Approaches to Assess the Effects and Risks of Veterinary Antibiotics Applied with Manure to Soil

In veterinary medicine, large quantities of antibiotic substances are administered each year for therapeutic and prophylactic purposes or to promote growth. As a consequence, the antibiotics and bacteria carrying transferable antibiotic resistance genes are excreted by the animals and reach the environment through run-off, leaching, and/or following manure application to agricultural fields, where they have been found to affect the structure and function of soil bacterial communities. However, we are only beginning to understand the global effects of environmental pollution with antibiotics and resistance determinants and the resulting risks for human health. For regulatory purposes, there is urgent need for criteria and methods that allow reliable and reproducible assessment of risks associated with release of realistic concentrations of antibiotics and resistance determinants into the environment following manure application. In this chapter, we will summarize recent advances, limitations, and research needed to optimize the methods to quantify and evaluate the effects and risks associated with these compounds. Approaches that are discussed focus on antibiotic resistance genes and include classical tools such as cultivation and PCR detection as well as quantitative real-time PCR and next-generation sequencing technologies used in combination with functional screening

Interaction between Salmonella and Plants: Potential Hosts and Vectors for Human Infection

Fruits and vegetables are important for a healthy diet. However, when eaten raw and contaminated with human pathogens (HPs) they may cause a disease outbreak. Contamination with HPs can occur along the entire farm-to-fork production chain and Salmonella enterica is one of the most common foodborne pathogens. A range of biotic and abiotic environmental factors can influence the complex interactions between Salmonella and plants. Moreover, the outcome of experiments largely depends on the experimental design and parameters or methods employed, and on top, on the accompanying plant microbiome and the genetic equipment of the plant and the Salmonella strain. Particularly mobile genetic elements contribute to the diversification and adaptation of Salmonella to the plant environment. So far, little is known about the key processes and factors influencing the attachment and potential internalization of Salmonella in plants and the plant specific responses. It is therefore important to better understand the ecology of Salmonella in the soil and plant environment, in order to propose practicable recommendations for prevention of foodborne diseases. This also requires improved sensitivity and specificity of detection methods. In this chapter, we present the current knowledge, research needs, and methodology regarding the complex interactions between Salmonella and plants

Sequestration of quaternary ammonium compounds in soil and its relevance for the proliferation of antibiotic resistance in the environment

Quaternary ammonium compounds (QACs) are a group of surface-active, biocidal, high production volume chemicals. In the agricultural sector, their applications are especially broad and range from disinfectants and detergents in animal husbandry to their use as adjuvants in pesticide formulations. Inputs of QACs into agroecosystems are potentially high where manures, sewage sludge or wastewater are applied to the farmer’s fields for nutrient recycling. The presence of QACs in the environment has frequently been inflicted in the co-selection for antibiotic resistance genes (ARGs) with unforeseeable risks for environmental and human health [1]–[3]. The selection of ARGs depends on concentrations of QACs in bio-accessible form and the persistence of these compounds. However, a comprehensive overview on i) predicted & measured concentrations of QACs in soils including their analysis, ii) mechanisms of their sequestration in soils based on their physicochemical and structural properties, and iii) the implications of the concentrations and the fate of QACs in soils for the proliferation of ARGs in the environment is missing. Based on a review of these topics, we propose that QACs are sequestered in the interlayer regions of clay minerals in soils, which reduces their acute toxicity, but increases their persistence. The slow release of QACs from the interlayer regions may maintain concentrations levels in soil solution that are large enough to co-select for antibiotic resistant soil bacteria promoting the proliferation of ARGs in the environment

Outcome of Patients With Esophageal Atresia and Very Low Birth Weight (<= 1,500 g)

Introduction: Primary repair of esophageal atresia (EA) in infants with very low birth weight (VLBW) and extremely low birth weight (ELBW) has been widely performed in pediatric surgery. However, several studies have shown that complication rates in infants with VLBW are high. We hypothesize preterm children benefit from a shorter, less-traumatizing operation in the first days of life, as staged repair implies. Methods: Patients with EA and VLBW were retrieved from the database of a large national patient organization KEKS e.V. Structured questionnaires were sent to all the patients' families; the responses were pseudonymized and sent to our institution. Results: Forty-eight questionnaires from patients were analyzed. The mean birth weight was 1,223 g (720–1,500 g). Primary repair was performed in 25 patients (52%). Anastomotic insufficiency (AI) was reported in 9 patients (19%), recurrent fistula (RF) in 8 (17%), and anastomotic stenosis in 24 patients (50%). Although AI was almost twice as common after primary repair than after staged repair (24 vs. 13%; p = 0.5), the difference was not statistically significant. RF was more frequent after primary repair (28 vs. 4%; p = 0.04), gastroesophageal reflux was more frequent in the group after staged repair (78 vs. 52%; p = 0.04), and both correlations were statistically significant. Intracranial hemorrhage (ICH) was reported in 11 patients (23%) and was observed in 7 of them (64%, p = 0.4) after primary repair. ICH was reported in 60% of patients with ELBW and 75% of patients when ELBW was paired with primary repair. Conclusion: This study demonstrates the complication rate in patients with VLBW is higher than the average of that in patients with EA. The study indicates that a staged approach may be an option in this specific patient group, as less RF and AI are seen after staged repair. ICH rate in patients with ELBW seemed to be especially lower after staged repair. Interestingly, gastroesophageal reflux was statistically significantly higher in the group after staged repair, and postoperative ventilation time was longer. It is therefore necessary to individually consider which surgical approach is appropriate for this special patient group

Composted sewage sludge influences the microbiome and persistence of human pathogens in soil

Composted sewage sludge (CSS) gained attention as a potential fertilizer in agriculture. Application of CSS increases soil microbial activity and microbial biomass, however, it can also lead to increased chemical and microbiological risks. In this study, we performed microcosm experiments to assess how CSS reshapes the microbial community of diluvial sand (DS) soil. Further, we assessed the potential of CSS to increase the persistence of human pathogens in DS soil and the colonization of Chinese cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt). The results revealed that CSS substantially altered the prokaryotic community composition. Moreover, addition of CSS increased the persistence of Salmonella enterica serovar Typhimurium strain 14028s and S. enterica serovar Senftenberg in DS soil. However, the enhanced persistence in soil had no impact on the colonization rate of B. rapa grown on soil inoculated with Salmonella. We detected Salmonella in leaves of 1.9% to 3.6% of plants. Addition of CSS had no impact on the plant colonization rate. The use of sewage sludge composts is an interesting option. However, safety measures should be applied in order to avoid contamination of crop plants by human pathogens