Tetracyclines in the Modern Era: Global Consumption, Antimicrobial Resistance, Environmental Occurrence, and Degradation Techniques

Tetracyclines are among the oldest classes of antibiotics, with broad activity against Gram-positive and Gram-negative bacteria, as well as <i>Chlamydia</i>, <i>Legionella</i>, <i>Rickettsia</i>, and <i>Mycoplasma</i> species. Widely used in human and veterinary medicine, agriculture, and aquaculture, they represent approximately 10-12% of the global antimicrobial market. Extensive use has driven the emergence and spread of antimicrobial resistance, posing ecological and public health risks. However, the full extent of these risks remains unclear due to limited data on tetracycline consumption, environmental occurrence, and resistance patterns across sectors. Recent One Health-oriented strategies have promoted the rational use of tetracyclines in medicine, veterinary practice, and agriculture. To reduce environmental accumulation, various degradation and remediation techniques have been developed, though most remain restricted to laboratory or engineered settings. This narrative review provides a comprehensive overview of global tetracycline consumption; environmental occurrence; distribution and concentration levels; resistance mechanisms and prevalence; and mitigation strategies, including antimicrobial stewardship and degradation approaches. Understanding these aspects is essential for developing evidence-based interventions to minimize the environmental and public health impacts of tetracycline use.