eThe use of oral vancomycin or metronidazole for treatment of Clostridium difficile infection (CDI) may promote colonization by health care-associated pathogens due to disruption of the intestinal microbiota. Because the macrocyclic antibiotic fidaxomicin causes less alteration of the intestinal microbiota than vancomycin, we hypothesized that it would not lead to a loss of colonization resistance to vancomycin-resistant enterococci (VRE) and extended-spectrum-␤-lactamase-producing Klebsiella pneumoniae (ESBL-Kp). Mice (8 per group) received orogastric saline, vancomycin, or fidaxomicin daily for 5 days at doses resulting in stool concentrations in mice similar to those measured in humans. The mice were challenged with 10 5 CFU of orogastric VRE or ESBL-Kp on day 2 of treatment and concentrations of the pathogens in stool were monitored. The impact of drug exposure on the microbiome was measured by cultures, real-time PCR for selected anaerobic bacteria, and deep sequencing. In comparison to saline controls, oral vancomycin promoted establishment of high-density colonization by VRE and ESBL-Kp in stool (8 to 10 log 10 CFU/g; P < 0.001), whereas fidaxomicin did not (<4 log 10 CFU; P > 0.5). Vancomycin treatment resulted in significant reductions in enterococci, Bacteroides spp., and Clostridium leptum, whereas the population of aerobic and facultative Gramnegative bacilli increased; deep-sequencing analysis demonstrated suppression of Firmicutes and expansion of Proteobacteria during vancomycin treatment. Fidaxomicin did not cause significant alteration of the microbiota. In summary, in contrast to vancomycin, fidaxomicin treatment caused minimal disruption of the intestinal microbiota and did not render the microbiota susceptible to VRE and ESBL-Kp colonization.O ral vancomycin and oral metronidazole are the most commonly used antibiotics for treatment of Clostridium difficile infection (CDI). One limitation of these agents is that they are nonselective (i.e., they inhibit normal anaerobic intestinal microbiota in addition to C. difficile) (1-4). For example, oral vancomycin treatment may result in suppression of Bacteroides/Prevotella, Clostridium coccoides, and Clostridium leptum group organisms in stool (2, 3). Inhibition of the anaerobic microbiota by vancomycin and metronidazole during CDI treatment may contribute to recurrences of CDI and to colonization by health care-associated pathogens such as vancomycin-resistant enterococci (VRE) (4, 5).Fidaxomicin is a macrocycle antibiotic approved by the Food and Drug Administration for the treatment of CDI (1). In comparison to vancomycin, fidaxomicin causes minimal disruption of the anaerobic microbiota and in clinical studies was associated with fewer recurrences of CDI and less frequent acquisition of VRE and Candida spp. during CDI treatment (1, 6). Given the relative sparing of the microbiota during fidaxomicin treatment, we hypothesized that this agent would not lead to a loss of colonization resistance to VRE and extended-spectrum-␤-lactamaseproducing Kleb...

Light insufficient stress caused by canopy interception and mutual shading is a major factor limiting plant growth and development in intensive crop cultivation. Supplemental lighting can be used to give light to the lower canopy leaves and is considered to be an effective method to cope with low irradiation stress. Leaf photosynthesis, stomatal regulation, and plant growth and development of young tomato plants were examined to estimate the effects of supplemental lighting with various composite spectra and different light orientations. Light-emitting diodes (LEDs) of polychromatic light quality, red + blue (R/B), white + red + blue (W/R/B), white + red + far-red (W/R/FR), and white + blue (W/B) were assembled from the underneath canopy or from the inner canopy as supplemental lighting resources. The results showed that the use of supplemental lighting significantly increased the photosynthetic efficiency, and reduced stomatal closure while promoting plant growth. Among all supplemental lighting treatments, the W/R/B and W/B from the underneath canopy had best performance. The different photosynthetic performances among the supplemental lighting treatments are resulted from variations in CO2 utilization. The enhanced blue light fraction in the W/R/B and W/B could better stimulate stomatal opening and promote photosynthetic electron transport activity, thus better improving photosynthetic rate. Compared with the inner canopy treatment, the supplemental lighting from the underneath canopy could better enhance the carbon dioxide assimilation efficiency and excessive energy dissipation, leading to an improved photosynthetic performance. Stomatal morphology was highly correlated to leaf photosynthesis and plant development, and should thus be an important determinant for the photosynthesis and the growth of greenhouse tomatoes.

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Alkynol served as an enolizable carbonyl equivalent to react with (thio)urea and aromatic aldehydes, furnishing a variety of spirofuran-hydropyrimidinone compounds in good yields and excellent diastereoselectivities. The one-pot multicomponent reactions were realized with co-catalysis of palladium chloride and trifluoroacetic acid through a Biginelli-like tandem reaction pathway.

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