Efficacy of antimicrobial therapy in aquaculture

In commercial aquaculture, the efficacy of any course of antibiotic therapy is dependent on the ability of the dosage regimen employed to deliver a concentration of the agent to the appropriate site in the host that is sufficient to inhibit the infecting bacterium. Thus, the major factors that influence efficacy are the dose regimen used and the susceptibility or resistance of the target bacterium. 

Of particular interest here is the duration of the therapy period. Lambert (1999) has argued that, even for human treatments, there is little empirical data to justify the duration of recommended therapies. He suggests that, for many human infections, much shorter treatments are just as effective as the longer treatments currently recommended. In aquaculture there appears to have been totally inadequate investigation of the influence of the length of therapies on their clinical efficacy. 

There is a variety of ways in which bacteria can reduce their susceptibility 

The important issue for susceptibility testing is to note that resistance can be achieved by a number of mechanisms and that these mechanisms 

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