characteristics and the results of phylogenetic analyses, strains CY18T and CY8 represent a novel species of the genus Nocardia , for which the name Nocardia sputi sp. nov. is proposed. The type strain is CY18T (=GDMCC 1.3318T = JCM 33932T).

Nocardia beijingensis isolated from an adrenal abscess in a diabetic host

We describe the case of a 57-year-old man with poorly controlled type 2 diabetes mellitus who presented with 30 days of left-sided abdominal pain. He was found to have a left adrenal abscess and underwent adrenalectomy. Intraoperative cultures grew Nocardia beijingensis, which is an uncommonly identified Nocardia species rarely affecting immunocompetent patients. We review the published literature on cases of N. beijingensis among immunocompetent patients. This is the first report summarizing the diagnosis and management of N. beijingensis isolated from an adrenal abscess.

Multiple Brain Abscesses Caused by Nocardia Beijingensis in a Patient With HIV Infection

The etiologic agents of central nervous system infections in HIV-infected patients comprise a broad range of opportunistic pathogens. We presented a 49-year-old male patient with HIV infection and low adherence to antiretroviral therapy. He presented with multiple cerebral abscesses, and his microbiological diagnosis approach resulted in the isolation of Nocardia beijingensis, a species rarely reported in America. Central nervous system nocardial infection in HIV-infected patients should be considered, and a diagnosis at species level is mandatory because the antibiotic susceptibility profile varies among species.

Disseminated nocardiosis in an immunocompetent host with occupational exposure

Nocardia is a genus of Gram-positive, partially acid-fast bacteria consisting of over 120 species, of which 50 are recognized as human pathogens. Nocardia spp. are common colonizers in the environment, particularly in soil and water. Nocardia spp. typically cause opportunistic infections in the immunocompetent host, although cases of nocardiosis have been described in those with a normal immune system. Nocardiosis can be localized, most often in the skin or lung, or be disseminated, with involvement of the brain, bone, and visceral organs. Treatment of nocardiosis is complex, as multiple culture-directed antibacterials with appropriate tissue penetration may need to be used for a prolonged duration. To our knowledge, we describe the first successfully treated case of disseminated Nocardia beijingensis infection in an immunocompetent host with doxycycline and trimethoprim-sulfamethoxazole and hypothesize that his occupational exposure to ubiquitous saprophytes may have led to his infection.

Nocardia beijingensis lung mass in an immunocompetent adult

A 47-year-old man was referred for ongoing workup of an enlarging lung mass. Extensive workup of the mass had been unrevealing for several months until cultures grew Nocardia beijingensis He was successfully treated with trimethoprim/sulfamethoxazole and then doxycycline with near-complete resolution of the mass on follow-up. This case presents a rare species of N. beijingensis It highlights the importance of considering nocardiosis in immunocompetent adults and the challenge in initiating targeted treatment due to delayed culture results.

Genomic Virulence Features of Two Novel Species Nocardia barduliensis sp. nov. and Nocardia gipuzkoensis sp. nov., Isolated from Patients with Chronic Pulmonary Diseases

Strains 335427^T and 234509^T, isolated from two 76-year-old patients with chronic pulmonary diseases, were the subject of polyphasic taxonomic studies and comparative genomic analyses for virulence factors. The 16 rRNA gene sequence similarity between strains 335427^T and 234509^T and their closest phylogenetic neighbors Nocardia asiatica NBRC 100129^T and Nocardia abscessus NBRC 100374^T were 99.5% and 100%, respectively. Digital DNA-DNA hybridization values between the aforementioned studied strains were well below the 70% threshold for assigning prokaryotic strains to a novel species. Strains 335427^T and 234509^T have genome sizes of 8.49 Mpb and 8.07 Mpb, respectively, with G + C content of 68.5%. Isolate 335427^T has C_16:0, C_18:1 ω₉c, C_18:0 and C_18:0 10 methyl as major fatty acids (>15%) and mycolic acids formed of 52-54 carbon atoms. However, only C_18:1 ω₉c was detected for isolate 234509^T, which had mycolic acids with 44-56 carbon. Based on phenotypic and genetic data, strains 335427^T (DSM 109819^T = CECT 9924^T) and 234509^T (DSM 111366^T = CECT 30129^T) merit recognition as novel species, which are named Nocardia barduliensis sp. nov. and Nocardia gipuzkoensis sp. nov., respectively. All the strains studied had homologous VF-associated genes to those described in M. tuberculosis, including experimentally verified virulence genes in humans related to tuberculosis. The narGHIJ (nitrate reduction pathway) and gvpAFGOJLMK (gas vesicles) genetic maps of strains 335427^T, 234509^T, NBRC 100129^T and NBRC 100374^T showed the same syntenic block and raise the question of whether their functions are interlinked during the infection of the human host. However, further research is required to decipher the role of the gas vesicle in the pathogenicity mechanism of Nocardia spp.

Disseminated Nocardia beijingensis Infection in an Immunocompetent Patient

Nocardia is a genus of aerobic, non-motile and non-spore-forming filamentous branching bacteria with fragmentation into bacillary or coccoid forms. Infections caused by Nocardia often occur in immunocompromised hosts and are potentially life-threatening. Nocardia beijingensis has rarely been reported to cause infection in immunocompetent hosts. We present a case of disseminated infection due to Nocardia beijingensis in a patient with no known medical comorbidities, who presented with new-onset seizure. Another interesting finding in our case is that our patient did not have any pulmonary symptoms despite chest CT showing the pulmonary system as the likely primary site of infection. As per our literature review, this is the seventh reported case of infection due to Nocardia beijingensis in an immunocompetent host.

LEARNING POINTS

To recognize Nocardia beijingensis, a slow-growing weakly acid-fast filamentous bacteria commonly causing opportunistic infections in immunocompromised hosts, as an emerging pathogen in immunocompetent patients.Tissue biopsy with Gram staining showing variable filamentous bacteria and confirmation of species using restriction enzyme analysis and 16S rRNA analysis is needed to establish a diagnosis of infection.Trimethoprim/sulfamethoxazole has been successfully used to treat infection due to Nocardia beijingensis.

Disseminated Nocardia beijingensis Masquerading as Pulmonary Tuberculosis in a Patient With Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome

Case of disseminated Nocardia beijingensis, initially diagnosed and treated by health department as tuberculosis, presented with worsening symptoms and new lesions. Adjustment to antinocardial treatment resulted in significant clinical and radiographic improvement. Maintain a high index of suspicion for Nocardia in patients diagnosed with tuberculosis with worsening lesions despite therapy.

Miliary cerebrospinal lesions caused by Nocardia beijingensis in an immunocompetent patient

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We present a case of Nocardia beijingensis infection in an immunocompetent patient.

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Magnetic resonance imaging (MRI) scan showed countless miliary-like ring-enhancing cerebrospinal lesions.

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A brain biopsy is essential to confirm the diagnosis and to identify the etiological species of Nocardia.

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16S ribosomal RNA sequencing is useful for species identification.

The genus Nocardia usually infect immunocompromised patients. Pulmonary nocardiosis is the most common Nocardia-induced infection while central nervous system (CNS) is the most common extrapulmonary site to develop nocardial disease. Approximately 54 % cases of previously reported nocardial brain abscesses were solitary lesions, while 38 % cases had multiple lesions; but miliary-like ring enhancing lesions have not been reported previously.

We present a case of immunocompetent patient with miliary-like cerebrospinal lesions caused by Nocardia beijingensis. A 68-year-old Japanese man presented with acute-onset headache, vomiting, and progressive disturbance of consciousness. A contrasted magnetic resonance imaging (MRI) scan showed countless miliary-like ring-shaped enhancing lesions on the patient’s whole brain, brain stem, and cervical spinal cord. A brain biopsy was performed and Kinyoun stain suggested that the brain lesions were abscesses caused by Nocardia species. 16S ribosomal RNA sequencing identified Nocardia beijingensis as the causative microorganism. The trimethoprim/sulfamethoxazole regimen was continued for 7 months and the patient showed good improvement with recovery of consciousness.

Clinical manifestation of Nocardia beijingensis infection is poorly studied. Further cases are needed to be accumulated.

Pulmonary Infections Caused by Emerging Pathogenic Species of Nocardia

Pulmonary infections are the most common clinical manifestations of Nocardia species. There is an increase in cases of nocardial infections occurring worldwide attributable to the increase in the immunosuppressed population. The availability of molecular methods has aided the detection of more number of cases as well as unusual species. Still, it remains one of the most underdiagnosed pathogens. Recognition of drug resistance in this organism has now mandated early and precise identification with speciation for effective treatment and management. Nocardial species identity can predict antimicrobial susceptibility and guide clinical management. Here, we report two cases of pulmonary nocardiosis caused by unusual species of Nocardia, namely, N. cyriacigeorgica and N. beijingensis identified by 16S rRNA gene-based sequencing. These cases are being reported for their rarity.

Beijinchromes A-D, Novel Aromatic Compounds Isolated from Nocardia beijingensis NBRC 16342

Nocardia is a potent bacterial producer of bioactive compounds. From a culture of Nocardia beijingensis NBRC 16342, we isolated four aromatic compounds, named beijinchromes A-D (1-4). We purified them by silica gel chromatography and reverse phase HPLC, and identified their structures by NMR and high resolution (HR)-MS analyses. 1, 2, and 4 are novel 1,2,3,8-tetrasubstituted naphthalenes, and 3 is a novel 3,8-disubstituted ortho-naphthoquinone. 1 and 2 exert antioxidant activities, and 3 exhibits antibiotic activity. Remarkably, the putative biosynthetic gene clusters for 1-4 are widely distributed in 37 Nocardia species, implying their potential to produce this family of compounds and important biological functions of beijinchromes.

Immunocompetent patient with a brain abscess caused by Nocardia beijingensis in Latin America: A case report

RATIONALE

Nocardia species are not commonly referred as primary infectious entities but rather as opportunistic pathogens. Infectious cases of Nocardia spp. in immunocompetent individuals are rare.

PATIENT CONCERNS

An immunocompetent 58-year-old patient presented with recurrent headaches.

DIAGNOSIS

A brain abscess was found and surgically drained. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry and heat shock protein 65/16S-23S rRNA gene intergenic spacer genotyping from the sample revealed the etiological agent as Nocardia beijingensis.

INTERVENTIONS

Meropenem/amikacin/Trimethoprim-sulfamethoxazole were administered.

OUTCOMES

The infection persisted leading to the patient's death.

LESSONS

Here we present the first case of N. beijingensis infection of the central nervous system in an immunocompetent patient from Latin America. Further inquiry is needed to establish whether this species is more virulent than other Nocardia isolates.

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.

Identification and antimicrobial susceptibility of clinical Nocardia species in a tertiary hospital in China

OBJECTIVES

There is a lack of information on the activities of antimicrobial agents against Nocardia clinical isolates of specific species in China. The aim of this study was to determine the antibiotic susceptibility of 28 clinical isolates of Nocardia spp. isolated from Beijing Chao-Yang Hospital (Beijing, China).

METHODS

Molecular diagnosis of Nocardia spp. was performed using partial 16S rRNA and rpoB gene sequences. Antimicrobial susceptibility testing was performed by broth microdilution according to Clinical and Laboratory Standards Institute (CLSI) recommendations.

RESULTS

The species distribution was as follows: Nocardia cyriacigeorgica (n=13); Nocardia farcinica (n=6); Nocardia beijingensis (n=3); Nocardia abscessus (n=2); Nocardia wallacei (n=2); Nocardia otitidiscaviarum (n=1); and Nocardia nova (n=1). The susceptibility rates to trimethoprim/sulfamethoxazole (SXT), linezolid, amikacin, imipenem, tobramycin, ceftriaxone and cefotaxime were 100.0%, 100.0%, 92.9%, 75.0%, 67.9%, 67.9% and 64.3%, respectively, whilst the resistance rate both to ciprofloxacin and clarithromycin was 71.4%.

CONCLUSIONS

N. cyriacigeorgica was the most frequently isolated Nocardia spp. All clinical isolates showed low susceptibility to ciprofloxacin and clarithromycin and complete susceptibility both to SXT and linezolid, which can be considered the primary choice for the treatment of Nocardia infections in China.

Nocardia beijingensis brain abscesses in an HIV-infected individual

We describe a case of a 50-year-old Hispanic man diagnosed with HIV/AIDS who presented with a generalized tonic clonic seizure and ring enhancing cerebral lesions on imaging. He was initially treated for CNS toxoplasmosis but presented to the hospital with another tonic clonic seizure despite prescribed therapy. Brain biopsy was performed which revealed Nocardia beijingensis. He was treated with intravenous meropenem and trimethoprim/sulfamethoxazole for six weeks followed by long term oral trimethoprim/sulfamethoxazole with radiographic and clinical improvement.

Second report of a Nocardia beijingensis infection in the United States: nodular scleritis with in vitro imipenem resistance

We describe the case of a 52-year-old woman with scleritis caused by an imipenem-resistant strain of Nocardia beijingensis. The patient presented with pain, redness, and nodules on the sclera of 8 weeks' duration. A Gram stain from a nodule on the superonasal aspect of the globe was initially negative. After empiric treatment for an autoimmune etiology, cytopathology confirmed filamentous bacteria. A presumptive diagnosis of Nocardia scleritis was made, and medical management was based on a literature review on treatments for Nocardia infections. Cultures returned confirming Nocardia beijingensis. Antibiotic sensitivity testing confirmed the correct initial management. The patient's scleritis resolved with a good visual outcome.

Endobronchial Enigma: A Clinically Rare Presentation of Nocardia beijingensis in an Immunocompetent Patient

Nocardiosis is an opportunistic infection caused by the Gram-positive weakly acid-fast, filamentous aerobic Actinomycetes. The lungs are the primary site of infection mainly affecting immunocompromised patients. In rare circumstances even immunocompetent hosts may also develop infection. Diagnosis of pulmonary nocardiosis is usually delayed due to nonspecific clinical and radiological presentations which mimic fungal, tuberculous, or neoplastic processes. The present report describes a rare bronchoscopic presentation of an endobronchial nocardial mass in a 55-year-old immunocompetent woman without underlying lung disease. The patient exhibited signs and symptoms of unresolving community-acquired pneumonia with a computed tomography (CT) scan that showed a space-occupying lesion and enlarged paratracheal lymph node. This patient represents the unusual presentation of pulmonary Nocardia beijingensis as an endobronchial mass. Pathology obtained during bronchoscopy demonstrated polymerase chain reaction (PCR) confirmation of nocardiosis. Symptoms and clinical findings improved with antibiotic treatment. This patient emphasizes the challenge in making the diagnosis of pulmonary nocardiosis, especially in a low risk host. A literature review presents the difficulties and pitfalls in the clinical assessment of such an individual.

Nocardiosis in 132 patients with cancer: microbiological and clinical analyses

OBJECTIVES

To correlate the microbiological and clinical features of infections caused by Nocardia species.

METHODS

We determined the species and drug susceptibility of 138 Nocardia strains isolated from 132 patients at the University of Texas M. D. Anderson Cancer Center (Houston, TX) from 2002 through 2012 and analyzed the clinical features.

RESULTS

The 132 patients included 82 men and 50 women with a mean age of 59.1 years. All except two had underlying cancer, and 47 (35.6%) also received a stem cell transplant. These patients experienced 136 episodes of Nocardia infection, including pulmonary infection, abscess of deep skin and soft tissue, bacteremia and dissemination, and brain abscess. The 138 Nocardia strains involved 27 species, of which 20 species have been described since 2000. Common species included Nocardia nova, Nocardia cyriacigeorgica, Nocardia farcinica, and Nocardia abscessus, together accounting for 59.4%. N nova caused most bacteremia cases, whereas N farcinica caused most of the skin and brain infections. Infections with a few recent species likely represented first confirmation or report of human infections. Antimicrobial susceptibility tests of 117 strains showed that they were all susceptible to trimethoprim-sulfamethoxazole and linezolid but variably susceptible to other drugs depending on species. Most patients who were treated for the infection showed improvement or resolution.

CONCLUSIONS

Diverse Nocardia species can cause secondary infections in patients with cancer. Timely species identification and antimicrobial susceptibility tests may guide treatment.

First report of Nocardia beijingensis infection in an immunocompetent host in the United States

Here we describe the first reported case of Nocardia beijingensis infection in the United States, made rarer by its presence in an immunocompetent patient.

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

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

Taxonomy and chemical characterization of new antibiotics produced by Saccharothrix SA198 isolated from a Saharan soil

Actinomycete strain SA198, isolated from a Saharan soil sample of Algeria, exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria, and phytopathogenic and toxinogenic fungi. The morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus Saccharothrix. Analysis of the 16S rRNA gene sequence of strain SA198 showed a similarity level ranging between 97.2 and 98.8% within Saccharothrix species, S. australiensis being the most closely related. Two new active products were isolated by reverse HPLC using a C18 column. The ultraviolet-visible (UV-VIS), infrared (IR), mass, and (1)H and (14)C nuclear magnetic resonance (NMR) spectra showed that these products were new bioactive compounds. The minimum inhibitory concentrations of these antibiotics showed a strong activity against fungi and moderate activities against Gram-positive and Gram-negative bacteria.

Isolation of Nocardia beijingensis from a pulmonary abscess reveals human immunodeficiency virus infection

A strain of Nocardia was isolated from a pulmonary abscess of a human immunodeficiency virus-infected patient in France. Comparative 16S rRNA gene sequence analysis revealed that the isolate represented a strain of Nocardia beijingensis. Antimicrobial susceptibility testing was essential to guide the clinicians to successfully treat this infection.

Nocardia beijingensis pulmonary infection successfully treated with intravenous beta-lactam antibiotics and oral minocycline

We report a case of pulmonary infection caused by a rare Nocardia species, Nocardia beijingensis, in a 48-year-old man who received multiple immunosuppressive therapy after renal transplantation. This pathogen was isolated from a bronchoscopic protected specimen brush and was identified as N. beijingensis by 16S rRNA gene sequence analysis. The patient was initially treated with imipenem/cilastatin followed by ceftriaxone and oral minocycline. Traditionally, trimethoprim-sulfamethoxazole (SXT) has been one of the first-line antibiotics chosen as an initial therapy for pulmonary nocardiosis, but this case was successfully treated without SXT. Considering recent reports about failures of both prophylaxis and treatment for nocardial infections with SXT and its various side effects, treatment with beta-lactam antibiotics and minocycline for pulmonary nocardiosis can be chosen in mild to moderate cases with confirmed susceptibility to these antibiotics in vitro.

Nocardia iowensis sp. nov., an organism rich in biocatalytically important enzymes and nitric oxide synthase

Nocardia strain NRRL 5646, isolated from a garden soil sample in Osceola, Iowa, USA, was initially of interest as an antibiotic producer. It contained biocatalytically important enzymes and represented the first described nitric oxide synthase enzyme system in bacteria. The present polyphasic taxonomic study was undertaken to differentiate strain NRRL 5646(T) from related species of the genus Nocardia. Chemotaxonomic analyses included determinations of the fatty acid methyl ester profile (C(16 : 1)omega6c/C(16 : 1)omega7c, C(16 : 0), C(18 : 1)omega9c and C(18 : 0) 10-methyl as major components), quinone [cyclo MK-8(H(4)) as the major component], polar lipid (diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside as major components) and mycolic acid. These results supported its placement within the genus Nocardia. Biochemical testing and 16S rRNA, 65-kDa heat-shock protein (hsp65) and preprotein translocase (secA1) gene sequence analyses differentiated strain NRRL 5646(T) from recognized Nocardia species. Previous studies have demonstrated that other genetic sequences (carboxylic acid reductase, Nocardia phosphopantetheinyl transferase and GTP cyclohydrolase I) from strain NRRL 5646(T) can also be used to substantiate its uniqueness. The level of 16S rRNA gene sequence similarity between strain NRRL 5646(T) and the type strains of Nocardia tenerifensis and Nocardia brasiliensis was 98.8 %. However, strain NRRL 5646(T) could be clearly distinguished from these Nocardia species based on DNA-DNA hybridization data. Consequently, strain NRRL 5646(T) is considered to represent a novel species of the genus Nocardia, for which the name Nocardia iowensis sp. nov. is proposed. The type strain is NRRL 5646(T) (=UI 122540(T)=NRRL B-24671(T)=DSM 45197(T)).

Pulmonary nocardiosis: risk factors, clinical features, diagnosis and prognosis

PURPOSE OF REVIEW

Pulmonary infection by Nocardia spp. has been recognized for the past 100 years. The number of cases of pulmonary nocardiosis reported in the literature is increasing, and in some cases, a diagnosis is reached even postmortem. This increase is partly due to the growing number of patients with depressed cellular immunity. The diagnosis of this infection, which has a high rate of mortality, is usually delayed, due to a nonspecific clinical-radiological presentation and the difficulties in cultivating the bacteria. This review analyzes the current situation, in order to better understand this infection and enhance awareness and clinical suspicion that would lead to further specific microbiological studies and treatment.

RECENT FINDINGS

The number of case series in the literature is increasing. This development may be due to an absolute increase in the number of immunocompromised patients, but also to improvements in laboratory techniques and molecular methods to detect nocardiosis.

SUMMARY

It is important to keep in mind, and suspect the presence of pulmonary nocardiosis in the immunodepressed patients with clinical pulmonary infection. Furthermore, the laboratory should be notified when Nocardia is suspected in a clinical specimen so that measures can be taken to optimize recognition and recovery of the organism.

Nocardia amamiensis sp. nov., isolated from a sugar-cane field in Japan

An actinomycete, strain TT 00-78T, was isolated from soil from a sugar-cane field on Amami Island in Japan, using an SDS/yeast extract pre-treatment method, and the taxonomy was studied using a polyphasic approach. The chemotaxonomic and morphological characterizations clearly demonstrated that the strain belongs to the genus Nocardia. 16S rRNA gene sequencing studies showed that the strain was closely related to the type strains of Nocardia pneumoniae (98.6 %), Nocardia araoensis (98.1 %), Nocardia arthritidis (97.9 %) and Nocardia beijingensis (97.7 %). However, the results of DNA–DNA hybridization and physiological and biochemical tests showed that strain TT 00-78T could be differentiated from its closest phylogenetic relatives both genotypically and phenotypically. Therefore this strain represents a novel species of the genus Nocardia, for which the name Nocardia amamiensis sp. nov. is proposed. The type strain is TT 00-78T (=NBRC 102102T=DSM 45066T=KCTC 19208T).

Nocardia gamkensis sp. nov

A novel actinomycete, strain CZH20(T), was isolated from a soil sample taken from the banks of the Gamka River in the Swartberg Nature Reserve, Western Cape Province, South Africa. Strain CZH20(T) was identified as a member of the genus Nocardia by a polyphasic approach. Strain CZH20(T) could be differentiated from other members of the genus Nocardia on the basis of physiology and 16S-rRNA gene sequence analysis. It exhibited weak antibiosis against Mycobacterium aurum A+. Organic solvent extracts of the culture filtrate and mycelial mass of CZH20(T) exhibited moderate antibiotic activity against Mycobacterium smegmatis LR222 and Mycobacterium tuberculosis H37Rv. The name Nocardia gamkensis is proposed, with the type strain CZH20(T) (=DSM 44956(T) =NRRL B-24450(T)).

Clinical and laboratory features of the Nocardia spp. based on current molecular taxonomy

The recent explosion of newly described species of Nocardia results from the impact in the last decade of newer molecular technology, including PCR restriction enzyme analysis and 16S rRNA sequencing. These molecular techniques have revolutionized the identification of the nocardiae by providing rapid and accurate identification of recognized nocardiae and, at the same time, revealing new species and a number of yet-to-be-described species. There are currently more than 30 species of nocardiae of human clinical significance, with the majority of isolates being N. nova complex, N. abscessus, N. transvalensis complex, N. farcinica, N. asteroides type VI (N. cyriacigeorgica), and N. brasiliensis. These species cause a wide variety of diseases and have variable drug susceptibilities. Accurate identification often requires referral to a reference laboratory with molecular capabilities, as many newer species are genetically distinct from established species yet have few or no distinguishing phenotypic characteristics. Correct identification is important in deciding the clinical relevance of a species and in the clinical management and treatment of patients with nocardial disease. This review characterizes the currently known pathogenic species of Nocardia, including clinical disease, drug susceptibility, and methods of identification.

Nocardia lijiangensis sp. nov., a novel actinomycete strain isolated from soil in China

A novel actinomycete strain YIM 33378T was isolated from a soil sample collected from Lijiang, Yunnan Province, China. Based on the results of phenotypic and genotypic characteristics, strain YIM 33378T should be assigned to a new species of the genus Nocardia, for which the name Nocardia lijiangensis sp. nov. is proposed. The type strain is YIM 33378T (= CCTCC AA 204005T = KCTC 19028T). The GenBank accession number for the sequence reported in this paper is AY779043.

Nocardia concava sp. nov., isolated from Japanese patients

Two actinomycete strains, IFM 0354T and IFM 0576, isolated from Japanese patients, were found to have morphological, biochemical and chemotaxonomic properties consistent with their classification in the genus Nocardia. The strains resembled Nocardia otitidiscaviarum and Nocardia uniformis in their phenotypic properties. Comparative 16S rRNA gene sequence analysis showed that the strains are closely related to Nocardia seriolae. DNA–DNA relatedness values and phenotypic differences from N. seriolae indicated that the strains belong to a novel species of Nocardia, for which the name Nocardia concava sp. nov. is proposed. The type strain is IFM 0354T (=NBRC 100430T=JCM 12351T=DSM 44804T).

Nocardiopsis and Saccharothrix genera in Saharan soils in Algeria: isolation, biological activities and partial characterization of antibiotics

Twenty-five soil samples were collected in the Algerian Sahara and analyzed to isolate rare actinomycetes. Eighty-six isolates with the same Nocardiopsis or Saccharothrix morphology were isolated on humic-vitamin B agar medium using dilution techniques and several antibiotics as selective agents. Certain of these antibiotics seemed to be very selective for some phenotypes. Morphological and chemotaxonomic characteristics led to identifying 54 isolates belonging to the Nocardiopsis genus and 32 isolates belonging to the Saccharothrix genus. An assessment of the antimicrobial properties of the isolates showed activities against Gram-positive bacteria, fungi and yeasts. Saccharothrix isolates possessed better antifungal activity than Nocardiopsis. One of them, labeled SA 103, was therefore selected for identification of its antifungal antibiotic activities. Production of overall antifungal and antibacterial activities was checked on the complex medium ISP2 and a synthetic medium (SM) that contains glucose or starch as carbon source, and ammonium or nitrate as nitrogen source. The SM medium containing ammonium sulfate (0.2%), supplemented with starch (0.5%) and yeast extract (0.3%), was retained for production of antibiotics. Active substances were purified by a G25-80 Sephadex column and reverse phase HPLC. Two pure substances were obtained and named ZA01 and ZA02; they were characterized on the basis of combined data resulting from chemical tests, UV visibile and IR spectra and mass spectrometry. The two antibiotics were found to be related and were partially characterized as nucleotidic or nucleosidic antibiotics. Their structures consisted of a chain of three sugar units linked to an aromatic base containing a phosphate residue.

Nocardia polyresistens sp. nov

A novel actinomycete strain YIM 33361T was isolated from a soil sample collected from Yunnan, China. Comparative 16S rRNA gene sequencing showed that the strain constituted a distinct subclade within the genus Nocardia, displaying more than 3 % sequence divergence from established species. Based on its morphological, chemotaxonomic, phenotypic and genotypic characteristics, strain YIM 33361T (=CCTCC AA 204004T=KCTC 19027T) is proposed as the type strain of a novel species, Nocardia polyresistens sp. nov.

Nocardia shimofusensis sp. nov., isolated from soil, and Nocardia higoensis sp. nov., isolated from a patient with lung nocardiosis in Japan

Three actinomycete strains isolated from soils and one strain isolated from a patient with lung nocardiosis in 1999 and 2001 in Japan have been provisionally assigned to the genus Nocardia on the basis of morphological criteria. These isolates were further investigated to determine their specific taxonomic status. Detailed chemotaxonomic characterization and 16S rRNA gene sequence analysis of these isolates confirmed that they belong to the genus Nocardia. The 16S rRNA gene sequences of the four strains were most similar to that of Nocardia farcinica. However, the sequence similarity values between these four strains and N. farcinica were <98.9 %. These four strains were susceptible to 5-fluorouracil, and they have the ability to decompose urea, which is a very characteristic trait. Furthermore, DNA-DNA relatedness data revealed that IFM 10311(T), IFM 10312 and IFM 10313 comprise a single novel species of Nocardia, that IFM 10084(T) represents another novel species of Nocardia and that these two novel species could be distinguished from N. farcinica. The names Nocardia shimofusensis sp. nov. and Nocardia higoensis sp. nov. are proposed, with IFM 10311(T) (=NBRC 100134(T)=JCM 12122(T)=DSM 44733(T)) and IFM 10084(T) (=NBRC 100133(T)=JCM 12121(T)=DSM 44732(T)) as the respective type strains.

Nocardia araoensis sp. nov. and Nocardia pneumoniae sp. nov., isolated from patients in Japan

Two actinomycete strains isolated from two patients with lung nocardiosis between 1995 and 1997 in Japan were assigned to novel species of the genus Nocardia based on morphological and chemical criteria. Comparative 16S rRNA gene sequence analysis of the two strains revealed that they belong to the genus Nocardia and are most closely related to the species Nocardia beijingensis. Determination of DNA-DNA relatedness indicated that these strains could be assigned to two novel species. Based on their phenotypic and phylogenetic characters, two novel species of the genus Nocardia are proposed: Nocardia araoensis sp. nov. for IFM 0575(T) (=NBRC 100135(T)=JCM 12118(T)=DSM 44729(T)) and Nocardia pneumoniae sp. nov. for IFM 0784(T) (=NBRC 100136(T)=JCM 12119(T)=DSM 44730(T)).

Nocardia aobensis Sp. Nov., isolated from patients in Japan

Five clinical isolates, strains IFM 0137, 0372(T), 0496, 0556, and 0952, were provisionally assigned to the genus Nocardia based on morphological criteria. Nearly complete 16S rDNA sequences were determined for these strains. These data showed that they are most similar to that of Nocardia africana, Nocardia cerradoensis and Nocardia veterana. However, DNA-DNA relatedness data showed that the five strains were of a single species and were distinguishable from N. africana, N. cerradoensis and N. veterana. Therefore, these strains represent a new species within the genus Nocardia. The designation of these five strains is Nocardia aobensis sp. nov. The type strain is IFM 0372(T) (=NBRC 100429(T)=JCM 12352(T)=DSM 44805(T)).

Nocardia takedensis sp. nov., isolated from moat sediment and scumming activated sludge

Chemotaxonomic and morphological characterization of two actinomycete strains, MS1-3T and AS4-2, respectively isolated from moat sediment and scumming activated sludge, was carried out. This characterization clearly demonstrated that strains MS1-3T and AS4-2 belong to the genus Nocardia. 16S rRNA gene sequencing studies showed that these isolates are most closely related to Nocardia beijingensis (98.1-98.3 % similarity), Nocardia brasiliensis (97.9-98.0 %) and Nocardia tenerifensis (97.8-97.9 %). However, the results of DNA-DNA hybridizations and physiological and biochemical tests showed that strains MS1-3T and AS4-2 could be differentiated from their closest phylogenetic relatives both genotypically and phenotypically. It is proposed that the two isolates be classified as representatives of a novel species of Nocardia, Nocardia takedensis sp. nov. The type strain is MS1-3T (=NBRC 100417T=DSM 44801T); AS4-2 (=NBRC 100418=DSM 44802) is a reference strain.

Nocardia pigrifrangens sp. nov., a novel actinomycete isolated from a contaminated agar plate

A polyphasic study was undertaken to establish the taxonomic position of an actinomycete strain isolated from a contaminated agar plate. The strain, designated 7031T, had morphological and chemotaxonomic properties typical of the genus Nocardia. An almost-complete 16S rRNA gene sequence determined for the strain was aligned with available sequences for nocardiae, and phylogenetic trees were inferred using three tree-generating algorithms. Strain 7031T clustered with the type strains of Nocardia carnea and Nocardia flavorosea, showing low 16S rRNA gene sequence similarities to these species (97.2 and 97.5 %, respectively). The strain was also distinguished from the closest species by a range of phenotypic properties. It is proposed that the strain be recognized as a novel species of Nocardia, Nocardia pigrifrangens sp. nov., the type strain of which is 7031T (= AS 4.1808T = JCM 11884T).

Can whole genome analysis refine the taxonomy of the genus Rhodococcus?

The current systematics of the genus Rhodococcus is unclear, partly because many members were originally included before the application of a polyphasic taxonomic approach, central to which is the acquisition of 16S rRNA sequence data. This has resulted in the reclassification and description of many new species. Hence, the literature is replete with new species names that have not been brought together in an organized and easily interpreted form. This taxonomic confusion has been compounded by assigning many xenobiotic degrading isolates with phylogenetic positions but without formal taxonomic descriptions. In order to provide a framework for a taxonomic approach based on multiple genetic loci, a survey was undertaken of the known genome characteristics of members of the genus Rhodococcus including: (i) genetics of cell envelope biosynthesis; (ii) virulence genes; (iii) gene clusters involved in metabolic degradation and industrially relevant pathways; (iv) genetic analysis tools; (v) rapid identification of bacteria including rhodococci with specific gene RFLPs; (vi) genomic organization of rrn operons. Genes encoding virulence factors have been characterized for Rhodococcus equi and Rhodococcus fascians. Based on peptide signature comparisons deduced from gene sequences for cytochrome P-450, mono- and dioxygenases, alkane degradation, nitrile metabolism, proteasomes and desulfurization, phylogenetic relationships can be deduced for Rhodococcus erythropolis, Rhodococcus globerulus, Rhodococcus ruber and a number of undesignated Rhodococcus spp. that may distinguish the genus Rhodococcus into two further genera. The linear genome topologies that exist in some Rhodococcus species may alter a previously proposed model for the analysis of genomic fingerprinting techniques used in bacterial systematics.

Nocardia testaceus sp. nov. and Nocardia senatus sp. nov., isolated from patients in Japan

Two actinomycete strains isolated from sputum between 1999 and 2001 in Japan were provisionally assigned to the genus Nocardia based on morphological criteria. These isolates were further studied in order to determine their specific taxonomic status. Detailed chemotaxonomic characterization and 16S rDNA gene sequence analysis of these isolates also confirmed that they belong to the genus Nocardia. The 16S rDNA sequence data of the two strains showed that they are most similar to that of Nocardia carnea and Nocardia flavorosea. However, DNA-DNA relatedness data showed that the two strains could be distinguished from N. carnea and N. flavorosea and therefore represented two new species within the genus Nocardia. The designation of the two isolated strains are Nocardia testaceus for IFM 0937(T) (=JCM 12235(T), DSM 44765(T)) and Nocardia senatus for IFM 10088(T) (=JCM 12236(T), DSM 44766(T)).

Nocardia arthritidis sp. nov., a new pathogen isolated from a patient with rheumatoid arthritis in Japan

Two different bacterial strains with different drug susceptibilities were isolated from the sputum and an inflammatory discharge from a swelling in the left thigh of a patient with rheumatoid arthritis. Both bacterial strains were provisionally assigned to the genus Nocardia on the basis of their morphological and chemotaxonomic characteristics and were further studied in order to establish their taxonomic status. One strain (IFM 10034) was identified as Nocardia farcinica on the basis of its physiological characteristics. The other strain, which was designated Nocardia sp. strain IFM 10035(T), revealed a unique pattern of phenotypic properties that distinguished it from other representatives of established Nocardia species. Comparative 16S rRNA gene sequence studies of Nocardia sp. strain IFM 10035(T) also showed that the bacterium was closely related to the species Nocardia beijingensis. Determination of DNA-DNA relatedness, however, indicated that Nocardia sp. strain IFM 10035(T) could be delineated from N. beijingensis. The genotypic and phenotypic data combined indicated that the bacterium merits description as a new Nocardia species. The name proposed for the new species is Nocardia arthritidis sp. nov., the type strain being IFM 10035(T) (NBRC 100137(T), JCM 12120(T), DSM44731(T)). The present study suggests that Nocardia infections can be caused by multiple species of the bacterium.

Sequence-based identification of aerobic actinomycetes

We investigated the utility of 500-bp 16S rRNA gene sequencing for identifying clinically significant species of aerobic actinomycetes. A total of 28 reference strains and 71 clinical isolates that included members of the genera Streptomyces, Gordonia, and Tsukamurella and 10 taxa of Nocardia were studied. Methods of nonsequencing analyses included growth and biochemical analysis, PCR-restriction enzyme analysis of the 439-bp Telenti fragment of the 65 hsp gene, susceptibility testing, and, for selected isolates, high-performance liquid chromatography. Many of the isolates were included in prior taxonomic studies. Sequencing of Nocardia species revealed that members of the group were generally most closely related to the American Type Culture Collection (ATCC) type strains. However, the sequences of Nocardia transvalensis, N. otitidiscaviarum, and N. nova isolates were highly variable; and it is likely that each of these species contains multiple species. We propose that these three species be designated complexes until they are more taxonomically defined. The sequences of several taxa did not match any recognized species. Among other aerobic actinomycetes, each group most closely resembled the associated reference strain, but with some divergence. The study demonstrates the ability of partial 16S rRNA gene sequencing to identify members of the aerobic actinomycetes, but the study also shows that a high degree of sequence divergence exists within many species and that many taxa within the Nocardia spp. are unnamed at present. A major unresolved issue is the type strain of N. asteroides, as the present one (ATCC 19247), chosen before the availability of molecular analysis, does not represent any of the common taxa associated with clinical nocardiosis.

Nocardia inohanensis sp. nov., Nocardia yamanashiensis sp. nov. and Nocardia niigatensis sp. nov., isolated from clinical specimens

Comparative 16S rDNA studies on six strains of actinomycete isolated from clinical specimens revealed that they belong to the genus Nocardia and are closely related to Nocardia seriolae, Nocardia otitidiscaviarum, Nocardia uniformis, Nocardia pseudobrasiliensis and Nocardia crassostreae. However, the novel organisms consistently formed a clade distinct from that of the five latter species. Determination of DNA-DNA relatedness indicated that these strains could be classified under three novel species. Based on their phenotypic and phylogenetic characters, three novel species of the genus Nocardia are established: Nocardia inohanensis sp. nov. for IFM 0092(T) (=NBRC 100128(T)=JCM 11891(T)=DSM 44667(T)), Nocardia yamanashiensis sp. nov. for IFM 0265(T) (=NBRC 100130(T)=JCM 11893(T)=DSM 44669(T)) and Nocardia niigatensis sp. nov. for IFM 0330(T) (=NBRC 100131(T)=JCM 11894(T)=DSM 44670(T)), IFM 0260, IFM 0636 and IFM 0833.