does anyone know why?...., page-27

cmq imu bdm Savvy consumers are going to put the squeeze on the use of antibiotics in pigs and chicken!
The beneficiaries will be the consumers; and the innovative AUSSIE biotecs who are leading the world in this area! BDM IMU CMQ

Australia imports about 7 hundred tonnes of antibiotics annually. More than half of that goes into stock-feed, about 8% is for veterinary use, leaving only one-third for human use.

Antibiotics & Agriculture

Antibiotics are used widely in food animals as growth promoters and to prevent and treat infection. Avoparcin, a glycopeptide related to the human last line drug Vancomycin, is used in Australia as a growth promotant in pigs, chickens and feedlot cattle. Virginiamycin is used as a growth promotant but also for treating resistant human bacteria.

As well as oral administration and injection of antibiotics, small amounts are mixed into animal feed for weeks or months at a time. Feed dosing provides ripe conditions for the emergence of resistant strains.

Antibiotics are also sprayed onto fruit trees to prevent and treat infection. Traces of antibiotics that remain after the initial spraying may encourage emergence of resistant strains of bacteria. During spraying the wind can spread low concentrations of the antibiotic further afield, possibly increasing the risk of resistant bacteria. In both cases, it is possible for antibiotic resistant bacteria to enter the food chain, ultimately reaching humans.


Transferral of resistant bacteria to humans

There is a growing body of evidence that antibiotic resistant bacteria are transferred to humans. In 1997, the World Health Organisation’s report on ‘The medical impact of antimicrobial use in Food Animals’ highlighted several cases where transfer of resistance from animals to humans had occurred. It can happen through: direct contact with animals; the consumption of meat; drinking contaminated water or the transfer of genes between animal and human bacteria.

A 1998 review of literature by Australia’s JETACAR committee also concluded that resistant animal bacteria did transfer to humans and cause disease. Antibiotic resistant genes also spread from animal bacteria to human pathogens.

It is the gut bacteria or ‘tummy bugs’, rather than the killer bacteria, like pneumonia, which transfer in this way. However, E.coli and Salmonella, which can be transmitted through food or direct contact with animals, are deadly in some circumstances.

Consequences

This transferral of resistance is having an effect. The UN reported that, after the introduction of the fluoroquinolone antibiotics for use in food animals, strains of Salmonella with decreased susceptibility to this class of antibiotics were found in humans in France, Germany, Ireland, the Netherlands, Russia Federation, Spain and the United Kingdom.

The emergence of vancomycin-resistant Enterococcus (VRE) may also be related to the use of Avoparcin as an animal growth promoter. "There is fairly convincing evidence in Europe that the VRE germ probably developed in animals, pigs and chickens in particular, and this was acquired by the general population through the food chain," says Associate Professor Collignon. The European Union's suspension of the use of Avoparcin, pending further inquiries, lead manufacturer Roche to end production of the antibiotic. Roche cited a lack of market access as making Avoparcin no longer economic. Curiously, Australian agriculture does use Avoparcin extensively, but the most common VRE identified, doesn't appear to be connected to its use.

A review of the use of Avoparcin in Australia by the Agricultural and Chemical Registration body, the National Registration Authority (NRA) was suspended in January 2000, when Roche announced that Avoparcin stocks were running out. In the past the NRA has put extensive restrictions on the use of another widely used animal antibiotic known colloquially as Pen-Strep, mainly because of residue levels in meats.