Emergency Medicine Providers' Knowledge and Management of Pediatric Tropical Diseases: A Needs Assessment.

OBJECTIVE: The aim of this study was to perform a needs assessment of pediatric (PEM) and general emergency medicine (EM) provider knowledge, comfort, and current practice patterns in the evaluation of pediatric tropical infectious diseases. METHODS: An online survey was developed based on educational priorities identified by an expert panel via modified Delphi methodology. The survey included assessment of providers' typical evaluation, diagnosis, and treatment of tropical diseases and was distributed to PEM and EM providers in 2 large professional organizations. RESULTS: A total of 333 physicians (285 PEM, 32 EM, 8 combined PEM/EM, and 8 general pediatricians in emergency department) participated. Fifty-five percent of vignettes were answered correctly. Those who trained outside the United States or Canada (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1-3.0) and PEM-trained providers (OR, 2.6; 95% CI, 1.2-5.9) were more likely to answer questions correctly. Providers answered more questions correctly about dengue (76%) and tuberculosis (77%) than typhoid (53%) and malaria (39%) (OR, 3.8; 95% CI, 3.0-4.9). Diagnostic evaluation for tropical diseases was variable with greater than 75% agreement for only 2 tests: blood smears in febrile patients from Africa (86%) and bacterial stool cultures in patients with bloody stools from Africa, Asia, or Latin America (94%). Providers had low (62%) or medium (35%) comfort level with pediatric tropical diseases, and 93% were interested in accessing emergency department-specific resources. CONCLUSIONS: Pediatric EM and EM providers' knowledge and evaluation for pediatric tropical diseases are variable. Providers recognized their knowledge gaps and expressed interest in gaining access to resources and guidelines to standardize and improve evaluation and treatment of these diseases.

Chikungunya in a Pediatric Traveler.

Chikungunya is a mosquito-transmitted virus found primarily in Africa and Asia. In late 2013, chikungunya virus emerged in the Western hemisphere, spreading from the Caribbean to South, Central, and North America (MMWR Morb Mortal Wkly Rep. 2014;63:1121-1128). Symptoms can be similar to nonspecific viral presentations including fever, joint pain, joint swelling, and rash. The diagnosis of infectious tropical diseases in the emergency department often requires a high index of suspicion, given the nonspecific early findings that characterize many of these tropical diseases. This report presents a case of chikungunya in a pediatric patient traveling from Guatemala to the United States. Proper recognition of infection and diagnosis are vital from a public health perspective. Considering patients will remain viremic for up to a week and potentially expose local mosquitoes to infection, it is important to educate the patient on mosquito bite prevention in geographic areas of the United States where competent mosquito vectors exist as a means of avoiding further spread.

Adding tetrahydrofuran to dilute acid pretreatment provides new insights into substrate changes that greatly enhance biomass deconstruction by Clostridium thermocellum and fungal enzymes.

BACKGROUND: Consolidated bioprocessing (CBP) by anaerobes, such as Clostridium thermocellum, which combine enzyme production, hydrolysis, and fermentation are promising alternatives to historical economic challenges of using fungal enzymes for biological conversion of lignocellulosic biomass. However, limited research has integrated CBP with real pretreated biomass, and understanding how pretreatment impacts subsequent deconstruction by CBP vs. fungal enzymes can provide valuable insights into CBP and suggest other novel biomass deconstruction strategies. This study focused on determining the effect of pretreatment by dilute sulfuric acid alone (DA) and with tetrahydrofuran (THF) addition via co-solvent-enhanced lignocellulosic fractionation (CELF) on deconstruction of corn stover and Populus with much different recalcitrance by C. thermocellum vs. fungal enzymes and changes in pretreated biomass related to these differences. RESULTS: Coupling CELF fractionation of corn stover and Populus with subsequent CBP by the anaerobe C. thermocellum completely solubilized polysaccharides left in the pretreated solids within only 48 h without adding enzymes. These results were better than those from the conventional DA followed by either CBP or fungal enzymes or CELF followed by fungal enzyme hydrolysis, especially at viable enzyme loadings. Enzyme adsorption on CELF-pretreated corn stover and CELF-pretreated Populus solids were virtually equal, while DA improved the enzyme accessibility for corn stover more than Populus. Confocal scanning light microscopy (CSLM), transmission electron microscopy (TEM), and NMR characterization of solids from both pretreatments revealed differences in cell wall structure and lignin composition, location, coalescence, and migration-enhanced digestibility of CELF-pretreated solids. CONCLUSIONS: Adding THF to DA pretreatment (CELF) greatly enhanced deconstruction of corn stover and Populus by fungal enzymes and C. thermocellum CBP, and the CELF-CBP tandem was agnostic to feedstock recalcitrance. Composition measurements, material balances, cellulase adsorption, and CSLM and TEM imaging revealed adding THF enhanced the enzyme accessibility, cell wall fractures, and cellular dislocation and cell wall delamination. Overall, enhanced deconstruction of CELF solids by enzymes and particularly by C. thermocellum could be related to lignin removal and alteration, thereby pointing to these factors being key contributors to biomass recalcitrance as a barrier to low-cost biological conversion to sustainable fuels.

Comparative evaluation of Populus variants total sugar release and structural features following pretreatment and digestion by two distinct biological systems.

BACKGROUND: Populus natural variants have been shown to realize a broad range of sugar yields during saccharification, however, the structural features responsible for higher sugar release from natural variants are not clear. In addition, the sugar release patterns resulting from digestion with two distinct biological systems, fungal enzymes and Clostridium thermocellum, have yet to be evaluated and compared. This study evaluates the effect of structural features of three natural variant Populus lines, which includes the line BESC standard, with respect to the overall process of sugar release for two different biological systems. RESULTS: Populus natural variants, SKWE 24-2 and BESC 876, showed higher sugar release from hydrothermal pretreatment combined with either enzymatic hydrolysis or Clostridium thermocellum fermentation compared to the Populus natural variant, BESC standard. However, C. thermocellum outperformed the fungal cellulases yielding 96.0, 95.5, and 85.9% glucan plus xylan release from SKWE 24-2, BESC 876, and BESC standard, respectively. Among the feedstock properties evaluated, cellulose accessibility and glycome profiling provided insights into factors that govern differences in sugar release between the low recalcitrant lines and the BESC standard line. However, because this distinction was more apparent in the solids after pretreatment than in the untreated biomass, pretreatment was necessary to differentiate recalcitrance among Populus lines. Glycome profiling analysis showed that SKWE 24-2 contained the most loosely bound cell wall glycans, followed by BESC 876, and BESC standard. Additionally, lower molecular weight lignin may be favorable for effective hydrolysis, since C. thermocellum reduced lignin molecular weight more than fungal enzymes across all Populus lines. CONCLUSIONS: Low recalcitrant Populus natural variants, SKWE 24-2 and BESC 876, showed higher sugar yields than BESC standard when hydrothermal pretreatment was combined with biological digestion. However, C. thermocellum was determined to be a more robust and effective biological catalyst than a commercial fungal cellulase cocktail. As anticipated, recalcitrance was not readily predicted through analytical methods that determined structural properties alone. However, combining structural analysis with pretreatment enabled the identification of attributes that govern recalcitrance, namely cellulose accessibility, xylan content in the pretreated solids, and non-cellulosic glycan extractability.