Tag: Antibiotic resistance

Published paper: Computational discovery of novel qnr genes

BMC Genomics today published a paper first-authored by my long-time colleague Fredrik Boulund, which describes a computational screen of genomes and metagenomes for novel qnr fluoroquinolone resistance genes (1). The study makes use of Fredrik’s well-designed and updated qnr-prediction pipeline, but in contrast to his previous publication based on the pipeline from 2012 (2), we here study a 20-fold larger dataset of almost 13 terabases of sequence data. Based on this data, the pipeline predicted 611 putative qnr genes, including all previously described plasmid-mediated qnr gene families. 20 of the predicted genes were previously undescribed, and of these nine were selected for experimental validation. Six of those tested genes improved the survivability under ciprofloxacin exposure when expressed in Escherichia coli. The study shows that qnr genes are almost ubiquitous in environmental microbial communities. This study also lends further credibility to the hypothesis that environmental bacterial communities can act as sources of previously uncharacterized antibiotic resistance genes (3-7). The study can be read in its entirety here.

References

  1. Boulund F, Berglund F, Flach C-F, Bengtsson-Palme J, Marathe NP, Larsson DGJ, Kristiansson E: Computational discovery and functional validation of novel fluoroquinolone resistance genes in public metagenomic data sets. BMC Genomics, 18, 682 (2017). doi: 10.1186/s12864-017-4064-0
  2. Boulund F, Johnning A, Pereira MB, Larsson DGJ, Kristiansson E: A novel method to discover fluoroquinolone antibiotic resistance (qnr) genes in fragmented nucleotide sequences. BMC Genomics, 13, 695 (2012). doi: 10.1186/1471-2164-13-695
  3. Bengtsson-Palme J, Larsson DGJ: Antibiotic resistance genes in the environment: prioritizing risks. Nature Reviews Microbiology, 13, 369 (2015). doi: 10.1038/nrmicro3399-c1
  4. Allen HK, Donato J, Wang HH et al.: Call of the wild: antibiotic resistance genes in natural environments. Nature Reviews Microbiology, 8, 251–259 (2010).
  5. Berendonk TU, Manaia CM, Merlin C et al.: Tackling antibiotic resistance: the environmental framework. Nature Reviews Microbiology, 13, 310–317 (2015).
  6. Martinez JL: Bottlenecks in the transferability of antibiotic resistance from natural ecosystems to human bacterial pathogens. Frontiers in Microbiology, 2, 265 (2011).
  7. Finley RL, Collignon P, Larsson DGJ et al.: The scourge of antibiotic resistance: the important role of the environment. Clinical Infectious Diseases, 57, 704–710 (2013).

New employment – same work

Today, I started my new position at the University of Gothenburg as a non-tenured assistant professor (forskarassistent)*. In essence, this means that I have a position funded by my own grant until the end of 2020, although I will be on a leave-of-absence while doing my PostDoc with Jo Handelsman in Wisconsin. Speaking of which, I will be leaving to the US on Thursday next week for a month of setting things up at her lab (and also going to the EDAR4 conference in Lansing). I will return to Sweden in mid-September and leave for the US for real early next year.

In terms of actual work, this change of position will not mean very much at the moment. I will continue to do the same things for some time, and I will remain closely associated with Joakim Larsson’s lab at the Dept. of Infectious Diseases. And luckily, I will retain my lovely roommates for at least the time being. In the long run, however, this means that I will shift my research focus slightly, away from antibiotic resistance risk management towards interactions in microbial communities (still related to antibiotics though). Exciting times ahead!

Note
* For some reason, the university administration refuses to call this position assistant professor in English at this time, instead referring to the position as “Postdoctoral research fellow”. I guess that it might be bloody annoying explaining that this is not the same as “postdoctoral researcher” and virtually everywhere else would be called “(non-tenured) assistant professor”, but then on the other hand, who cares about titles anyway?

Published paper: Investigating resistomes using metagenomics

Today, a review paper which I wrote together with Joakim Larsson and Erik Kristiansson was published in Journal of Antimicrobial Chemotherapy (1). We have for a long time used metagenomic DNA sequencing to study antibiotic resistance in different environments (2-6), including in the human microbiota (7). Generally, our ultimate purpose has been to assess the risks to human health associated with resistance genes in the environment. However, a multitude of methods exist for metagenomic data analysis, and over the years we have learned that not all methods are suitable for the investigation of resistance genes for this purpose. In our review paper, we describe and discuss current methods for sequence handling, mapping to databases of resistance genes, statistical analysis and metagenomic assembly. We also provide an overview of important considerations related to the analysis of resistance genes, and end by recommending some of the currently used tools, databases and methods that are best equipped to inform research and clinical practice related to antibiotic resistance (see the figure from the paper below). We hope that the paper will be useful to researchers and clinicians interested in using metagenomic sequencing to better understand the resistance genes present in environmental and human-associated microbial communities.

References

  1. Bengtsson-Palme J, Larsson DGJ, Kristiansson E: Using metagenomics to investigate human and environmental resistomes. Journal of Antimicrobial Chemotherapy, advance access (2017). doi: 10.1093/jac/dkx199 [Paper link]
  2. Bengtsson-Palme J, Boulund F, Fick J, Kristiansson E, Larsson DGJ: Shotgun metagenomics reveals a wide array of antibiotic resistance genes and mobile elements in a polluted lake in India. Frontiers in Microbiology, 5, 648 (2014). doi: 10.3389/fmicb.2014.00648 [Paper link]
  3. Lundström S, Östman M, Bengtsson-Palme J, Rutgersson C, Thoudal M, Sircar T, Blanck H, Eriksson KM, Tysklind M, Flach C-F, Larsson DGJ: Minimal selective concentrations of tetracycline in complex aquatic bacterial biofilms. Science of the Total Environment, 553, 587–595 (2016). doi: 10.1016/j.scitotenv.2016.02.103 [Paper link]
  4. Bengtsson-Palme J, Hammarén R, Pal C, Östman M, Björlenius B, Flach C-F, Kristiansson E, Fick J, Tysklind M, Larsson DGJ: Elucidating selection processes for antibiotic resistance in sewage treatment plants using metagenomics. Science of the Total Environment, 572, 697–712 (2016). doi: 10.1016/j.scitotenv.2016.06.228 [Paper link]
  5. Pal C, Bengtsson-Palme J, Kristiansson E, Larsson DGJ: The structure and diversity of human, animal and environmental resistomes. Microbiome, 4, 54 (2016). doi: 10.1186/s40168-016-0199-5 [Paper link]
  6. Flach C-F, Pal C, Svensson CJ, Kristiansson E, Östman M, Bengtsson-Palme J, Tysklind M, Larsson DGJ: Does antifouling paint select for antibiotic resistance? Science of the Total Environment, 590–591, 461–468 (2017). doi: 10.1016/j.scitotenv.2017.01.213 [Paper link]
  7. Bengtsson-Palme J, Angelin M, Huss M, Kjellqvist S, Kristiansson E, Palmgren H, Larsson DGJ, Johansson A: The human gut microbiome as a transporter of antibiotic resistance genes between continents. Antimicrobial Agents and Chemotherapy, 59, 10, 6551–6560 (2015). doi: 10.1128/AAC.00933-15 [Paper link]

Talk on emission limits in Stockholm

In two weeks time, on the 15th of June, I will participate in a seminar organised by Landstingens nätverk för läkemedel och miljö (the Swedish county council network for pharmaceuticals and environment; the seminar will be held in Swedish) in Stockholm. I will give a talk on our proposed emission limits for antibiotics published last year (the paper is available here), but there will also be talks on wastewater treatment, sustainable pharmaceutical usage and environmental standards for pharmaceuticals. The full program can be found here, and you may register here until June 9. The seminar is free of charge.

And if you are interested in this, I can also recommend the webinar given by Healthcare Without Harm next week (on June 8), which will deal with sustainable procurement as a means to deal with pharmaceutical pollution in the environment. I will at least tune in to hear how the discussion goes here.

Report on JRC AMR workshop

In March, I attended a workshop on the role of NGS technologies in the coordinated action plan against antimicrobial resistance, organised by JRC in Italy. I was, together with 14 other experts, invited to discuss where and how sequencing can be used to investigate and manage antibiotic resistance. The report from the workshop has just recently been published, and is available here. There will be follow-up activities on this workshop, which I also hope that I will be able to participate in, since this is an important and very interesting pet topic of mine.

Reference

  • Angers A, Petrillo P, Patak, A, Querci M, Van den Eede G: The Role and Implementation of Next-Generation Sequencing Technologies in the Coordinated Action Plan against Antimicrobial Resistance. JRC Conference and Workshop Report, EUR 28619 (2017). doi: 10.2760/745099 [Link]
  • Webinar online and the Science Festival

    First of all, I am happy to announce that the webinar I participated in on the (un)recognised pathways of AMR: Air pollution and food, organised by Healthcare Without Harm is now put online so that you can view it, in case you missed out on this event. To be honest it is probably not one of my best public appearances, but the topic is highly interesting.

    Second, next week I am taking part in Vetenskapsfestivalen – the Science Festival in Gothenburg. Specifically, I will be on of the researchers participating in the Science Roulette, taking place in the big ferris wheel at Liseberg. This will take place between 17.00 and 18.00 on May 11th. The idea is that people will be paired with researchers in diverse subjects, of which I am one, and then have a 20 minute chat while the wheel is spinning. Sounds like potential for lot of fun, and I hope to see you there! I will discuss antibiotic resistance, and for how much longer we can trust that our antibiotics will work.

    Published paper: Does antifouling paint select for antibiotic resistance?

    After the usual (1,2) long wait between acceptance and publication, Science of the Total Environment today put a paper online in which I have played a role in the bioinformatic analysis. In the paper, we investigate whether antifouling paint containing copper and zinc could co-select for antibiotic resistance, using microbiological methods and metagenomic sequencing (3).

    In this work, we have studied marine microbial biofilms allowed to grow on surfaces painted with antifouling paint submerged in sea water. Such antifouling paints often contain metals that potentially could co-select for antibiotic resistance (4). Using microbiological culturing, we found that the heavy-metal based paint co-selected for bacteria resistant to tetracycline. However, the paint did not enrich neither the total abundance of known mobile antibiotic resistance genes nor the abundance of tetracycline resistance genes in the biofilm communities. Rather, the communities from the painted surfaces were enriched for bacteria with genetic profiles suggesting increased capacity for extrusion of antibiotics via RND efflux systems. In addition, these communities were also enriched for genes involved in mobilization of DNA, such as ISCR transposases and integrases. Finally, the biofilm communities from painted surfaces displayed lower taxonomic diversity and were at the same time enriched for Gammaproteobacteria. The paper builds on our previous work in which we identify certain co-occurences between genes conferring metal and antibiotic resistance (4). However, the findings of this paper do not lend support for that mobile resistance genes are co-selected for by copper and zinc in the marine environment – rather the increase in antibiotic resistance seem to be due to taxonomic changes and cross-resistance mechanisms. The entire paper can be read here.

    References

    1. Bengtsson-Palme J: Published paper: Community MSCs for tetracycline. https://microbiology.se/2016/03/22/published-paper-community-mscs-for-tetracycline/
    2. Bengtsson-Palme J: Published paper: Antibiotic resistance in sewage treatment plants . https://microbiology.se/2016/08/17/published-paper-antibiotic-resistance-in-sewage-treatment-plants/
    3. Flach C-F, Pal C, Svensson CJ, Kristiansson E, Östman M, Bengtsson-Palme J, Tysklind M, Larsson DGJ: Does antifouling paint select for antibiotic resistance? Science of the Total Environment, in press (2017). doi: 10.1016/j.scitotenv.2017.01.213 [Paper link]
    4. Pal C, Bengtsson-Palme J, Kristiansson E, Larsson DGJ: Co-occurrence of resistance genes to antibiotics, biocides and metals reveals novel insights into their co-selection potential. BMC Genomics, 16, 964 (2015). doi: 10.1186/s12864-015-2153-5 [Paper link]

    Published paper: Antibiotic resistance in the food supply chain

    I am happy to announce that the opinion/review piece I wrote for Current Opinion in Food Science has been published. The paper (1) extends on some of my thoughts on how high-throughput sequencing and metagenomics can aid in risk assessment of antibiotic resistant bacteria that I outlined in my PhD thesis (2), but specifically focuses on the food supply chain and its role in resistance dissemination and selection.

    In the paper, I argue for that the food supply chain is a special type of setting in the resistance puzzle, as it not only serves as a connection between environmental habitats for bacteria and humans, but also sometimes presents a substantial selection for resistance, due to use of antibiotics in agri- and aquaculture. International food standards are clear that both selection and dissemination of foodborne resistance should be considered in the risk analysis of food production (3). However, the current main use of DNA sequencing in food safety is whole genome sequencing to delineate which specific strains that are involved in foodborne disease outbreaks, including the resistance factors they may carry (4,5). Further, I argue that while shotgun metagenomics could be used to screen samples for a large number of genes involved in resistance and virulence in the food supply chain, it would at present be very costly and therefore of doubtful benefit to employ in routine screening programs. Still, metagenomics can contribute knowledge that can be used in quantitative risk assessment of antibiotic resistance in the food supply chain.

    The entire paper can be read here.

    References

    1. Bengtsson-Palme J: Antibiotic resistance in the food supply chain: Where can sequencing and metagenomics aid risk assessment? Current Opinion in Food Science, in press (2017). doi: 10.1016/j.cofs.2017.01.010 [Paper link]
    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. Codex Alimentarius Commission: Guidelines for risk analysis of foodborne antimicrobial resistance. Food and Agriculture Organization of the United Nations & World Health Organization2011. [Link]
    4. Franz E, Gras LM, Dallman T: Significance of whole genome sequencing for surveillance, source attribution and microbial risk assessment of foodborne pathogens. Current Opinion in Food Science, 8, 74-79 (2016). doi: 10.1016/j.cofs.2016.04.004
    5. Stasiewicz MJ, Bakker den HC, Wiedmann M: Genomics tools in microbial food safety. Current Opinion in Food Science, 4, 105-110 (2015). doi: 10.1016/j.cofs.2015.06.002

    New year – new challenges

    So 2017 has begun, and this year will bring new challenges and exciting opportunities. First of all, my application for a 3.5 year grant from the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) to go to Prof. Jo Handelsman‘s lab in the US was granted. Since Prof. Handelsman in is moving her lab to University of Wisconsin in Madison, where she will be heading the Wisconsin Institute of Discovery (after returning from the White House), it means that this summer I will be moving to Wisconsin. I will retain a link to the University of Gothenburg and the Joakim Larsson lab though, and part of the grant is actually for covering my salary after returning from the US, so Gothenburg won’t get rid of me so easily.

    The granted project will use high-throughput sequencing techniques to identify genes improving colonization and invasion ability or resistance to invasion in microbial communities, using a model system developed by the Handelsman lab. The project will focus on genes important for colonization, invasion and resistance to invasion under exposure to sub-lethal antibiotics concentrations. The project will contribute important knowledge towards the understanding of microbial colonization and invasion and highlight disturbances to the interactions in microbial communities caused by anthropogenic activities. In addition, the results of the project will hopefully allow for prediction of secondary effects of antibiotic exposure in the environment, and the preparation for future challenges related to infections with pathogenic bacteria. The project has already been highlighted by CARe (although this was before Jo announced her move from Yale) and a FORMAS press release (in Swedish).

    The project will go under the acronym InSiDER, and I intend to write about it in a special section of the website, called the Wisconsin Blog. My intention is to include personal reflections on life in Wisconsin and work in the Handelsman lab there, but we’ll see how those plans turn out. Anyway, I am very thankful for FORMAS funding this project and giving me the opportunity to work with one of the leading scientists within microbial ecology in the world!