PubMed · 10658762
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T L Pitt. 1999. Molecular typing in practice.. https://doi.org/10.1016/s0195-6701(99)90069-5
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Two novel aerobic bacterial strains, designated SGZ-38T and sgz301269T, were isolated from the root of Pennisetum sp. and paddy soil, respectively. Strain SGZ-38T grew at 10-40 ℃ (optimum 30 °C) and pH 5.0-12.0 (optimum 6.5) and tolerated up to 1.0% NaCl (w/v), whereas strain sgz301269T grew at 15-37 °C (optimum 30 °C), pH 5.0-9.5 (optimum 7.0) and 0-2% NaCl (optimum 0%). Phylogenetic trees based on the 16S rRNA gene and genomes placed both strains into distinct lineages, forming separated clades from their closest relatives. Strain SGZ-381T exhibited the highest 16S rRNA gene similarities to "Neorhizobium deserti" ACCC 61627T (97.4%), and strain sgz301269T had the highest 16S rRNA gene sequence similarity to Neotabrizicola shimadae N10T (97.6%). The respiratory quinone in both strains was ubiquinone-10. The main fatty acids of SGZ-381T were Summed feature 8, Summed feature 2 and C16:0, whereas strain sgz301269T included C10:0 3OH, C18:0 3OH and Summed feature 8. The DNA G+C content of SGZ-381T and sgz301269T was 62.1% and 65.5%, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between each strain and their respective closest species were 74.6% and 20.1%, 75.3% and 17.4% respectively, below the thresholds for species delineation. Based on the comprehensive chemotaxonomic, phylogenetic, and phenotypic evidence, proposed names of the novel strains are Neorhizobium fuzhouense sp. nov. (type strain SGZ-381T=GDMCC1.4207T=JCM 36770T), Neotabrizicola paludis sp. nov. (type strain sgz301269T=MCCC 1K09178T=KCTC 8856T).
A nonfluorescent low-cost, low-density oligonucleotide array was designed for detecting the whole coronavirus genus after reverse transcription (RT)-PCR. The limit of detection was 15.7 copies/reaction. The clinical detection limit in patients with severe acute respiratory syndrome was 100 copies/sample. In 39 children suffering from coronavirus 229E, NL63, OC43, or HKU1, the sensitivity was equal to that of individual real-time RT-PCRs.
Alpha-hemolytic streptococci are very difficult to identify by phenotypic methods. In this study, a pyrosequencing method for the identification of streptococcal species based on two variable regions of the 16S rRNA gene is described. Almost all studied streptococcal species (n = 51) represented by their type strains could be differentiated except for some closely related species of the Streptococcus bovis or S. salivarius group. The pyrosequencing results of alpha-hemolytic streptococci isolated from blood (n = 99) or from the normal pharyngeal microbiota (n = 25) were compared to the results obtained by the VITEK 2 with GP card (bioMérieux, Marcy l'Etoile, France). As expected, the results of the two methods did not completely agree, but 93 (75.0%) of the isolates assigned to the same streptococcal group by both methods and 57 (46.0%) reached consistent results at the species level. However, 10 strains remained unidentified by VITEK 2, and 4 isolates could not be assigned to any streptococcal group by pyrosequencing. Identification of members of the S. mitis and S. sanguinis groups proved difficult for both methods. Furthermore, the pyrosequencing analysis revealed great sequence variation, since only 43 (32.3%) of the 133 isolates analyzed by pyrosequencing had sequences identical to a type strain. The variation was greatest in the pharyngeal isolates, slightly lower in the blood culture isolates, and nonexistent in invasive pneumococcal isolates (n = 17) that all had the S. pneumoniae type strain sequence. The resolution of the results obtained by the two methods is impeded by the lack of a proper gold standard.