Las pruebas fisiologicas y bioquimicas constituyen dos de las principales metodologias utilizadas, principalmente en los laboratoriosde microbiologia, para la identificacion y diferenciacion de los actinomicetos. La finalidad de este trabajo fue comparar y evaluarlos metodos fenotipicos que son utilizados de manera rutinaria en la identificacion de estos microorganismos. Se estudiaron setenta y trescepas de actinomicetos provenientes de tres laboratorios de microbiologia de Venezuela. El comportamiento fisiologico y bioquimico delas cepas en estudio fue evaluado mediante pruebas de descomposicion de diferentes sustratos. Los resultados obtenidos permitieronobservar diferencias en la identificacion preliminar de las cepas realizada por estos laboratorios, conduciendo algunas veces a una nuevaidentificacion de las mismas, gracias a la utilizacion de estos sustratos. Se pudo observar que la metodologia empleada permitio la reclasificaciontaxonomica de casi todas las cepas estudiadas, lo que sugiere que es necesario estandarizar la metodologia de identificacion paralos actinomicetos.

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A novel actinomycete, strain OFN S31(T), was isolated from a complex biofilm in the Altamira Cave, Spain. A polyphasic study was carried out to clarify the taxonomic position of this strain. Phylogenetic analysis with 16S rRNA gene sequences of representatives of the genera Corynebacterium, Dietzia, Gordonia, Millisia, Mycobacterium, Nocardia, Rhodococcus, Segniliparus, Skermania, Tsukamurella and Williamsia indicated that strain OFN S31(T) formed a distinct taxon in the 16S rRNA gene tree that was more closely associated with the Mycobacterium clade. The type strain of Mycobacterium fallax was the closest relative of strain OFN S31(T) (95.6% similarity). The cell wall contained meso-diaminopimelic acid, arabinose and galactose, which are characteristic components of cell-wall chemotype IV of actinomycetes. The sugars of the peptidoglycan were acetylated. The polar lipid pattern was composed of phosphatidylinositol, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Strain OFN S31(T) is characterized by the absence of mycelium and mycolic acids. Strain OFN S31(T) had MK-8 as the major menaquinone. The DNA G + C content was 49.3 mol%, the lowest found among all taxa included in the suborder Corynebacterineae. Based on morphological, chemotaxonomic, phenotypic and genetic characteristics, strain OFN S31(T) is considered to represent a novel species of a new genus, for which the name Hoyosella altamirensis gen. nov., sp. nov. is proposed. The type strain of Hoyosella altamirensis is strain OFN S31(T) (= CIP 109864(T) = DSM 45258(T)).

A novel actinomycete strain, OFN S17(T), was isolated from a sample collected from Altamira Cave, Cantabria, Spain. This strain was identified by using a polyphasic taxonomic approach. The 16S rRNA, hsp65 and sod gene sequences of the strain were determined and compared with those of representative Nocardia species. The results showed that strain OFN S17(T) should be assigned to the genus Nocardia. Phylogenetic analysis indicated that strain OFN S17(T) was most closely related to the type strain of Nocardia tenerifensis (98.6, 96.2 and 96% similarity, respectively, for the 16S rRNA, hsp65 and sod gene sequences). The DNA G+C content was 64.4 mol%. DNA-DNA hybridization analyses revealed 29% relative reassociation between the DNA of strain OFN S17(T) and N. tenerifensis DSM 44704(T). The phenotypic and genotypic data show that strain OFN S17(T) merits recognition as a representative of a novel species of the genus Nocardia, for which the name Nocardia altamirensis sp. nov. is proposed. The type strain is OFN S17(T) (=CIP 109606(T) =DSM 44997(T)).

Las bacterias del genero Nocardia son actinomicetos aerobios cuyo habitat es el suelo y la materia organica en descomposicion. La infeccion natural por especies de este genero ha sido reportada en humanos y animales, sin embargo, la infeccion natural en ratones no ha sido descrita. En este estudio se demuestra por primera vez el aislamiento de la especie recientemente descrita, Nocardia cyriacigeorgica , en pulmones de ratones Balb/c. El estudio microbiologico de las muestras de pulmon reporto la presencia de filamentos grampositivos ramificados fragmentados en forma cocobacilares. Los estudios de PCR demostraron que la especie aislada fue N. cyriacigeorgica Se evidencia en este trabajo que N. cyriacigeorgica es potencialmente patogena en ratones Balb/c.

Le nombre de patients atteints de nocardiose dans le monde est en constante augmentation. En raison de la nature et de la gravité de cette infection, l'identification rapide et précise des Nocardia est capitale. Les techniques conventionnelles de diagnostic (chimiotaxonomiques, biochimiques, physiologiques et morphologiques) ne permettent plus qu'une approche diagnostique présomptive. Des techniques moléculaires d'identification des Nocardia sont actuellement proposées aux laboratoires de microbiologie pour détecter plus rapidement et identifier les différentes espèces de Nocardia.

A Gram-positive and acid-fast filamentous bacterium (OFN 02.72(T)) was isolated from a bronchial aspirate from a 53-year-old patient. Chemotaxonomic data supported the affiliation of this organism to the genus Nocardia, and the phenotypic characteristics demonstrated that the strain differed from all previously described Nocardia species. Restriction enzyme analysis of the hsp65 gene (encoding the 65 kDa heat-shock protein) and sequencing of the 16S rRNA and hsp65 genes confirmed that this isolate is unique. The most closely related type strains were Nocardia alba YIM 30243(T) (=DSM 44684(T)) and Nocardia jejuensis N3-2(T) (=JCM 13281(T)) (with 16S rRNA gene sequence similarities of 98.3 and 97.2 %, respectively). On the basis of this polyphasic study, strain OFN 02.72(T) represents a novel species within the genus Nocardia, for which the name Nocardia ninae sp. nov. is proposed. The type strain is OFN 02.72(T) (=CIP 108955(T)=DSM 44978(T)).

Pulmonary nocardiosis is the major clinical manifestation of human nocardiosis and disseminated infection can be seen in immunocompromised patients. N. asteroides is the predominant pathogen associated with disseminated diseases. We report 2 cases of pulmonary nocardiosis admitted with disseminated infection, caused by rare species of Nocardia: Nocardia transvalensis and Nocardia cyriacigeorgica.