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The discovery of complete ammonia oxidizers (comammox) has dramatically altered our perception of nitrogen (N) biogeochemistry. However, their functional importance vs. the canonical ammonia oxidizers (i.e., ammonia oxidizing-archaea (AOA) and bacteria (AOB)) in agroecosystems is still poorly understood. Accordingly, a new assay using acetylene, 3,4-dimethylpyrazole phosphate (DMPP), and 1-octyne was adopted to assess the ammonia (NH3) oxidation and nitrous oxide (N2O) production activity of these functional guilds in a subtropical Inceptisol under long-term different fertilization regimes. These regimes include CK (no fertilizer control), synthetic fertilizer only (NPK), organic manure only (M) and organic manure plus synthetic fertilizer (MNPK). AOA dominated NH3 oxidation in the M treatment, while AOB dominated both NH3 oxidation and N2O production in all treatments except M. Comammox always played a minor role in both NH3 oxidation and N2O production across all treatments. Both M and MNPK treatments significantly increased the activity and growth of comammox. Compared to NPK, comammox exhibited increases of 270 % and 326 % in the NH3 oxidation rates, and increases of 1472 % and 563 % in the N2O production rates in M and MNPK, respectively. Random forest model revealed that copper (Cu), comammox abundance, and dissolved organic nitrogen (DON) were the most important predictors for the NH3 oxidation rates of comammox. Redundancy analyses (RDA) showed that fertilizer treatments significantly altered the community composition of NH3 oxidizers, and pH was the overarching parameter underpinning the community shift of the NH3 oxidizers. Overall, this study provides evidence that comammox play a minor yet unneglectable role in the nitrification of agroecosystems, and the long-term addition of organic manure stimulates the growth and activity of comammox in a subtropical Inceptisol.

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Phytolith is a form of SiO2 in plants. Carbon can be sequestrated as phytolith-occluded carbon (PhytOC) during the formation of phytoliths. PhytOC is characterized by its high resistance to temperature, oxidation and decomposition under protection of phytoliths and can be stored in the soil for thousands of years. Soil also is a huge PhytOC sink; however, most studies focus on PhytOC storage in straw and other residues. Wheat is a major staple food crop accumulating high content of Si and distributed widely, while its potential for PhytOC is not clear. At present, PhytOC storage only considers on the average value, but not on the relationship between ecological factors and the spatial distribution of PhytOC sequestration. Climatic factors and soil physiochemical properties together affect the formation process and stability of phytoliths. In our study, we collected wheat straw and soil samples from 95 sites among five provinces to extract phytolith and PhytOC. We constructed XGBoost model to predict the spatial distribution of phytolith and PhytOC across the country using the national soil testing and formula fertilization nutrient dataset and climate data. As a result, soil physiochemical factors such as available silicon (Siavail), total carbon (Ctot) and total nitrogen (Ntot) and climate factors related to temperature and precipitation have a great positive impact on the production of phytoliths and PhytOC. Meanwhile, PhytOC storage in wheat ecosystems was estimated to be 7.59 × 106 t, which is equivalent to 27.83 Tg of CO2. In China, the distribution characteristics of phytoliths and PhytOC in wheat straw and soil display a trend of decrease from south to north. He'nan Province is the largest wheat production area, producing approximately 1.59 × 106 t PhytOC per year. Therefore, PhytOC is a stable CO2 sink pathway in the agricultural ecosystems, which is of great importance for mitigating climate warming.

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Semiconductor nanocrystals are promising candidates for generating chemical feedstocks through photocatalysis. Understanding the role of ligands used to prepare colloidal nanocrystals in catalysis is challenging due to the complexity and heterogeneity of nanocrystal surfaces. We use in situ single-molecule fluorescence imaging to map the spatial distribution of active regions along individual tungsten oxide nanowires before and after functionalizing them with ascorbic acid. Rather than blocking active sites, we observed a significant enhancement in activity for photocatalytic water oxidation after treatment with ascorbic acid. While the initial nanowires contain inactive regions dispersed along their length, the functionalized nanowires show high uniformity in their photocatalytic activity. Spatial colocalization of the active regions with their surface chemical properties shows that oxidation of ascorbic acid during photocatalysis generates new oxygen vacancies along the nanowire surface. We demonstrate that controlling surface-ligand redox chemistry during photocatalysis can enhance the active site concentration on nanocrystal catalysts.

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The current processes used in clinical microbiology laboratories take ~24 h for incubation to identify the bacteria after the blood culture has been confirmed as positive and fa further ~24 h to report the results of antimicrobial susceptibility tests (ASTs). Patients with suspected bloodstream infection are treated with empiric broad-spectrum antibiotics but delayed targeted antimicrobial therapy. This study aimed to develop a method with a significantly shortened turnaround time for clinical application by identifying the optimal incubation period of a subculture. A total of 188 positive blood culture samples obtained from Nov. 2019 to Aug. 2020 were included. Compared to the conventional 24-h incubation for bacterial identification, our approach achieved 96.1% and 97.4% identification accuracy after shortening the incubation time to 4.5 and 3.5 h for gram-positive (GP) and gram-negative (GN) bacterial samples, respectively. Samples from short-term incubation without any intermediate step or process were directly subjected to analysis with the Phoenix M50 AST. Compared to the conventional disk diffusion AST, the category agreements for GP (excluding Streptococcus spp.), Streptococcus spp., and GN bacterial samples were 91.8%, 97.5%, and 92.7%, respectively. Our approach significantly reduced the average turnaround time from 48 h to 28 h for reporting bacterial identity and decreased average AST from 72 h to 50.3 h compared to the conventional methods. Accordingly, this approach allows a physician to prescribe the appropriate antibiotic(s) ~21.7 h earlier, thereby improving patient outcomes.

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The surface structure of semiconductor photocatalysts controls the efficiency of charge-carrier extraction during photocatalytic reactions. However, understanding the connection between surface heterogeneity and the locations where photogenerated charge carriers are preferentially extracted is challenging. Herein we use single-molecule fluorescence imaging to map the spatial distribution of active regions and quantify the activity for both photocatalytic oxidation and reduction reactions on individual bismuth oxybromide (BiOBr) nanoplates. Through a coordinate-based colocalization analysis, we quantify the spatial correlation between the locations where fluorogenic probe molecules are oxidized and reduced on the surface of individual nanoplates. Surprisingly, we observed two distinct photochemical behaviors for BiOBr particles prepared within the same batch, which exhibit either predominantly uncorrelated activity where electrons and holes are extracted from different sites or colocalized activity in which oxidation and reduction take place within the same nanoscale regions. By analyzing the emissive properties of the fluorogenic probes, we propose that electrons and holes colocalize at defect-deficient regions, while defects promote the selective extraction of one carrier type by trapping either electrons or holes. Although previous work has used defect engineering to enhance the activity of bismuth oxyhalides and other semiconductor photocatalysts for useful reductive half-reactions (e.g., CO2 or N2 reduction), our results show that defect-free regions are needed to promote both oxidation and reduction in fuel-generating photocatalysts that do not rely on sacrificial reagents.

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Oxygen vacancies in semiconductor photocatalysts play several competing roles, serving to both enhance light absorption and charge separation of photoexcited carriers as well as act as recombination centers for their deactivation. In this Letter, we show that single-molecule fluorescence imaging of a chemically activated fluorogenic probe can be used to monitor changes in the photocatalytic activity of bismuth oxybromide (BiOBr) nanoplates in situ during the light-induced formation of oxygen vacancies. We observe that the specific activities of individual nanoplates for the photocatalytic reduction of resazurin first increase and then progressively decrease under continuous laser irradiation. Ensemble structural characterization, supported by electronic-structure calculations, shows that irradiation increases the concentration of surface oxygen vacancies in the nanoplates, reduces Bi ions, and creates donor defect levels within the band gap of the semiconductor particles. These combined changes first enhance photocatalytic activity by increasing light absorption at visible wavelengths. However, high concentrations of oxygen vacancies lower the photocatalytic activity both by introducing new relaxation pathways that promote charge recombination before photoexcited electrons can be extracted and by weakening binding of resazurin to the surface of the nanoplates.

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The function of pressure has long been overlooked in the hydrothermal synthesis of zeolites, which is typically carried out under an autogenous pressure (below 2 MPa). We herein report, the first of its kind, a detailed investigation on the hydrothermal synthesis of zeolites under external high pressures, where crystallization behaviors contradicting the common observations were generated.

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This study reports an integrated analysis of three randomized controlled trials to compare the clinical efficacies and safety of the ceftazidime-avibactam (CAZ-AVI) combination and meropenem in the treatment of adult patients with complicated intra-abdominal infections (cIAIs). Overall, a total of 1677 patients (CAZ-AVI: 835 patients; meropenem: 842 patients) were included in this analysis. CAZ-AVI had a clinical cure rate at test of cure in the clinically evaluable (CE) population similar to that of meropenem (OR, 0.88; 95% CI, 0.58-1.32; I2 = 0%). Similar trends were also observed in the modified intent-to-treat (MITT) population (OR, 0.80; 95% CI, 0.59-1.09; I2 = 0%) and microbiological evaluable (ME) population (OR, 0.73; 95% CI, 0.32-1.68; I2 = 0%). In terms of clinical cure rate at the end of treatment, the efficacy of CAZ-AVI was comparable to that of meropenem in the CE population (OR, 0.77; 95% CI, 0.47-1.25; I2 = 0%), MITT population (OR, 0.70; 95% CI, 0.47-1.06; I2 = 5%), and ME population (OR, 1.26; 95% CI, 0.39-4.08; I2 = 0%). CAZ-AVI had a similar risk of (i) treatment emergent adverse events (TEAEs) (OR, 1.03; 95% CI, 0.79-1.36; I2 = 38%), (ii) any serious adverse events (OR, 0.97; 95% CI, 0.67-1.40; I2 = 0%), (iii) discontinuation of study drug due to TEAE (OR, 2.14; 95% CI, 1.00-4.57), and iv) all-cause mortality (OR, 1.66; 95% CI, 0.78-3.53; I2 = 0%) when compared with meropenem. In conclusion, CAZ-AVI had comparable efficacy and safety profile to those of meropenem in the treatment of cIAI.

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We found significant correlation between the incidence of severe influenza and Aspergillus antigenemia among medical intensive care unit patients for 7-month observation (coefficient γ=0.976, p<0.001). High-level ambient pollution was noticed for 2 months before the epidemic, highlighting that influenza patients might coinfect with aspergillosis in the community.

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BACKGROUND/PURPOSE: Aspergillus-associated infection might comprise up to 23-29% of severe influenza patients from the community throughout stay in an intensive care unit (ICU). In Taiwan, cases of severe influenza with aspergillosis are increasingly reported. Therefore, we describe the relative risk of mortality among severe influenza patients with aspergillosis and other coinfections compared to severe influenza patients without Aspergillus coinfections. METHODS: We retrospectively reviewed 124 adult patients with severe influenza in a tertiary medical center in southern Taiwan from January 2015 through March 2016. The definition of probable aspergillosis required abnormal radiological findings and positive Aspergillus galactomannan (GM) antigen and/or Aspergillus isolation. RESULTS: Probable aspergillosis (detected throughout the whole course) and other coinfections (only community-acquired) were diagnosed in 21 (17%) and 38 (31%) of all patients respectively. Klebsiella pneumoniae (36.8%), Pseudomonas aeruginosa (31.6%) and Staphylococcus aureus (31.6%) were the most frequent isolates of other coinfections. In-ICU mortality of Aspergillus group (66.7%) was significantly higher than other coinfections (23.7%, p = 0.001) or control group without coinfections (15.4%, p < 0.001), with significant odds ratios after adjusting for important variables. The factor of GM index ≥0.6 had a 19.82 (95% CI, 4.91 to 80.07, p < 0.0001) odds of expiring in an ICU among the Aspergillus group. CONCLUSION: Dual Aspergillus and influenza infection is emerging in southern Taiwan. Meanwhile, community-acquired P. aeruginosa should be listed in the common copathogens with severe influenza. The 67% mortality linked to aspergillosis highlights the need for physicians to focus attention on patients with GM ≥ 0.6.

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ST elevation myocardial infarction (STEMI), one main type of acute myocardial infarction with high mortality, requires percutaneous coronary intervention (PCI) with balloon inflation. Current guidelines recommend a door-to-balloon (D2B) interval (i.e., starts with the patient's arrival in the emergency department and ends when PCI with a catheter guidewire and balloon inflation crosses the culprit lesion) of no more than 90 min. However, promptly implementing PCI requires coordinating various medical teams. Checklists can be used to ensure consistency and operating sequences when executing complex tasks in a clinical routine. Developing an effective D2B checklist would enhance the care of STEMI patients who need PCI. Mobile information and communication technologies have the potential to greatly improve communication, facilitate access to information, and eliminate duplicated documentation without the limitations of space and time. In a research project by the Chi Mei Medical Center, "Developing a Mobile Electronic D2B Checklist for Managing the Treatment of STEMI Patients Who Need Primary Coronary Intervention," a prototype version of a mobile checklist was developed. This study describes the research project and the four phases of the system development life cycle, comprising system planning and selection, analysis, design, and implementation and operation. Face-to-face interviews with 16 potential users were conducted and revealed highly positive user perception and use intention toward the prototype. Discussion and directions for future research are also presented.

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Validamycin A (VAL-A) is an important agricultural antibiotic produced by Streptomyces hygroscopicus 5008, which uses starch as carbon source occupying about 20% of total production cost. To reduce the medium cost, corncob hydrolysate - a hemicellulose hydrolysate was applied as a low-cost substrate to VAL-A fermentation. It was found that three major sugars in corncob hydrolysate including d-glucose, d-xylose and l-arabinose could all be utilized by S. hygroscopicus 5008 to produce VAL-A while d-xylose was the main contributor. A higher VAL-A production titer from d-xylose was achieved by using a genetically engineered strain TC03 derived from S. hygroscopicus 5008, which resulted in 1.27-fold improvement of VAL-A production from the medium containing 13% (v/v) corncob hydrolysate compared to that by its original strain. A medium cost analysis was done and compared with previous reports. This work indicates a great potential of the hemicellulose hydrolysate as substrate for antibiotic fermentation.

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BACKGROUND/PURPOSE: This study investigated the correlation between antibiotic consumption and the incidence of health care-associated infections (HCAIs) caused by imipenem-resistant Acinetobacter baumannii (IRAB) at a hospital in Taiwan from 2005 to 2010. METHODS: Data on annual consumption (defined daily dose per 1000 patient-days) of extended-spectrum cephalosporins, ß-lactam-ß-lactamase inhibitor combinations, carbapenems, aminoglycosides, and fluoroquinolones from 2005 to 2010 were analyzed. Yearly aggregated data on the number of nonduplicate clinical IRAB isolates causing HCAI were collected. The incidence rates of HCAI caused by IRAB were defined as the number of patients infected with IRAB per 1000 inpatient-days. RESULTS: The trend of total consumption (defined daily dose per 1000 patient-days) of extended-spectrum cephalosporins, carbapenems, and fluoroquinolones was significantly increased, but the use of aminoglycosides decreased during 2005 to 2010. During the same period, the incidence of HCAI caused by IRAB gradually increased. The consumptions of carbapenems and fluoroquinolones were positively correlated with the incidence of HCAI caused by IRAB. There was no significant association between the use of extended-spectrum cephalosporins, ß-lactam-ß-lactamase inhibitor combinations, and aminoglycosides and the incidence of HCAI caused by IRAB. CONCLUSION: The increasing use of carbapenems and fluoroquinolones was associated with the increasing incidence of HCAI caused by IRAB.

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Validamycin A (VAL-A) is a widely used antifungal antibiotic for the treatment of sheath blight disease of rice and other plants. It can be produced from agro-industrial by-products by Streptomyces hygroscopicus 5008. To enhance its production titer, in this work, the entire val gene cluster was amplified in tandem in S. hygroscopicus 5008 by integrating the zouA-mediated DNA amplification system into between the two boundaries of val gene cluster, resulting in multiple copies (mainly three to five) of the val gene cluster. The genetic stability of the amplified copies was confirmed by Southern blot and fermentation experiments. In shake flask fermentation, the recombinant strain (TC03) led to a 34% enhancement of VAL-A production titer compared to that of the wild-type strain, while the accumulation of intermediate validoxylamine A was decreased in TC03. Additionally, both the structural gene transcription levels and the ValG enzyme activity were significantly increased in TC03. This work demonstrated that the amplification of the val gene cluster was an efficient strategy to enhance VAL-A production by S. hygroscopicus 5008, and the information obtained would be helpful for engineering other interesting antibiotic biosynthesis by gene cluster amplification.

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BACKGROUND/PURPOSE: To investigate the clinical characteristics of Clostridium difficile infection (CDI) at a medical center in Taiwan. METHODS: Patients with CDI were identified from medical records at the National Taiwan University Hospital (Taipei, Taiwan). The following information was gathered and analyzed to better understand the clinical manifestations of CDI: age; sex; underlying immunocompromised conditions; laboratory data; in-hospital mortality; and previous use of drugs such as antimicrobial agents, steroids, and antipeptic ulcer agents. RESULTS: During the years 2000-2010, 122 patients were identified as having CDI. This included 92 patients with nontoxigenic CDI (i.e., positive stool culture for C. difficile but negative results for toxins A and B) and 30 patients with toxigenic CDI (i.e., positive stool culture cultures for C. difficile and positive results for toxins A and B). Of the 122 patients, 48 (39%) patients were older than 65 years and most patients acquired the CDI while in the hospital. Active cancer was the most common reason for hospitalization, followed by diabetes mellitus, and end-stage renal disease. More than 90% of the patients had received antibiotics before acquiring CDI. The results of fecal leukocyte examinations were positive in 33 (27%) patients. The overall in-hospital mortality rate was 26.2%. There were no significant differences between patients with nontoxigenic CDI and patients with toxigenic CDI. CONCLUSION: Clostridium difficile infection can develop in healthcare facilities and in community settings, especially in immunocompromised patients.

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OBJECTIVES: To investigate the impact of the directly observed therapy, short course (DOTS) and DOTS-Plus strategies on changes in resistance profiles among Mycobacterium tuberculosis (MTB). METHODS: We performed a retrospective analysis of resistance profiles among isolates of MTB obtained from 2160 consecutive patients with culture-confirmed pulmonary tuberculosis (TB) between 2005 and 2011 at a referral centre in southern Taiwan. RESULTS: Of the 2160 patients, 70 (3.2%) had primary multidrug-resistant (MDR)-TB, 178 (8.2%) had acquired MDR-TB, 10 (0.5%) had primary extensively drug-resistant (XDR)-TB, 23 (1.1%) had acquired XDR-TB and 5 (0.2%) had totally drug-resistant (TDR)-TB. Trend analysis revealed that the rates of acquired MDR-TB were significantly lower after implementation of the DOTS and DOTS-Plus programmes (P < 0.01). There was a significant negative correlation between the coverage rates of the DOTS and DOTS-Plus programmes and the rates of acquired MDR-TB (r = -0.84, P = 0.02 and r = -0.92, P = 0.03, respectively). The rates of resistance to rifampicin, isoniazid, ofloxacin, moxifloxacin, levofloxacin and para-aminosalicylic acid also decreased significantly during the study period. However, the rates of primary MDR-TB remained stable (P = 0.11). Multivariate logistic regression analysis showed that age ranging from 45 to 64 years, positive acid-fast stain results at the initiation of treatment and treatment without DOTS were independent risk factors associated with acquired MDR-TB. In addition, previous treatment for TB (100% versus 19% for TDR-TB and non-TDR-TB, P < 0.01) and treatment without DOTS (80% versus 44% for TDR-TB and non-TDR-TB, P = 0.18) were risk factors for TDR-TB. CONCLUSIONS: DOTS and DOTS-Plus are both effective at preventing the acquisition of MDR-TB in Taiwan.

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