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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, strB, sul1, sul2, qacG, tet(A), tet(B), tet(C), tet(W), and floRgrouped together. A statistically significant increase in abundance of qacG, strB, sul1, and several tetgenes 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. Point sources contribute to antimicrobial resistance (AMR) in the environment.Antibiotic resistance genes (ARG) were quantified in river sediment samples.Freshwater trout farms in southern Chile increased ARG abundance in the watershed.The extent of the contribution of the trout farms on ARG dissemination is uncertain.Epidemiological methods are needed to attribute environmental AMR to specific point sources.

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.

Biblical exegesis played a central role in the theoretical construction of “orthodoxy” throughout the Middle Ages, even as it was progressively formalized into an independent genre separate from theology. Medieval interpreters of Sacred Scripture legitimized their own contributions by linking them to the tradition of early Christian writing, building upon the authoritative legacy of the church fathers and gaining for themselves a place as authorities. While reinforcing Catholic doctrine, exegetes also provided complementary reflections on erroneous, distorted, and deceptive interpretations of the divine word. They sought in Scripture prefigurations of the church's enemies, gleaning from the Bible and the patristic tradition the characteristics of a dangerous population of sinners, dissidents, infidels, and heretics. Alongside polemical, canonical, homiletic, judicial, and hagiographic writings, biblical commentaries made a key contribution to the shaping of the antiheretical discourse of the central and later Middle Ages.