Fig. 1.

Mechanisms of antibiotic resistance adopted by bacteria

(a) Modification of antimicrobial targets- some bacterial membranes lack the target molecule for a particular antibiotic, and thus become impermeable to the passage of such antibiotics across their cell membranes; (b) decrease in drug uptake- a few bacteria modify their cell membranes in order to reduce or diminish the drug uptake; (c) activation of efflux mechanisms to extrude the harmful molecules-these mechanisms increase the efflux of antibiotics at a faster pace such that they are not able to produce much effect on the cell; (d) changes in important metabolic pathways-effect of antibiotics can be produced through many biochemical pathways, hence by incorporating changes in these pathways, bacteria rescue themselves from the effect of antibiotics; (e) drug inactivation- drugs are inactivated by processes such as acetylation or methylation once they enter in the cell, thus making them ineffective; (f) mutations in genes encoding target sites-drugs have targets such as DNA polymerase/ RNA/ DNA gyrase and topoisomerase etc., so the genes encoding such target molecules are mutated/ suspended by some bacteria to protect them from the effect of antibiotics (Fig. 1).