Study warns excess fish farming drug use promotes resistance
in the rearing of fish could promote bacterial resistance leading
to the evolution of resistant strains of bacteria in humans as well
as the fish themselves.
The news places further burden on the pharmaceutical industry, which has already seen its arsenal of antibiotic treatments dwindle alarmingly as cases of bacterial resistance continues to increase.
According to figures released by the Centers for Disease Control and Prevention (CDC), nearly 2m patients in the US get an infection in the hospital each year.
About 90,000 of those patients die each year as a result of their infection, up from 13,300 patient deaths in 1992.
More than 70 per cent of the bacteria that cause hospital-acquired infections are resistant to at least one of the antibiotics most commonly used to treat them.
The report published in >Environmental Microbiology, July 2006, details the common practices that occur in the fish industry, particularly in developing countries, where large amounts of antibiotics are used to prevent infection.
The antibiotics used are often non-biodegradable and remain in the aquaculture environment for long periods of time. This encourages the growth of bacteria, which can survive in the presence of these antibiotics, acquiring a resistance that is passed on to subsequent generations.
The danger is these bacteria can be transferred to human and animal pathogens, leading to increased infectious disease in fish, animals and humans alike.
"If we don't curb the heavy use of prophylactic antibiotics in aquaculture, then we will ultimately see more and more antibiotic resistant pathogens emerging, causing increased disease to fish, animals and humans alike," said Dr Felipe Cabello, author of this study.
In his study, Cabello found that when antibiotics are mixed with fish food, residual antibiotics could be found in fish products and fish meat.
People who eat these products will be inadvertently consuming antibiotics, leading to changes in their normal microbial environment, or 'microflora' and making them more susceptible to bacterial infection.
The report recommended a more judicious approach to the use of prophylactic (preventative) antibiotics was necessary as was a global effort to curb the over-use of antibiotics in the rearing of finfish.
