Uso inadecuado y excesivo de antibióticos: salud pública y salmonicultura en Chile

Resumen

Salmon aquaculture constituted one of the major growing and exporting industries in Chile. Its development was accompanied by an increasing and excessive use of major amounts of antibiotics. These included hundreds of metric tonnes of quinolones, tetracyclines and florfenicol. This imprudent use of antibiotics remained unacknowledged by the industry and the regulatory institutions of the Chilean government until an abrupt and uncontrolled epizootic produced by infectious salmon anemia (ISA) virus virtually destroyed the industry’s productivity in 2008.  Examination of sanitary conditions in the industry as part of a more general investigation into the uncontrolled and extensive dissemination of the ISA epizootic found numerous and wide-ranging shortcomings and limitations in management of preventive fish health. In the presence of these sanitary shortcomings, the growing industrial use of large amounts of antibiotics can be seen as attempts at prophylaxis of bacterial infections resulting from widespread unsanitary and unhealthy fish rearing conditions.  As might be expected, these attempts were unsuccessful and this heavy antibiotic use failed to prevent viral and parasitic epizootics.

            Comparative analysis of the amounts of antibiotics, especially quinolones, consumed in salmon aquaculture and in human medicine in Chile robustly suggests that the most important selective pressure for antibiotic resistant bacteria in the country will be excessive antibiotic use in this industry. This excessive use will facilitate selection of antibiotic resistant bacteria and antibiotic resistance genes in water environments. The commonality of antibiotic resistance genes between environmental marine bacteria, fish pathogens and pathogens of terrestrial animals and humans suggests that horizontal gene transfer occurs between the resistome of these apparently independent and isolated bacterial populations. Thus, excessive antibiotic use in the marine environment in aquaculture is not innocuous and can potentially negatively affect therapy of bacterial infections of humans and terrestrial animals.  These observations suggest that regulations need to be implemented regarding use of antibiotics in aquaculture in Chile and other countries with important aquaculture industries. This is especially true regarding use of quinolones which are still currently the most effective antibiotics in use in human and veterinary medicine. Education and dialogue among all the stakeholders will be necessary to achieve this important public health goal.