RESUMEN
Twenty-five Burkholderia cepacia-like isolates of human and environmental origin, comprising five different recA RFLP types, were examined by using a polyphasic taxonomic approach, including recA gene sequence analysis, 16S rRNA gene sequence analysis, DNA:DNA hybridisation studies, tDNA-PCR, fatty acid analysis and biochemical analysis. The results of the present study demonstrated that twenty-three of these strains belong to Burkholderia pyrrocinia, a B. cepacia complex species thus far comprising one single soil isolate only. An emended description of Burkholderia pyrrocinia is proposed. The taxonomic status of the remaining two isolates requires further analysis.
Asunto(s)
Complejo Burkholderia cepacia/clasificación , Complejo Burkholderia cepacia/aislamiento & purificación , Técnicas de Tipificación Bacteriana , Infecciones por Burkholderia/microbiología , Complejo Burkholderia cepacia/química , Complejo Burkholderia cepacia/genética , Complejo Burkholderia cepacia/metabolismo , Fibrosis Quística/complicaciones , Fibrosis Quística/microbiología , Dermatoglifia del ADN , ADN Bacteriano/análisis , ADN Bacteriano/química , ADN Bacteriano/aislamiento & purificación , ADN Ribosómico/química , ADN Ribosómico/aislamiento & purificación , Ácidos Grasos/análisis , Genes Bacterianos , Genes de ARNr , Humanos , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Filogenia , Polimorfismo de Longitud del Fragmento de Restricción , ARN Ribosómico 16S/genética , Rec A Recombinasas/genética , Análisis de Secuencia de ADN , Homología de Secuencia , Microbiología del SueloRESUMEN
Three strains of a previously undescribed, Gram-positive, coryneform bacterium, which were isolated from cattle, were subjected to polyphasic taxonomic analysis. Comparative 16S rRNA gene sequencing revealed that the unknown isolates were members of the genus Arthrobacter and were phylogenetically closely related to Arthrobacter luteolus. However, DNA-DNA hybridization indicated that the strains belonged to a new sub-lineage within the genus Arthrobacter. The unknown isolates can be distinguished from related species by biochemical tests. It is proposed that the Arthrobacter-like bacteria of veterinary origin should be classified in the genus Arthrobacter as Arthrobacter gandavensis sp. nov., with the type strain LMG 21285(T) (=DSM 15046(T)).
Asunto(s)
Arthrobacter/clasificación , Bovinos/microbiología , Filogenia , Animales , Arthrobacter/genética , Arthrobacter/aislamiento & purificación , ADN Bacteriano/genética , Datos de Secuencia Molecular , Hibridación de Ácido NucleicoRESUMEN
Nowadays, tentative identification of B. cepacia complex bacteria in routine diagnostic laboratories is based on a combination of selective media, conventional biochemical reactions, commercial test systems and PCR-based assays. Some of these assays have the capacity to discriminate reliably among several members of the B. cepacia complex, however one single method differentiating all B. cepacia-like organisms is not available. In this study, the applicability of tDNA-PCR for the differentiation and rapid identification of the different members of the B. cepacia complex was evaluated. For B. gladioli and most of the B. cepacia genomovars, differentiable patterns were obtained. For some of the members of the B. cepacia complex however, the tDNA-PCR patterns were very similar and sometimes multiple patterns existed within in a single genomovar. No distinction could be made between the tDNA-PCR patterns of B. vietnamiensis and B. pyrrocinia and of B. cepacia genomovars I and VIII respectively. We could conclude that, although tDNA-PCR is not sufficient as a single method to identify all the members of the B. cepacia complex unambiguously or to replace the currently used methods, it is a very fast and easily applicable method that could be a very useful tool for the differentiation and identification of B. cepacia-like organisms.
Asunto(s)
Burkholderia cepacia/clasificación , ADN Intergénico/análisis , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo Genético , ARN de Transferencia/genética , Animales , Infecciones por Burkholderia/microbiología , Burkholderia cepacia/genética , Fibrosis Quística/microbiología , ADN Bacteriano/análisis , Electroforesis Capilar , Microbiología Ambiental , Humanos , Programas InformáticosRESUMEN
The use of Single Base C-Sequencing of the first 500 bases of the 16S rRNA-gene (SBCS) combined with capillary electrophoresis was evaluated for the identification of reference strains of 30 different species within the genus Streptococcus. For SBCS, only dd-CTP's are used in the sequencing reactions instead of the four dideoxy bases and the primer is fluorescently labeled. The reproducibility, interlaboratory exchangeability and discriminative power of this method were studied by comparing the patterns obtained in three laboratories under highly standardized conditions. The interlaboratory reproducibility proved to be high, enabling the construction of a common database for the identification of strains belonging to the streptococcal species studied. Most of the examined species generated distinguishable profiles. SBCS did not differentiate between the closely related species S. constellatus and S. intermedius. Also S. thermophilus and S. vestibularis as well as S. mitis and S. pneumoniae showed highly resembling profiles. The previously reported heterogeneity within the species S. equinus was reflected by SBCS. For all other species, strains belonging to the same species generated indistinguishable patterns. In conclusion, Single Base C-sequencing of the first 500 bases of the 16S rRNA-gene could be a useful and widely applicable method for the identification of bacteria at the species level, with the added advantage of being more rapid and easier to automatize than full sequence determination.
