Escherichia coli str. K-12 substr. MG1655 Genome sequencing and assembly. Escherichia coli str. K-12 substr. MG1655

Two spontaneous amikacin-resistant mutants were isolated to investigate the molecular mechanisms of resistance in Escherichia coli. These mutants exhibited resistance not only to amikacin but also to several other aminoglycoside antibiotics, including gentamicin, hygromycin B, streptomycin, and kanamycin. Whole-genome sequencing unveiled specific mutations in two genes, acrE (C440 to T440) and fusA (C1774 to T1774). The acrE gene encodes the AcrE multidrug efflux pump membrane fusion lipoprotein, while fusA encodes Elongation Factor G. These mutations were identified as causative factors in conferring resistance to multiple aminoglycosides. To validate the role of these mutations in aminoglycoside resistance, we conducted co-transduction-based genetic analyses. The results provided compelling evidence that the identified mutations alone are sufficient to confer resistance to multiple aminoglycosides in Escherichia coli. This study significantly advances our understanding of the genetic basis of aminoglycoside resistance mechanisms, offering valuable insights into how bacteria develop resistance to critically important antibiotics.