Skip to main content

Table 1 Main resistance mechanisms in Gram-negative pathogens

From: Multidrug Resistant Gram-Negative Bacteria in Community-Acquired Pneumonia

Microorganism Mechanism
Pseudomonas aeruginosa Efflux pumps
Mutant topoisomerases
Modifying enzymes
AmpC/porin reduction combinations
Outer membrane permeability
Extended spectrum β-lactamases
Acinetobacter baumannii β-lactamases
Efflux pumps
Membrane permeability
Aminoglycoside-modifying enzymes
Alteration of target sites
Klebsiella pneumoniae Modifying enzyme
Efflux pumps
Mutant topoisomerases
Extended spectrum β-lactamases
Stenotrophomonas maltophilia β-lactamases (L1 and L2)
Multidrug efflux pumps
Antibiotic-modifying enzymes
Mutations of bacterial topoisomerase and gyrase genes
Reduction in outer membrane permeability