These observations support the application of gyrB analyses for differentiating and identification of the species of Stenotrophomonas. Furthermore, these results lend support to the notion that many strains identified as S. maltophilia, often on the basis of limited or inadequate data, in fact represent distinct species. Further investigations of gyrB variation within the ‘S. maltophilia complex’, as well as among all the species of the genus, will be necessary to evaluate the full potential of this

taxonomic and identification tool. However, the low gyrB similarities between some strains with very high 16S rRNA gene sequence similarities offer a caveat to relying too heavily upon 16S rRNA gene sequence analyses for identifications, not only among selleck screening library strains of S. maltophilia, but also between different species of the Stenotrophomonas genus. This study was supported by funding from The Health & Medical Care Committee of the Regional Executive Board, Region Västra Götaland, Sweden (Project Nos. ALFGBG-3238, ALFGBG 11574, VGREG-30781 and VGFOU-72241). “
“Indole is most commonly known as a diagnostic marker and a malodorous chemorepellent. selleck More recently, it has been recognized that

indole also functions as an extracellular signaling molecule that controls bacterial physiology and virulence. The gene (tnaA) for tryptophanase, which produces indole, ammonia, and pyruvate via β-elimination of l-tryptophan, was cloned from Prevotella intermedia ATCC 25611 and recombinant TnaA was purified and enzymatically characterized. Analysis by reverse transcriptase-mediated PCR showed that the gene was not cotranscribed with flanking genes in P. intermedia. The results of gel-filtration chromatography suggested that P. intermedia TnaA forms homodimers, unlike other reported TnaA proteins. Alectinib clinical trial Recombinant TnaA exhibited a Km of 0.23 ± 0.01 mM and kcat of 0.45

± 0.01 s−1. Of 22 Prevotella species tested, detectable levels of indole were present in the culture supernatants of six, including P. intermedia. Southern hybridization showed that tnaA-positive signals were present in the genomic DNA from the six indole-producing strains, but not the other 16 strains tested. The indole-producing strains, with the exception of Prevotella micans, formed a phylogenetic cluster based on trees constructed using 16S rRNA gene sequences, which suggested that tnaA in P. micans might have been transferred from other Prevotella species relatively recently. Strains of the genus Prevotella are strictly anaerobic, non-spore-forming, gram-negative, moderately saccharolytic, bile-sensitive rods that are frequently recovered as members of the polymicrobial flora, including in humans, of the oral, intestinal, and urogenital tracts (Shah & Collins, 1990).