Antimicrobial use in aquaculture re‐examined: its relevance to antimicrobial resistance and to animal and human health

Abstract

SummaryThe worldwide growth of aquaculture has been accompanied by a rapid increase in therapeutic and prophylactic usage of antimicrobials including those important in human therapeutics. Approximately 80% of antimicrobials used in aquaculture enter the environment with their activity intact where they select for bacteria whose resistance arises from mutations or more importantly, from mobile genetic elements containing multiple resistance determinants transmissible to other bacteria. Such selection alters biodiversity in aquatic environments and the normal flora of fish and shellfish. The commonality of the mobilome (the total of all mobile genetic elements in a genome) between aquatic and terrestrial bacteria together with the presence of residual antimicrobials, biofilms, and high concentrations of bacteriophages where the aquatic environment may also be contaminated with pathogens of human and animal origin can stimulate exchange of genetic information between aquatic and terrestrial bacteria. Several recently found genetic elements and resistance determinants for quinolones, tetracyclines, and b-lactamases are shared between aquatic bacteria, fish pathogens, and human pathogens, and appear to have originated in aquatic bacteria. Excessive use of antimicrobials in aquaculture can thus potentially negatively impact animal and human health as well as the aquatic environment and should be better assessed and regulated.

Occurrence and ecological hazard assessment of selected antibiotics in the surface waters in and around Lake Honghu, China

“…According to the data from Cabello et al (2013), there are about 1120 tons of antibiotics input into this water area just only considering aquaculture. These huge amounts of antibiotics would produce deep impacts, not only on aquatic ecosystem, but also on human health.…”

“…The resistance genes of these selected bacteria in nature waters could transfer to the terrestrial bacteria and human pathogens by Horizontal Gene Transfer (HGT) in the complicated biosphere (Cabello et al, 2013). As a result of HGT, these new genetic entities may be incorporated into the pangenome of terrestrial bacteria including human pathogens, linking aquatic and terrestrial resistomes and complicating the treatment of human infections (Cabello et al, 2013;Wellington et al, 2013;Sharma et al, 2016). In addition, aquatic products for human consumption can become contaminated with antibiotics residues.…”

Antibiotic resistance in urban aquatic environments: can it be controlled?

“…The amount (tons) of antibiotics consumed for food-producing animals is generally higher than for human therapy (EFSA/ECDC 2015; Done et al 2015). For this rea-son, it is arguable that the selective pressures found in animal production environments are important drivers for antibiotic resistance dissemination (Cabello et al 2013;Done et al 2015;Xiong et al 2015). Although the same active principles can be used in human medicine and in animal production, the pattern of utilization is different (Cabello et al 2013;WHO 2014;EFSA/ECDC 2015;Done et al 2015).…”

“…For this rea-son, it is arguable that the selective pressures found in animal production environments are important drivers for antibiotic resistance dissemination (Cabello et al 2013;Done et al 2015;Xiong et al 2015). Although the same active principles can be used in human medicine and in animal production, the pattern of utilization is different (Cabello et al 2013;WHO 2014;EFSA/ECDC 2015;Done et al 2015). While human medicine, mainly in what concerns antibiotics administration in health care units, tends to use last-generation antibiotics of classes of fluoroquinolones, cephalosporins, or carbapenems, in animal production, "older" antibiotics such as tetracyclines, sulfonamides, or penicillins are preferred (WHO 2014; EFSA/ECDC 2015; Done et al 2015).…”

“…Moreover, effluents of animal production facilities contain ubiquitous bacteria that may be also found in the human microbiome (Vaz-Moreira et al, 2014;Done et al 2015). Be-cause ARB&ARG from animal production effluents are able to spread in the environment and enter the human food chain, these facilities should also be placed among the critical control points to mitigate antibiotic resistance propagation (Cabello et al 2013;Done et al 2015;Xiong et al 2015).…”