*4.3.4 Other drugs*

Other drugs with different modes of action and clinical indications have been evaluated as antibacterial agents in monotherapy and in combined therapy with a large list of antibiotics against *E. coli* and *K. pneumoniae in vitro* and in animal models. Amoxapine has been reported to present therapeutic efficacy in an experimental murine model of respiratory infection by *K. pneumoniae* [93]. In addition, pentamidine in combination with different antibiotics ([novobiocin, erythromycin and rifampin] and [amikacin, tobramycin, tigecycline and rifampin]) has presented synergistic activity *in vitro* against different clinical isolates of *E. coli* harboring *mcr-1* and *K. pneumoniae* producing carbapenemases, respectively [94]. In turn, robenidine has been recently showed to present only synergy with polymyxin B nanopeptide against reference strains of *K. pneumoniae in vitro* [60]. Finally, auronafin and simvastatin exhibited synergy with sub-inhibitory concentrations of polymyxin B and colistin against a collection of reference strains of *E. coli* and *K. pneumoniae in vitro*, reducing the MIC of auronafin from >256 mg/L to 0.25–1 mg/L and the MIC of simvastatin from >256 mg/L to 8–32 mg/L, respectively [58, 59].
