January 31, 2007


Antibiotic resistance rising despite controlled use



Disease resistance to antibiotics among humans and animals continues to rise, despite their controlled use as a feed-ration additive to prevent illness and promote growth in livestock and poultry, according to industry members.


The use of antibiotics to treat animals has increased in the last seven years, but total use remains below mid-1990s peaks, according to statistics for Europe by the Danish government.


According to a report, total antibiotic use in the European Union (EU) reached its peak in 1994. By the end of 1999, antibiotic use as a growth promoter was banned in the EU, although the industry had begun to take it out of the rations before then.


The US Food and Drug Administration says about 70 percent of infection-causing bacteria are resistant to at least one of the drugs most commonly used to treat infections.


Subtherapeutic use among US producers has been declining because studies have made a connection between feed use and a growing incidence of antibiotic-resistant bacteria among humans, said Ron Phillips, vice president of legislative and public affairs for the Animal Health Institute. Antibiotics are being removed from animal feeds because consumers want them removed, and the USDA guidelines require the move in order for the meats to be labelled as organic.


In Jul 2005, the FDA removed its approval for Baytril, made by Bayer Corporation for feed use because of its similarity to human antibiotics and concerns about resistant diseases. Baytril was used in poultry feed.


However, a western Kansas veterinarian with a cattle feedlot practice said many of his clients continue to use low-dose antibiotics as growth promoters.


An Iowa veterinarian felt it was important to cut back on antibiotics in feed, but incidentally, it was a part of production. They not only acted as growth promoters but prevented pneumonia or diarrhoea, he said.


Amidst the growing debate on the use of antibiotics, the FDA recently approved another antibiotic for feed use in hogs, although it is to be done by "veterinary directive" only, the Iowa veterinarian said.


In 2005, total US production of antibiotics for use in animals rose 12.3 percent to 24.4 million pounds, according to AHI data. On the other hand, the percentage of overall production used to maintain the health of animals and enhance growth dropped to 4.5 percent from 5.4 percent the previous year, Phillips said.