Table 4.

Current treatment strategies against major superbugs

Superbug	Mechanism of resistance	Drug of choice	Mechanism of drug action
Methicillin-resistant Staphylococcus aureus (MRSA)	Production of Penicillin-Binding Protein (PBP2a)	Vancomycin	Inhibits cell wall synthesis by binding to the D-Ala-D-Ala terminal of the growing peptide chain [45]
Carbapenem-resistant Enterobacteriaceae (CRE)	β-Lactamase activity and production of carbapenemases	Polymyxin, Tigecycline, and Aminoglycosides	Disrupt the membrane by binding to lipopolysaccharide. Inhibition of protein synthesis [49]
Vancomycin-resistant Enterococcus (VRE)	Production of low-affinity pentapeptide precursor of cell wall	Daptomycin	Disrupting the membrane potential [51]
Multidrug-resistant Pseudomonas aeruginosa	Genetic alterations	Ceftazidime–avibactam and Ceftolozane–tazobactam	Inhibits penicillin-binding proteins and also inhibits many serine β-lactamases. Inhibition of cell wall biosynthesis [61]
Multidrug-resistant Escherichia coli	Presence of resistance genes	Mecillinam	Inhibits penicillin-binding protein 2 [65]