Fig. 3
From: Production systems and important antimicrobial resistant-pathogenic bacteria in poultry: a review
Schematic representation of Gram-positive and Gram-negative antimicrobial resistance mechanisms. 1. Decreased permeability of antibiotics due to outer membrane, 2. Increased expression of efflux pumps, 3. Modification/mutation of target sites (i.e. topoisomerases, ribosomes, penicillin-binding proteins (PBPs), fluoroquinolones, etc.), 4. Inactivation and modification of antibiotics via inactivating enzymes (i.e. β-lactamases, tetracycline-inactivating enzymes)