Longitudinal fluctuations of common antimicrobial resistance genes in the gut microbiomes of healthy Dutch individuals

• Published in: International journal of antimicrobial agents 2023-03, Vol.61 (3), p.106716-106716, Article 106716
• Main Authors: Malin, Jakob J., von Wintersdorff, Christian J.H., Penders, John, Savelkoul, Paul H.M., Wolffs, Petra F.G.
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antimicrobial resistance genes; ARG; Drug Resistance, Bacterial - genetics; Feces - microbiology; Gastrointestinal Microbiome - genetics; Genes, Bacterial - genetics; Gut microbiome; Gut resistome; Humans; Microbiota; Resistome
• ISSN: 0924-8579; 1872-7913
• DOI: 10.1016/j.ijantimicag.2023.106716

•Prevalence and acquisition rates of blaCTX-M, qnrB and qnrS were low compared with travellers (previous data).•Fluctuations in highly prevalent cfxA, tetM and ermB were quantified using quantitative polymerase chain reaction.•Results were adjusted for 16SrDNA, and expressed as absolute and relative shifts in gene abundance.•Abundance shifts did not differ from those found before and after international travel.•Thus, commonly occurring fluctuations in the abundance of antimicrobial resistance genes were determined. The human gut microbiome is an important reservoir of antimicrobial resistance genes (ARGs), collectively termed the ‘resistome’. To date, few studies have examined the dynamics of the human gut resistome in healthy individuals. Previously, the authors observed high rates of ARG acquisition and significant abundance shifts during international travel. In order to provide insight into commonly occurring dynamics, this study investigated longitudinal fluctuations in prevalent ARGs (cfxA, tetM and ermB) in the resistomes of non-travelling healthy volunteers. In addition, this study assessed the prevalence of acquirable ARGs (blaCTX-M, qnrB, qnrS, vanA and vanB) over time. Faecal samples from 23 participants were collected at baseline and after 2 and 4 weeks. DNA was isolated, and ARG quantification was performed by quantitative polymerase chain reaction adjusting for the total amount of bacterial 16S rDNA. vanA and qnrS were not detected in any of the samples, while the prevalence rates of vanB of non-enterococcal origin and qnrB were 73.9% and 5.7%, respectively. The ß-lactamase encoding blaCTX-M was detected in 17.4% of healthy participants. The results were compared with previous data from 122 travellers. ARG acquisitions observed in travellers were rare in non-travelling individuals during 4 weeks of follow-up, supporting the hypothesis of ARG acquisition during international travel. However, median -1.04- to 1.04-fold abundance changes were observed for 100% of cfxA, tetM and ermB, which did not differ from those found in travellers. Thus, common abundance shifts in prevalent ARGs of the gut resistome were found to occur independent of travel behaviour.