The rise of multi-drug resistant bacteria is currently one of thegreatest threats to global public health. As a prove, most clinically relevantGram-negative pathogens are reluctant to several of the antibiotics used totreat the infections they cause, which includes in several cases last line antimicrobialtreatments (Santajit and Indrawattana, 2016).
Mobilization of resistance genes is one of the factors that hascontributed the most to this phenomenon (Deng etal., 2015; Gillings, 2014; Hall et al., 2017) since pathogenic bacteriaoften owe their resistance phenotypes to genes harboured on MGEs (Hall et al., 2017).
With more and more data being retrieved,it is now obvious that the human use of antibiotics exerts effects on theabundance of MGEs, both in the environment and the clinic (Gillings et al., 2017). Resistance determinantspresent in environmental compartments have been proved to be the source of manyof the resistance genes present in pathogenic bacterial species (Forsberg et al., 2012; Gillings, 2014). Anthropogenicactivities related to the use and disposalof antibiotics have contributed, and still do, to the selection of new resistance determinantsin environmental reservoirs (Wellington et al.,2013). These new determinants can potentially be horizontallytransferred to pathogens as it has already been the case for many of them (Forsberg et al.
, 2012) and nowadays, we, humanbeings are exposed to potentially new antibiotic-resistant environmental determinantsby several routes such as crops exposed to contaminated sludge or manure (Wellington et al., 2013). As pointed out byWellington et al. (2013), when bacteria pass through the human gut they haveplenty of opportunities to allow antimicrobial resistance genes to betransferred horizontally to the gut microflora, bacterial species withpotential to become opportunistic pathogens. We rely on antibiotics for thetreatment of infectious diseases, yet, the use and misuse of these compounds hasresulted in the enrichment of resistance mutations and acquired resistancegenes rendering antibiotics ineffective and, thus, we are heading as a societytowards a postantibiotic era where ourquality of life and life expectancy areat risk. Microorganisms do not respect geographical borders and, thus,resistance needs to be tackled at a global scale.