Enterohemorrhagic Escherichia coli (EHEC) and specifically serotype O157:H7 are a significant cause of hemorrhagic gastrointestinal disease and the hemolytic uremic syndrome. Methods currently used in clinical microbiology labs, such as sorbitol-MacConkey (SMAC) agar, reliably detect only O157:H7. We have evaluated a two-step method that has the potential to identify and isolate all EHEC serotypes, including serotype O157:H7. This method utilizes a chromogenic selective-differential medium for the isolation of E. coli together with an enzyme-linked immunosorbent assay (ELISA) that detects the Shiga-like toxins Stx1 and Stx2. Both are commercially available and usable in a wide range of clinical microbiology laboratories. Compared to a Vero cell cytotoxic assay, SMAC had sensitivities of 23.5% for the identification of all EHEC serotypes and of 50.0% for the identification of O157:H7 alone. The two-step method had sensitivities of 76.5 and 100%, respectively. The ELISA alone had a sensitivity of 82.4% in the detection of Stx1 and Stx2. The specificity was 100% in all cases. Overall, 14 EHEC isolates were obtained: 8 (58%) O157:H7, 2 (14%) O26, 2 (14%) O111:NM, 1 (7%) O103:H2, and 1 (7%) O121:H19. All but one were isolated during the months of May to September. The two-step method was found to be considerably more expensive than SMAC for both positive and negative samples.
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http://dx.doi.org/10.1128/JCM.38.2.547-551.2000 | DOI Listing |
Pharm Stat
January 2025
Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.
A recent study design for clinical trials with small sample sizes is the small n, sequential, multiple assignment, randomized trial (snSMART). An snSMART design has been previously proposed to compare the efficacy of two dose levels versus placebo. In such a trial, participants are initially randomized to receive either low dose, high dose or placebo in stage 1.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China. Electronic address:
Hydrogel-based flexible electronic devices have garnered significant attention due to their excellent mechanical properties, high electrical conductivity, and signal sensitivity. Nevertheless, internal water molecules crystallize inevitably at low temperatures, impairing the performance of hydrogels. Designing anti-freezing and tough hydrogels to meet long-term stability requirements is extremely challenging.
View Article and Find Full Text PDFLangmuir
January 2025
ESYCOM, CNRS-UMR 9007, Université Gustave Eiffel, F-77454 Marne-la-Vallée, France.
This study investigates the synthesis, characterization, and functional properties of well-aligned zinc oxide (ZnO) nanowires (NWs) obtained by a two-step hydrothermal method. ZnO NWs were grown on silicon substrates precoated with a ZnO seed layer. The growth process was conducted at 90 °C for different durations (2, 3, and 4 h) to examine the time-dependent evolution of the nanowire properties.
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Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Anal Chem
January 2025
Analytical Chemistry Group, ‡VI-NEXT Group, Regeneron Pharmaceuticals, Inc., Tarrytown, New York 10591-6706, United States.
Phosphorothioate (PS) modifications in single-guided RNA (sgRNA) are crucial for genome editing applications using the CRISPR/Cas9 system. These modifications may enhance sgRNA stability, pharmacokinetics, and binding to targets, thereby facilitating the desired genetic alterations. Incorporating multiple PS groups at varying positions may introduce chiral centers into the sgRNA backbone, resulting in a complex mixture of constitutional- and stereoisomers that challenges current analytical capabilities for reliable identification and quantification.
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