Development and validation of novel PCR primers for identification of plasmid-mediated colistin resistance (mcr) genes in various environmental settings

Antibiotic resistance is considered one of the biggest threats to public health and has become a major concern for governments and international organizations. Combating this problem starts with improving global surveillance of antibiotic resistance genes (ARGs) and applying standardized protocols, both in a clinical and environmental context, in agreement with the One Health approach. Exceptional efforts should be directed to controlling ARGs conferring resistance to Critically Important Antimicrobials (CIA). In this study, a systematic literature review to synthesize data on the identification of mcr genes using a PCR technique was performed. Additionally, a novel set of PCR primers for mcr-1 – mcr-9 genes detection was proposed. The developed primers were in silico and experimentally validated by comparison with mcr-specific PCR primers reported in the literature. This validation, besides being a proof-of-concept for primers’ usefulness, provided insight into the distribution of mcr genes in municipal wastewater, clay and river sediments, glacier moraine, manure, seagulls and auks feces and daphnids from four countries. This analysis proved that commonly used primers may deliver false results, and some mcr genes may be overlooked in tested samples. Newly-developed PCR primers turned out to be relevant for the screening of mcr genes in various environments.info:eu-repo/semantics/publishedVersio

Monitoring antibiotic resistance genes in wastewater environments: The challenges of filling a gap in the One-Health cycle

Antibiotic resistance (AR) is a global problem requiring international cooperation and coordinated action. Global monitoring must rely on methods available and comparable across nations to quantify AR occurrence and identify sources and reservoirs, as well as paths of AR dissemination. Numerous analytical tools that are gaining relevance in microbiology, have the potential to be applied to AR research. This review summarizes the state of the art of AR monitoring methods, considering distinct needs, objectives and available resources. Based on the overview of distinct approaches that are used or can be adapted to monitor AR, it is discussed the potential to establish reliable and useful monitoring schemes that can be implemented in distinct contexts. This discussion places the environmental monitoring within the One-Health approach, where two types of risk, dissemination across distinct environmental compartments, and transmission to humans, must be considered. The plethora of methodological approaches to monitor AR and the variable features of the monitored sites challenge the capacity of the scientific community and policy makers to reach a common understanding. However, the dialogue between different methods and the production of action-oriented data is a priority. The review aims to warm up this discussion

The Paleozoic Origin of Enzymatic Lignin Decomposition Reconstructed from 31 Fungal Genomes

Wood is a major pool of organic carbon that is highly resistant to decay, owing largely to the presence of lignin. The only organisms capable of substantial lignin decay are white rot fungi in the Agaricomycetes, which also contains non–lignin-degrading brown rot and ectomycorrhizal species. Comparative analyses of 31 fungal genomes (12 generated for this study) suggest that lignin-degrading peroxidases expanded in the lineage leading to the ancestor of the Agaricomycetes, which is reconstructed as a white rot species, and then contracted in parallel lineages leading to brown rot and mycorrhizal species. Molecular clock analyses suggest that the origin of lignin degradation might have coincided with the sharp decrease in the rate of organic carbon burial around the end of the Carboniferous period

Presentation1_Diversity of antibiotic resistance gene variants at subsequent stages of the wastewater treatment process revealed by a metagenomic analysis of PCR amplicons.pdf

Wastewater treatment plants have been recognised as point sources of various antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG) which are considered recently emerging biological contaminants. So far, culture-based and molecular-based methods have been successfully applied to monitor antimicrobial resistance (AMR) in WWTPs. However, the methods applied do not permit the comprehensive identification of the true diversity of ARGs. In this study we applied next-generation sequencing for a metagenomic analysis of PCR amplicons of ARGs from the subsequent stages of the analysed WWTP. The presence of 14 genes conferring resistance to different antibiotic families was screened by PCR. In the next step, three genes were selected for detailed analysis of changes of the profile of ARG variants along the process. A relative abundance of 79 variants was analysed. The highest diversity was revealed in the ermF gene, with 52 variants. The relative abundance of some variants changed along the purification process, and some ARG variants might be present in novel hosts for which they were currently unassigned. Additionally, we identified a pool of novel ARG variants present in the studied WWTP. Overall, the results obtained indicated that the applied method is sufficient for analysing ARG variant diversity.</p

Development of the LCPDb-MET database facilitating selection of PCR primers for the detection of metal metabolism and resistance genes in bacteria

Bacterial metal metabolism and resistance genes are important indicators for microbial ecology, biogeochemistry, and biotechnology. Their investigation enables understanding how bacteria influence the geochemical cycles of elements and how bacteria can be employed in the bioremediation of polluted areas. For environmental screening, the polymerase chain reaction (PCR) technique has been used as the method of choice for the detection of metal metabolism and resistance genes, and subsequently, many different PCR primer pairs have been developed for such screening. The aim of this study was the development of a database of PCR primers suitable for the screening of metal metabolism and resistance genes in environmental samples. We conducted an in silico benchmark of 291 previously published PCR primer pairs designed to amplify genes involved in bacterial metabolism and resistance to arsenic, cadmium, chromium, cobalt, copper, gold, iron, lead, mercury, nickel, silver, and zinc. Our analysis showed that only 16 PCR primer pairs can be considered well designed and suitable for reliable screening in an environmental setup. Furthermore, 55 primer pairs delivered ambiguous results, while the remaining 220 pairs showed no in silico PCR product within their expected product size range. Based on the obtained results, we developed a ranked database (LCPDb-MET; http://lcpdb.ddlemb.com/met/) of primers suitable for the screening of bacterial metal metabolism and resistance genes in various environmental settings. Moreover, since in the course of the study we recognized a serious problem with the classification of metal metabolism and resistance reference sequences, we developed also the METGeneDb database (http://lcpdb.ddlemb.com/downloads). This database covers 106 genes with 7,624 unique sequences divided into 137 potential gene subclusters and it can be used as the reference database in the genomic and metagenomic studies

Genomic and Biotechnological Characterization of the Heavy-Metal Resistant, Arsenic-Oxidizing Bacterium Ensifer sp. M14

Ensifer (Sinorhizobium) sp. M14 is an efficient arsenic-oxidizing bacterium (AOB) that displays high resistance to numerous metals and various stressors. Here, we report the draft genome sequence and genome-guided characterization of Ensifer sp. M14, and we describe a pilot-scale installation applying the M14 strain for remediation of arsenic-contaminated waters. The M14 genome contains 6874 protein coding sequences, including hundreds not found in related strains. Nearly all unique genes that are associated with metal resistance and arsenic oxidation are localized within the pSinA and pSinB megaplasmids. Comparative genomics revealed that multiple copies of high-affinity phosphate transport systems are common in AOBs, possibly as an As-resistance mechanism. Genome and antibiotic sensitivity analyses further suggested that the use of Ensifer sp. M14 in biotechnology does not pose serious biosafety risks. Therefore, a novel two-stage installation for remediation of arsenic-contaminated waters was developed. It consists of a microbiological module, where M14 oxidizes As(III) to As(V) ion, followed by an adsorption module for As(V) removal using granulated bog iron ores. During a 40-day pilot-scale test in an abandoned gold mine in Zloty Stok (Poland), water leaving the microbiological module generally contained trace amounts of As(III), and dramatic decreases in total arsenic concentrations were observed after passage through the adsorption module. These results demonstrate the usefulness of Ensifer sp. M14 in arsenic removal performed in environmental settings

Monitoring antibiotic resistance genes in wastewater environments: The challenges of filling a gap in the One-Health cycle

Antibiotic resistance (AR) is a global problem requiring international cooperation and coordinated action. Global monitoring must rely on methods available and comparable across nations to quantify AR occurrence and identify sources and reservoirs, as well as paths of AR dissemination. Numerous analytical tools that are gaining relevance in microbiology, have the potential to be applied to AR research. This review summarizes the state of the art of AR monitoring methods, considering distinct needs, objectives and available resources. Based on the overview of distinct approaches that are used or can be adapted to monitor AR, it is discussed the potential to establish reliable and useful monitoring schemes that can be implemented in distinct contexts. This discussion places the environmental monitoring within the One-Health approach, where two types of risk, dissemination across distinct environmental compartments, and transmission to humans, must be considered. The plethora of methodological approaches to monitor AR and the variable features of the monitored sites challenge the capacity of the scientific community and policy makers to reach a common understanding. However, the dialogue between different methods and the production of action-oriented data is a priority. The review aims to warm up this discussion.BT/Environmental Biotechnolog

Genome-Guided Characterization of Ochrobactrum sp. POC9 Enhancing Sewage Sludge Utilization—Biotechnological Potential and Biosafety Considerations

Sewage sludge is an abundant source of microorganisms that are metabolically active against numerous contaminants, and thus possibly useful in environmental biotechnologies. However, amongst the sewage sludge isolates, pathogenic bacteria can potentially be found, and such isolates should therefore be carefully tested before their application. A novel bacterial strain, Ochrobactrum sp. POC9, was isolated from a sewage sludge sample collected from a wastewater treatment plant. The strain exhibited lipolytic, proteolytic, cellulolytic, and amylolytic activities, which supports its application in biodegradation of complex organic compounds. We demonstrated that bioaugmentation with this strain substantially improved the overall biogas production and methane content during anaerobic digestion of sewage sludge. The POC9 genome content analysis provided a deeper insight into the biotechnological potential of this bacterium and revealed that it is a metalotolerant and a biofilm-producing strain capable of utilizing various toxic compounds. The strain is resistant to rifampicin, chloramphenicol and &beta;-lactams. The corresponding antibiotic resistance genes (including blaOCH and cmlA/floR) were identified in the POC9 genome. Nevertheless, as only few genes in the POC9 genome might be linked to pathogenicity, and none of those genes is a critical virulence factor found in severe pathogens, the strain appears safe for application in environmental biotechnologies

The Paleozoic origin of enzymatic mechanisms for lignin degradation reconstructed using 31 fungal genomes

Wood is a major pool of organic carbon that is highly resistant to decay, owing largely to the presence of lignin. The only organisms capable of substantial lignin decay are white rot fungi in the Agaricomycetes, which also contains non?lignin-degrading brown rot and ectomycorrhizal species. Comparative analyses of 31 fungal genomes (12 generated for this study) suggest that lignin-degrading peroxidases expanded in the lineage leading to the ancestor of the Agaricomycetes, which is reconstructed as a white rot species, and then contracted in parallel lineages leading to brown rot and mycorrhizal species. Molecular clock analyses suggest that the origin of lignin degradation might have coincided with the sharp decrease in the rate of organic carbon burial around the end of the Carboniferous period