PFAS Remediation: Evaluating the Infrared Spectra of Complex Gaseous Mixtures to Determine the Efficacy of Thermal Decomposition of PFAS.

Due to their widespread production and known environmental contamination, the need for the detection and remediation of per- and polyfluoroalkyl substances (PFAS) has grown quickly. While destructive thermal treatment of PFAS at low temperatures (e.g., 200 to 500oC) is of interest due to lower energy and infrastructure requirements, the range of possible degradation products remains underexplored. To better understand the low temperature decomposition of PFAS species, we have coupled gas-phase infrared spectroscopy with a multivariate curve resolution (MCR) analysis and a database of high-resolution PFAS infrared reference spectra to characterize and quantify a complex mixture resulting from potassium perfluorooctanesulfonate (PFOS-K) decomposition. Nine prevalent decomposition products (namely smaller perfluorocarbon species) are identified and quantified.

Pediatric urinary tract infections caused by poultry-associated Escherichia coli.

Escherichia coli is the leading cause of urinary tract infections (UTIs) in children and adults. The gastrointestinal tract is the primary reservoir of uropathogenic E. coli, which can be acquired from a variety of environmental exposures, including retail meat. In the current study, we used a novel statistical-genomic approach to estimate the proportion of pediatric UTIs caused by foodborne zoonotic E. coli strains. E. coli urine isolates were collected from DC residents aged 2 months to 17 years from the Children's National Medical Center Laboratory, 2013-2014. During the same period, E. coli isolates were collected from retail poultry products purchased from 15 sites throughout DC. A total of 52 urine and 56 poultry isolates underwent whole-genome sequencing, core genome phylogenetic analysis, and host-origin prediction by a Bayesian latent class model that incorporated data on the presence of mobile genetic elements (MGEs) among E. coli isolates from multiple vertebrate hosts. A total of 56 multilocus sequence types were identified among the isolates. Five sequence types-ST10, ST38, ST69, ST117, and ST131-were observed among both urine and poultry isolates. Using the Bayesian latent class model, we estimated that 19% (10/52) of the clinical E. coli isolates in our population were foodborne zoonotic strains. These data suggest that a substantial portion of pediatric UTIs in the Washington DC region may be caused by E. coli strains originating in food animals and likely transmitted via contaminated poultry meat.IMPORTANCEEscherichia coli UTIs are a heavy public health burden and can have long-term negative health consequences for pediatric patients. E. coli has an extremely broad host range, including humans, chickens, turkeys, pigs, and cattle. E. coli derived from food animals is a frequent contaminant of retail meat products, but little is known about the risk these strains pose to pediatric populations. Quantifying the proportion of pediatric UTIs caused by food-animal-derived E. coli, characterizing the highest-risk strains, and identifying their primary reservoir species could inform novel intervention strategies to reduce UTI burden in this vulnerable population. Our results suggest that retail poultry meat may be an important vehicle for pediatric exposure to zoonotic E. coli strains capable of causing UTIs. Vaccinating poultry against the highest-risk strains could potentially reduce poultry colonization, poultry meat contamination, and downstream pediatric infections.

Persistence of vaccine origin Salmonella Typhimurium through the poultry production continuum, and development of a rapid typing scheme for their differentiation from wild type field isolates.

Salmonella enterica serovar Typhimurium is one of the top Salmonella serovars annually linked to poultry production and corresponding human illnesses. Because of this, vaccination of commercial poultry against Salmonella Typhimurium has been a focal point in recent years. There are several commercially available Salmonella Typhimurium vaccines available for use in poultry production. Among these are modified live vaccines, including Poulvac ST (Zoetis), Megan Egg (AviPro), and Megan Vac 1 (AviPro). In this study, analyses of 27 field isolates of Salmonella Typhimurium from poultry sources indicated evidence for the persistence of some vaccine-origin strains through the commercial production cycle. Further analyses of 26,812 database isolates indicated vaccine-origin isolates are persisting frequently through processing, are present on retail meat products, and are even occasionally found in human patients. A novel polymerase chain reaction (PCR) was created and validated which enables simultaneous identification of Salmonella enterica sp., the Salmonella Typhimurium serovar, and differentiation of wild type Salmonella Typhimurium from live attenuated vaccines involving mutations in the cya/crp or aroA genes. The PCR was developed considering whole genome differences between the vaccines and wild type field isolates and was validated using different field isolates and recovered vaccine strains. This method enables poultry producers to rapidly determine if recovered field isolates have a vaccine origin.

Assessing the Risk of Antimicrobial Resistant Enterococcal Infections in Humans Due to Bacitracin Usage in Poultry.

Bacitracin is an antimicrobial used in the feed or water of poultry in the U.S. for the prevention, treatment, and control of clostridial diseases such as necrotic enteritis. Concern has been raised that bacitracin can select for antimicrobial-resistant bacteria that can be transmitted to humans and subsequently cause disease that is more difficult to treat because of the resistance. The objective of the present study was to perform a quantitative risk assessment (QRA) to estimate the potential risk in the U.S. of human infection with antimicrobial-resistant Enterococcus faecalis and E. faecium derived from chicken and turkey products as a result of bacitracin usage in U.S. poultry. The modeling approach estimated the annual number of healthcare-associated enterococcal infections in the U.S. that would be resistant to antimicrobial therapy and that would be derived from poultry sources because of bacitracin use in poultry. Parameter estimates were developed to be "maximum risk" to overestimate the risk to humans. While approximately 60% of E. faecalis and E. faecium derived from poultry were predicted to possess bacitracin resistance based on the presence of the bcrABDR gene locus, very few human-derived isolates possessed this trait. Furthermore, no vancomycin or linezolid-resistant strains of E. faecalis or E. faecium were detected in poultry sources between the years 2002 and 2019. The model estimated the number of antimicrobial-resistant E. faecalis and E. faecium cases per year that might resist therapy due to bacitracin use in poultry as 0.86 and 0.14, respectively, which translates to an annual risk estimate for E. faecalis of less than 1 in 350 million and for E. faecium of less than 1 in 2 billion for members of the U.S. population. Even with the use of risk-maximizing assumptions, the results indicate that there is a high probability that the use of bacitracin according to label instructions in U.S. poultry presents a negligible risk to human health.

Combination of autochthonous Lactobacillus strains and trans-Cinnamaldehyde in water reduces Salmonella Heidelberg in turkey poults.

Reducing the colonization of Salmonella in turkeys is critical to mitigating the risk of its contamination at later stages of production. Given the increased susceptibility of newly hatched poults to Salmonella colonization, it is crucial to implement interventions that target potential transmission routes, including drinking water. As no individual intervention explored to date is known to eliminate Salmonella, the United States Department of Agriculture-Food Safety Inspection Service (USDA-FSIS) recommends employing multiple hurdles to achieve a more meaningful reduction and minimize the potential emergence of resistance. Probiotics and plant-derived antimicrobials (PDAs) have demonstrated efficacy as interventions against Salmonella in poultry. Therefore, this study aimed to investigate the use of turkey-derived Lactobacillus probiotics (LB; a mixture of Lactobacillus salivarius UMNPBX2 and L. ingluviei UMNPBX19 isolated from turkey ileum) and a PDA, trans-cinnamaldehyde (TC), alone and in combination (CO), against S. Heidelberg in turkey drinking water and poults. The presence of 5% nutrient broth or cecal contents as contaminants in water resulted in S. Heidelberg growth. TC eliminated S. Heidelberg, regardless of the contaminants present. In contrast, the cecal contents led to increased survival of Lactobacillus in the CO group. Unlike TC, LB was most effective against S. Heidelberg when the nutrient broth was present, suggesting the role of secondary metabolites in its mechanism of action. In the experiments with poults, individual TC and LB supplementation reduced cecal S. Heidelberg in challenged poults by 1.2- and 1.7-log10 colony-forming units (CFU)/g cecal contents, respectively. Their combination yielded an additive effect, reducing S. Heidelberg by 2.7 log10 CFU/g of cecal contents compared to the control (p ≤ 0.05). However, the impact of TC and LB on the translocation of S. Heidelberg to the liver was more significant than CO. TC and LB are effective preharvest interventions against S. Heidelberg in poultry production. Nonetheless, further investigations are needed to determine the optimum application method and its efficacy in adult turkeys.

Method to derive the infrared complex refractive indices n(λ) and k(λ) for organic solids from KBr pellet absorption measurements.

Obtaining the complex refractive index vectors n(ν~) and k(ν~) allows calculation of the (infrared) reflectance spectrum that is obtained from a solid in any of its many morphological forms. We report an adaptation to the KBr pellet technique using two gravimetric dilutions to derive quantitative n(ν~)/k(ν~) for dozens of powders with greater repeatability. The optical constants of bisphenol A and sucrose are compared to those derived by other methods, particularly for powdered materials. The variability of the k values for bisphenol A was examined by 10 individual measurements, showing an average coefficient of variation for k peak heights of 5.6%. Though no established standards exist, the pellet-derived k peak values of bisphenol A differ by 11% and 31% from their single-angle- and ellipsometry-derived values, respectively. These values provide an initial estimate of the precision and accuracy of complex refractive indices that can be derived using this method. Limitations and advantages of the method are discussed, the salient advantage being a more rapid method to derive n/k for those species that do not readily form crystals or specular pellets.

Optimal Spectral Resolution for Infrared Studies of Solids and Liquids.

Due to a legacy originating in the limited capability of early computers, the spectroscopic resolution used in Fourier transform infrared spectroscopy and other systems has largely been implemented using only powers of two for more than 50 years. In this study, we investigate debunking the spectroscopic lore of, e.g., using only 2, 4, 8, or 16 cm-1 resolution and determine the optimal resolution in terms of both (i) a desired signal-to-noise ratio and (ii) efficient use of acquisition time. The study is facilitated by the availability of solids and liquids reference spectral data recorded at 2.0 cm-1 resolution and is based on an examination in the 4000-400 cm-1 range of 61 liquids and 70 solids spectra, with a total analysis of 4237 peaks, each of which was also examined for being singlet/multiplet in nature. Of the 1765 liquid bands examined, only 27 had widths <5 cm-1. Of the 2472 solid bands examined, only 39 peaks have widths <5 cm-1. For both the liquid and solid bands, a skewed distribution of peak widths was observed: For liquids, the mean peak width was 24.7 cm-1 but the median peak width was 13.7 cm-1, and, similarly, for solids, the mean peak width was 22.2 cm-1 but the median peak width was 11.2 cm-1. While recognizing other studies may differ in scope and limiting the analysis to only room temperature data, we have found that a resolution to resolve 95% of all bands is 5.7 cm-1 for liquids and 5.3 cm-1 for solids; such a resolution would capture the native linewidth (not accounting for instrumental broadening) for 95% of all the solids and liquid bands, respectively. After decades of measuring liquids and solids at 4, 8, or 16 cm-1 resolution, we suggest that, when accounting only for intrinsic linewidths, an optimized resolution of 6.0 cm-1 will capture 91% of all condensed-phase bands, i.e., broadening of only 9% of the narrowest of bands, but yielding a large gain in signal-to-noise with minimal loss of specificity.

Risk factors for extended-spectrum beta-lactamase (ESBL)-producing E. coli carriage among children in a food animal-producing region of Ecuador: A repeated measures observational study.

BACKGROUND: The spread of antibiotic-resistant bacteria may be driven by human-animal-environment interactions, especially in regions with limited restrictions on antibiotic use, widespread food animal production, and free-roaming domestic animals. In this study, we aimed to identify risk factors related to commercial food animal production, small-scale or "backyard" food animal production, domestic animal ownership, and practices related to animal handling, waste disposal, and antibiotic use in Ecuadorian communities. METHODS AND FINDINGS: We conducted a repeated measures study from 2018 to 2021 in 7 semirural parishes of Quito, Ecuador to identify determinants of third-generation cephalosporin-resistant E. coli (3GCR-EC) and extended-spectrum beta-lactamase E. coli (ESBL-EC) in children. We collected 1,699 fecal samples from 600 children and 1,871 domestic animal fecal samples from 376 of the same households at up to 5 time points per household over the 3-year study period. We used multivariable log-binomial regression models to estimate relative risks (RR) of 3GCR-EC and ESBL-EC carriage, adjusting for child sex and age, caregiver education, household wealth, and recent child antibiotic use. Risk factors for 3GCR-EC included living within 5 km of more than 5 commercial food animal operations (RR: 1.26; 95% confidence interval (CI): 1.10, 1.45; p-value: 0.001), household pig ownership (RR: 1.23; 95% CI: 1.02, 1.48; p-value: 0.030) and child pet contact (RR: 1.23; 95% CI: 1.09, 1.39; p-value: 0.001). Risk factors for ESBL-EC were dog ownership (RR: 1.35; 95% CI: 1.00, 1.83; p-value: 0.053), child pet contact (RR: 1.54; 95% CI: 1.10, 2.16; p-value: 0.012), and placing animal feces on household land/crops (RR: 1.63; 95% CI: 1.09, 2.46; p-value: 0.019). The primary limitations of this study are the use of proxy and self-reported exposure measures and the use of a single beta-lactamase drug (ceftazidime with clavulanic acid) in combination disk diffusion tests for ESBL confirmation, potentially underestimating phenotypic ESBL production among cephalosporin-resistant E. coli isolates. To improve ESBL determination, it is recommended to use 2 combination disk diffusion tests (ceftazidime with clavulanic acid and cefotaxime with clavulanic acid) for ESBL confirmatory testing. Future studies should also characterize transmission pathways by assessing antibiotic resistance in commercial food animals and environmental reservoirs. CONCLUSIONS: In this study, we observed an increase in enteric colonization of antibiotic-resistant bacteria among children with exposures to domestic animals and their waste in the household environment and children living in areas with a higher density of commercial food animal production operations.

Leveraging the COVID-19 pandemic as a natural experiment to assess changes in antibiotic use and antibiotic-resistant E. coli carriage in semi-rural Ecuador.

The coronavirus 2019 (COVID-19) pandemic has had significant impacts on health systems, population dynamics, public health awareness, and antibiotic stewardship, which could affect antibiotic resistant bacteria (ARB) emergence and transmission. In this study, we aimed to compare knowledge, attitudes, and practices (KAP) of antibiotic use and ARB carriage in Ecuadorian communities before versus after the COVID-19 pandemic began. We leveraged data collected for a repeated measures observational study of third-generation cephalosporin-resistant E. coli (3GCR-EC) carriage among children in semi-rural communities in Quito, Ecuador between July 2018 and September 2021. We included 241 households that participated in surveys and child stool sample collection in 2019, before the pandemic, and in 2021, after the pandemic began. We estimated adjusted Prevalence Ratios (aPR) and 95% Confidence Intervals (CI) using logistic and Poisson regression models. Child antibiotic use in the last 3 months declined from 17% pre-pandemic to 5% in 2021 (aPR: 0.30; 95% CI 0.15, 0.61) and 3GCR-EC carriage among children declined from 40 to 23% (aPR: 0.48; 95% CI 0.32, 0.73). Multi-drug resistance declined from 86 to 70% (aPR: 0.32; 95% CI 0.13; 0.79), the average number of antibiotic resistance genes (ARGs) per 3GCR-EC isolate declined from 9.9 to 7.8 (aPR of 0.79; 95% CI 0.65, 0.96), and the diversity of ARGs was lower in 2021. In the context of Ecuador, where COVID-19 prevention and control measures were strictly enforced after its major cities experienced some of the world's the highest mortality rates from SARS-CoV-2 infections, antibiotic use and ARB carriage declined in semi-rural communities of Quito from 2019 to 2021.

FUTIs: an In-Person or Online Graphing, Bioinformatics, and Scientific Literacy Exercise That Explores the Presence of Antibiotic Resistance in Foodborne Urinary Tract Infections.

We developed a course-based undergraduate research experience (CURE) that gives students an opportunity to practice the process of science in a context that intersects with their everyday lives: purchasing grocery store chicken. Student mastery of concepts was assessed by pre- and postassessment questions and lab report worksheets that guided them through the process of writing a scientific paper. Learning to produce graphs from large data sets and comparing the results with published data emphasized quantitative reasoning, while working as a group and writing helped students practice scientific communication. Most students (>90%) met the learning objectives, and students in both groups reported feeling more confident producing graphs and figures; they also showed large gains in confidence and interest in bioinformatics. Lab protocols require biosafety level 2 safety guidelines; however, students in an online or dry lab setting can use the compiled data sets and whole-genome sequences to complete the objectives. Group discussions and essay prompts at the end encourage students to use evidence-based arguments to make decisions that impact the global issue of antimicrobial resistance.

Evidence of host specificity in Lactobacillus johnsonii genomes and its influence on probiotic potential in poultry.

To date, the selection of candidate strains for probiotic development in production animals has been largely based upon screens for desired phenotypic traits. However, increasing evidence indicates that the use of host-specific strains may be important, because coevolution with the animal host better prepares a bacterial strain to colonize and succeed in its respective host animal species. This concept was applied to Lactobacillus johnsonii in commercial poultry production because of its previous correlation with enhanced bird performance. Using 204 naturally isolated chicken- and turkey-source L. johnsonii, we demonstrate that there is a strong phylogenetic signal for coevolution with the animal host. These isolates differ phenotypically, even within host source, and these differences can be correlated with certain L. johnsonii phylogenetic clades. In commercial turkey poults, turkey-specific strains with strong in vitro phenotypes performed better early in life than strains lacking those phenotypes. A follow-up performance trial in broiler chickens demonstrated that chicken-specific strains result in better overall bird performance than nonchicken-specific strains. Collectively, this work provides evidence for the impact of host adaptation on a probiotic strain's potential. Furthermore, this top-down approach is useful for screening larger numbers of isolates for probiotic candidates.

Using source-associated mobile genetic elements to identify zoonotic extraintestinal E. coli infections.

A one-health perspective may provide new and actionable information about Escherichia coli transmission. E. coli colonizes a broad range of vertebrates, including humans and food-production animals, and is a leading cause of bladder, kidney, and bloodstream infections in humans. Substantial evidence supports foodborne transmission of pathogenic E. coli strains from food animals to humans. However, the relative contribution of foodborne zoonotic E. coli (FZEC) to the human extraintestinal disease burden and the distinguishing characteristics of such strains remain undefined. Using a comparative genomic analysis of a large collection of contemporaneous, geographically-matched clinical and meat-source E. coli isolates (n = 3111), we identified 17 source-associated mobile genetic elements - predominantly plasmids and bacteriophages - and integrated them into a novel Bayesian latent class model to predict the origins of clinical E. coli isolates. We estimated that approximately 8 % of human extraintestinal E. coli infections (mostly urinary tract infections) in our study population were caused by FZEC. FZEC strains were equally likely to cause symptomatic disease as non-FZEC strains. Two FZEC lineages, ST131-H22 and ST58, appeared to have particularly high virulence potential. Our findings imply that FZEC strains collectively cause more urinary tract infections than does any single non-E. coli uropathogenic species (e.g., Klebsiella pneumoniae). Our novel approach can be applied in other settings to identify the highest-risk FZEC strains, determine their sources, and inform new one-health strategies to decrease the heavy public health burden imposed by extraintestinal E. coli infections.

Survey of clinical and commensal Escherichia coli from commercial broilers and turkeys, with emphasis on high-risk clones using APECTyper.

Molecular characterization of avian pathogenic Escherichia coli (APEC) is challenging due to the complex nature of its associated disease, colibacillosis, in poultry. Numerous efforts have been made toward defining APEC, and it is becoming clear that certain clonal backgrounds are predictive of an avian E. coli isolate's virulence potential. Thus, APEC can be further differentiated as high-risk APEC based upon their clonal background's virulence potential. However, less clear is the degree of overlap between clinical isolates of differing bird type, and between clinical and gastrointestinal isolates. This study aimed to determine genomic similarities and differences between such populations, comparing commercial broiler vs. turkey isolates, and clinical vs. gastrointestinal isolates. Differences were observed in Clermont phylogenetic groups between isolate populations, with B2 as the dominant group in turkey clinical isolates and G as the dominant group in broiler clinical isolates. Nearly all clinical isolates were classified as APEC using a traditional gene-based typing scheme, whereas 53.4% and 44.1% of broiler and turkey gastrointestinal isolates were classified as APEC, respectively. High-risk APEC were identified among 31.0% and 46.9% of broiler and turkey clinical isolates, compared with 5.7% and 2.9% of broiler and turkey gastrointestinal isolates. As found in previous studies, no specific known virulence or fitness gene sets were identified which universally differentiate between clinical and gastrointestinal isolates. This study further demonstrates the utility of a hybrid APEC typing approach, considering both plasmid content and clonal background, for the identification of dominant and highly virulent APEC clones in poultry production.

Efficacy of Antibiotic and Non-antibiotic Interventions in Preventing and Treating Necrotic Enteritis in Broiler Chickens: A Systematic Review.

The objective of this systematic review was to compare the efficacy of antibiotic and non-antibiotic alternatives in the prevention and treatment of necrotic enteritis (NE) in broiler chickens. In vivo experimental and observational studies that compared the administration of non-antibiotic compounds with antibiotics to prevent or treat NE in broiler chickens and that evaluated mortality and/or clinical or subclinical NE outcome measures were eligible. Four electronic databases were searched in December 2019 and updated in October 2021. Retrieved studies were evaluated in two phases: abstract and design screening. Data were then extracted from included studies. Risk of bias was assessed by outcome following the Cochrane Risk of Bias 2.0 tool. A meta-analysis was not conducted due to heterogeneity across interventions and outcomes. The non-antibiotic and antibiotic groups were compared at the outcome level for individual studies using the mean difference and 95% confidence interval (CI) calculated post hoc from raw data. In total, 1282 studies were originally identified, and 40 were included in the final review. The overall risk of bias for the 89 outcomes was either "high" (n = 34) or "some concerns" (n = 55). Individual study comparisons showed a beneficial trend toward the antibiotic group for reduced mortality, NE lesion scores (overall, jejunum, and ileum), Clostridium perfringens counts, and for most histologic measurements (duodenum, jejunum, and ileum villi height, and jejunum and ileum crypt depth). The non-antibiotic groups showed a beneficial trend for NE duodenum lesion scores and duodenum crypt depth measurements. Based on this review, there is a trend that mostly favors antibiotic compounds in preventing and/or treating NE, but the evidence also suggests no difference when comparing them with non-antibiotic alternatives. Studies assessing this research question were heterogeneous in their intervention conditions and outcomes measured, and there were key aspects of the experimental design not reported in some of the studies.

Eficacia de las intervenciones con antibióticos y compuestos no antibióticos para prevenir y tratar la enteritis necrótica en pollos de engorde: Una revisión sistemática El objetivo de esta revisión sistemática fue comparar la eficacia de antibióticos y alternativas a los antibióticos en la prevención y tratamiento de la enteritis necrótica (NE) en pollos de engorde. Se incluyeron estudios experimentales in vivo y estudios observacionales que compararon la administración de compuestos no considerados antibióticos con compuestos antibióticos usados para prevenir o tratar la enteritis necrótica en pollos de engorde, y que evaluaran mortalidad, signos clínicos, u otros resultados subclínicos. Se buscaron referencias en cuatro bases de datos bibliográficos en Diciembre de 2019 y por segunda vez en Octubre de 2021. Los estudios que se encontraron se evaluaron en dos fases: resumen y diseño del estudio de escrutinio. Posteriormente se extrajeron los datos de aquellos estudios que se incluyeron después del escrutinio. Se evaluó el riesgo de sesgos siguiendo la herramienta de Cochrane Risk of Bias 2.0. No se pudo realizar un meta-análisis debido a la heterogeneidad de las intervenciones y de los resultados de los estudios incluidos. Los grupos de compuestos no antibióticos y de antibióticos se compararon con base a los resultados individuales de cada estudio usando la diferencia entre medias e intervalos de confianza al 95%, calculados post-hoc usando los datos originales. Se identificaron un total de 1282 estudios, y 40 fueron finalmente incluidos en la revisión. El riesgo de sesgos para el total de los 89 resultados individuales fue alto (n = 34) o con "ciertos problemas" (n = 55). Las comparaciones individuales entre estudios mostraron una tendencia beneficiosa hacia el grupo de antibióticos en términos de mortalidad reducida, puntaje de lesiones de enteritis necrótica (total, yeyuno e íleo), conteos de Clostridium perfringens, así como para la mayoría de las medidas histológicas (altura de las vellosidades del duodeno, yeyuno e íleo, y profundidad de la cripta del yeyuno e íleo). El grupo de no antibióticos mostró una tendencia beneficiosa para el puntaje de lesiones de enteritis necrótica del duodeno y para las medidas de profundidad de la cripta del duodeno. Según esta revisión, hay una tendencia que favorece al grupo de antibióticos en la prevención y/o tratamiento de enteritis necrótica, pero la evidencia también sugiere que no hay diferencia entre los grupos. Los estudios incluidos en la comparación eran muy heterogéneos en cuanto a las condiciones de las intervenciones y a los resultados que se midieron, además de que algunos aspectos importantes del diseño experimental en algunos de los estudios no se reportaron.

An Interactive Spectral Analysis Tool for Chemical Identification and Quantification of Gas-Phase Species in Complex Spectra.

A spectral analysis tool has been developed to interactively identify and quantify individual gas-phase species from complex infrared absorbance spectra obtained from laboratory or field data. The SpecQuant program has an intuitive graphical interface that accommodates both reference and experimental data with varying resolution and instrumental lineshape, as well as algorithms to readily align the wavenumber axis of a sample spectrum with the raster of a reference spectrum. Using a classical least squares model in conjunction with reference spectra such as those from the Pacific Northwest National Laboratory (PNNL) gas-phase infrared database or simulated spectra derived from the HITRAN line-by-line database, the mixing ratio of each identified species is determined along with its associated estimation error. After correcting the wavelength and intensity of the field data, SpecQuant displays the calculated mixing ratio versus the experimental data for each analyte along with the residual spectrum with any or all analyte fits subtracted for visual inspection of the fit and residuals. The software performance for multianalyte quantification was demonstrated using moderate resolution (0.5 cm-1) infrared spectra that were collected during the time-resolved infrared photolysis of methyl iodide.

Effects of a postbiotic, with and without a saponin-based product, on turkey performance.

Modern poultry production relies on an ability to prevent and mitigate challenges to bird health, while maintaining a productive bird. A number of different classes of biologics-based feed additives exist, and many have been tested individually for their impacts on poultry health and performance. Fewer studies have examined the combinations of different classes of products. In this study, we examined the use of a well-established postbiotic feed additive (Original XPC, Diamond V) on turkey performance, with and without the addition of a proprietary saponin-based feed additive. This was accomplished in an 18-wk pen trial utilizing 22 pen replicates per treatment across 3 treatments (control, postbiotic, and postbiotic plus saponin). Significant differences in body weight were identified at wk 12 and 15 of age, with the postbiotic plus saponin treatment group resulting in heavier birds at both timepoints. Significant differences in feed conversion ratio were observed from 0 to 18 wk of age, with the postbiotic alone having improved FCR compared with the control group. No significant differences were observed for livability or feed intake. This study demonstrates that a combination of a postbiotic plus saponin may exert additive effects on the growth of the turkey.

Complete Genome Sequences of Two Pasteurella multocida Isolates from Seabirds.

Pasteurella multocida is one of the major causes of mass mortalities in wild birds. Here, we report the complete genome sequences of two P. multocida isolates from wild populations of two endangered seabird species, the Indian yellow-nosed albatrosses (Thalassarche carteri) and the northern rockhopper penguins (Eudyptes moseleyi).

Complete Genome Sequences of Three Ornithobacterium rhinotracheale Strains from Avian Sources, Using Hybrid Nanopore-Illumina Assembly.

Ornithobacterium rhinotracheale has been associated with respiratory disease in poultry, particularly turkeys, leading to significant economic losses. However, O. rhinotracheale is poorly studied, and a very limited number of complete genomes are available. Here, we report the complete genome sequences of three O. rhinotracheale strains, generated using a Nanopore-Illumina hybrid assembly approach.

Plugging the leaks: antibiotic resistance at human-animal interfaces in low-resource settings.

Antibiotic resistance is one of the greatest public health challenges of our time. International efforts to curb resistance have largely focused on drug development and limiting unnecessary antibiotic use. However, in areas where water, sanitation, and hygiene infrastructure is lacking, we propose that bacterial flow between humans and animals can exacerbate the emergence and spread of resistant pathogens. Here, we describe the consequences of poor environmental controls by comparing mobile resistance elements among Escherichia coli recovered from humans and meat in Cambodia, a middle-income country with substantial human-animal connectivity and unregulated antibiotic use. We identified identical mobile resistance elements and a conserved transposon region that were widely dispersed in both humans and animals, a phenomenon rarely observed in high-income settings. Our findings indicate that plugging leaks at human-animal interfaces should be a critical part of addressing antibiotic resistance in low- and especially middle-income countries.

Identification and Validation of a Novel Antibacterial Compound MZ-01 against Methicillin-Resistant Staphylococcus aureus.

The discovery of new classes of antibiotics is slow, and it is being greatly outpaced by the development of bacterial resistance. This disparity places us in an increasingly vulnerable position because we are running out of safe and effective therapeutic options to treat antibiotic-resistant infections. This is exemplified by the emergence and persistence of hospital-acquired and community-associated methicillin-resistant S. aureus (MRSA), which has markedly narrowed our options for treating life-threatening staph infections. Thus, there is an urgent need to develop novel, potent, preventive, and therapeutic agents. In our current study, we performed a whole-cell screening assay of synthetic libraries for antibacterial activity and identified a novel molecule, MZ-01. MZ-01 exhibited potent bactericidal activity against Gram-positive bacterial pathogens, including MRSA, Streptococcus pyogenes, and Streptococcus pneumoniae, at low concentrations. MZ-01 killed and lysed both the late exponential phase of an S. aureus population and bacteria inside mammalian cells. Furthermore, MZ-01 exhibited low cytotoxicity. These results indicate that MZ-01 is a promising scaffold to guide the development of novel, potent antibacterial agents against multidrug-resistant Gram-positive bacterial pathogens such as MRSA.