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Yeasts are emerging as important etiological agents of nosocomial bloodstream infections. A multiplex PCR method was developed to rapidly identify clinically important yeasts that cause fungemia. The method amplified the internal transcribed spacer 1 (ITS1) region between the 18S and 5.8S rRNA genes and a specific DNA fragment within the ITS2 region of Candida albicans. With this method, C. albicans produced two amplicons, whereas other species produced only one. Through sequence analysis, the precise lengths of the PCR products were found to be as follows: C. glabrata (482 or 483 bp), C. guilliermondii (248 bp), C. parapsilosis (229 bp), C. albicans (218 or 219 and 110 bp), C. tropicalis (218 bp), Cryptococcus neoformans (201 bp), and C. krusei (182 bp). The PCR products could be effectively separated by disk polyacrylamide gel electrophoresis. The method was used to test 249 positive blood cultures (255 isolates), from which the following species (strain number) were isolated: C. albicans (128), C. tropicalis (51), C. glabrata (28), C. parapsilosis (23), C. neoformans (9), C. krusei (5), C. guilliermondii (3), and other, minor species (8). The test sensitivity of the method was 96.9% (247 of 255 isolates). The eight minor species were either misidentified (one strain) or not identified (seven strains). From the time at which a positive bottle was found, the multiplex PCR could be completed within 8 h; the present method is simpler than any previously reported molecular method for the identification of blood yeasts.

Nodal‐line semimetals (NLSs) represent a new type of topological semimetallic phase beyond Weyl and Dirac semimetals in the sense that they host closed loops or open curves of band degeneracies in the Brillouin zone. Parallel to the classification of type‐I and type‐II Weyl semimetals, there are two types of NLSs. The type‐I NLS phase has been proposed and realized in many compounds, whereas the exotic type‐II NLS phase that strongly violates Lorentz symmetry has remained elusive. First‐principles calculations show that Mg 3 Bi 2 is a material candidate for the type‐II NLS. The band crossing is close to the Fermi level and exhibits the type‐II nature of the nodal line in this material. Spin–orbit coupling generates only a small energy gap (≈35 meV) at the nodal points and does not negate the band dispersion of Mg 3 Bi 2 that yields the type‐II nodal line. Based on this prediction, Mg 3 Bi 2 single crystals are synthesized and the presence of the type‐II nodal lines in the material is confirmed. The angle‐resolved photoemission spectroscopy measurements agree well with the first‐principles results below the Fermi level and thus strongly suggest Mg 3 Bi 2 as an ideal material platform for studying the as‐yet unstudied properties of type‐II nodal‐line semimetals.

SUMMARYAim: To identify optimal antibiotics for secondline quadruple therapy of Helicobacter pylori after failed 1-week triple therapy. Methods: One hundred patients were enrolled in this study after the failure of 1-week triple therapy. They were randomized to receive 1-week quadruple therapy consisting of amoxicillin, omeprazole and bismuth salts, plus either metronidazole or tetracycline. Before quadruple therapy, the H. pylori culture of each patient was tested for metronidazole resistance or clarithromycin resistance by E-test. Six weeks later, an endoscopy or 13 C-urea breath test was used to define the success of H. pylori eradication.Results: The H. pylori eradication rates by intentionto-treat and per protocol analysis were higher in the tetracycline group than in the metronidazole group (intention-to-treat: 78% vs. 58%, P < 0.05; per protocol: 89% vs. 67%, P < 0.05). In the metronidazole group, but not in the tetracycline group, the per protocol eradication rate of quadruple therapy was lower for the infected isolates with metronidazole resistance than for those without metronidazole resistance (77% vs. 33%, P < 0.05). Conclusion: Quadruple therapy, including tetracycline and amoxicillin, improves the H. pylori eradication rate after failed triple therapy.

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