First case of cerebral abscess due to a novel Nocardia species in an immunocompromised patient.

We report the first case of cerebral abscess due to a novel species of Nocardia in a heart transplant patient and describe the antimicrobial susceptibility of this isolate. As our patient was intolerant to trimethoprim-sulfamethoxazole, we also discuss alternative therapeutic options in brain abscess due to Nocardia sp.

Cavitary pneumonia caused by Nocardia otitidiscaviarum.

We report a case of cavitary pneumonia caused by N. otitidiscaviarum in a man with diabetes mellitus and thrombocytopenia treated with systemic corticosteroid. Taxonomic identification involved phenotypic testing and molecular identification that was carried out by DNA sequencing of the 16SrRNA gene.

First Spanish case of nocardiosis caused by Nocardia takedensis.

Nocardia takedensis is a recently described species isolated from soil. The first clinical isolate in Japan has recently been reported. This report describes the first clinical isolate of N. takedensis in Spain from a respiratory specimen.

[Nocardia aroensis and lung infection: first case report in Africa ]. / Infection pulmonaire à Nocardia aroensis: première observation en Afrique.

Nocardiosis is a rare disease that is difficult to diagnose. Pulmonary forms are most common in association with a variety of nonspecific symptoms. Up to now isolation of the offending species, i.e., Nocardia aroensis, has been reported only once during the first description in Japan. The purpose of this article is to report the second world case of isolation of the Nocardia aroensis in a 50-year-old immunocompetent African woman.

Antibiotic susceptibility testing and species identification of Nocardia isolates: a retrospective analysis of data from a French expert laboratory, 2010-2015.

OBJECTIVES: Nocardia, a Gram-positive bacterium, is responsible for rare and severe infections. Accurate microbiological data are essential to guide antibiotic treatment. Our primary objective was to describe species identification and results of antimicrobial susceptibility testing (AST) for Nocardia isolates analysed over a 6-year period. Secondary objectives were to study temporal trends in species distribution and AST results. METHODS: We retrospectively analysed results from Nocardia isolates sent between January 2010 and December 2015 to a French laboratory dedicated to Nocardia (Observatoire Français des Nocardioses). Species identification was obtained by amplification and sequencing of a 600-bp fragment of the 16S rRNA gene (for all isolates) and of hsp65 (when required). AST was performed using disk diffusion. RESULTS: We included 793 Nocardia isolates, mostly from the lungs (53.8%). The most frequent species were Nocardia farcinica (20.2%), Nocardia abscessus complex (19.9%) and Nocardia nova complex (19.5%). The proportion of N. farcinica increased significantly over time from 13% in 2010 to 27.6% in 2014. Linezolid, amikacin, trimethoprim-sulfamethoxazole, minocycline and imipenem were the most frequently identified active antibiotics with, respectively, 0% (0/734), 2.9% (21/730), 5.4% (40/734), 9.4% (69/734) and 19.5% (143/732) of isolates not susceptible. Nocardia farcinica was frequently not susceptible to cefotaxime (118/148, 79.7% of the isolates), but only about 5% of Nocardia cyriacigeorgica and N. abscessus complex isolates were not susceptible to cefotaxime. CONCLUSIONS: In this first epidemiological study of Nocardia isolated from human samples in France, N. farcinica was the species most frequently identified and its prevalence increased over time.

[Disseminated nocardiosis in a child with acute lymphoblastic leukemia]. / Nocardiose viscérale disséminée chez un enfant atteint de leucémie aiguë lymphoblastique.

Nocardiosis is a rare infectious disease in children. We report here a disseminated nocardiosis in a child with acute lymphoblastic leukemia. The patient presented prolonged febrile neutropenia and nodular pneumopathy. Based on the amplification of a 16S rDNA, a PCR assay detected Nocardia sp. in the patient's bronchoalveolar lavage (BAL) fluid. Culture of BAL samples yielded Nocardia nova colonies after 2 weeks of incubation. Hepatic, splenic, renal and cerebral localisations were detected on extension checkup. trimethoprime-sulfamethoxazole and amikacine were started given the results of PCR assay, with a good response. Improvement of the patient's general condition led to complete chemotherapy under ciprofloxacine and ceftriaxone treatment, without nocardiosis reactivation. Nocardiosis is a rare complication in children with acute lymphoblastic leukemia. trimethoprime-sulfamethoxazole prophylaxis is widely used to prevent Pneumocystis jiroveci infection in children with haematologic malignancies. As Nocardia species are usually sensible, trimethoprime-sulfamethoxazole could play a role in Nocardia prophylaxis in such population. In our patient, compliance with trimethoprime-sulfamethoxazole had been low. Nocardia species are relatively fastidious growth bacteria and are difficult to isolate with classical bacteriological techniques. Molecular methods are now available, with a good sensitivity and fast results allowing to start an appropriate antibiotherapy before culture results, as early treatment is a major prognosis factor in nocardiosis. Nocardia infection should be suspected in case of nodular pneumopathy in immunocompromised children. An extension checkup should be performed to detect secondary localisations.

High Intraspecific Genetic Diversity of Nocardia brasiliensis, a Pathogen Responsible for Cutaneous Nocardiosis Found in France: Phylogenetic Relationships by Using sod and hsp65 Genes.

This study aims at genetic characterization and phylogenetic relationships of Nocardia brasiliensis focusing by using housekeeping rrs, hsp65, and sodA genes. N. brasiliensis is the species responsible for 80% of cases of actinomycetoma, one form of cutaneous nocardiosis which occurs mainly in tropical regions reaching immunocompetent patients in which the disease can lead to amputation. We analyze 36 indigenous cases of N. brasiliensis that happened in France. Phylogenetic analysis targeting rrs gene showed no robustness at phylogenetic nodes level. However, the use of a concatenation of hsp65 and sodA genes showed that the tested strains surprisingly ranked in 3 well-defined genotypes. Genotypes 2 and 3 were phylogenetically closer to each other and both diverged from genotype 1 sustained by a high bootstrap of 81%. This last genotype hosts all the cases of pulmonary forms (3), the sole cerebral form, and almost all the cases of immunocompromised patients (3 out of 4). Moreover, excepting one of them, all the strains belonging to this group present a susceptibility to imipenem which is not the case in the other genotypes that rarely count among them strains being susceptible to this drug. The haplotype diversity (Hd) of hsp65 (0.927) and sodA (0.885) genes was higher than that of rrs (0.824). For this gene, we obtained 16 polymorphic sites whereas, for hsp65 and sodA genes, up to 27 and 29 were identified, respectively. This study reveals that these two genes have an important genetic discriminatory power for the evaluation of the intraspecies genetic variability of N. brasiliensis and they may be useful for identification purposes at species level. This study also reveals the possible existence of a new species harbored by genotype 1.

[Imported mycosis: a review of paracoccidioidomycosis]. / Mycoses d'importation: le point sur la paracoccidioïdomycose.

Population migration is increasing the number of systemic mycosis cases, a condition little or not present in Metropolitan France, thus often weakly documented for medical teams. Paracoccidioidomycosis is a systemic mycosis geographically confined to Latin America. The causative agent is Paracoccidioides brasiliensis, a dimorphic fungus present at ground level. Discovering that the armadillo was a new host allowed documenting the ideal conditions for this fungus development. The mortality rate is currently 1.45 for one million people and the disease affects mainly farmers. The mode of infection is respiratory and all organs and mucous membranes can be affected by lymphatic dissemination. The chronic form with pulmonary, cutaneous and oral lesions is the most important. The diagnosis can be carried out by direct examination of samples revealing the presence of budding yeasts, as well as culture at 25 and 37 degrees C. Antifungals like the sulfamethoxazole-trimethoprime combination, amphotericin B, but especially azole derivatives are use in the therapeutic management of patients. Detection and gp 43 antigen assay is useful for the patient's follow-up.

Molecular identification of Nocardia species using the sodA gene: Identificación molecular de especies de Nocardia utilizando el gen sodA.

Currently for bacterial identification and classification the rrs gene encoding 16S rRNA is used as a reference method for the analysis of strains of the genus Nocardia. However, it does not have enough polymorphism to differentiate them at the species level. This fact makes it necessary to search for molecular targets that can provide better identification. The sodA gene (encoding the enzyme superoxide dismutase) has had good results in identifying species of other Actinomycetes. In this study the sodA gene is proposed for the identification and differentiation at the species level of the genus Nocardia. We used 41 type species of various collections; a 386 bp fragment of the sodA gene was amplified and sequenced, and a phylogenetic analysis was performed comparing the genes rrs (1171 bp), hsp65 (401 bp), secA1 (494 bp), gyrB (1195 bp) and rpoB (401 bp). The sequences were aligned using the Clustal X program. Evolutionary trees according to the neighbour-joining method were created with the programs Phylo_win and MEGA 6. The specific variability of the sodA genus of the genus Nocardia was analysed. A high phylogenetic resolution, significant genetic variability, and specificity and reliability were observed for the differentiation of the isolates at the species level. The polymorphism observed in the sodA gene sequence contains variable regions that allow the discrimination of closely related Nocardia species. The clear specificity, despite its small size, proves to be of great advantage for use in taxonomic studies and clinical diagnosis of the genus Nocardia.

Actualmente, para la identificación y clasificación bacteriana se utiliza como método de referencia la secuenciación el gen rrs que codifica al rRNA16S, en el caso del análisis de cepas del género Nocardia, sin embargo, no tiene el suficiente polimorfismo para diferenciarlas a nivel de especie lo que hace necesaria la búsqueda de blancos moleculares que puedan proporcionar una mejor identificación. El gen sodA (que codifica la enzima superóxido dismutasa) ha tenido buenos resultados en la identificación de especies de otros Actinomicetos. En este estudio se propone para la identificación y diferenciación a nivel de especie del género Nocardia. Se utilizaron 41 especies Tipo de diversas colecciones, se amplificó y secuenció un fragmento de 386 pb del gen sodA y se realizó un análisis filogenético comparando los genes rrs (1171 pb) hsp65(401pb) secA1 (494pb), gyrB (1195pb) y rpoB (401pb), las secuencias fueron alineadas utilizando el programa Clustal X, los árboles evolutivos de acuerdo con el método de "Neighbor-Joining"se hicieron con el programa Phylo_win y Mega 6. Se analizó la variabilidad específica del gen sodA del género Nocardia presentando una alta resolución filogenética, una variabilidad genética importante, especificidad y confiabilidad para la diferenciación de los aislados a nivel de especie. El polimorfismo observado en la secuencia del gen sodA contiene regiones variables que posibilitan la discriminación de especies de Nocardia estrechamente relacionadas, y una clara especificidad, a pesar de su pequeño tamaño, demostrando ser de gran ventaja para utilizarse en estudios taxonómicos y en el diagnóstico clínico del género Nocardia.

Nocardiosis in a teaching hospital in the Central Anatolia region of Turkey: treatment and outcome.

Predisposing factors, antimicrobial susceptibility patterns, treatment and outcome were analysed for nine consecutive patients with nocardiosis. Predisposing factors were identified in six (67%) of the nine patients. Clinical syndromes of nocardial infection were pulmonary infection (three patients), cerebral infection (five patients) and disseminated infection (one patient). The predominant (60%) species was Nocardia farcinica rather than the Nocardia asteroides complex. Treatment was started empirically, modified according to the antimicrobial susceptibility pattern, and then continued for 6-12 months. Overall mortality was 33%, with death being caused by the Nocardia infection in two cases.

Immunodiagnosis of nocardiosis.

A specific immunodominant 54-kDa antigen was purified from a culture filtrate of Nocardia asteroides by immunoaffinity chromatography. The chromatography column was prepared with immunoglobulin G obtained from sera from patients with lepromatous leprosy. Unbound solutes consisted of specific, partially purified N. asteroides antigens, primarily a 54-kDa band, accompanied by two others of 31 and 62 kDa. The Western blot (immunoblot) technique was applied to detecting the immunologic response to nocardiae in the serum of nocardiosis patients. Each of the serum samples from immunosuppressed or immunocompetent patients infected with N. asteroides reacted with the 54-kDa band, and two reacted with the 31- and 62-kDa bands. There was no reaction to either the 54- or the 31-kDa antigen with all serum samples obtained from patients with tuberculosis, except for one, with all serum samples obtained from patients with leprosy, or with all sera obtained from healthy controls. The partially purified 54-kDa antigen, specific for N. asteroides, was used as the immunogen to generate monoclonal antibodies (mAbs) and two mAbs were selected. As determined by Western blot, both mAbs reacted with the 54-kDa band. Using indirect immunofluorescence or enzyme immunoassay with whole N. asteroides micro-organisms, the mAbs did not react with N. asteroides cells. No cross-reactivity with mycobacterial antigens, either culture-filtrate antigens or tuberculin, was exhibited with any of the two mAbs. These mAbs are candidates to be used for the development of a sensitive and specific diagnostic test for nocardiosis.

Genetic relatedness analysis of nocardia strains by random amplification polymorphic Dna: validation and applications.

Until now, no simple and rapid technique existed for epidemiological study of strains belonging to the Nocardia genus. The application of the arbitrarily primed PCR procedure to generate randomly amplified polymorphic DNA (RAPD) fingerprints for such analysis of Nocardia isolates was investigated. Fifty-one unrelated clinical isolates of N. asteroides were tested. Two conditions of RAPD using two different primers generated RAPD fingerprints that allowed the differentiation of all strains. The patterns were reproducible and discriminating. The results highlight the diversity of N. asteroides species and confirm that RAPD analysis is a highly valuable tool for studying the epidemiology of the Nocardia genus. Several examples describe the advantage of RAPD analysis for establishing the relationship between isolates from a given patient (long-term infections, coinfections) and from different patients (i.e. during an outbreak). In the future, this technique will help us to investigate the source of infection in cases of nosocomial transmission, to understand the outcome of nocardiosis, and to follow the evolution and acquisition of resistance to Nocardia strains.

A phylogeny of the genus Nocardia deduced from the analysis of small-subunit ribosomal DNA sequences, including transfer of Nocardia amarae to the genus Gordona as Gordona amarae comb. nov.

According to phylogenetic analyses of nearly complete small-subunit ribosomal DNA sequences, the genus Nocardia should not comprise the two species Nocardia petroleophila and Nocardia amarae. N. amarae should be reassigned to the genus Gordona as Gordona amarae. All of the other Nocardia species form a monophyletic unit, closely related to species of the genus Rhodococcus. It is proposed to revive the name 'CMN' to comprise the genera Corynebacterium, Tsukamurella, Mycobacterium, Gordona, Rhodococcus and Nocardia that form a well identified and monophyletic unit. They are all characterized by a cell wall chemotype IV with mycolic acids.

Occurrence of plasmids in pathogenic strains of Nocardia.

The purpose of the present study was to determine the relative distribution of plasmids in 87 clinical isolates of Nocardia, belonging to the five major pathogenic species. A correlation between plasmid content and the site of infection within the host, resistance to antibiotics and enzymic profiles was also investigated. The plasmid extraction procedure of Kado and Liu was used. Electrophoretic analysis revealed one-to-four plasmid bands, ranging in size from <8 to >50 kb, in 27 strains (31%). Based on the number of isolates tested, the incidence of plasmid-bearing strains was significantly higher among N. farcinica than N. asteroides strains. Within N. farcinica, the incidence of plasmids was higher among strains isolated in the Paris area than in strains isolated elsewhere, such as in the French provinces or outside France. A statistically significant correlation was demonstrated between the cutaneous localisation of infections and the incidence of plasmid-bearing strains. The presence of plasmids in nocardiae could not be associated with specific phenotypic traits such as resistance to antibiotics or enzymic activity. The fact that the majority of Nocardia clinical isolates (60 of 87) did not contain plasmids suggests that plasmids are not involved directly in virulence and that there is no selective pressure for plasmid acquisition.

Primary brain abscess with Nocardia otitidiscaviarum in an intravenous drug abuser.

A primary brain abscess with Nocardia otitidiscaviarum in an intravenous drug abuser is reported. Nocardia brain abscess has been reported infrequently and normally only in immunocompromised patients. The lungs are the most common primary focus, but brain abscess may also occur following direct cutaneous inoculation. In this case the clinical presentation was first diagnosed as an astrocytoma. However, N. otitidiscaviarum was isolated from the lesion after emergency craniotomy. In contrast to five cases described previously the patient survived after surgical removal and antibiotic treatment with imipenem and trimethoprim-sulphamethoxazole.

Antimicrobial susceptibility profile of soil isolates of Nocardia asteroides from Kuwait.

OBJECTIVES: To find the antimicrobial susceptibility profile of 42 soil isolates of Nocardia asteroides against 14 antimicrobial agents representing beta-lactams, aminoglycosides, ciprofloxacin, minocycline, erythromycin and third generation cephalosporins. METHODS: The antimicrobial susceptibility was determined by the disk diffusion method using Mueller-Hinton agar medium. A homogeneous suspension giving an inoculum of 106-108 CFU/mL was used to streak the plates. The zone of inhibition was read after 36-48 h of incubation at 37 degrees C. RESULTS: All the soil isolates of N. asteroides were susceptible to amikacin, imipenem and tobramycin. Susceptibility to cephalosporins was quite variable; 86% of the isolates were susceptible to cefotaxime, 57% to ceftriaxone and 40% to cefamandole. Fifty-seven per cent of the isolates showed intermediate susceptibility to cefamandole, 33% to ceftriaxone and 5% to cefotaxime. Ninety-three per cent of the isolates were resistant to sulfamethoxazole alone or in combination with trimethoprim. CONCLUSIONS: The study reports a wide variation in the antimicrobial susceptibility profile of soil isolates of N. asteroides originating from a single geographical area. Of interest is the finding that over 90% of N. asteroides isolates were resistant to sulfamethoxazole without any previous exposure to this drug. This may have serious therapeutic implications as sulphonamides or the combination of trimethoprim-sulfamethoxazole is the therapy of choice for nocardiosis. Demonstration of resistance to beta-lactam antibiotics may be attributed to the presence of beta-lactamases which was detectable in > 90% of the soil strains of N. asteroides. The study underscores the importance of antimicrobial susceptibility testing for clinical isolates of Nocardia since individual strains show considerable differences in their susceptibility patterns necessitating therapeutic adjustments.

Widespread nocardiosis in two patients with Behçet's disease.

Nocardia spp., a group of gram-positive variably acid-fast aerobic bacteria, are opportunistic pathogens in immunocompromised hosts. We here-within describe 2 cases of widespread nocardiosis in patients with Behcet's disease. In addition to endogen endophthalmitis in case 1, both cases developed lung, brain and skin involvement. Despite brain involvement, the prognosis was good, although vision was completely lost in case 1, which was directly attributable to a delay in both diagnosis and treatment.

[Nocardia infections: clinical and biological aspects]. / Clinique et biologie de la nocardiose.

The nocardiosis is an infection caused by a bacterial pathogen agent, Nocardia, belonging to the Actinomycetales order. They are Gram-positive, strictly aerobic bacteria. Members of the genus Nocardia are ubiquitous. They are frequently isolated from soil, water, air dusts. The mode of contamination occurs by inhalation or by cutaneous or ocular traumatic lesion. Clinically, nocardiosis is essentially characterized by pulmonary diseases. Others secondary localizations are described, such as in the central nervous system. Nocardia can be responsible for important cutaneous, subcutaneous and lymphocutaneous manifestations. In the same way, some extrapulmonary diseases and spread nocardiosis are more rarely observed. Several factors seem to favour the development of Nocardia. The immunocompromised patients, particularly those with organ transplant and the patients treated with immunosuppressor treatments, offer strong predispositions to this opportunistic disease. The nocardiosis is nevertheless observed in healthy persons. In front of polymorphic and specific-less clinical manifestations, large phenotypic heterogeneity, and resistance profiles to specific antibiotics, a correct diagnosis for Nocardia species is necessary to apply an adequate treatment. The techniques of identification based on the chemotaxonomic analysis and the susceptibility to different inhibitors are efficient for the identification of genus and species. However, because of the slow growth rate of Nocardia, the reading of these tests can require several weeks of incubation. With the intention of the rapid identification of genus and species, the molecular techniques (PCR-RFLP) seem to be efficient. The technique of RAPD allows an efficient molecular typing, which will give a better knowledge concerning transmission, ecological niches and epidemic reservoirs.

Are Streptomyces bacteria involved in the ciguatoxicity of the surgeon fish Ctenochaetus striatus?

Several Streptomyces strains have been isolated from the digestive tract of the herbivorous fish C. striatus, a preeminent ciguateric fish of Polynesian waters. In order to study the possible role played by these bacteria in the toxicity of this fish, the quantitative and qualitative distributions of these isolates within toxic and non toxic fish are compared. The preliminary results are discussed.

[Disseminated infection due to an unusual strain of Nocardia farcinica]. / Infection disséminée due à un germe inhabituel, Nocardia farcinica.

Nocardia farcinica, isolated by Nocard in 1888, has recently been redefined as a separate species to asteroides and has been recognised as human pathogen since 1975. Following airborne contamination, lung infection is most usual with frequent dissemination especially to central nervous system. Usually drug resistance makes treatment difficult. The authors describe the first case of Nocardia farcinica disseminated infection in France with lung primarily affection, empyema and encephalitis.