Antimicrobial resistance (AMR) is one of the major challenges we are facing this century. Understanding the mechanism behind the rise of AMR is therefore crucial to tackle this global threat. This is the case for Mycobacterium abscessus (Mabs), a fast-growing non-tuberculous mycobacterium considered as a “clinical nightmare” due to difficulties in its treatment and its multiple resistance and tolerance mechanisms to antibiotics. Mabs is an environmental bacterium whose physiology is driven by environmental factors. Among those are transition metals such as copper, cobalt and nickel. How presence of these ions affects Mabs physiology and its drug susceptibility is unknown, and any research addressing this question will considerably increase our knowledge in AMR and help discovery of a potential drug target. During my PhD, I investigated the impact of transition metals on Mabs physiology and how it affects drug susceptibility, using microbiological and bioenergetic techniques in combination with targeted and untargeted metabolomics with liquid chromatography-mass spectrometry (LC-MS). Use of LC-MS flux analysis with stable isotope labelling identified how nickel (Ni2+), a transition metal ion widely present in the water system, perturb Mabs central carbon metabolism and nitrogen metabolism. These results agree with RNA sequencing and bioenergetics studies using Seahorse analyser showing decreased activity of TCA cycle activity and changes in expression of the related enzymes. Mass spectrometry also enabled quantification of intracellular uptake of antibiotics by Mabs in presence of Ni2+ and efflux pump inhibitors, showing that increased uptake of antibiotics, such as clarithromycin upon Ni2+ treatment, could be linked to increased susceptibility of Mabs. In conclusion, this study demonstrates that transition metals in environment interfere with carbon and nitrogen metabolism, which in turn shapes its drug susceptibility. Targeting Mabs metabolic enzymes or the way Mabs senses and responds to trace elements could offer new solutions to tackle AMR.