Tag: Environment

Finally the lab podcast is back! In this episode Microbiology Lab Pod, the team (Johan Bengtsson-Palme, Emil Burman, Anna Abramova, Marcus Wenne, Mirjam Dannborg and Agata Marchi) discusses the environmental antibiotic resistance in anticipation of the EDAR conference coming up later this week!

The specific papers discussed in the pod are as follows:

• Marcoleta, Andrés E., Patricio Arros, Macarena A. Varas, José Costa, Johanna Rojas-Salgado, Camilo Berríos-Pastén, Sofía Tapia-Fuentes, et al. “The Highly Diverse Antarctic Peninsula Soil Microbiota as a Source of Novel Resistance Genes.” Science of The Total Environment 810 (March 2022): 152003. https://doi.org/10.1016/j.scitotenv.2021.152003
• Yi, Xinzhu, Jie-Liang Liang, Jian-Qiang Su, Pu Jia, Jing-li Lu, Jin Zheng, Zhang Wang, et al. “Globally Distributed Mining-Impacted Environments Are Underexplored Hotspots of Multidrug Resistance Genes.” The ISME Journal 16, no. 9 (September 2022): 2099–2113. https://doi.org/10.1038/s41396-022-01258-z
• Johnning, Anna, Erik Kristiansson, Jerker Fick, Birgitta Weijdegård, and DG Joakim Larsson. “Resistance Mutations in GyrA and ParC Are Common in Escherichia Communities of Both Fluoroquinolone-Polluted and Uncontaminated Aquatic Environments.” Frontiers in Microbiology 6 (2015): 1355. https://doi.org/10.3389/fmicb.2015.01355
• Flach, Carl-Fredrik, Chandan Pal, Carl Johan Svensson, Erik Kristiansson, Marcus Östman, Johan Bengtsson-Palme, Mats Tysklind, and D. G. Joakim Larsson. “Does Antifouling Paint Select for Antibiotic Resistance?” The Science of the Total Environment 590–591 (July 15, 2017): 461–68. https://doi.org/10.1016/j.scitotenv.2017.01.213

The podcast was recorded on September 12, 2022. If you want to reach out to us with comments, suggestions, or other feedback, please send an e-mail to podcast at microbiology dot se or contact @bengtssonpalme via Twitter. The music that can be heard on the pod is composed by Johan Bengtsson-Palme and is taken from the album Cafe Phonocratique.

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Last week, a paper resulting from a collaboration with Stefanie Heß and Viktor Jonsson was published in Environmental Science & Technology. In the paper, we build a quantitative model for the emergence of antibiotic resistance genes in human pathogens and populate it using the few numbers that are available on different processes (bacterial uptake, horizontal gene transfer rates, rate of mobilization of chromosomal genes, etc.) in the literature (1).

In short, we find that in order for the environment to play an important role in the appearance of novel resistance genes in pathogens, there needs to be a substantial flow of bacteria from the environment to the human microbiome. We also find that most likely the majority of resistance genes in human pathogens have very small fitness costs associated with them, if any cost at all.

The model makes three important predictions:

1. The majority of ARGs present in pathogens today should have very limited effects on fitness. The model caps the average fitness impact for ARGs currently present in human pathogens between −0.2 and +0.1% per generation. By determining the fitness effects of carrying individual ARGs in their current hosts, this prediction could be experimentally tested.
2. The most likely location of ARGs 70 years ago would have been in human-associated bacteria. By tracking ARGs currently present in human pathogens across bacterial genomes, it may be possible to trace the evolutionary history of these genes and thereby identify their likely hosts at the beginning of the antibiotic era, similar to what was done by Stefan Ebmeyer and his colleagues (2). What they found sort-of corroborate the findings of our model and lend support to the idea that most ARGs may not originate in the environment. However, this analysis is complicated by the biased sampling of fully sequenced bacterial genomes, most of which originate from human specimens. That said, the rapid increase in sequencing capacity may make full-scale analysis of ARG origins using genomic data possible in the near future, which would enable testing of this prediction of the model.
3. If the origins of ARGs currently circulating in pathogens can be established, the range of reasonable dispersal ability levels from the environment to pathogens narrows dramatically. Similarly, if the rates of mobilization and horizontal transfer of resistance genes could be better determined by experiments, the model would predict the likely origins more precisely. Just establishing a ball-park range for the mobilization rate would dramatically restrict the possible outcomes of the model. Thus, a more precise determination of any of these parameters would enable several more specific predictions by the model.

This paper has a quite interesting backstory, beginning with me having leftover time on a bus ride in Madison (WI), thinking about whether you could quantize the conceptual framework for resistance gene emergence we described in our 2018 review paper in FEMS Reviews Microbiology (3). This spurred the first attempt at such a model, which then led to Stefanie Heß and me applying for support from the Centre for Antibiotic Resistance Research at the University of Gothenburg (CARe) to develop this idea further. We got this support and Stefanie spent a few days with me in Gothenburg developing this idea into a model we could implement in R.

However, at that point we realized we needed more modeling expertise and brought in Viktor Jonsson to make sure the model was robust. From there, it took us about 1.5 years to refine and rerun the model about a million times… By the early spring this year, we had a reasonable model that we could write a manuscript around, and this is what now is published. It’s been an interesting and very nice ride together with Stefanie and Viktor!

References

1. Bengtsson-Palme J, Jonsson V, Heß S: What is the role of the environment in the emergence of novel antibiotic resistance genes? A modelling approach. Environmental Science & Technology, Article ASAP (2021). doi: 10.1021/acs.est.1c02977 [Paper link]
2. Ebmeyer S, Kristiansson E, Larsson DGJ: A framework for identifying the recent origins of mobile antibiotic resistance genes. Communications Biology 4 (2021). doi: 10.1038/s42003-020-01545-5
3. Bengtsson-Palme J, Kristiansson E, Larsson DGJ: Environmental factors influencing the development and spread of antibiotic resistance. FEMS Microbiology Reviews, 42, 1, 68–80 (2018). doi: 10.1093/femsre/fux053 [Paper link]

We have been awarded with the first best article award from FEMS Microbiology Reviews for our 2018 review Environmental factors influencing the development and spread of antibiotic resistance. I and my co-authors Joakim Larsson and Erik Kristiansson are honoured and – of course – very happy with this recognition of our work. I was interviewed in relation to the prize, an interview that can be read here. But, also, the paper is open access, so you can go and check it all out in its full glory right now!

I am very happy to announce today (on the European Antibiotic Awareness Day), that the EMBARK project that I am coordinator for got funded by JPIAMR with almost 1.4 million Euros over three years!

The primary goal of EMBARK is to establish a baseline for how common resistance is in the environment and what resistance types that can be expected where. That background data will then underpin efforts to standardize different methods for resistance surveillance and identify high-priority targets that should be used for efficient monitoring. In addition, EMBARK will develop and evaluate methods to detect new resistance factors and thereby provide an early-warning system for emerging resistance threats.

EMBARK is an international collaboration funded by JPIAMR. The consortium consists of myself, Thomas Berendonk (TU-Dresden, Germany), Luis Pedro Coelho (Fudan University, China), Sofia Forslund (ECRC Max-Delbrück-Centrum für Molekulare Medizin, Germany), Etienne Ruppé (INSERM, France) and Rabaab Zahra (Quaid-i-Azam University, Pakistan).

EMBARK has a website where the protocols and data generated during the project will be released. Follow our progress towards better monitoring of antimicrobial resistance in the environment here and on the EMBARK Twitter account: @EMBARK_JPIAMR!

Since F1000Research uses a somewhat different publication scheme than most journals, I still haven’t understood if this paper is formally published after peer review, but I start to assume it is. There have been very little changes since the last version, so hence I will be lazy and basically repost what I wrote in April when the first version (the “preprint”) was posted online. The paper (1) is the result of a workshop arranged by the JRC in Italy in 2017. It describes various challenges arising from the process of designing a benchmark strategy for bioinformatics pipelines in the identification of antimicrobial resistance genes in next generation sequencing data.

The paper discusses issues about the benchmarking datasets used, testing samples, evaluation criteria for the performance of different tools, and how the benchmarking dataset should be created and distributed. Specially, we address the following questions:

• How should a benchmark strategy handle the current and expanding universe of NGS platforms?
• What should be the quality profile (in terms of read length, error rate, etc.) of in silico reference materials?
• Should different sets of reference materials be produced for each platform? In that case, how to ensure no bias is introduced in the process?
• Should in silico reference material be composed of the output of real experiments, or simulated read sets? If a combination is used, what is the optimal ratio?
• How is it possible to ensure that the simulated output has been simulated “correctly”?
• For real experiment datasets, how to avoid the presence of sensitive information?
• Regarding the quality metrics in the benchmark datasets (e.g. error rate, read quality), should these values be fixed for all datasets, or fall within specific ranges? How wide can/should these ranges be?
• How should the benchmark manage the different mechanisms by which bacteria acquire resistance?
• What is the set of resistance genes/mechanisms that need to be included in the benchmark? How should this set be agreed upon?
• Should datasets representing different sample types (e.g. isolated clones, environmental samples) be included in the same benchmark?
• Is a correct representation of different bacterial species (host genomes) important?
• How can the “true” value of the samples, against which the pipelines will be evaluated, be guaranteed?
• What is needed to demonstrate that the original sample has been correctly characterised, in case real experiments are used?
• How should the target performance thresholds (e.g. specificity, sensitivity, accuracy) for the benchmark suite be set?
• What is the impact of these performance thresholds on the required size of the sample set?
• How can the benchmark stay relevant when new resistance mechanisms are regularly characterized?
• How is the continued quality of the benchmark dataset ensured?
• Who should generate the benchmark resource?
• How can the benchmark resource be efficiently shared?

Of course, we have not answered all these questions, but I think we have come down to a decent description of the problems, which we see as an important foundation for solving these issues and implementing the benchmarking standard. Some of these issues were tackled in our review paper from last year on using metagenomics to study resistance genes in microbial communities (2). The paper also somewhat connects to the database curation paper we published in 2016 (3), although this time the strategies deal with the testing datasets rather than the actual databases. The paper is the first outcome of the workshop arranged by the JRC on “Next-generation sequencing technologies and antimicrobial resistance” held October 4-5 2017 in Ispra, Italy. You can find the paper here (it’s open access).

On another note, the new paper describing the UNITE database (4) has now got a formal issue assigned to it, as has the paper on tandem repeat barcoding in fungi published in Molecular Ecology Resources last year (5).

References and notes

1. Angers-Loustau A, Petrillo M, Bengtsson-Palme J, Berendonk T, Blais B, Chan KG, Coque TM, Hammer P, Heß S, Kagkli DM, Krumbiegel C, Lanza VF, Madec J-Y, Naas T, O’Grady J, Paracchini V, Rossen JWA, Ruppé E, Vamathevan J, Venturi V, Van den Eede G: The challenges of designing a benchmark strategy for bioinformatics pipelines in the identification of antimicrobial resistance determinants using next generation sequencing technologies. F1000Research, 7, 459 (2018). doi: 10.12688/f1000research.14509.1
2. Bengtsson-Palme J, Larsson DGJ, Kristiansson E: Using metagenomics to investigate human and environmental resistomes. Journal of Antimicrobial Chemotherapy, 72, 2690–2703 (2017). doi: 10.1093/jac/dkx199
3. Bengtsson-Palme J, Boulund F, Edström R, Feizi A, Johnning A, Jonsson VA, Karlsson FH, Pal C, Pereira MB, Rehammar A, Sánchez J, Sanli K, Thorell K: Strategies to improve usability and preserve accuracy in biological sequence databases. Proteomics, 16, 18, 2454–2460 (2016). doi: 10.1002/pmic.201600034
4. Nilsson RH, Larsson K-H, Taylor AFS, Bengtsson-Palme J, Jeppesen TS, Schigel D, Kennedy P, Picard K, Glöckner FO, Tedersoo L, Saar I, Kõljalg U, Abarenkov K: The UNITE database for molecular identification of fungi: handling dark taxa and parallel taxonomic classifications. Nucleic Acids Research, 47, D1, D259–D264 (2019). doi: 10.1093/nar/gky1022
5. Wurzbacher C, Larsson E, Bengtsson-Palme J, Van den Wyngaert S, Svantesson S, Kristiansson E, Kagami M, Nilsson RH: Introducing ribosomal tandem repeat barcoding for fungi. Molecular Ecology Resources, 19, 1, 118–127 (2019). doi: 10.1111/1755-0998.12944

My first original paper of the year was just published in PLoS ONE. This is a collaboration with Åsa Sjöling’s group at the Karolinska Institute and the Universidad Mayor de San Andrés in Bolivia, and the project has been largely run by Jessica Guzman-Otazo.

Poor drinking water quality is a major cause of diarrhea, especially in the absence of well-working sewage treatment systems. In the study, we investigate the numbers of bacteria causing diarrhea (or actually, marker genes for those bacteria) in water, soil and vegetable samples from the Choqueyapu River area in La Paz – Bolivia’s third largest city (1). The river receives sewage and wastewater from industries and hospitals while flowing through La Paz. We found that levels of ETEC – a bacterium that causes severe diarrhea – were much higher in the city than upstream of it, including at a site where the river water is used for irrigation of crops.

In addition, several multi-resistant bacteria could be isolated from the samples, of which many were emerging, globally spreading, multi-resistant variants. The results of the study indicate that there is a real risk for spreading of diarrheal diseases by using the contaminated water for drinking and irrigation (2,3). Furthermore, the identification of multi-resistant bacteria that can cause human diseases show that water contamination is an important route through which antibiotic resistance can be transferred from the environment back to humans (4).

The study was published in PLoS ONE and can be found here.

References

1. Guzman-Otazo J, Gonzales-Siles L, Poma V, Bengtsson-Palme J, Thorell K, Flach C-F, Iñiguez V, Sjöling Å: Diarrheal bacterial pathogens and multi-resistant enterobacteria in the Choqueyapu River in La Paz, Bolivia. PLoS ONE, 14, 1, e0210735 (2019). doi: 10.1371/journal.pone.0210735
2. Graham DW, Collignon P, Davies J, Larsson DGJ, Snape J: Underappreciated Role of Regionally Poor Water Quality on Globally Increasing Antibiotic Resistance. Environ Sci Technol 141001154428000 (2014). doi: 10.1021/es504206x
3. Bengtsson-Palme J: Antibiotic resistance in the food supply chain: Where can sequencing and metagenomics aid risk assessment? Current Opinion in Food Science, 14, 66–71 (2017). doi: 10.1016/j.cofs.2017.01.010
4. Bengtsson-Palme J, Kristiansson E, Larsson DGJ: Environmental factors influencing the development and spread of antibiotic resistance. FEMS Microbiology Reviews, 42, 1, 68–80 (2018). doi: 10.1093/femsre/fux053

Time flies, and my first 2019 publication (wait what?) is now out! It’s a chapter in the book “Management of Emerging Public Health Issues and Risks: Multidisciplinary Approaches to the Changing Environment” (1), edited by Benoit Roig, Karine Weiss and Véronique Thireau. I have to confess to not having read the other chapters in the book yet, but I think the subject is exciting and hope for a lot of good reading over Christmas here!

My chapter deals with assessment and management of risks associated with antibiotic resistance in the environment (2), and particularly I make an attempt at clarifying the different types of risks and how to deal with them. In short, I partition resistance risks into two categories: dissemination risks and risks for acquisition of new types of resistance (see also 3). While the former category largely encompasses quantifiable risks, the latter is to a large extent impossible (or at least extremely hard) to quantify with current means. This means that we need to be a bit more creative in assessing, prioritizing and managing these risks. Some lessons can be learnt from other fields dealing with very uncertain (and rare) risks, such as asteroid impact assessment, nuclear energy accidents and ecosystem destabilization (4,5). Incorporating elements from such risk management schemes will be necessary to understand and delay emergence of novel resistance in the future.

All these aspects are further discussed in the book chapter (2), which I encourage everyone working with environmental antibiotic resistance risks to read!

References

1. Roig B, Weiss K, Thoreau V (Eds.) Management of Emerging Public Health Issues and Risks: Multidisciplinary Approaches to the Changing Environment. Academic Press/Elsevier, UK (2019). doi: 10.1016/C2016-0-00995-6
2. Bengtsson-Palme J: Assessment and management of risks associated with antibiotic resistance in the environment. In: Roig B, Weiss K, Thoreau V (Eds.) Management of Emerging Public Health Issues and Risks: Multidisciplinary Approaches to the Changing Environment, 243–263. Elsevier, UK (2019). doi: 10.1016/B978-0-12-813290-6.00010-X
3. Bengtsson-Palme J, Kristiansson E, Larsson DGJ: Environmental factors influencing the development and spread of antibiotic resistance. FEMS Microbiology Reviews, 42, 1, 68–80 (2018). doi: 10.1093/femsre/fux053
4. WBGU GACOGC: World in Transition: Strategies for Managing Global Environmental Risks. Springer
   Berlin Heidelberg, Berlin, Heidelberg (2000).
5. Government Office for Science: Blackett Review of High Impact Low Probability Events. Department for
   Business, Innovation and Skills, London (2011).

I’m really late at this ball for a number of reasons, but last week Nature published our paper on the structure and function of the global topsoil microbiome (1). This paper has a long story, but in short I got contacted by Mohammad Bahram (the first author) about two years ago about a project using metagenomic sequencing to look at a lot of soil samples for patterns of antibiotic resistance gene abundances and diversity. The project had made the interesting discovery that resistance gene abundances were linked to the ratio of fungi and bacteria (so that more fungi was linked to more resistance genes). During the following year, we together worked on deciphering these discoveries, which are now published in Nature. The paper also deals with the taxonomic patterns linked to geography (1), but as evident from the above, my main contribution here has been on the antibiotic resistance side.

In short, we find that:

• Bacterial diversity is highest in temperate habitats, and lower both closer to the equator and the poles
• For bacteria, the diversity of biological functions follows the same pattern, but for fungi, the functional diversity is higher closer to the poles and the equator
• Higher abundance of fungi is linked to higher abundance and diversity of antibiotic resistance genes. Specifically, this is related to known antibiotic producing fungal lineages, such as Penicillium and Oidiodendron. There also seems to be a link between the Actinobacteria, encompassing the antibiotic-producing bacterial genus of Streptomyces and higher resistance gene diversity.
• Similar relationships between the fungus-like Oomycetes and resistance genes was also found in ocean samples from the Tara Oceans project (2)

The results of this study indicate that both environmental filtering and niche differentiation determine soil microbial composition, and that the role of dispersal limitation is minor at this scale. Soil pH and precipitation seems to be the strongest drivers of community composition. Furthermore, we interpret our data to reveal that inter-kingdom antagonism is important in structuring microbial communities. This speaks against the notion put forward that antibiotic resistance genes might not have a resistance function in natural settings (3). That said, the most likely explanation here is probably a bit of both warfare and repurposing of genes. Soil seems to be the largest untapped source of resistance genes for human pathogens (4), and the finding that natural antagonism may be driving resistance gene diversification and enrichment may be important for future management of environmental antibiotic resistance (5,6).

It was really great to work with Mohammad and his team, and I sure hope that we will collaborate again in the future. The entire paper can be found in the issue of Nature coming out this week, and is already online at Nature’s website.

References

1. Bahram M°, Hildebrand F°, Forslund SK, Anderson JL, Soudzilovskaia NA, Bodegom PM, Bengtsson-Palme J, Anslan S, Coelho LP, Harend H, Huerta-Cepas J, Medema MH, Maltz MR, Mundra S, Olsson PA, Pent M, Põlme S, Sunagawa S, Ryberg M, Tedersoo L, Bork P: Structure and function of the global topsoil microbiome. Nature, 560, 233–237 (2018). doi: 10.1038/s41586-018-0386-6
2. Sunagawa S et al. Structure and function of the global ocean microbiome. Science 348, 6237, 1261359 (2015). doi: 10.1126/science.1261359
3. Aminov RI: The role of antibiotics and antibiotic resistance in nature. Environmental Microbiology, 11, 12, 2970-2988 (2009). doi: 10.1111/j.1462-2920.2009.01972.x
4. Bengtsson-Palme J: The diversity of uncharacterized antibiotic resistance genes can be predicted from known gene variants – but not always. Microbiome, 6, 125 (2018). doi: 10.1186/s40168-018-0508-2
5. Bengtsson-Palme J, Kristiansson E, Larsson DGJ: Environmental factors influencing the development and spread of antibiotic resistance. FEMS Microbiology Reviews, 42, 1, 68–80 (2018). doi: 10.1093/femsre/fux053
6. Larsson DGJ, Andremont A, Bengtsson-Palme J, Brandt KK, de Roda Husman AM, Fagerstedt P, Fick J, Flach C-F, Gaze WH, Kuroda M, Kvint K, Laxminarayan R, Manaia CM, Nielsen KM, Ploy M-C, Segovia C, Simonet P, Smalla K, Snape J, Topp E, van Hengel A, Verner-Jeffreys DW, Virta MPJ, Wellington EM, Wernersson A-S: Critical knowledge gaps and research needs related to the environmental dimensions of antibiotic resistance. Environment International, 117, 132–138 (2018).

I have just published a popular-science-for-scientists type of post at the Nature Microbiology Community about my recent paper published in Microbiome. I personally think that it might be worth a read, so feel free to head over here and read it!

Over the weekend, Microbiome put online my most recent paper (1) – a project which started as an idea I got when I finished up my PhD thesis in 2016. One of my main points in the thesis (2), which was also made again on our recent review on environmental factors influencing resistance development (3), is that the greatest risks associated with antibiotic resistance in the environment may not be the resistance genes already circulating in pathogens (which are relatively easily quantified), but the ones associated with recruitment of novel resistance genes from bacteria in the environment (2-4). The latter genes are, however, impossible to quantify due to the fact that they are unknown. But what if we could use knowledge of the diversity and abundance of known resistance genes to estimate the same properties of the yet uncharacterized resistome? That would be a great advantage in e.g. ranking of risk environments, as then some property that is easily monitored can be used to inform risk management of both known and unknown resistance factors.

This just published paper explores this possibility, by quantifying the abundance and diversity of resistance genes in 1109 metagenomes from various environments (1). I have taken two different approaches. First, I took out smaller subsets of genes from the reference database (in this case Resqu, a database of antibiotic resistance genes with verified resistance functions, detected on mobile genetic elements), and used those subsets to estimate resistome diversity and abundance in the 1109 metagenomes. Then these predictions were compared to the results of the entire database. I then, in a second step, investigated if these predictions could be extended to a set of truly novel resistance genes, i.e. the resistance genes present in the FARME database, collecting data from functional metagenomics inserts (5,6).

The results show that generally the diversity and abundance of known antibiotic resistance genes can be used to predict the same properties of undescribed resistance genes (see figure above). However, the extent of this predictability is, importantly, dependent on the type of environment investigated. The study also shows that carefully selected small sets of resistance genes can describe total resistance gene diversity remarkably well. This means that knowledge gained from large-scale quantifications of known resistance genes can be utilized as a proxy for unknown resistance factors. This is important for current and proposed monitoring efforts for environmental antibiotic resistance (7-11) and has implications for the design of risk ranking strategies and the choices of measures and methods for describing resistance gene abundance and diversity in the environment.

The study also investigated which diversity measures were best suited to estimate total diversity. Surprisingly, some diversity measures described the total diversity of resistance genes remarkably bad. Most prominently, the Simpson diversity index consistently showed poor performance, and while the Shannon index performed relatively better, there is still no reason to select the Shannon index over normalized (rarefied) richness of resistance genes. The ACE estimator fluctuated substantially compared to the other diversity measures, while the Chao1 estimator more consistently showed performance very similar to richness. Therefore, either richness or the Chao1 estimator should be used for ranking resistance gene diversity, while the Shannon, Simpson, and ACE measures should be avoided.

Importantly, this study implies that the recruitment of novel antibiotic resistance genes from the environment to human pathogens is essentially random. Therefore, when ranking risks associated with antibiotic resistance in environmental settings, the knowledge gained from large-scale quantification of known resistance genes can be utilized as a proxy for the unknown resistance factors (although this proxy is not perfect). Thus, high-risk environments for resistance development and dissemination would, for example, be aquaculture, animal husbandry, discharges from antibiotic manufacturing, and untreated sewage (3,8,12-15). Further attention should probably be paid to antibiotic contaminated soils, as this study points to soils as a vast source of resistance genes not yet encountered in human pathogens. This has also been suggested previously by others (16-19). The results of this study can be used to guide monitoring efforts for environmental antibiotic resistance, to design risk ranking strategies, and to choose appropriate measures and methods for describing resistance gene abundance and diversity in the environment. The entire open access paper is available here.

References

1. Bengtsson-Palme J: The diversity of uncharacterized antibiotic resistance genes can be predicted from known gene variants – but not always. Microbiome, 6, 125 (2018). doi: 10.1186/s40168-018-0508-2
2. Bengtsson-Palme J: Antibiotic resistance in the environment: a contribution from metagenomic studies. Doctoral thesis (medicine), Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 2016. [Link]
3. Bengtsson-Palme J, Kristiansson E, Larsson DGJ: Environmental factors influencing the development and spread of antibiotic resistance. FEMS Microbiology Reviews, 42, 1, 68–80 (2018). doi: 10.1093/femsre/fux053
4. Bengtsson-Palme J, Larsson DGJ: Antibiotic resistance genes in the environment: prioritizing risks. Nature Reviews Microbiology, 13, 369 (2015). doi: 10.1038/nrmicro3399-c1
5. Wallace JC, Port JA, Smith MN, Faustian EM: FARME DB: a functional antibiotic resistance element database. Database, 2017, baw165 (2017).
6. Handelsman J, Rondon MR, Brady SF, Clardy J, Goodman RM: Molecular biological access to the chemistry of unknown soil microbes: a new frontier for natural products. Chemical Biology, 5, R245–249 (1998).
7. Berendonk TU, Manaia CM, Merlin C, Fatta-Kassinos D, Cytryn E, Walsh F, et al.: Tackling antibiotic resistance: the environmental framework. Nature Reviews Microbiology, 13, 310–317 (2015).
8. Pruden A, Larsson DGJ, Amézquita A, Collignon P, Brandt KK, Graham DW, et al.: Management options for reducing the release of antibiotics and antibiotic resistance genes to the environment. Environmental Health Perspectives, 121, 878–885 (2013).
9. Review on Antimicrobial Resistance: Antimicrobials in agriculture and the environment: reducing unnecessary use and waste. O’Neill J, ed. London: Wellcome Trust & HM Government (2015).
10. Angers-Loustau A, Petrillo M, Bengtsson-Palme J, Berendonk T, Blais B, Chan KG, Coque TM, Hammer P, Heß S, Kagkli DM, Krumbiegel C, Lanza VF, Madec J-Y, Naas T, O’Grady J, Paracchini V, Rossen JWA, Ruppé E, Vamathevan J, Venturi V, Van den Eede G: The challenges of designing a benchmark strategy for bioinformatics pipelines in the identification of antimicrobial resistance determinants using next generation sequencing technologies. F1000Research, 7, 459 (2018). doi: 10.12688/f1000research.14509.1
11. Larsson DGJ, Andremont A, Bengtsson-Palme J, Brandt KK, de Roda Husman AM, Fagerstedt P, Fick J, Flach C-F, Gaze WH, Kuroda M, Kvint K, Laxminarayan R, Manaia CM, Nielsen KM, Ploy M-C, Segovia C, Simonet P, Smalla K, Snape J, Topp E, van Hengel A, Verner-Jeffreys DW, Virta MPJ, Wellington EM, Wernersson A-S: Critical knowledge gaps and research needs related to the environmental dimensions of antibiotic resistance. Environment International, 117, 132–138 (2018). doi: 10.1016/j.envint.2018.04.041
12. Allen HK, Donato J, Wang HH, Cloud-Hansen KA, Davies J, Handelsman J: Call of the wild: antibiotic resistance genes in natural environments. Nature Reviews Microbiology, 8, 251–259 (2010).
13. Graham DW, Collignon P, Davies J, Larsson DGJ, Snape J: Underappreciated role of regionally poor water quality on globally increasing antibiotic resistance. Environmental Science & Technology, 48,11746–11747 (2014).
14. Larsson DGJ: Pollution from drug manufacturing: review and perspectives. Philosophical Transactions of the Royal Society of London, Series B Biological Sciences, 369, 20130571 (2014).
15. Cabello FC, Godfrey HP, Buschmann AH, Dölz HJ: Aquaculture as yet another environmental gateway to the development and globalisation of antimicrobial resistance. Lancet Infectious Diseases, 16, e127–133 (2016).
16. Forsberg KJ, Reyes A, Wang B, Selleck EM, Sommer MOA, Dantas G: The shared antibiotic resistome of soil bacteria and human pathogens. Science, 337, 1107–1111 (2012).
17. Allen HK, Moe LA, Rodbumrer J, Gaarder A, Handelsman J: Functional metagenomics reveals diverse beta-lactamases in a remote Alaskan soil. ISME Journal, 3, 243–251 (2009).
18. Riesenfeld CS, Goodman RM, Handelsman J: Uncultured soil bacteria are a reservoir of new antibiotic resistance genes. Environmental Microbiology, 6, 981–989 (2004).
19. McGarvey KM, Queitsch K, Fields S: Wide variation in antibiotic resistance proteins identified by functional metagenomic screening of a soil DNA library. Applied and Environmental Microbiology, 78, 1708–1714 (2012).