Bacterial Resistance to the Tetracyclines and Antimicrobial Therapeutics: A Review

Abstract

Tetracycline antibiotics are known to exhibit their therapeutic activity against a wide range of gram-positive and gram-negative bacteria, chlamydia, mycoplasmas, rickettsiae and protozoan parasites. Moreover, during the past few decades, many bacterial groups have been exhibiting tetracycline antibiotics resistance, as a result of profligate use. Therefore, different tetracycline resistance genes have been characterized. They encode two major mechanisms of resistance: active efflux of the antibiotic and protection of ribosomes. Further mechanisms of tetracycline resistanceinclude enzymatic inactivation of antibiotic, permeability barriers, mutations or multidrug transporter systems. Effective horizontal spread is favoured by the location of tetracycline antibiotics resistance genes on mobile genetic elements such as plasmids and transposons. Their exchange, enhanced by the use of tetracycline antibiotics, is observed between bacteria of the same or different species and genera as well. Optimizing of tetracycline antibiotics dosing and duration in human and animal healthcare and food production might help minimize the emergence of resistance in some situations. New approaches to antimicrobial chemotherapy are needed if we are to survive the increasing rates of tetracycline antibiotic resistance predicted for the future. Solving this puzzle is a challenge that would ensure reduction of tetracycline antibiotics resistances and its attendant problems in pharmacotherapy.

Keywords: Tetracyclines, Bacteria, Resistance