The genomic and epidemiological virulence patterns of Salmonella enterica serovars in the United States.

The serovars of Salmonella enterica display dramatic differences in pathogenesis and host preferences. We developed a process (patent pending) for grouping Salmonella isolates and serovars by their public health risk. We collated a curated set of 12,337 S. enterica isolate genomes from human, beef, and bovine sources in the US. After annotating a virulence gene catalog for each isolate, we used unsupervised random forest methods to estimate the proximity (similarity) between isolates based upon the genomic presentation of putative virulence traits We then grouped isolates (virulence clusters) using hierarchical clustering (Ward's method), used non-parametric bootstrapping to assess cluster stability, and externally validated the clusters against epidemiological virulence measures from FoodNet, the National Outbreak Reporting System (NORS), and US federal sampling of beef products. We identified five stable virulence clusters of S. enterica serovars. Cluster 1 (higher virulence) serovars yielded an annual incidence rate of domestically acquired sporadic cases roughly one and a half times higher than the other four clusters combined (Clusters 2-5, lower virulence). Compared to other clusters, cluster 1 also had a higher proportion of infections leading to hospitalization and was implicated in more foodborne and beef-associated outbreaks, despite being isolated at a similar frequency from beef products as other clusters. We also identified subpopulations within 11 serovars. Remarkably, we found S. Infantis and S. Typhimurium subpopulations that significantly differed in genome length and clinical case presentation. Further, we found that the presence of the pESI plasmid accounted for the genome length differences between the S. Infantis subpopulations. Our results show that S. enterica strains associated with highest incidence of human infections share a common virulence repertoire. This work could be updated regularly and used in combination with foodborne surveillance information to prioritize serovars of public health concern.

Advancing antimicrobial stewardship in companion animal veterinary medicine: a qualitative study on perceptions and solutions to a One Health problem.

OBJECTIVE: The term antimicrobial stewardship (AMS) is used to describe the coordinated efforts and programs required to sustain the clinical efficacy of antimicrobials and slow the development of antimicrobial resistance. However, companion animal veterinarians are provided with few "cage-side" resources to achieve these goals. The aims of our study were to understand the current perceptions, attitudes, and knowledge of AMS among companion animal veterinarians and to source technology-based solutions that reduce barriers to judicious antimicrobial drug prescribing. PROCEDURES: 6 focus groups were conducted via a teleconference platform. The focus group recordings were transcribed and coded thematically using a grounded theory approach and inductive coding. RESULTS: A total of 25 companion animal veterinarians participated in 6, 1-hour focus groups. Two themes emerged from the data: (1) Veterinarians feel that AMS is important and understand the principles of AMS, but experience barriers to practicing judicious AMD use principles. (2) Veterinarians agree that technology can promote AMS, but express that a tool needs to support their prescribing decisions, provide accurate and concise stewardship information, and be integrated into the existing workflow. CLINICAL RELEVANCE: For an AMS technology tool to be successful in improving AMS in companion animal medicine, veterinarians need centralized information on antimicrobial use, improved access to geographical AMR patterns, and communication support with clients and their hospital teams.

Colorado pet owners' perceptions of and attitudes towards antimicrobial drug use and resistance.

BACKGROUND: Antimicrobial drug (AMD) use in companion animal medicine may contribute to antimicrobial resistance (AMR) in both pets and humans. However, pet owners' attitudes and perceptions regarding AMD use and AMR have not been extensively studied in the United States. METHODS: A cross-sectional survey at five Colorado veterinary hospitals collected information about pet owners' knowledge and perceptions of AMD use and AMR, adherence with AMD treatment instructions and the role of the veterinarian in the AMD prescribing process. RESULTS: The pet owners surveyed did not have an adequate understanding of AMR and were unaware of the potential human health impact of AMD use in pets. However, most pet owners reported adherence with veterinary prescription instructions and indicated that they trusted their veterinarian to make appropriate decisions for their pets. LIMITATIONS: The cross-sectional design focusing on Colorado pet owners limits the generalisability of the results. Selection and social desirability biases may have occurred, which could have affected who participated and how participants responded to statements. CONCLUSIONS: Pet owners play an important role in the AMD prescription process, and their lack of AMR understanding should be addressed in antimicrobial stewardship plans. Further research on how to effectively incorporate pet owners into  stewardship interventions is needed.

Codex Alimentarius Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance Are Incompatible with Available Surveillance Data.

ABSTRACT: Foodborne antimicrobial-resistant (AMR) microorganisms are a global food safety concern. Antimicrobial drug use (AMU) in livestock may increase the risk of resistant foodborne bacterial infections in humans via contaminated animal products. Consequently, countries have implemented different livestock AMU restriction policies, opening the potential for trade disputes. AMR risk equivalence between countries with different AMU policies must be established by using scientifically justified risk assessments. The Codex Alimentarius Commission's Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance (AMR Codex) recommends an approach that requires quantification of detailed information, for which, in many instances, little to no data exist. Using AMR Salmonella exposure from beef consumption as an example, we demonstrate the difficulty of implementing the AMR Codex by comparing key regionally specific parameters within the United States and European Union, two regions with substantial beef production and consumption, robust foodborne pathogen sampling and surveillance systems, and different AMU policies. Currently, neither region fully captures data for key regional variables to populate a detailed risk assessment as outlined in the AMR Codex, nor are they able to adequately link AMU in livestock to AMR infections in humans. Therefore, the AMR Codex guidelines are currently aspirational and not a viable option to assess the impact of livestock AMU reductions on the human health risk of AMR salmonellosis from beef or produce regionally comparable estimates of risk. More flexible risk assessment guidelines that more directly link livestock AMU to human health risk and are amenable to currently available data are needed to allow for country variations and to calculate comparable regional risk estimates, which can be used to guide international trade policy.

Survey of companion animal veterinarians' antimicrobial drug prescription practices and awareness of antimicrobial drug use guidelines in the United States.

Antimicrobial drug use in companion animal medicine, the subsequent development of antimicrobial resistance and the potential hazard of animals transmitting resistant bacteria to humans are of increasing concern. Antimicrobial prescription patterns among companion animal veterinarians in the United States are understudied, and the association between antimicrobial drug use guideline awareness and antimicrobial drug prescription practices is unknown. Information on antimicrobial recommendations for five hypothetical clinical scenarios, including canine pyoderma, acute canine diarrhoea, feline lower urinary tract illness, canine dental procedures and feline upper respiratory illness, was gathered using an anonymous, online cross-sectional survey. A logistic regression approach was used to assess the association between self-reported awareness of antimicrobial drug use guidelines and prescribing recommendations for the five hypothetical scenarios. Responses (n = 2,410) indicated antimicrobial drugs were commonly recommended for the five hypothetical clinical scenarios. After controlling for key demographic characteristics, prescribers who reported an awareness of existing antimicrobial drug use guidelines were significantly less likely to recommend antimicrobial drugs for the scenarios describing feline lower urinary symptoms, feline upper respiratory illness and canine acute diarrhoea. Results from hypothetical clinical scenarios point to the possibility for widespread unsupported prescribing of antimicrobial drugs in companion animal medicine. Additionally, results provide evidence of an association between awareness of antimicrobial drug use guidelines and lower prescribing levels for certain hypothetical disease presentations.

Survey of production animal veterinarians' prescription practices, factors influencing antimicrobial drug use, and perceptions of and attitudes toward antimicrobial resistance.

OBJECTIVE: To assess production animal medicine veterinarians' prescription practices and identify factors influencing their use of antimicrobial drugs (AMDs) and their perceptions of and attitudes toward antimicrobial resistance (AMR). SAMPLE: 157 production animal veterinarians in the United States. PROCEDURES: An online cross-sectional survey and digital diary were used to gather information regarding perceptions on AMD use and AMR and on treatment recommendations for production setting-specific disease scenarios. Results were compared across respondents grouped by their selected production setting scenarios and reported years as veterinarians. RESULTS: The most commonly selected production setting disease scenarios were dairy cattle (96/157 [61.1%]), backgrounding cattle (32/157 [20.4%]), and feedlot cattle (20/157 [12.7%]). Because few respondents selected swine (5/157 [3.2%]) or poultry (4/157 [2.5%]) scenarios, those responses were excluded from statistical analysis of AMD prescription practices. Most remaining respondents (147/148 [99.3%]) reported that they would recommend AMD treatment for an individual ill animal; however, responses differed for respondents grouped by their selected production setting scenarios and reported years as veterinarians when asked about AMD treatment of an exposed group or high-risk disease-free group. Most respondents reported that government regulations influenced their AMD prescribing, that owner and producer compliance was a veterinary-related factor that contributed to AMR, and that environmental modifications to prevent disease could be effective to mitigate AMR. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study helped fill important knowledge gaps pertaining to prescription practices and influencing factors for AMD use in production animal medicine and provided baseline information for future assessments. This information could be used to inform future interventions and training tools to mitigate the public health threat of AMR.

Cannabis Use Is Associated With Increased Risk for Diabetic Ketoacidosis in Adults With Type 1 Diabetes: Findings From the T1D Exchange Clinic Registry.

OBJECTIVE: We examined the frequency of diabetic ketoacidosis (DKA) in cannabis users compared with nonusers in the T1D Exchange clinic registry (T1DX). RESEARCH DESIGN AND METHODS: The association between cannabis use by total substance score for cannabis (TSC) and DKA in the past 12 months was examined using a logistic regression model adjusted for potential confounders among adults in the T1DX. RESULTS: Of 932 adults with type 1 diabetes, 61 had a TSC >4, which classified them as moderate cannabis users. Adjusting for sex, age at study visit, and HbA1c, cannabis use was associated with a twofold increase in risk for DKA among adults with type 1 diabetes (odds ratio 2.5 [95% CI 1.0-5.9]). CONCLUSIONS: Cannabis use was associated with an increased risk for DKA among adults in the T1DX. Providers should inform their patients of the potential risk of DKA with cannabis use.

Structural studies of the perovskite series La1-xSrxCoO3-δ during chemical looping with methane.

Perovskite oxides are promising materials as oxygen carriers in chemical looping applications. We analyze in situ X-ray diffraction data on the perovskite phases La1-xSrxCoO3-δ for x = 0, 0.25, 0.5, and 0.75 under chemical looping conditions. We report and discuss their structural evolution, cycling stability, and suitability as oxygen storage materials.

Influence of transition metal electronegativity on the oxygen storage capacity of perovskite oxides.

The selection of highly efficient oxygen carriers (OCs) is a key step necessary for the practical development of chemical looping combustion (CLC). In this study, a series of ABO3 perovskites, where A = La, Ba, Sr, Ca and B = Cr, Mn, Fe, Co, Ni, Cu, are synthesized and tested in a fixed bed reactor for reactivity and stability as OCs with CH4 as the fuel. We find that the electronegativity of the transition metal on the B-site (λB), is a convenient descriptor for oxygen storage capacity (OSC) of our perovskite samples. By plotting OSC for total methane oxidation against λB, we observe an inverted volcano plot relationship. These results could provide useful guidelines for perovskite OC design and their other energy related applications.

Stabilization of cubic Sr2FeMoO6 through topochemical reduction.

Sr2FeMoO6 has been extensively studied for application in spintronic devices. Through the topochemical de-intercalation of oxygen anions with metal hydride reduction, we demonstrate that the high temperature cubic phase is stabilized, at room temperature, whilst leaving the magnetic ordering intact. Synchrotron X-ray and neutron powder diffraction were used to characterize the structure and stoichiometry of the reduced oxide.

PZT-like structural phase transitions in the BiFeO3-KNbO3 solid solution.

Despite the high prominence of the perovskites BiFeO(3) and KNbO(3) the solid solution between the two has received little attention. We report a detailed neutron and synchrotron X-ray powder diffraction, and Raman spectroscopy study which demonstrates an R3c→P4mm→Amm2 series of structural phase transitions similar to that exhibited by the PbZrO(3)-PbTiO(3) solid solution.

Lesion severity at processing as a predictor of Salmonella contamination of swine carcasses.

OBJECTIVE: To measure the relationship between gross lesions in swine carcasses observed at a processing plant and Salmonella contamination and to determine whether nonexpert assessments of lesion status would correspond with swine pathologists' judgments. ANIMALS: Carcasses of 202 conventionally raised and 156 antimicrobial-free pigs in a Midwestern US processing plant examined from December 2005 to January 2006. PROCEDURES: 4 replicates were conducted. For each, freshly eviscerated carcasses were identified as having or lacking visceral adhesions by a nonexpert evaluator and digital carcass photographs were obtained. Swab specimens were obtained from carcasses before the final rinse stage of processing, and bacterial culture for Salmonella spp and Enterococcus spp was performed. Subsequently, carcass photographs were numerically scored for lesion severity by 3 veterinary pathologists. Results were used to test the ability of lesion detection to predict bacterial contamination of carcasses and the agreement between judgments of the inexperienced and experienced assessors. RESULTS: The probability of Salmonella contamination in carcasses with lesions identified at the abattoir was 90% higher than that in carcasses lacking lesions, after controlling for replicate identity and antimicrobial use. The receiver operating characteristic curve and Cohen κ indicated close agreement between lesion detection at the abattoir and by the 3 pathologists. CONCLUSIONS AND CLINICAL RELEVANCE: Findings indicated the presence of lesions could be used to predict Salmonella contamination of swine carcasses and that a nonexpert processing-line assessment of lesions could be used to discriminate between healthy and chronically ill swine before their entry into the human food supply.