Tag: Katariina Pärnänen

I’ve been terribly bad at keeping updates on what we have published in the last year or so – there have just been a bit too much other things to do. So I thought it was time to take a look at what we have published in the last year before some really cool stuff hits the press this summer and fall (hopefully more on that soon!!)

Let’s start with some EMBARK/SEARCHER output. Several lab members (Anna, Marcus and I) have been involved in a paper using functional metagenomics to find novel cefiderocol resistance genes (1). We found four resistance genes, including three ꞵ-lactamases (VEB-3, an OXA-372 homolog, and a YbxI homolog) and a partial penicillin-binding protein homolog, none of which had been previously reported as a cefiderocol resistance gene. The blaVEB-3 gene was associated with a mobile genetic element. We could find three of them using shotgun metagenomics, showing that the blaVEB-3 gene was widespread across France, Sweden, Germany and Pakistan, hinting at efficient dissemination of this gene.

I have also been involved in a collaboration paper with Thomas Berendonk and Uli Klümper‘s labs, where we investigate if fish can be sentinels of environmental antibiotic resistance, and it turns out that they are… not great for that (2).

On the topic of antibiotic resistance gene (ARG) dissemination, Máté Vass (now at SLU) lead a study published in Communications Biology investigating how water stratification affects horizontal gene transfer, with a focus on ARGs (3). The main finding of this paper is that water stratification is a constraint on horizontal gene transfer, which may have implications on how we think about ARG spread through water environments.

While we are at the topic of large-scale quantifications of ARGs in big data sets, I was super-happy to be part of a collaboration with Katariina Pärnänen on how gender (and other factors) impact ARGs in the human microbiome (4). I kept telling Katariina that this would probably yield nothing – the microbiome data was too noisy, and the signal will get lost. Yet, she persisted, and indeed it turned out we are at the point where there is enough human microbiome data to get a signal even if there is a lot of noise. So hats off to Katariina, this was your “what did I say” moment with me!

Then we have a set of mechanistic AMR studies on ARG evolution. First, Lisa Teichmann published parts of her PhD thesis, first on the gradual evolution of fluoroquinolone resistance in E. coli (5) and how this is related to the SOS response in bacteria. She then followed up with a somewhat similar paper on amoxicillin evolution in E. coli (6). The general picture of these two papers on how E. coli adapts genetically to antibiotic stress is that resistance evolution is highly antibiotic-specific and that canonical stress-response or mutagenic pathways do not uniformly explain adaptive trajectories.

Somewhat connected, Nathália Abichabki recently published a paper where we propose screening cut-off values and tolerance disk tests (TDtests) for detection of tolerance/persistence to ceftazidime-avibactam in Klebsiella pneumoniae (7). This is also related to a bunch of papers on tolerance and low-level resistance to antibiotics that will be coming out of Nathália’s thesis, so there is more coming on this front soon!

Finally – on the AMR front – Anna Abramova led an effort together with Veronika Pettersen to investigate possibility for integration of AMR surveillance systems in the Nordic countries that recently got published in Public Health (8). Anna and Veronika did a huge amount of work on this paper, but this was largely the outcome of several meetings on the NoMoReAMR consortium, where we pinpointed missed opportunities for surveillance in the otherwise relatively homogenous Nordic countries. I hope to get to work more with this consortium in the future, as I think that we have had very fruitful discussions on both AMR research and monitoring and when and where it is useful.

And so two papers not related to AMR: We had a very nice collaboration with Daniel Bojar‘s group coming out late last year in Nature Communications, looking – from many different angles – at seal milk oligosaccharides and their potential uses. While the cool finding in this paper is that seal milk seems even more complex than human breast milk in terms of milk oligosaccharides (9), we did not contribute too much in that part. Instead, Mirjam Dannborg was studying the effects of these oligosaccharides on pathogen biofilms, work that will also be part of her PhD thesis when she defends this fall!

Finally, in a collaboration with colleagues in Brazil, we published a review article on the outlook for combining 3D organoid cultures and high-throughput analysis techniques to better understand host-pathogen interactions (10). This was the result of a cross-visit collaboration between Brazil and Sweden, where me and Mirjam visited the lab of Elaine de Martinis, and Elaine, Leonardo Andrade and Nathália Abichabki visited our lab back in 2023. It’s nice to see our discussions take paper form and I hope to be working more with this wonderful team in Brazil!

Papers mentioned:

1. Gschwind R, Bonnet M, Abramova A, Jarquín-Díaz VH, Wenne M, Löber U, Godron N, Kampouris ID, Tskhay F, Nahid F, Debroucker C, Bui-Hai M, El Aiba I, Klümper U, Berendonk TU, Forslund-Startceva SK, Zahra R, Bengtsson-Palme J, Ruppé E: Cefiderocol resistance genes identified in environmental samples using functional metagenomics. ISME Journal, 20, 1, wrag010 (2026). doi: 10.1093/ismejo/wrag010 [Paper link]
2. Tskhay F, Köbsch C, Elena AX, Bengtsson-Palme J, Berendonk TU, Klümper U: Fish are poor sentinels for surveillance of riverine antimicrobial resistance. One Health, 20, 101026 (2025). doi: 10.1016/j.onehlt.2025.101026 [Paper link]
3. Vass M, Abramova A, Bengtsson-Palme J: Antimicrobial resistance dissemination via horizontal gene transfer is constrained in stratified waters. Communications Biology, 9, 435 (2026). doi: 10.1038/s42003-026-09857-8 [Paper link]
4. Salehi M, Laitinen V, Bhanushali S, Bengtsson-Palme J, Collignon P, Beggs JJ, Pärnänen K, Lahti L: Gender differences in global antimicrobial resistance. npj Biofilms and Microbiomes, 11, 79 (2025). doi: 10.1038/s41522-025-00715-9 [Paper link]
5. Teichmann L, Luitwieler SH, Bengtsson-Palme J, ter Kuile BH: Fluoroquinolone-specific resistance trajectories in E. coli and their dependence on the SOS-response. BMC Microbiology, 27, 37 (2025). doi: 10.1186/s12866-025-03771-5 [Paper link]
6. Teichmann L, Wenne M, Luitweiler S, Dugar G, Bengtsson-Palme J, ter Kuile B: Genetic Adaptation to Amoxicillin in Escherichia coli: The Limited Role of dinB and katE. PLoS ONE, 20, 2, e0312223 (2025). doi: 10.1371/journal.pone.0312223 [Paper link]
7. Abichabki N, Bellissimo-Rodrigues F, Gaspar GG, Pocente RHC, Lima DAFS, Bollela VR, Braga GUL, De Martinis ECP, Ferreira JC, Darini ALC, Bengtsson-Palme J, Andrade LN: Proposal for screening cut-off values and use of Tolerance Disk Test (TDtest) for detection of tolerance/persistence to ceftazidime-avibactam in Klebsiella pneumoniae. Diagnostic Microbiology and Infectious Disease, 116, 3, 117515 (2026). doi: 10.1016/j.diagmicrobio.2026.117515 [Paper link]
8. Abramova A, Baral A, Osińska AD, Metsä-Simola N, Räisänen K, Ribeiro Duarte AS, Helgason KO, Halldórsdóttir AM, Pärnänen K, Skov Simonsen G, Sariola S, Lahti L, Bengtsson-Palme J, Wasteson Y, Munk P, Pettersen VK: Roadmap for integrated One Health AMR surveillance in Nordic countries. Public Health, 255, 106285 (2026). doi: 10.1016/j.puhe.2026.106285 [Paper link]
9. Jin C, Lundstrøm J, Cori CR, Guu S-Y, Bennett AR, Dannborg M, Bengtsson-Palme J, Hevey R, Khoo K-H, Bojar D: Seal milk oligosaccharides rival human milk complexity and exhibit functional dynamics during lactation. Nature Communications, 16, 10067 (2025). doi: 10.1038/s41467-025-66075-2 [Paper link]
10. de Martinis ECP, Alves VF, Pereira MG, Andrade LN, Abichabki N, Abramova A, Dannborg M, Bengtsson-Palme J: Applying 3D cultures and high-throughput technologies to study host-pathogen interactions. Frontiers in Immunology, 16 (2025). doi: 10.3389/fimmu.2025.1488699[Paper link]

Together with our collaborators in Tromsø in Norway, we published a paper over the weekend in eBioMedicine describing the early colonization patterns of preterm infants, both in terms of the microbes that arrive early to the infants, but also in terms of the antibiotic resistance genes they carry.

In the paper (1), which is a continuation of an earlier study by part of the team (2), we analysed metagenomic data from six Norwegian neonatal intensive care units to better understand the bacterial microbiota of infants born preterm or on term and receiving different treatments. These groups included probiotic-supplemented and antibiotic-exposed extremely preterm infants (n = 29), antibiotic-exposed very preterm infants (n = 25), antibiotic-unexposed very preterm infants (n = 8), and antibiotic-unexposed full-term infants (n = 10). Stool samples were collected from the infants after 7, 28, 120, and 365 days of life and were analysed using shotgun metagenomics. We were particularly interested in the maturation of the preterm infant microbiome into a ‘normal’ healthy gut microbiome, and the colonization with bacteria carrying antibiotic resistance genes.

We found that microbiota maturation was largely determined by the length of hospitalisation for the infants and how much preterm they were. The use of probiotics rendered the gut microbiota and resistome of extremely preterm infants more alike to term infants on day 7 and partially restored the loss of species interconnectivity and stability associated with preterm delivery. Finally, colonisation with Escherichia coli was associated with the highest number of antibiotic-resistance genes in the infant microbiomes, followed by Klebsiella pneumoniae and Klebsiella aerogenes.

Being born very preterm, along with prolonged hospitalisation and frequent antibiotic use alters early life resistome and mobilome, leading to an increased gut carriage of antibiotic resistance genes and mobile genetic elements. On the other hand, the effect of probiotics was not unidirectional. Probiotics decreased resistome burden, but at the same time the bacterial strains in the probiotics appear to promote the activity of mobile genetic elements. Here, further study of the gut microbiota is necessary to be able to design strategies aiming to lower disease risk in vulnerable preterm infants.

As mentioned, this study was a collaboration with Veronika Pettersen‘s group in Tromsø, particularly Ahmed Bargheet, who have done a fabulous job on the bioinformatics and analysis of this study. I hope that we will continue this collaboration in the future (first step will be me visting Tromsø again in June!) This also continues a nice little “sidetrack” of the group’s research into the early life microbiome – previously represented by the work of Katariina Pärnänen (3) and Tove Wikström‘s vaginal microbiome study (4), which is a very interesting and relevant subject in terms of both medicine and microbial ecology. We are also setting up new collaborations in this area, so I hope that more will come out of this track in the next couple of years.

Finally, thank you Veronika for inviting me to participate in this great project!

References

1. Bargheet A, Klingenberg C, Esaiassen E, Hjerde E, Cavanagh JP, Bengtsson-Palme J, Pettersen VK: Development of early life gut resistome and mobilome across gestational ages and microbiota-modifying treatments. eBio Medicine, 92, 104613 (2023). doi: 10.1016/j.ebiom.2023.104613
2. Esaiassen E, Hjerde E, Cavanagh JP, Pedersen T, Andresen JH, Rettedal SI, Støen R, Nakstad B, Willassen NP, Klingenberg C: Effects of Probiotic Supplementation on the Gut Microbiota and Antibiotic Resistome Development in Preterm Infants. Frontiers in Pediatrics, 16, 6, 347 (2018). doi: 10.3389/fped.2018.00347
3. Pärnänen K, Karkman A, Hultman J, Lyra C, Bengtsson-Palme J, Larsson DGJ, Rautava S, Isolauri E, Salminen S, Kumar H, Satokari R, Virta M: Maternal gut and breast milk microbiota affect infant gut antibiotic resistome and mobile genetic elements. Nature Communications, 9, 3891 (2018). doi: 10.1038/s41467-018-06393-w
4. Wikström T, Abrahamsson S, Bengtsson-Palme J, Ek CJ, Kuusela P, Rekabdar E, Lindgren P, Wennerholm UB, Jacobsson B, Valentin L, Hagberg H: Microbial and human transcriptome in vaginal fluid at midgestation: association with spontaneous preterm delivery. Clinical and Translational Medicine, 12, 9, e1023 (2022). doi: 10.1002/ctm2.1023

This week, a paper by my former roommate Katariina Pärnänen was published by Nature Communications. In the paper (1), we use shotgun metagenomics to show that infants carry more resistant bacteria in their gut than adults do, irrespective of whether they themselves have been treated with antibiotics or not. We also found that the antibiotic resistance gene and mobile genetic element profiles of infant feces are more similar to those of their own mothers than to those of unrelated mothers. This is suggestive of a pathway of transmission of resistance genes from the mothers, and importantly we find that the mobile genetic elements in breastmilk are shared with those of the infant feces, despite vast differences in their microbiota composition. Finally, we find that termination of breastfeeding and intrapartum antibiotic prophylaxis of mothers are associated with higher abundances of specific ARGs in the infant gut. Our results suggest that infants inherit the legacy of past antibiotic consumption of their mothers via transmission of genes, but that the taxonomic composition of the microbiota still strongly dictates the overall load of resistance genes.

I am not going to dwell in to details of the study here, but I instead encourage you to read the paper (hey, it’s open access!) or the excellent popular summary that Katariina has already written. Finally, I want to emphasize the great work Katariina has put into this (I would know, since I shared room with her) and congratulate her on her own little infant!

Reference

1. Pärnänen K, Karkman A, Hultman J, Lyra C, Bengtsson-Palme J, Larsson DGJ, Rautava S, Isolauri E, Salminen S, Kumar H, Satokari R, Virta M: Maternal gut and breast milk microbiota affect infant gut antibiotic resistome and mobile genetic elements. Nature Communications, 9, 3891 (2018). doi: 10.1038/s41467-018-06393-w [Paper link]