RESUMO
During the past decade, the clinically relevant genus Prevotella has expanded considerably. Prevotella species can be isolated from nearly all types of oral infections but also from various non-oral infections. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been introduced in clinical microbiology laboratories as a convenient method for identifying bacterial isolates from clinical specimens. Here we tested the diagnostic accuracy of a total of 123 oral Prevotella isolates, selected based on their biochemical profile, by Bruker MALDI-TOF MS. Partial 16S rRNA sequencing was used as a reference method. The performance of MALDI-TOF MS to identify the isolates to the genus level was excellent with 100.0% accuracy, while a good identification rate of 88.6% was achieved to the species level with a log score of ≥2.0. The isolates representing P. aurantiaca and P. jejuni, which are currently missing from the MALDI BioTyper database, were identified correctly to the genus level. Of the 123 isolates, one P. pallens isolate (0.8%) was identified with a score variation of 1.7-1.999. Overall, biochemical testing produced a high proportion (70.7%) of incorrect identifications within different species. MALDI-TOF MS offers a reliable and rapid method for the identification of Prevotella species included in the database.
Assuntos
Técnicas Bacteriológicas/métodos , Prevotella/química , Prevotella/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Humanos , Prevotella/classificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Peptostreptococcus anaerobius sensu lato, currently including two closely related species, P. anaerobius and P. stomatis, is known to be more resistant than other gram-positive anaerobic cocci. We reidentified potential Peptostreptococcus isolates and tested their susceptibilities to eight antimicrobials. Notably, P. anaerobius had constantly higher values for the MIC at which 50% of the isolates are inhibited (MIC(50)) and the MIC(90) than P. stomatis.
Assuntos
Antibacterianos/farmacologia , Bacteriemia/microbiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Peptostreptococcus/classificação , Peptostreptococcus/efeitos dos fármacos , Anaerobiose , Humanos , Testes de Sensibilidade Microbiana/normas , Peptostreptococcus/crescimento & desenvolvimento , Peptostreptococcus/isolamento & purificação , Especificidade da EspécieRESUMO
Two groups of previously unknown Gram-negative, strictly anaerobic, pigment-producing, rod-shaped bacteria, which phenotypically and phylogenetically displayed a close association with the recently described species Alistipes finegoldii, were characterized using phenotypic and molecular taxonomic methods. A 16S rRNA gene sequence divergence of approximately 3 % between the two unknown bacteria and A. finegoldii, as well as distinguishable biochemical characteristics, demonstrates that these organisms are genotypically and phenotypically distinct and that each group represents a previously unknown subline within the genus Alistipes. Chromosomal DNA-DNA reassociation studies further confirmed the separateness of the unidentified bacteria and A. finegoldii. On the basis of the phenotypic and phylogenetic findings, two novel species, Alistipes onderdonkii sp. nov. and Alistipes shahii sp. nov., are proposed. The type strains of A. onderdonkii and A. shahii are WAL 8169(T) (=CCUG 48946(T)=ATCC BAA-1178(T)) and WAL 8301(T) (=CCUG 48947(T)=ATCC BAA-1179(T)), respectively; their DNA G+C contents are 58 and 56 mol%, respectively.