Antibiotics


INDICATOR BACKGROUND AND RATIONAL FOR INCLUSION

A large percentage of marine finfish species is farmed in nets or cages in the marine environment, which makes them especially susceptible to a host of pathogen-borne diseases. To treat or, in some cases, prevent, disease, producers sometimes administer antibiotics that are often in the form of bath treatments or incorporated within feed (Burridge et al. 2008b). Given the open nature of most marine finfish production systems, a significant portion of the applied antibiotics is released into the ecosystem. Some of these antibiotics have been associated with a variety of impacts, including: selection for antibiotic-resistant bacteria (Burka et al. 1997; Cabello 2006); persistence in sediments and water column (Cabello 2006; Hektoen et al. 1995); and potential toxicity to non-target organisms (Christensen et al. 2006; Holten Lützhøft et al. 1999). Based on this evidence, there has been significant attention within both the conservation sector and aquaculture industry to minimise or eliminate the release of antibiotics into the environment. Of utmost concern is the use and release of antibiotics such as fluoroquinolones, which are considered critical in the prevention of infection and disease in humans.

INDICATOR FORMULA

Formula

ANTI = ∑(Amount Active Ingredient (kg) x WHO-OIE Score)

Units: Kilograms weighted by the WHO-OIE Score

Sample Calculation

Sample Normalised Calculation: Barramundi from Australia, 2007

The antibiotic indicator considers two primary factors: the absolute volume of antibiotics used in production and a measure of the environmental risk of each antibiotic. It assumes that antibiotic use is indirectly related to strong environmental performance; the fewer antibiotics used, the better the performer’s score for this indicator. Since antibiotics have varying degrees of potential ecological impact, it was also deemed necessary to weight the use of each antibiotic by some measure of potential impact or risk. Through expert consultation, the WHO and OIE ratings of antibiotics were determined to be the most readily accessible, yet accurate, measures of the risk of antibiotic use related to human and veterinary use, respectively. (For more detailed information on the WHO-OIE weightings visit the FAQ page).

ADDRESSING DATA GAPS

GAPI employed the following decision rules to treat gaps in antibiotic use data: