Tracing Listeria monocytogenes contamination in artisanal cheese to the processing environments in cheese producers in southern Chile.

Artisanal cheese from southern Chile is made primarily by rural families who raise dairy cows and produce cheese as a way to add value to their milk. The most common cheese produced is chanco, a semi-hard cheese that is typically sold in unauthorized markets. The methods of chanco production do not always follow good manufacturing practices; however, the presence of Listeria monocytogenes contamination in this cheese has not been previously documented. To better understand production practices and L. monocytogenes contamination, 39 cheese producers were surveyed with regard to infrastructure, cleaning and sanitation, pest control, personal hygiene, training, raw materials, and manufacturing. During four sampling trips in 2016 (March, May, August, and November), 546 samples were collected (468 cheese samples and 78 milk samples). For producers that tested positive for L. monocytogenes, environmental monitoring was also conducted, for which 130 additional samples were collected. Presumptive L. monocytogenes isolates (N = 94) were further characterized and subtyped using standard techniques and qPCR-based species/subtype verification; a subset of 52 isolates were also subtyped by Pulsed Field Gel Electrophoresis (PFGE). L. monocytogenes was found in 19 cheeses (4.1%) from five producers (12.8%). The most frequent serotypes were 1/2b (48.9%), group 4B (4b, 4d, 4e) (45.7%), and serotype 1/2a (5.4%). Although no milk samples tested positive for L. monocytogenes, all cheese samples from two producers tested positive during two of the samplings. Distinct PFGE types were recovered from each facility, demonstrating persistence of certain subtypes of the pathogen that ultimately caused end-product contamination. Environmental monitoring of the five positive producers revealed a prevalence of L. monocytogenes ranging from 0 to 30%, with food contact surfaces having the highest incidence of this organism. The findings of this study contribute to the understanding of L. monocytogenes incidence in artisanal cheese in the region of southern Chile.

Retrospective and Predictive Investigation of Fish Kill Events.

Fish kill investigations are critical to understanding threats to aquatic ecosystems and can serve as a measure of environmental disruption as well as an early indicator of emerging disease. The goal of this study was to analyze historical data related to such events among wild fish populations in Minnesota in order to assess the quality and completeness of the data and potential trends in fish kills. After excluding events with incomplete data (e.g., in which the location was not reported), we analyzed 225 unique fish kills from 2003 to 2013 that were recorded in two Minnesota Department of Natural Resources databases. The most reported fish kills occurred during 2007 (n = 41) and during the month of June (n = 81) across all years. Centrarchid species were present in the most fish kills (138), followed by cyprinid and ictalurid species, which were present in 53 and 40 events, respectively. Environmental factors were the most common cause of death reported. Models of environmental factors revealed that the maximum nighttime land surface temperature was the most critical factor in fish mortality, followed by changes in primary productivity and human disturbances. During the course of this study, data gaps were identified, including underreporting, inconsistent investigation, and the lack of definitive diagnoses, making interpretation of our results challenging. Even so, understanding these historical trends and data gaps can be useful in generating hypotheses and advancing data collection systems for investigating future fish kills. Our study is a primer investigation of fish kills providing information on the plausible areas, seasons, and fish groups at risk that can guide active environmental monitoring and epidemiological surveillance of fishes.

Distraction Osteogenesis in Two Wild Raptors.

Distraction osteogenesis was used in 2 wild raptor patients for the repair of tibiotarsal fractures. The first case was a hatching year female peregrine falcon (Falco peregrinus) admitted with an open oblique right distal tibiotarsal fracture. The fracture was surgically managed with the external skeletal fixator intramedullary pin tie-in technique (ESF-IM pin tie-in). Appropriate healing of the fracture site occurred with the ESF-IM pin tie-in. However, there was significant pelvic limb shortening of the affected leg, and the bird consequently developed pododermatitis on the contralateral foot. The second case was an adult female great horned owl (Bubo virginianus) that was admitted with a closed, partially healed, overriding right tibiotarsal fracture. Because of the advanced stage of this fracture, which presented with a fibrous callus, and the already apparent pelvic limb shortening, the ESF-IM pin tie-in was not used. Both patients were fitted with a circular external skeletal fixator (CESF), and distraction osteogenesis was performed until the length of the pelvic limb was deemed anatomically adequate. It is critical that rehabilitated raptors be released without any physical conditions that may reduce their ability to survive and reproduce in the wild. Pelvic limb shortening can potentially predispose a raptor patient to pododermatitis, even with fatal consequences, in both captive and wild environments. The orthopedic technique used here proved useful to repair the limb shortening in both raptor cases, and each bird fully recovered and was released.

Factors influencing detection and co-detection of Ranavirus and Batrachochytrium dendrobatidis in Midwestern North American anuran populations.

Amphibian populations are in decline worldwide as they face a barrage of challenges, including infectious diseases caused by ranaviruses and the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). Here we describe seasonal dynamics of Bd and ranavirus detection in free-ranging post-metamorphic wood frogs Lithobates sylvaticus, boreal chorus frogs Pseudacris maculata/triseriata, and gray treefrogs Hyla versicolor/chrysoscelis, sampled over a 3 season gradient in Minnesota (USA) wetlands. We detected Bd in 36% (n = 259) of individuals sampled in 3 wetlands in 2014, and 33% (n = 255) of individuals sampled in 8 wetlands in 2015. We also detected ranavirus in 60% and 18% of individuals sampled in 2014 and 2015, respectively. Ranavirus and Bd were detected concurrently in 26% and 2% of animals sampled in 2014 and 2015, respectively. We report clinical signs and associated infection status of sampled frogs; of the clinical signs observed, skin discoloration was significantly associated with ranavirus infection. Using generalized estimating equations, we found that species, season, wetland, and a species × season interaction term were significant predictors of Bd detection, whereas test year approached significance as a predictor of ranavirus detection. The odds of detecting both pathogens concurrently was significantly influenced by species, season, a species × season interaction term, year, and environmental ammonia. We propose an amphibian health monitoring scheme that couples population size surveys with seasonal molecular surveys of pathogen presence. This information is crucial to monitoring the health of remaining strongholds of healthy amphibian populations, as they face an uncertain future of further anthropogenic change.

Surgical Removal of a Ventricular Foreign Body in a Captive African Black-footed Penguin ( Spheniscus demersus ).

Anterior gastrointestinal tract obstruction by a foreign body has been reported in several avian species, most commonly in captive birds. It is often associated with behavioral issues that lead to compulsive consumption of bedding materials or bright moving objects. In penguins, foreign bodies are most commonly identified at necropsy and often are found in the ventriculus because of anatomic characteristics of the species. A captive African black-footed penguin ( Spheniscus demersus ) was diagnosed with a ventricular foreign body. The anatomic and physiologic differences that should be taken into account when surgically removing a ventricular foreign body in a penguin are described. These differences include the caudal location in the coelom and the large size of the ventriculus in proportion to the penguin's body size; the presence of a simple stomach, uniform in thickness and lacking muscular development; a simple gastrointestinal cycle (gastric contraction); and variability in pH of stomach contents. No complications were observed after surgery, and the bird recovered completely. Management of foreign bodies in birds should be based on the clinical signs of the individual bird, the species affected and its anatomic characteristics, the nature and location of the foreign body, available tools, and the preference and experience of the surgeon. This particular case demonstrates that the most indicated and preferred method is not always possible and that knowledge of biologic, anatomic, and physiologic differences of the species may allow the use of an alternative and more invasive approach with favorable outcomes.

Surveillance for highly pathogenic avian influenza A (H5N1) in a raptor rehabilitation center-2022.

An ongoing, severe outbreak of highly pathogenic avian influenza virus (HPAI) A H5N1 clade 2.3.4.4b has been circulating in wild and domestic bird populations throughout the world, reaching North America in 2021. This HPAI outbreak has exhibited unique characteristics when compared to previous outbreaks. The global distribution of disease, prolonged duration, extensive number of species and individual wild birds affected, and the large impact on the global poultry industry have all exceeded historical impacts of previous outbreaks in North America. In this study, we describe the results of HPAI surveillance conducted at The Raptor Center, a wildlife rehabilitation hospital at University of Minnesota (Saint Paul, MN, U.S.A.), from March 28th-December 31, 2022. All wild raptors admitted to the facility were tested for avian influenza viruses using polymerase chain reaction (PCR) testing. All non-negative samples were submitted to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories for confirmatory HPAI testing and genetic sequencing. During the study period, 996 individual birds representing 20 different species were tested for avian influenza, and 213 birds were confirmed HPAI positive. Highly pathogenic avian influenza surveillance conducted at The Raptor Center contributed 75% of the HPAI positive raptor detections within the state of Minnesota, located within the Mississippi flyway, significantly augmenting state wildlife surveillance efforts. The viral genotypes observed in birds sampled at The Raptor Center were representative of what was seen in wild bird surveillance within the Mississippi flyway during the same time frame. Wildlife rehabilitation centers provide an opportune situation to augment disease surveillance at the human, wildlife and domestic animal interface during ongoing infectious disease outbreaks.

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.

Biodegradation, photolysis, and sorption of antibiotics in aquatic environments: A scoping review.

The presence of antibiotics in surface waters is a potential driver of antibiotic resistance and thus of concern to human and environmental health. Key factors driving the potential impact of antibiotics are their persistence and transport in rivers and lakes. The goal of this study was to describe the peer-reviewed published literature on the photolysis (direct and indirect), sorption, and biodegradation of a selected group of antibiotic compounds following a scoping review methodology. Primary research from 2000 to 2021 was surveyed to compile information on these processes for 25 antibiotics from 6 classes. After compilation and assessment of the available parameters, the results indicate that information is present to predict the rates of direct photolysis and reaction with hydroxyl radical (an indirect photolysis process) for most of the selected antibiotics. There is insufficient or inconsistent information for including other indirect photolysis processes, biodegradation, or removal via sorption to settling particles for most of the targeted antibiotic compounds. Future research should focus on collecting fundamental parameters such as quantum yields, second-order rate constants, normalized biodegradation rates, and organic carbon or surface area normalized sorption coefficients rather than pseudo-first order rate constants or sorption equilibrium constants that apply only to specific conditions/sites.

Intracoronary Administration of Microencapsulated HGF in a Reperfused Myocardial Infarction Swine Model.

Therapy microencapsulation allows minimally invasive, safe, and effective administration. Hepatocyte growth factor (HGF) has angiogenic, anti-inflammatory, anti-apoptotic, and anti-fibrotic properties. Our objective was to evaluate the cardiac safety and effectiveness of intracoronary (IC) administration of HGF-loaded extended release microspheres in an acute myocardial infarction (AMI) swine model. An IC infusion of 5 × 106 HGF-loaded microspheres (MS+HGF, n = 7), 5 × 106 placebo microspheres (MS, n = 7), or saline (SAL, n = 7) was performed two days after AMI. TIMI flow and Troponin I (TnI) values were assessed pre- and post-treatment. Cardiac function was evaluated with magnetic resonance imaging (cMR) before injection and at 10 weeks. Plasma cytokines were determined to evaluate the inflammatory profile and hearts were subjected to histopathological evaluation. Post-treatment coronary flow was impaired in five animals (MS+HGF and MS group) without significant increases in TnI. One animal (MS group) died during treatment. There were no significant differences between groups in cMR parameters at any time (p > 0.05). No statistically significant changes were found between groups neither in cytokines nor in histological analyses. The IC administration of 5 × 106 HGF-loaded-microspheres 48 h post-AMI did not improve cardiac function, nor did it decrease inflammation or cardiac fibrosis in this experimental setting.

Identifying the spatiotemporal vulnerability of soils to antimicrobial contamination through land application of animal manure in Minnesota, United States.

Antimicrobials may reach the soil environment from a variety of sources and pathways, including land application of human biosolids and animal manure. Once in soil, antimicrobials can affect the abundance and activity of soil microorganisms and exert selection pressures that enhance the emergence and spread of antimicrobial resistance (AMR). To mitigate the spread of AMR it is important to understand the spatial and temporal interactions between antimicrobials and soil. The goal of this study was to assess the vulnerability of Minnesota (U.S.) soil to contamination with specific antimicrobial compounds at temperatures experienced throughout the year. Soil contamination potential was estimated based upon specific antimicrobial drug binding and permanence, and average monthly temperature. Minnesota soil vulnerability was estimated by incorporating spatially explicit soil contamination potential, land cover type, and livestock density. Assessment of antimicrobials used in livestock production showed that soils are most vulnerable to antimicrobial contamination in southwestern Minnesota, to enrofloxacin, chlortetracycline, and oxytetracycline, and in the months of April and October. While the assessment herein was not based on actual on-farm antimicrobial use data and subsequent excretion of antimicrobial metabolites into the environment, this study provides an overview of the spatial and temporal potential for Minnesota soil to be contaminated by several antimicrobial drugs and demonstrates how specific vulnerability assessments might be conducted for geographic areas with known exposure (e.g., cropland fertilized with livestock manure and/or human biosolids). Such assessments might be used to identify best practices for mitigating antimicrobial exposure to soils and guide additional research to understand the role of environmental antimicrobial contamination in the problem of AMR.

Minnesota One Health Antibiotic Stewardship Collaborative: A Reproducible Approach to Facilitate Antimicrobial Stewardship Progress.

The Minnesota One Health Antibiotic Stewardship Collaborative (MOHASC) was launched in 2016 with the mission of providing a collaborative environment to promote judicious antibiotic use and antibiotic stewardship (AS) and to reduce the impact of antibiotic-resistant pathogens of human, animal, and environmental health importance. MOHASC goals include improving AS programs in healthcare and veterinary medicine, advancing understanding of environmental impacts of antibiotic use, and promoting a One Health (OH) approach to AS. These goals are accomplished through quarterly meetings of 4 work groups, field trips, collaborative research, an annual member meeting, and public education events. This novel OH approach has strengthened multidisciplinary relationships within Minnesota and led to procurement of funding to enhance AS initiatives beyond the Collaborative. This perspective serves as a blueprint for other jurisdictions, and we advocate for use of this reproducible OH strategy to facilitate broad AS goals.

Seabirds as anthropization indicators in two different tropical biotopes: A One Health approach to the issue of antimicrobial resistance genes pollution in oceanic islands.

Antimicrobial resistance is a quintessential One Health issue, among the most serious 21st century global threats to human health. Seabirds may act as sentinels of natural and anthropogenic changes in the marine ecosystem health, including pollution by antimicrobial resistance genes (ARGs). We used real time PCR to identify and quantify 22 plasmid-mediated ARGs in the gastrointestinal microbiome of six wild seabird species, comparing an anthropized (Fernando de Noronha Archipelago - FNA) and a pristine biotope (Rocas Atoll - ROA), Brazil. Of 257 birds, 218 (84.8%) were positive to at least one ARG. ARG classes encoding resistance to tetracyclines (75.1%), quinolones (10.5%) and phenicols (10.5%) were the most prevalent, with tetracyclines significantly greater than the remaining classes (p < 0.05). Genes tet(S) (29.2%), tet(A) (28.8%), and tet(B) (24.9%) were the most commonly found and had a significantly greater prevalence when compared to the remaining ARGs (p < 0.05). The anthropized biotope presented statistically significant higher prevalence of sulfonamide- and quinolone-encoding ARGs in comparison with the pristine (respectively, p = 0.01 and p = 0.03), and higher sulII gene prevalence (p = 0.04), consistent with anthropogenic pressure. Migratory species (only present in ROA) showed statistically significant higher mcr-1 (polymyxins) and blaTEM (betalactam) prevalences (respectively, p = 0.009 and p = 0.02), and mcr-1 percentage load (p = 0.0079) in comparison with non-migratory. To our knowledge, this is the largest ARGs survey based on direct detection and quantification in seabirds worldwide, and the first to evaluate non-synanthropic species in oceanic islands. This is the first detection of mcr-1 in wild free-ranging seabirds in Brazil and in free-ranging migratory non-synanthropic seabirds worldwide. Our findings show the importance of biological and ecological factors, highlighting the role of seabirds as anthropization sentinels and ARGs-pollution environmental indicators (even in a pristine biotope), and their involvement in the One Health epidemiological chain of ARGs.

Quantifying and predicting antimicrobials and antimicrobial resistance genes in waterbodies through a holistic approach: a study in Minnesota, United States.

The environment plays a key role in the spread and persistence of antimicrobial resistance (AMR). Antimicrobials and antimicrobial resistance genes (ARG) are released into the environment from sources such as wastewater treatment plants, and animal farms. This study describes an approach guided by spatial mapping to quantify and predict antimicrobials and ARG in Minnesota's waterbodies in water and sediment at two spatial scales: macro, throughout the state, and micro, in specific waterbodies. At the macroscale, the highest concentrations across all antimicrobial classes were found near populated areas. Kernel interpolation provided an approximation of antimicrobial concentrations and ARG abundance at unsampled locations. However, there was high uncertainty in these predictions, due in part to low study power and large distances between sites. At the microscale, wastewater treatment plants had an effect on ARG abundance (sul1 and sul2 in water; blaSHV, intl1, mexB, and sul2 in sediment), but not on antimicrobial concentrations. Results from sediment reflected a long-term history, while water reflected a more transient record of antimicrobials and ARG. This study highlights the value of using spatial analyses, different spatial scales, and sampling matrices, to design an environmental monitoring approach to advance our understanding of AMR persistence and dissemination.

Antimicrobial resistance in wildlife and in the built environment in a wildlife rehabilitation center.

Injured and orphaned wildlife are often brought to Wildlife Rehabilitation Centers (WRC) to be cared for by professionals to ultimately be released back to their natural habitats. In these centers, animals may spend months and frequently receive prolonged antibiotic therapy. Therefore, WRC may play a role in the emergence and dissemination of antimicrobial resistance (AMR). The goal of this study was to investigate the presence and antibiotic resistance profiles of Gram-negative bacteria with reduced susceptibility to cephalosporins in both the wildlife admitted to a WRC and in the WRC built environment in Chile. A cross-sectional study was conducted sampling animals undergoing rehabilitation (n = 64) and the WRC environment (n = 160). Isolated bacterial species were identified with MALDI-TOF, and antimicrobial susceptibility determined using the disk diffusion method. Enterobacteriaceae and Pseudomonadaceae were the dominant bacterial families among the environmental (n = 78) and animal (n = 31) isolates. For Enterobacteriaceae, isolates of the most abundant species (E. coli) were classified into 20 antibiotic resistance profiles, with eight of those isolates being resistant to more than nine antibiotics, including imipenem. Isolates of the Pseudomonadaceae family identified 11 isolates with resistance to antibiotics such as carbapenems and quinolones. Even though a cluster analysis based on antibiotic resistance patterns did not show a clear overlap between environmental and animal isolates, it is important to highlight the identification of isolates resistant to carbapenems, which is very relevant from a public health perspective. Further, numerous antibiotic resistance profiles were observed in different bacterial species, indicating not only environmental contamination with a wide diversity of bacteria, but also a wide diversity of resistant bacteria in animals at the WRC. The approach taken by sampling animals and their hospital environment can be useful in understanding AMR dynamics in wildlife rehabilitation settings, as well as the potential dissemination of AMR into the natural environment.

Anesthesia Protocols used to Create Ischemia Reperfusion Myocardial Infarcts in Swine.

The porcine ischemia-reperfusion model is one of the most commonly used for cardiology research and for testing interventions for myocardial regeneration. In creating ischemic reperfusion injury, the anesthetic protocol is important for assuring hemodynamic stability of the animal during the induction of the experimental lesion and may affect its postoperative survival. This paper reviews the many drugs and anesthetic protocols used in recent studies involving porcine models of ischemiareperfusion injury. The paper also summarizes the most important characteristics of some commonly used anesthetic drugs. Literature was selected for inclusion in this review if the authors described the anesthetic protocol used and also reported the mortality rate attributed to the creation of the model. This information is an important consideration because the anesthetic protocol can influence hemodynamic stability during the experimental induction of an acute myocardial infarction, thereby impacting the survival rate and affecting the number of animals needed for each study.

Role of wastewater treatment plants on environmental abundance of Antimicrobial Resistance Genes in Chilean rivers.

BACKGROUND: Point sources such as wastewater treatment plants (WWTPs) commonly discharge their effluent into rivers. Their waste may include antibiotic residues, disinfectants, antibiotic resistant bacteria (ARB), and Antimicrobial Resistance Genes (ARG). There is evidence that ARG can be found in the natural environment, but attribution to specific point sources is lacking. OBJECTIVES: The goal of this study was to assess the release and dissemination of ARG from three WWTPs in southern Chile via two pathways: through the river systems, and through wild birds. METHODS: A longitudinal study was conducted, collecting river sediment samples at different distances both upstream and downstream from each WWTP. Wild birds were sampled from around one of the WWTPs once a month for 13 months. A microfluidic q-PCR approach was used to quantify 48 genes covering different molecular mechanisms of resistance, and data was analyzed using ordination methods and linear mixed regression models. RESULTS: There was a statistically significant increase downstream from the WWTPs (p < 0.05) for 17 ARG, but the downstream dissemination through the rivers was not clear. Beta-lactamase genes blaKPC, blaTEM, and blaSHV were the most abundant in birds, with higher abundance of blaSHV in migratory species compared to resident species (p < 0.05). The gene profile was more similar between the migratory and resident bird groups compared to the WWTP gene profile. CONCLUSIONS: While results from this study indicate an influence of WWTPs on ARG abundance in the rivers, the biological significance of this increase and the extent of the WWTPs influence are unclear. In addition, wild birds were found to play a role in disseminating ARG, although association to the specific WWTP could not be ascertained.

Antibiotic Resistance Genes in Freshwater Trout Farms in a Watershed in Chile.

Point sources such as wastewater treatment plants, terrestrial agriculture, and aquaculture may release antibiotic residues, antibiotic resistant bacteria, and antibiotic resistance genes (ARGs) into aquatic ecosystems. However, there is a lack of quantitative studies attributing environmental ARG abundance to specific sources. The goal of this study was to evaluate the role of freshwater trout farms in the release and dissemination of ARGs into the environment. Sediment samples upstream and downstream from five rainbow trout farms were collected over time in southern Chile. A microfluidic quantitative polymerase chain reaction approach was used to quantify an ARG array covering different mechanisms of resistance, and data were analyzed using principal component analysis (PCA) and linear mixed regression models. Surveys were also conducted to obtain information about management practices, including antibiotic use, at the farms. Florfenicol and oxytetracycline were used at these farms, although at different rates. A total of 93 samples were analyzed. In the PCA, , , , , (A), (B), (C), (W), and grouped together. A statistically significant increase in abundance of , , , and several genes was found downstream from the farms compared with upstream sites, and retention ponds had the highest ARG abundance at each site. Antibiotic resistance gene levels returned to baseline at an average distance of 132.7 m downstream from the farms. Although results from this study indicate an influence of trout farms on the presence of ARGs in the immediate environment, the extent of their contribution to ARG dissemination is unknown and deserves further investigation.

Impact of point sources on antibiotic resistance genes in the natural environment: a systematic review of the evidence.

There is a growing concern about the role of the environment in the dissemination of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG). In this systematic review, we summarize evidence for increases of ARG in the natural environment associated with potential sources of ARB and ARG such as agricultural facilities and wastewater treatment plants. A total of 5247 citations were identified, including studies that ascertained both ARG and ARB outcomes. All studies were screened for relevance to the question and methodology. This paper summarizes the evidence only for those studies with ARG outcomes (n = 24). Sixteen studies were at high (n = 3) or at unclear (n = 13) risk of bias in the estimation of source effects due to lack of information or failure to control for confounders. Statistical methods were used in nine studies; three studies assessed the effect of multiple sources using modeling approaches, and none reported effect measures. Most studies reported higher ARG concentration downstream/near the source, but heterogeneous findings hindered making any sound conclusions. To quantify increases of ARG in the environment due to specific point sources, there is a need for studies that emphasize analytic or design control of confounding, and that provide effect measure estimates.

What is the evidence that point sources of anthropogenic effluent increase antibiotic resistance in the environment? Protocol for a systematic review.

Herein we describe a protocol for a systematic review of the evidence on whether point sources of anthropogenic effluent are associated with an increase in antibiotic resistance in the adjacent environment. The review question was based on the Population, Exposure, Comparator, Outcome, Study Design (PECOS) framework as follows: Is the prevalence or concentration of antibiotic resistant bacteria or resistance genes (O) in soil, water, air or free-living wildlife (P) higher in close proximity to, or downstream from, known or suspected sources of anthropogenic effluent (E) compared to areas more distant from or upstream from these sources (C)? A comprehensive search strategy was created to capture all relevant, published literature. Criteria for two stages of eligibility screening were developed to exclude publications that were not relevant to the question, and determine if the study used a design that permitted estimation of an association between a source and levels of resistance. A decision matrix was created for assessment of risk of bias to internal validity due to sample selection bias, information bias, and confounding. The goal of this protocol is to provide a method for determining the state of knowledge about the effect of point sources on antibiotic resistance in the environment.

External skeletal fixator intramedullary pin tie-in for the repair of tibiotarsal fractures in raptors: 37 cases (1995-2011).

OBJECTIVE: To evaluate the outcome of the application of an external skeletal fixator intramedullary pin tie-in (TIF) to tibiotarsal fractures in raptors. DESIGN: Retrospective case series. ANIMALS: Thirty-four raptors with 37 tibiotarsal fractures. PROCEDURES: Medical records and radiographs for raptors with tibiotarsal fractures that were treated at The Raptor Center at the University of Minnesota between 1995 and 2011 were reviewed. Descriptive statistics were generated and univariate logistic regression analyses were used to assess whether age, sex, body weight, location and nature of the fracture, and type of surgical reduction were significantly associated with whether the fracture healed following surgical reduction and TIF application. RESULTS: 31 of 37 (84%) tibiotarsal fractures successfully healed following surgical reduction and TIF application. The mean healing time was 38 days (range, 15 to 70 days). None of the variables assessed were significantly associated with whether the tibiotarsal fracture healed. Twenty of the 34 (59%) raptors were eventually rehabilitated and released. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that most tibiotarsal fractures were successfully managed by surgical reduction and stabilization with a TIF. However, other comorbidities (eg, systemic infections and visual deficits) negatively affected the rehabilitation of raptors and sometimes resulted in euthanasia despite the fact that the tibiotarsal fracture had healed, and those comorbidities, along with the variables evaluated (eg, age, sex, and nature of the fracture), should be used as triage criteria and prognostic indicators.